United States Environmental Protection Agency Office of Emergency and Remedial Response EPA/ROD/R06-86/013 Sept. 1986 &EPA Superfund Record of Decision ------- TECHNICAL REPORT DATA (PlelUe read Intlructions on the revene /Hlore completing) 1. REPORT NO. 12. 3. RECIPIENT'S ACCESSION NO. EPA/ROD/R06-86/013 .. TITLE AND SUBTITLE 5. REPORT DATE SUPERFUND RECORD OF DECISION September 18, 1986 Sikes Disposal Pits 6. PERFORMING ORGANIZATION CODE 7. AUTHORCSI 8. PERFORMING ORGANIZATION REPORT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO. 11. CONTRACT/GRANT NO. 12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED U.S. Environmental Protection Agency Final ROD Report 401 M Street, S.W. 14. SPONSORING AGENCY CODE Washington, D.C. 20460 800/00 15. SUPPLEMENTARY NOTES 16. ABSTRACT The Sikes Disposal pits site is located on a 185-acre site, approximately 2 miles southwest of Crosby, TX. It is bordered by the San Jacinto River on the west, Jackson Bayou on the north, and U.S. Highway 90 on the south. The site lies in the 100-year floodplain of the river while portions lie within the 10-year and 50-year floodplain. The site has been flooded four times since 1969. The area immediately surrounding the site is largely underdeveloped with numerous active and abandoned sandpits and low lyinr swamp areas. The area plays host to sport fishermen as well as water sport enthusiasts on the nearby river and bayou. One family lives onsite. The only residential development in close proximity is 500 feet southwest. .~tween the early 1960s and 1967, Sikes Disposal pits operated as a waste depository. Chemical wastes from area petrochemical industries and numerous drums were deposited onsite in several old sand pits. A preliminary sampling a t the site in 1982 indicated the presence of phenolic compounds and other organics. In June 1983 a removal action performed at the site by the EPA removed approximately 440 cubic yards of phenolic tars from a partially buried pit. Subsequent studies at the site indicated the need for a total remedial site plan. Onsite soils and surface wa~er f r oIl! .-the sludge areas as well as Tank Lake were found to be contaminated. Ground water in the shallow aquifer below the site has been heavily contaminated ~ no residential wells are currently affected. Neither surface . (See Attached Sheet) 17. KEY WORDS AND DOCUMENT ANALYSIS a. DESCRIPTORS b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group Record of Decision Sikes Disposal pits contaminated Media: gw, sw, soils, sediment Key contaminants: phenols, sludges, toluene organics 1B. DISTRIBUTION STATEMENT 19. SECURITY CLASS (Tills Repo,,) 21. NO. OF PAGES None 56 20. SECURITY CLASS (Tllis page) 22. PRICE None . EPA h,,,, 2220-1 (Rev. ~-77) ------- EPA/ROD/R06-86/013 Sikes Disposal pits 16. ABSTRACT (continued) water or groundwater contamination has migrated beyond the site boundaries. The primary contaminants of concern include: organics, toluence, creosote, benzene, xylene, phenolic compounds, halides, dichloroethane, vinyl chloride. The selected remedial action includes: onsite incineration of sludges and contaminated soilsf onsite disposal of residue ash - use as backfillf ban use of upper aquifer onsite, while naturally attenuating to 10-5 Human Health Criteria (less than 30 years)f discharge contaminated surface water to river, treat as necessary to meet discharge criteriaf monitor lower aquifer and ban its use onsite if site degradation occurs. The estimated ------- RECORD OF DECISION REMEDIAL ALTERNATIVE SELECTION Site: Sikes Disposal Pits, .U.S. HWY 90, Crosby, Texas. DOCUMENTS REVIEWED I have reviewed the following documents describing the analysis of cost- effectiveness of remedial alternatives for the Sikes Disposal Pits site: o Sikes Disposal Pits Site Remedial Investigation Lockwood, Andrews, and Newnam July 1986. o Sikes Disposal Pits Site, Remedial Investigation Addendum Report, Lockwood, Andrews and Newnam, June 1986. 9 Sikes Disposal Pits Site Feasibility Study. Lockwood, Andrews, and Newnam, July 1986. o Responsiveness Summary o Staff Summaries and Recommendations. . DESCRIPTION OF SELECTED REMEDY o Onsite incineration of sludges and contaminated soils; o Onsite disposal of residue ash - use as backfill; o Ban use of upper aquifer onsite, while naturally attenuating to 10-5 Human Health Criteria (less than 30 years); ~ o Discharge contaminated surface water to river, treat as necessary to meet discharge criteria; o Monitor lower aquifer and ban its use onsite if site degradation occurs. DECLARATION Consistent with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) and the National Contingency Plan (40 CFR Part 300), I have determined that the selected remedy for the Sikes Disposal Pits site is a cost-effective remedy and provides adequate protection of public health, welfare and the environment. The State of Texas has been consulted and agrees with the approved remedy. In addition, the action will require future operation and maintenance activities to ensure the continued effectiveness of the remedy. These activities will be considered part of the approved action and eligible for Trust Fund ------- , I have also determined that the action being taken is appropriate when balanced against the availability of Trust Fund monies for use at other sites. In addition, onsite incineration of sludges and contaminated soils is the most cost-effective remedial action, since it provides the best protection to human health, welfare, and the environment. b1~' \81 DATE ~ ~(, . LA. Dick Whittington, P.E. Regional Administrator ------- SUMMARY OF REMEDIAL ALTERNATIVE SELECTION SIKES DISPOSAL PITS ------- TABLE OF CONTENTS 1. Site Location and Description ...8.."'" .................... 2. Site History ............................. ....... .... ........ 3. Current Site Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . '.' . . . . 4. Migration Pathways ................................... ... .... 5. Target Receptors ................ ...................... ..... 6. Enforcement Analysis . ........... ........ ............ ....... 7. Alternatives Evaluation ................................... . 8. Community Relations ..... ........... ....... ............ ..... 9. Consistency with other Environmental .................. Laws 10. Recommended Alternative ............... ..................... 11. Schedule . . . ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 1 1 5 8 14 14 15 24 24 24 ------- 1 Record of Decision Remedial Alternative Selection Sikes Disposal Pits Crosby, Texas Site Location and Description The Sikes Disposal Pits site is located on a l85-acre site, approximately 2 miles southwest of Crosby, Texas. It is bordered by the San Jacinto River on the west, Jackson Bayou on the north, and U.S. Highway 90 on the south (Figure 1 and 2). The area immediately surrounding the site is largely undeveloped with numerous active and abandoned sand pits and low- lying swampy areas. Some commercial timber operations and mineral exploration have been conducted in the past. The area plays host to ~port fishermen as well as water sport enthusiasts on nearby San Jacinto River and Jackson Bayou. One family lives onsite. The Riverdale Subdivision, 500 feet southwest of the site, is the only residential development in close proximity of the site. The site completely lies in the 100-year flood plain of the San Jacinto River, while portions lie within the lO-year and 50-year flood plains. - The site has been flooded four times since 1969. The site locations where significant waste deposits have been identified, and thus, are considered source areas include (Figure 2): o The main waste pit o The main waste pit overflow area o Tank Lake and slough o Small waste pits (3) o Drum waste areas o Suspect waste areas The approximate volumes of waste at these source areas are listed in Table 2. -\ ......,. Alluvial sand deposits, ranging from 17 to 34 feet thick, underlie the site and form a shallow aquifer. Many of the local inhabitants rely on this aquifer for drinking water (Figure 3). Site History The Sikes Disposal Pits site began operation as a waste depository in the early 1960's and closed in 1967. During this period, a variety of chemical wastes from area petrochemical industries were deposited onsite in several' old sand pits. Numerous drums of wastes were also left on the property. The dike around the unlined main waste pit was not adequate to withstand the periodic flooding of the site. Floodwaters have breached the dike and transported wastes across a large, low-lying area east of the main ------- ,- :- ,-.,.,- ..\, ~ ___I ,-, I '.-', : ..,- \__...J -I , ... " I " '- --..., ..- r""~.'" ... -'1 .I ~.. ,..1 U "-...... " HOUSTON INTUCONTINENT Al A"~T ,--, --- , ,-, V.........-.. , ~ ..... I' r) \1 .. '" 4? 2 4 6 8 GRAPHIC SCALE 10 MILES FIGURE I SIKES DISPOSAL PITS SITE LOCATION PrIDor'd for: TEXAS WATER COMMISSION SIKES DISPOSAL PITS CROSBY, TEXAS ISln = ------- JACIfSQ '-. '.. ~.8~.~OIJ RIVERDAlE SUBDIVISION I 200 ',000 I I 300 "'.,." ',soo ,.., I o ~N I L!!..i I O. I I I I '00 SOl I Figure 2 . OVERFLOW AREA SIKES .DISPOSAl PITS CROSBY. TE XAS Prep.red lor: R ,. TEXAS DEPARTMENT OF WATE ,. RESOURCES agn/ESE/ ~ rnOHCT NO. ,~n1l10'11 oJ OA T(: JAN. ,?tI~ ) , ) .. ... ------- , .. ... ) ) ) .. ... "'f o <::' OlSPOSAL . SITE SIKES PITS \I.!t. 4)0 MAIN WASTE ~IT GULF PUMP RD. TO BARRETT .- '- )0 n z. ... o Ui UIUI ~ en ...,01 en en en en ~ U) 01 ...,en RIVERO ALE SUBDIVISION J 1500 J 1000 1-- . o 500 NOTE: MAP REFERENCE No. KEYED TO TABLE 3-2 Prep.red lor: TEXAS DEPARTMENT OF WATER RESOURCES ~.r /ESE/ B~,~ Figure 3 SHALLOW WATER SUPPLY WELLS RIVERDALE SUBDIVISION SIKES DISPOSAL PITS CROSBY, TEXAS p"OJFCT NO. Ib1nOO'll ------- 5 The Sikes Disposal Pits site was one of the original sites ranked under the Hazard Ranking System and placed on the National Priorities List in 1983 (score: 61.62). Preliminary sampling at the site in 1982 indicated the presence of phenolic compounds, xylene, benzene, creosote, toluene, and other organics. An Immediate Removal Action was performed at the site by the U.S. EPA Emergency Response Branch in June of 1983. Approximately 440 cubic yards of phenolic tars were removed from a partially buried pit near the temporary living quarters of the Sikes family, immediately north of U.S. Hwy 90. The Sikes family was temporarily relocated away from the onsite activities to protect their health and safety, and to reduce their interference with ongoing operations. Relocation was handled by the Texas Department of Emergency Management (OEM) using three travel trailers provided by the Federal Emergency Management Agency (FEMA). Total cost of the relocation, which ~as completed on May 6, 1983, was $30,000. The Texas Department of Water Resources (now the Texas Water Commission) under a Cooperative Agreement signed with the U.S. EPA in June 1982, contracted with Lockwood, Andrews, and Newnam, Inc., Environmental Science and Engineering, Inc., and Harding Lawson Associates in January 1983, to . conduct a Remedial Site Investigation (RI). The preceeding work was conducted in two phases, one in May of 1983, and a follow-up effort in February of 1984. The final report was submitted in July 1985, and contains the results of both efforts. Following completion of the original RI activities and prior to submission of the final RI document, work began on the Feasibility Study (FS) (October 1984). Several data gaps were identified in the ~I that were essential for the development of the FS. The decision was to finalize the RI Report and conduct a supplemental sampling program. Field work for the supplemental sampling activities began in July 1985. The final Addendum RI Report for these field activities was submitted in June 1986, and the draft FS was also received in June 1986. Current Site Status The Remedial Investigation Phase 1 and 2 and the Supplemental Sampling effort, performed at the Sikes Disposal Pits site, were used to describe the nature and extent of contamination. Pathways and receptors are described in detail in the RI/FS Reports. Several waste areas have been identified as being sources of contamination. The contamination is broken down as waste or sludges and underlying contaminated soils. Table 1 shows the estimated waste volumes f~r the site. Sludges onsite are composed of the wide variety of organics shown on Table 2. Soils underlying the waste areas appear to be significantly contaminated to depths ranging from 3 to 18 f~et beneath the sludge/water/soil interface. Contaminants found in the underlying soils are similar to those found in the overlying sludg~s (Table 2 gives the highest concentrations for ------- Tab 1 e 1 Approximate Waste Volu~es at the Sikes Disposal Pits Site, July 1985 Volume Medium/Area I. Wastes Pits 5,900 Barrels 2,600 Sp i 11 s 43,300 Suspected 16,700 Total 68,500 C.Y. II. Contaminated 50ils Main Waste Pit 21,000 Sludge Overflow Area 58,300 Total 79,300 C.Y. III. Contaminated Sediment Tank Lake 2,000 Slough 300 Total 2,300 C.Y. I V. Contaminated Surface Water Main Waste Pit 4,700,000 Small Waste Pits 417,000 Tank Lake 7 , 071 ,000 Slough 412,200 Total 12,600,000 Gal. Note: Volume totals have been rounded to the nearest 100 cubic yards and the nearest 1000 gallons. For complete volume calculations ------- TABLE 2 MAXIMUM CONTAMINANT CONCENTRATIONS IN SOILS AND SLUDGES AT THE SIKES DISPOSAL PITS SITE PARAMETER SO I LS SLUDGES Concentration, PPB Concentration, PPB Benzene 320,000 400,000 1,2-Dichloro- ethane 1,000,000 1,400,000 1,2,-Trichloro- ethane 500,000 290,000 Toluene 93,000 48,000 Ethyl benzene 100,000 52,000 Napthalene 1,200,000 78,300,000 Fluorene 290,000 1,600,000 Pyrene 590,000 0-3,300.000 Lead 370,000 4,150,000 -~ ------- 8 Surface water from the sludge areas as well as a natural surface water body, called Tank lake, and natural drainage ways were found to be contaminated. The contaminants.were similar to those found in the underlying sludge/sediments except at lower concentrations. Table 3 shows the highest concentrations of contaminants found in the surface water onsite. Dewatering operations in the local sand pits have altered the ground- water gradients and subsequently spread contaminants. Groundwater contamination appears to be moving from the main waste pit to the south, southeast, and northwest. Groundwater contaminants are shown in Table 3. Groundwater in the shallow aquifer has been heavily contaminated by the leaching action of organic wastes deposited in pits and spread on the surface. At this time, only the shallow aquifer below the site is significantly contaminated, no residential wells are currently affected. Neither surface water or groundwater contamination has migrated beyond the site boundaries. A second aquifer lies below the first, separated from it by approximately 65 feet of highly plastic clay strata. This lower aquifer appears to contain trace concentrations of one or more volatile organic compounds . which seem to be originating from an upgradient source. Underlying the two aquifers previously discussed and separated by several hundred feet of clay are the Chicot and Evangeline Aquifers, the primary drinking water source for metropolitan Houston. These aquifers do not appear to be in any danger of future contaminatton. Air quality at the site has not- been measurably degraded, however, if the wastes were to be disturbed in an uncontrolled situation the air releases could be substantial. Migration Pathways Groundwater in the upper aquifer enters the site area from the east and northeast. Ultimate discharge of the shallow groundwater flow is to the San Jacinto River. Onsite there are localized areas of groundwater recharge from surface water ponds which include abandoned sand pits, the main waste pit, Tank lake, and possibly the small waste pits. The overflow area also receives recharge from the north, the east, and the southeast. The flow of shallow groundwater across the site is intercepted by the surface drainages in the overflow area, by dewatered sand pits to the south, by Jackson Bayou to the north, and the San Jacinto River to the ------- Tab 1 e 3 Summary of Maximum Conta~inant Concentrations at Sikes Disposal Pits and Human Health Criteria (All Units in ug /1 or ppb) Highest Observed Human Levels Parameters Health Ground Surface Criterion* Water Water Conventional Analysis Pheno 1 s, Tota 1 3,500 15,000 23 Metals Beryllium 0.037 15 Cadmium 10 770 Chromium 50 44 13 Mercury 0.144 0.4 Nickel 13.4 18 Lead 50 46 Thallium 13 93 GClMS Volatiles Benzene ~ 6.6 10,000 9 Chlorobenzene 488 390 3 Chloroform 1.9 290 2 ~ 1,2-DiChloroethane 9.4 2,200 91 T-l, 3-Dichloropropene 87 9 Ethylbenzene 1,400 1,700 1,12,2-Tetrachloroethane 1.7 5 l,l,2-Trichloroethane 6.0 390 4 Trichloroethene 23 44 Toluene 14,300 4,300 2 Vinyl Chloride 20 400 6 GC/MS Base/Neutral 20.01 Acenaphthene 68.0 5 Acenaphthylene 0.028 2 Anthracene 0.028 2 Benzo(A)anthracene 0.028 3 Benzo(B)fluoranthene 0.028 3 Benzo(A)pyrene 0.028 2 Bis(2-ethylhexyl)phthalate 15,000 190 37 Chrysene 0.028 ? ... 1,4-DiChlorobenzene 400 6 1,2-DiChlorobenzene 400 6 Di-N-butylphthalate 34,000 2 Fluoranthene 42 6 2 Naphthalene 5900 Phenanthene 0.028 290 Pyrene 0.028 190 ------- 10 Contaminated wastes within the main waste pit and the overflow area are the primary sources of shallow groundwater contamination. The groundwater within this immediate vicinity is heavily contaminated. In addition, because numerous smaller sources of contamination (i.e., small waste pits, scattered drum stockpiles, and possibly undiscovered buried wastes) exist, and because groundwater flow patterns were previously altered by sand.pit dewatering, groundwater contamination is widespread onsite (Figure 4). North of Jackson Bayou the shallow groundwater flow is suspected to be toward the south. Thus, the contaminated groundwater plume has advanced north of the railroad tracks, based on contaminated groundwater seeps observed under the railroad trestle, and in some areas has advanced to Jackson Bayou, based on surface water sampling. The most rapid advance of shallow groundwater contamination is presently located around Love Sand Pit south of the main waste pit. Groundwater in . this area has become heavily contaminated due to extensive pumping of water from the sand pit. A groundwater seep visible in the pit indicates that movement of contaminants through the upper aquifer toward the Love Sand Pit is occurring. Pumping in the pit has resulted in the formation of a large cone of depression that effectively isolates groundwater in the western portion of the Riverda1e community from the more heavily contaminated groundwat~r to the north. If pumping were discontinued, the groundwater gradient would decrease and the contaminated groundwater . would disperse covering a larger area. This would increase the risk of the Riverda1e community's groundwater becoming contaminated. The ground- water flow would maintain a southwesterly direction but would proceed at . a reduced rate. Data from the borings and wells indicate that the upper and lower aquifers are separated by an aquitard consisting of 64 to 69 feet of low permeability (less than 10-7 cm/sec) clay which appears to be continuous and relatively uniform across the site. The estimated vertical groundwater velocity in the aquitard between the upper and low~r aquifer is approximately 0.2 feet/year. Groundwater in the lower aquifer has at times exhibited elevated concentrations of total organic carbon (TOC), total organic halides and total phenols, as well as traces of benzene, ch10robenzene, 1,1-dich1oroethane, and vinyl chloride. . 50i1 core samples collected in the aquitard at depths between 31 and 88 feet below the ground surface (elevations -11 feet and -68 feet MSL, respectively) revealed no apparent vertical migration of the contaminants mentioned. (TOX), Similar contamination in the background monitoring well as in the onsite monitoring wells indicates that contamination in the lower aquifer is not from the Sikes site. This assumption is reinforced by the lack of evidence indicating a mechanism through which contamination of the lower ------- -~i o MONITOR WELL * BORING & MONITOR WELL . SOIL BORING )40(50 . ';"',.. 'IV 84"n.. .-.,.... .'.... I....... rVu RIVERDAlE . SUBDIVISION nm DEFIN ITE ~ POTENTIAL o ~N I 'L!!..f' I o SOl t,ooo I I 300 M.,.r, t.500 Fe., I I I I I tOO 200 Figure 4 SHALLOW GROUNDWATER CONTAMINATION SIKES DISPOSAL PITS CROSBY, TEXAS P'.p.,.d 10': TEXAS DEPARTMENT OF WATER RESOURCES ~n/ESE/ ~ PROJECT N,?~OO1 ) DATE: JIIN.. '985 ) ) -. ------- 12 The general surface water flow pattern at the site is southwest towards the San Jacinto River. The drainage of the site is poor and generally dominated by man-made features such as roads, sand pits, berms, ditches and cu1 verts. The main waste pit drains to the east into the overflow area via a ditch and a 24 inch culvert. The overflow area acts as a runoff detention area, releasing stormwater to the two drainageways located to the south. These drainageways join and ultimately discharge to the San Jacinto River just north of U.S. Highway 90. Contamination is carried along this surface drainage path to the San Jacinto River. Surface water and sediments along this drainage pattern exhibit decreasing concentration~ of TOX, TOC, and total extractable organics (TOE) with distance from the main waste pit and sludge overflow area. The northern portion of the site, including the area around the small waste pits, drains northwest toward Jackson Bayou. The small waste pits are bermed with no outlet. Tank Lake has no defined outlet but drains south across the road to the slough during periods of heavy rainfall. TOE concentrations in sediments from Jackson Bayou indicate that some transport and deposition of contaminants is occurring along the drainage . pattern in the northern portions of the site. Because the site is in the floodplain of the San Jacinto River, it is frequently inundated by floodwaters. In the past 20 years there has been flooding, including major ones in 1969, 1979 and 1983. The effects of flooding on contaminant migration include surficial transport and deposition of cohtaminants. In the past, floodwaters have deposited large quantities of waste in various areas of the.-site. Most notable of these areas is the 8 acre sludge overflow area. Floodwaters move across the site in the patterns shown on Figure 5. Several residences in the western portion of the Riverdale Community are located in the path of the floodwaters. However, soil samples collected in the Riverda1e area exposed to floodwaters indicate that no significant deposition of contaminated soils and sediments has occurred. Two possible pathways exist for airborne contamination at the Sikes site. Truck traffic travelling along the A and B Sand Company Road across the overflow area approximately 150 to 300 feet east of the main waste pit raises dust particles possibly contaminated by wastes. Wind may. potentially transport dust particles offsite. However, because the dust appears to settle quickly, the quantity of contaminated dust particles ------- .. RlVERDAlE SUBDIVISION -- - TItANSmCIN MfA: RON Dnt£CTICH VMI£S DEPUONG ON CONDITIONS . ~N I ~I o seo t.- I , 300 M...,. t.sou ,.., , I I I I '00 200 Figure 5 ROOD ROW PATTERNS MAY 24,1983 SIKES DISPOSAL PITS CROSBY. TEXAS pr.p.red 'or: TEXAS DEPARTMENT OF WATER RESOURCES ~n/ESE/~ ) OAT(: Wf. '''''5' PRonCT Nr 'JO 0111 '" ------- 14 The second airborne contamination pathway is by volatilization of organic compounds in the wastes. Preliminary screening of air quality around the site indicated that if left undisturbed volatilization of organics is minimal. However, volatilization may be catalyzed by rainwater in the hot summer months. Short term rains that evaporate quickly appear to produce higher than normal readings. Target Receptors The following target receptors were identified in the remedial investigation: o Members of the Sikes family, who live on the site; o residents in the western portions of the Riverda1e community; o employees of the nearby sand mining operations; o people who use potentially contaminated sands from the Love Sand Pit; o sport fishermen that frequent Jackson Bayou and the San Jacinto River; o persons who make unauthorized or inadvertent entrance to the site; o Southern Pacific Railroad maintenance personnel; and o boaters and skiers on the San Jancinto River. Results of the RI study indicate that remedial action is required to reduce the potential for pub1tc health exposure through: o Direct contact with sludges and contaminated soils; o consumption of contaminated groundwater; o direct contact with contaminated surface waters; and. i I ~ ~ ~ o inhalation of toxic organic compounds through uncontrolled disturbance of the waste. Enforcement Analysis Approximately 10 potentially responsible parties (PRPs) have been identified for the site. PRPs for the Sikes Disposal Pits site consist of t~e owners, the Sikes family, in addition to several corporations, designated as either generators or transporters. At the present time, the Sikes family is the only PRP to indicate inability to fund any portion of the ------- 15 At the termination of the investigative proceedings, all identified PRPs will be offered the opportunity to voluntarily implement the preferred remedy. If anticipated negotiations are unsuccessful, the Fund will be utilized for cleanup of the site. However, no negotiations have been initiated to date. If the PRPs decline to implement the remedy, EPA will seek appropriate enforcement action. One of the generators identified has acknowledged partial responsibility. Two of the generators identified have requested additional information from EPA on their status as a PRP. No task force has been formed yet. Alternatives Evaluation The Feasibility Study for the Sikes Disposal Pits site was performed to de~ermine what actions, if any, would be appropriate as part of a permanent remedy for the site. Several alternative remedial methods were developed to mitigate damage to, and provide adequate protection of public health, welfare, and the environment from past and future releases of contaminants onsite. The National Contingency Plan (NCP), 40 CFR Part 300.68(e)(2) states that - "Source control remedial actions may be appropriate if a substantial concentration of hazardous substances remains at or near the area where they were originally located and inadequate barriers exist to retard migration of substances into the environment." In accordance with the NCP, and based on the (onclusions of the Remedial Investigation, a source control remedial action is necessary at the Sikes Disposal Pits site. The major threats to public health and the environment attributed to contaminants at the site are: 1. 2. 3. 4. 5. Direct contact with sludges and contaminated soils; continued direct contamination of the upper aquifer; potential contamination of the lower aquifer; direct contact with contaminated surface waters; and releases of toxic volatile organic compounds into the air, uncontrolled disturbances of the waste. through Remedial Objectives The Feasibility Study performed by Lockwood, Andrews and Newnam, Inc., in July 1986, developed the following objectives and criteria based on the results of the Remedial Investigation: 1. Prevent human contact with contaminated soils and wastes. Criteria: No direct contact with waste containing greater than ------- 16 2. Minimize impact of contaminated runnoff. Criteria: Surface Water Quality Criteria: a maximum of 0.1 mg/1 benzene, 0.3 mg/l vinyl chloride, 0.3 mg/l of total phenols, and metals as per Section 156.19.15.002 of the Texas Water Code. 3.. Prevent human contact with contaminated surface water. Criteria: Surface Water Quality Criteria. 4. Minimize site related degradation of the San Jacinto River and Jackson Bayou. Criteria: Surface Water Quality Criteria. 5. Prevent use of contaminated groundwater (upper aquifer). Criteria: Drinking Water Standards and Human Health Criteria (10-4 to 10-7 risk range). 6. Protect against contamination of the lower aquifer. Criteria: Existing background water quality in lower aquifer. 7. Prevent migration of waste offsite during flood events. Criteria: Surface Water Quality Criteria. 8. Prevent use of groundwater (lower aquifer) contaminated above background. Criteria: Existing background water quality in lower aquifer. 9. Minimize the potential of any adverse air discharge. Criteria: OSHA standards at site boundary, Federal Ambient Air Standards. Initial Screening of Alternatives and Identification of Potential Remedial iechnologies Section 300.68(h) of the National Contingency Plan states that the following broad criteria should be used in the initial screening of alternatives and technologies: j , 1. Cost. For each alternative, the cost of installing or implementing ~remedial action must be considered, including operation and' maintenance costs. An alternative that far exceeds the costs of other alternatives and does not provide substantially greater public health or environmental benefit should usually be excluded ------- 17 3. Effects of the Alternative. The effects of each alternative should be evaluated in two ways: (i) whether the alternative itself or its implementation has any adverse environmental effects; and (ii) for source control remedial actions, whether the alternative is likely to achieve adequate control of source material, or for offsite . remedial actions, whether the alternative is likely to effectively mitigate and minimize the threat of harm to public health, welfare, or the environment. If an alternative has significant adverse effects, it should be excluded from further consideration. Only those alternatives that effectively contribute to protection of public health, welfare, or the environment should be considered. Acceptable Engineering Practices. Alternatives must Qe feasible for the location and conditions of the release, applicable to the problem, and represent a reliable means of addressing the problem. 2. Identi.fication of Response Actions and Applicable Technologies In the screening process, only technologies applicable to the following objective response actions were considered: 1. 2. Removing and disposing of sludges and contaminated soils; removing and treating (if necessary) surface waters; and 3. groundwater restoration. Table 4 lists the technologies initially screened and their applicability to the site. No air emission control/abatement technologies are presented since air pollution is not a significant problem at this time. Air emission control/monitoring technologies will be considered as part of the health and safety plan for remedial action, since excavation could cause air releases. Development of Site Remedial Alternatives The alternative technologies which were retained after the initial screening proc~ss were combined into remedial alternatives for a permanent remedy at the site. Twelve remedial alternatives plus the no-action alternative were formulated for mitigating the problems at the Sikes Disposal Pits site. The prescreened alternatives are described in Table 4. All alternatives listed in Table 5 are composed of the following common elements except the No Action alternative (FS Alternative 13). 1) 2) Discharge surface waters to river or treat as necessary to meet discharge criteria. Ban use of upper aquifer onsite while restoring upper aquifer to Drinking Water Standards or (10-4 to 10-7 range) Human Health Criteria. ------- TABLE 4 SUMMARY REVIEW OF TECHNOLOGIES SIKES DISPOSAL PITS Technology Applicability (1) Comments Removal/Disposal Treatment of Sludges and Contaminated Soils Waste Removal Technologies Dragline/Dozer/Backhoe A Applicable in combination with other technologies that treat or dispose of waste. Hydraulic Dredging NA Would produce large volumes of contaminated, possibly emulsified water. . Waste Disposal Technologies RCRA Landfill A Applicable for onsite and offsite disposal in combination with excavation. Non-RCRA Landfill (slurry walls and caps) A Applicable for onsite disposal on ly . Waste Treatment Technologies Biodegradation A Biological land application has a high potential for surface water contamination. It is also not feasible due to the large volume and type of waste and limited surface area. Other biodegradation methods are not considered proven technologies. Fixation A Applicable to offsite and onsite treatment in combination with excavation technology. Rotary kiln is the most appropriate for treating solid wastes. Applicable with excavation and landfill technologies. Incineration (Rotary kiln, fluidized bed, multiple health) A Stabilization A Applicable to sludges with onsite landfilling. (1) A = applicable major technology a = applicable minor technology, used in conjunction with major technologies. ------- TABLE 4 (CONT.) SUMMARY REVIEW OF TECHNOLOGIES Technology (1) App 1 i cabil i ty Comments Surface Water and Groundwater Treatment Physical Treatment Technologies Air Stripping A Applicable to volatile contaminants. Activated Carbon A Applicable to non-polar contaminants. Fil trat ion a Applicable with other treatment technologies. Not applicable due to quantities involved and cost. Membrane Filtration NA Biological Treatment Activated Sludge NA High cost with poor removal of trace organics. Aerated Lagoons NA High cost with poor removal of trace organics. Chemical Treatment Oxidation NA High cost with bench scale testing required. ., ..'"" Neutral ization a Applicable to some groundwater contamination with other treatment technologies. Not suitable for removal of organic contaminants. Hydro lys is NA High cost with bench scale testing required. Produces only a partial treatment and requires bench scale testing. Ultraviolet/Ozonation NA Natural Flushing A Applicable to the upper aquifer on ly . (1) A = applicable major technology a = applicable minor technology, used in conjunction with major technologies. ------- 20 These twelve alternatives were then screened according to the guidelines given in the NCP, especially 40 CFR 300.68 (g). The objective of the screening process was to narrow down the twelve remedial alternatives to a smaller list of potential remedial alternatives for further detailed analysis. Each remedial alternative was evaluated for the following specific criteria which includes technical feasibility, environmental and public health factors: o Performance o Reliability o Engineering Implementability/Constructability o Public Health and Welfare o Environmental Impacts o Institutional Factors o Costs Cost estimates and brief descriptions of the englneering feasibility, and effectiveness, as well as screening results are also summarized on Table 5. The rating system that was used for the non-cost screening of alternatives is described below: Rating Symbol Definition Extremely negative effects, even with mitigating measures. Alternative not worth further consideration in this' category. Negat i"ve effects, but not- st rong enough to be sole justification for eliminating an alternative; or only of moderate negative effects. o Of very little apparent positive or negative effects, but inclusion can be justified for some special reason; or no change from existing conditions. ++ A positive or moderately positive benefit. An extremely positive benefit. + Detailed Evaluation of Alternatives Based upon the screening process, six alternatives were retained for detailed evaluation in accordance with the HCP, 40 CFR 300.68(h). These alternatives were selected to demonstrate a reasonable range of remedial' ------- ,>,,..1110..,..._> TA81.E S INITIAL At.TERNATIVES SCREENING SUMMARY SIKES DISPOSAl. PITS SITE Errectiveness Shallow Groundwater F.nj;lnccrlnR Effectiveness Feaslhll ity Re 1. Cost (Sm Retained for further Eval. AllcrnaU YC Sludges" ContAminated Soils EnRlneerlnR Feaslbillty 1. Slud~c9: Offslte RCRA Landfill Soils: Offsltc RenA Landfill 2. nlu,l~es: Offsite Incineration SoUs: Fix & backfill Ash: Offslte RcnA Landfill 3. nludges: Offsite RCRA Landflll 50118: FIx & backfill 4. tiiudgel: On-site incineration So J Is: On- s Ilc RCRA tand fill Ash: Fix & backfill 5. nIudp,e: On-sile II1c1neraUon Snlls: Fix & backfill Ash: Fix & backfill 6. Sh,d~c9: On-sile Incineration Soils: Off-site RCRA Landfill Ash: Fix & backfill 7. SludRe: 5011 s: On-site RCRA Landfill On-site RCRA Landfill 8. mlJ(l~es: On-site RCHA Landf111 Solts: Fix & backftJl 9. S\ud~e: On-slt.e Incineration Solis: Off-site ReRA l.andftl1 Ash: Off-site RCRA l.andfltl 10. nlllll~e: (In-slle Incineration So 11 s: On-slt.e I nc I nerst Ion II!;": hackflll 11. S I III I p,c : On-s I t.e "on- HCRA Landi 111 Sui Is: t'lx & hackflll 12. SludRe: 5 t. S: Slurry walll , Cap Fix and backfill 11. No Action + + + + 93-143 + + + + 7)-103 + + + + H-83 + + ~J-12 Yrs "0 + + + + )J-S3 y"s + + + + 1)-11) Yrs + + H-63 "0 + + 38-43 "0 ++ + ++ + 108-163 "0 + + + + 43-68 Yes o o ))-43 o + o + 2J-28 Yes 0-.4 Yes RaLionaie "0 C05tly;Risks durlnR transport. 1115(1U581 cApAcity IMY not be avallahlr, , Incinerator capacity may not be available. Hore costly than other eqllttahle altern- atives. Risks durlnR transport. Provides protecllon f'qun I to 1I1I.er- vnt.lve 2 at less cost. Risk durlnj; 10nR transport. ~Iorr cuslly lhan Alternatlv(' 10 vi t.h no Atld III onR I prot"e lion; f, Itr renvtl n5 closrd. v/lomlflll on-sl t.e IMJor I.pch- prClblrms; e.g. sl7.e, locnllnn, spll.lr- ""~lIt, subject to floodlllK erosion. "0 \.Jt:05troys worst contamlllAnts. Imml'hll- hes rest. HIp-hI. provide equnl clrAllup ('ffeel os lot.ol Inclnrrath'n. Nu transpnrt r 1!Jks. 1!I'sl.roys worst contaminants. R1!Jk durlnp; trnnsport, but less than for Alternative 1, 2, 3. HnJor technical problems; sl7.e,loca- tlon, settlrmcnt subject to flo~lln~ erosIon. Hny require lonl': term monl- torln". RIsk of liner failure. Greater risks than Alternative 4. Slmltar technical problems as Alt. 4,1. tess r1!Jks than AlL 7) No transport risks. CO!;lIy; 1115posol CRpRC ty IMY not. h.. avo Ilnhle. I,('nl(lhly trRn5rort time . vi I.h altendnnt exrosure risk!':. "0 l~stroY5 or rend('rs vnsles ('ffeet.lvely nun-hn7.Rrdolls. Onlyl.olnl desl.ruel.lnn nll.prnAlIve. "0 lonl( tcrm mnnl'.r,..llI~ dUP 1.0 d I SpOSR I opll on chosrn. J.onRer cleanup time. No transport rlsk~ "h,)or t.eehnlcnl probl('m!;; r.p;. 517.(' locntlon, selll"""'lIt, 511b,)...... 1.0 flouls. "'"sIr ,'('m.'\11I In 11"55 I.hAII 1117 II A frwlJII.Y. J."nR terlll monltorlllR required. Contains or Immobilizes wastes. Requires 10nR term monltorlnK Inspection and maintenance. ------- 22 All the alternatives retained for detailed analysis, except the No Action. Alternative, include natural flushing of the upper aquifer as the restoration technique. Contamination of groundwater in the upper aquifer attenuates due to the effects of advection, dispersion, and biotransformation as the distance from the contaminant source increases. Also, approximately 572,000 gallons per day of uncontaminated groundwater flows into the aquifer under the site (which itself contains about 271 million gallons) towards the San Jacinto River or Jackson Bayou. The aquifer water entering the river or bayou meets the Surface Water Quality Criteria because of significant dilution by the clean groundwater. To meet the objective of Human Health Standards (10-4 to 10-7 range) or Drinking Water Quality in the aquifer under the site, removaJ or isolation of the source of contamination has to be accomplished. With the limited sources of contamination remaining infiltration and flushing would effectively attenuate this aquifer to a 10-5 Human Health Risk in less than 30 years. Alternative 1 (FS Alternative 13) No Action Section 300.68(f) of the National Contingency Plan (NCP) specifies that the "No Action" alternative be evaluated. Under this alternative no construction activities are implemented. This means the site remains in . its present state and continues to pose a risk to public health and the environment. Periodic monitoring of the upper and lower aquifers is ongoing to detect changes in upper aquifer contamination and areal extent, and in lower aquifer water quality. ~ Alternative 2 (FS Alternative 3) Offsite RCRA landfilling of Sludges, Onsite Fixation of Soils. Alternatives 2 through 7 contain several supporting work tasks (referred to as common components) that will not be repeated under each alternative description. These include: I 4 f o Perimeter fence; o protecting the site against flooding; o stormwater run-on and run-off collection/disposal system; and o pit surface water/infiltration water collection and treatment system. It should be noted that for costing purposes the most conservative approach to flood protection (i .e., perimeter diking) was used, however the exact nature of flood protection to be used will be determined during the design phase. Also, for alternatives which involve incineration, fixation of residue ash was assumed for costing purposes, though this may be eliminated ------- 23 This alternative includes the excavation of sludges to the 100 ppm polynuclear aromatic hydrocarbon (PNA) criteria level and contaminated soils to the 10 ppm volatile organic aromatic (VOA) criteria level. The sludges are then trucked offsite to an EPA approved RCRA landfill. The contaminated soils are chemically fixed with a cement based agent and utilized as backfill onsite. Use of the contaminated upper aquifer is banned onsite until restored to drinking water quality through natural flushing. Both the upper and lower aquifers are monitored following completion of remedial action and continued for up to 30 years, if needed. Alternative 3 (FS Alternative 5) Onsite Incineration of Sludges, Fixation of Soils and Ash For this alternative, sludges are excavated to the 100 ppm PNA criteria l~vel and contaminated soils to the 10 ppm VOA criteria level. The sludge organics are then destroyed by onsite incineration while the ash and contaminated soils are chemically fixed with.a cement based agent and utili2ed as backfill onsite. Use of the contaminated upper aquifer is banned onsite until restored to drinking water quality through natural flushing. Both the upper and lower aquifers are monitored following completion of the remedial action and continued for up to 30 years, if needed. - Alternative 4 (FS Alternative 6) Onsite Incineration of Sludges, Offsite RCRA Landfilling of Soils This alternative includes excavation of sludges to the 100 ppm PNA criteria level and soils to the 10 ppm VOA criteria level. Sludges are then incinerated onsite and contaminated soils trucked offsite for disposal at an EPA approved RCRA landfill.- Incinerator ash is chemically fixed onsite using a cement based agent. The resulting solid is used as backfill. Use of the contaminated upper aquifer is banned onsite until restored to drinking water quality through natural flushing. Both the upper and lower aquifers are monitored for up to 30 years following completion of the remedial. action. . Alternative 5 (FS Alternative 10) Incineration of Sludges and Soils For this alternative sludges and soils are excavated to the 10 ppm VOA criteria level, combined and incinerated onsite. The ash is tested, and if appropriate used as backfill. Use of contaminated upper aquifer water is banned onsite until restored to drinking water quality through natural flushing. Both the upper and lower aquifers are monitored for up to 30 ------- 24 Alternative 6 (FS Alternative 12) Cap and Slurry Wall This alternative involves dewatering of the main waste pit and Tank Lake. Sludges are excavated to the 100 ppm PNA criteria level and placed in these two pits. Prior to dewatering and excavation, a slurry wall is placed around both pits and tied into the upper aquitard. Following transfer of sludges into these pits, a geomembrane and clay cap are placed over each pit and tied into the slurry walls. Contaminated soils are then excavated, chemically fixed and the solids utilized for onsite backfill. Use of the contaminated upper aquifer water is banned onsite until restored to drinking water quality through natural flushing. Both the upper and lower aquifers are monitored for up to 30 years following completion of the remedial action. Information, including cost estimates on all these alternatives, are summarized in Table 6. Community Relations Public interest in the Sikes Disposal Pits site initial project phases has been minimal, except during periodical flooding of the site. In May 1983, when the flooded San Jacinto River inundated the site, local residents voiced their concerns over possible contamination of their . neighborhoods from the flood waters. Public interest increased upon completion of the Feasibility Study. The two week public notice period began on July 14, 1986. This was followed by a 21-day public comment period from July 30, 1986, to August 20, 1986. A briefing of local officials, primarily Chamber of Commerce members from Crosby, Texas, was held August 7, 1986. A public meeting was held later in the same day, with approximately 120 people attending. With a few exceptions, incineration (EPAs preferred alternative) appeared to be acceptable as long as wastes only from Sikes were incinerated at the site, and adequate controls were used to prevent upsets and pollution. Responses to the comments received during the comment period are presented in the IICommunity Relations Responsiveness Summaryll attached to this Record of Decision. Consistency with other Environmental Laws It is EPA policy to give primary consideration to remedial actions that attain or exceed applicable and relevant standards of other Federal public health and environmental laws. Environmental laws which will have an impact on the proposed remedies for the Sikes Disposal Pits site are summarized on Table 7. Provisions of the applicable and relevant or appropriate requirements of these laws are summarized in Table 8. Recommended Alternative Section 300.68(i) of the National Contingency Plan states that lithe appropriate extent of remedy shall be determined by the lead agency's selection of a cost-effective remedial alternative that effectively mitigates and minimizes threats to and provides adequate protection of ------- Remedial AHernat ive , TAOLE 6 SUMMARY OF DETAILED [VALUATION or REMEOIAL ALTERNATIVES SIkES DISPOSAL PITS SIT£ Pubtic Health Considerations Present Worth Cost ($M) Implenentat ion O~M 3 - Off-Site RCRA Land- filling of Sludges. On-Site Fixation of Contaminated Soils. 5 - On-Site Incinera- tion of Sludges. Fixation of Con- taminated Soils and Ash. 6 - On-Site Incinera- tion of Sludges, Off -Site RCRA Landfi11tng of Contaminated Soils, On-Site Fixation of Ash. 10 - On-Site Inciner- ation of Sludges and Contaminated So 11 s . 12 - On-Site 8urial of Sludges in Pits with Slurry Wa 11 s and Caps. Fixation of Con- taminated Soi1s. 13 - No Act ion 56.0 53.8 111.3 92.9 23.4 0.4 0.4 Removes direct contact or ingestion hazard. low cancer risk. Use of upper a~uifer banned until restored. Trans- portation risks. Removes direct contact or ingestion hazard. low cancer rhk.Use of uPller aquifer banned until restored. , 0.4 Removes direct contact or ingestion hazard. Very low cancer risk. Use of upper a(lui fer banned until restored. Reduced transportation risks than Alt. 3. 0.4 Achieves maximum pro- tection against direct contact or ingestion hazard. Very low cancer risk. Use of upper a~uifer banned until restored. 1.3 Removes direct contact or ingestion hazard. low cancer risk. Use of upper a~ulfer banned unti I res tored. 0.4 Continued potential for direct contact on- site and off-site. Potential Ingestion hazard on-sHe. Environmental Considerations ------------ Removes or isolates waste. Promotes a~uifer restoration. Potential for leach- inq from fixed soils. least time to implenent. Ren~ves or Isolates waste. Promotes aquifer restoration. Potential for leach- InQ from fixed soils. longer Implementat ion tine than Alt. 3 & 12. Destroys or removes waste. Promotes aqui- fer restoration. lonqer implementation tin~ than A H. 3 and 12. Destroys organic waste on-site. Provides greater protection against potential aquifer contamination than Alt. 3. 5 and 12. longer Implenent- ation time than other a Herna ti ve s . Wastes Isolated or inll10billzed but not destroyed. leaching potenlial greatly reduced, although sludges left on~site. Wasles remains in p I ace. Conl i nlled pOlential for (on- tamin.1t ing lower aqlli fer. Upper aqulfl'r remains un- suil.lhle for uSP. Technical Considerations Institutional Cons id~r!l-.! i.!>I1~_- Demonstrated tech- nolo~y effectiveness if fixation is effective. Demonstrated tech- nology effectiveness if fixation is effective. Demonstrated tech- nologies. More rei iable. Demonstrated tech- nologies used. Maximum reliability. Not totally demon- strated technology. System fat1ure possible. Continued maintenance required. Collection and disposal of leachate required. Not applicable. 'Oannlng use of llpper Aquifer continued. Long term grollndwater monitoring refluirf'!d. Longtenn monilorilHI may affecl sHe use. Use of Upper Aqui fer banned. Longlerm groundwaler moniloring re~uired. longlerm monHodng may affect s He use. . Use of llpper Aqul fer banned. Longterm groundwater monitoring required. longterm n~nitoring may affect site use. Use of Upper Aquifer banned. lonQlerm groundwater n~nitoring required. Long term n~nitorinQ may affect s He use. Use of Upper Aquifer banned. lomllerm monitoring required. Use of land area prohibited. Direct contact and ingestion hazards ------- TABLE 7 REMEDIAL ALTERNATIVE COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS Remedial Alternative No. law or Regulation Analysis 3 5 6 10 12 - - - Federal Water Quality Implementation of this alternative X X X X X Criteria (FWQC) should result in compliance with FWQC in groundwater. Floodplain Management Implementation of this alternative will X X X X X Executiv.e Order No. 11988 be consistent with Floodplain Management May 24, 1977 requirements as ,prescribed in Executive Order 11988. State - Texas Water Commission (TWC) Implementation of this alternative will X X X X X Surface Water Quality produce a point source discharge. The Criteria (SWQC) discharge will be treated on-site as necessary to satisfy' State SWQC. , Texas Air Control 80ard Implementation of this alternative may X X X X X Regulations produce a point source emission from on-site equipment. Emissions will be in compliance with State regulations. Texas Solid Waste Act Implementation of this alternative would X. X require the transport and disposal of waste off -s i te. Transport and disposal wi 11 be in compl iance with State requirements. Local Loca 1 Approva 1 S . local agency approval for implementing this X X X X X ------- TABLE 7 REMEDIAL ALTERNATIVE COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS Remedial Alternative No. Law or Regulation Analysis 3 5 6 10 12 Federal Resource Conservation and Implementation of th~ source controls X X X X Recovery Act (RCRA) for this alternative will be consistent with current RCRA regulations, including standards for owners and operators of hazardous waste treatment, storage and disposal facilities and closure perform- ance standards for faci11tles located within a IOO-year f oodp aln. Department of Transportation Implementation of this alternative does X X X (DOT) Hazardous Materials not specifically require the off-site Transport Rules transport of hazardous materials. Implementation of this alternative requires X X the off-site transport of hazardous mater- ials. Transport will be in compliance with these rules, including use of properly constructed and marked transport vehicles~ use of licensed transporter, and use of hazardous waste manifests. Clean Air Act (CAA) and Implementation of this alternative may X X X X X National Ambient Air Quality result in the emission of pollutants Standards (NAAQS) into the air. On-site personnel will be adequately protected. Implementation of this alternative will X X X X X require point source emissions to the air. Pollution control equipment will be placed on the on-site treatment facility to ------- TABLE 8 PROVISIONS OF APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS Page 1 0 f 3 RCRA Part 264 Subpart B - General Facilities Standards Requires that facilities located in the 100-year floodplain be designed, constructed. operated and maintained to prevent washout of any'hazardous waste by a 100-year flood. o Could be applied to anyon-site landfill which would be constructed in the future to dispose of wastes. Subpart E - Manifest system, recordkeeping. and reporting o Hazardous waste manifesting procedures would be required if any waste is transported to an off-site TSD facility. Subpart F - Groundwater Protection o Requires that levels of hazardo~ constituents (40 CFR. Part 261 Appendix VIII) in the uppermost aquifer at the point of compliance (generally site boundary) meet limits set by U.S. EoPA as: 1) Background, or 2) Maximum Contaminant levels (MCLs), or 3) An alternate concentration limit (ACL) posing no present or future hazard to human health or the environment. o Will be more fully addressed in Upper Aquifer restoration. Subpart G - Closure and post-Closure " Requires closure in a manner that minimizes the need for further maintenance and prevents future release of contaminants. o Could be applied to in-place capping of wastes or closure of anyon-site landfills constructed as part of the ------- TABLE 8 PROVISIONS OF APPLICABLE OR RELEVA~T AND APPROPRIATE REQUIREMENTS Page 2 of 3 Subpart N - Landfills Requires that RCRA compliant landfill~ be double-lined and contain leachate collection and leak detection systems; does not allow placement of liquid, ignitable, or reactive wastes in landfill; also provides specific closure requirements. o Could be applied to anyon-site landfill which would be constructed in the future to dispose of wastes. Subpart 0 - Incinerators Requires detailed waste analysis and trial burns on incinerator before operations commence and on-line monitoring during operation. o Would apply to anyon-site incineration. Maximum Contaminant Level for Drinking Water (MCLs): 141.11 - 141.16 40 CFR Section Sets water quality standards for several metals and compounds based on health protection. o MCL values must be met for Upper Aquifer restoration. Clean Water Act: 40 CFR Section 301 and 403 Requires NPDES permit for discharge of treated water to natural surface water systems Occupational Safety and Health Standards: 29 CFR 1910 OSHA sets standards for protection of workers. o Would be applied to site workers during any remedial action; some standards may be considered in developing safe exposure levels (in air for example) for near ------- TABLE 8 PROVISIONS OF APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS Page 3 of 3 Clean Air Act: 42 U.S.C. 7401 Regulates primary air pollutants; does not address volatile organics or most toxics in air. . o Application to site limited, possibly applies during remedial actions involving waste excavation. D.O.T. Rules for the Transportation of Hazardous Materials: Parts 107, 171.11 - 171.500 49 CFR Regulates the transport of hazardous wastes through licensing of qU3lified transporters. Regulates hazardous waste manifesting system. Regulates transport placarding. EPA Groundwater Protection Strategy Ranks aquifers in the order to be protected: Class Class Class I - sole source aquifer II - usable aquifer, other supplies available III - water unfit for consumption (due to high salt content for example), or aquifer ------- 31 Alternative 5 (FS Alternative 10) is the recommended alternative for the Sikes Disposal Pits site. Costs for this alternative are summarized on Table 9. This alternative consists of: - Flood protection during remedial action; - Storm water run-on and run-off collection system; - Excavation of 150,000 cubic yards soils and sludges with greater than 10 ppm VOA's; - Onsite incineration of excavated sludges and soils; Onsite disposal of residue ash; - Backfilling of pits and excavated areas; - Collection and treatment, if necessary of contaminated surface water; Natural restoration of upper aquifer; and Post closure monitoring of upper and lower aquifer. The rationale for selection of Alternative 5 (FS Alternative 10) is as follows: Alternative 1 (FS Alternative 13 - No Action) was eliminated because the site would remain as it is, continuing to pose a risk to public health and the environment. - Alternative 2 and 3 (FS Alternatives 3 and 5 - Fixation of soils on-site) were eliminated because adequate protection of public health and the environment would not be provided. Soil fixation at this site poses several problems. For one, the effectiveness of soil fixing in preventing contaminant leaching is questionable when organics relatively high in solvents, such as those present at Sikes, are involved. In addition cert~in site factors increase the risk of leaching from any fixated soils. These factors are a high water table which lies only 10 feet below the surface, and inundation from frequent flooding. Taking this into consideration, while direct contact with contaminants would be eliminated, there is the substantial potential for leaching from the fixed soils. This~reduce~~he long-term integrity of these remedies. Because of the high levels of contaminants remaining onsite, this would not provide adequate protection of the upper aquifer, which needs 30 years to restore itself. This reasoning precludes the use of this technology. Alternative 4 (FS Alternative 6) was eliminated because transport and off-site disposal of soils increases the cost of this alternative $18,000,000 over the next less expensive alternative (Alternative 5, EPAs preferred alternative). The increased cost is not justified by a commensurate increase in protection because the waste is not being permanently treated. Furthenmore, there is the risk of a transportation ------- TABLE 9 COST SUIIMRY REIIEDIAL ALTERNATIvE 10 ONSITE INCINERATION OF SLUDGES AND CONTAIIINATED SO!LS,FIXATION OF ASH SIKES DISPOSAL PITS SITE !TEll IIIPLEIIENTATION CAPITAL 0 ~ II POST IIIPLEIIENT A TI ON o ~ II PRESENT !lORTH 10% ------------------------------------------------------------------------------------------- 6ENERAL "obilization and Delc~ilization 5113,000 Sl13\000 Office Area t $224,000 515,000 1210,000 Security t .500,000 .100,000 $'08.000 Environlental Permitting $300,000 .300,000 Health and Safety Progral ttt 1360,000 .40,000 1363,000 -Air "oni toring -Report Generating Dnslte Laboratory ttt S400,000 HO I 000 1350,000 -Operation and "alntenance, Including Technicians . Parking FacilIty t .24,000 S2,000 S22,OOO SITE PREPARATION ---------------- Road Construction t .83,000 55,500 $78,000 Deccntalination Facility tn $77,000 $13,000 S66,000 -Concrete Pad -Water Storage Tank -Steil Sprayer -SUlp Storl !later Collection Runo;; '450,000 '20,000 '433,000 and Disposal ttt Surface !later/Infiltration !later '455,000 870,000 '397,000 Collection and Treatlent ttt Dike Construction $1,526,000 Sl,526,000 Dike Ruoval $718,000 '718,000 Fencing and Lighting $126,000 5126,000 Clearing and Grubbing 586,000 '86,000 ------- TABLE 9 CO~T. EXCAVATIDN,INCINERATION AND DISPOSAL ----------------------------.-.----- ExCiVit! Wistes '1,127,000 Sheet Piling '379,000 Incinerator: -"obilization and Delobilization of Onsite Incineration Unit '1,825,000 -Construct Drying/Holding Pad ttt '66,000 -Load Incinerator ttt '1,112,000 '4,000 '278,000 -Annual Op~ration and ~aint. Costs ttf '38,880,000 '9,720,000 D~watering and Storage '25,000 Fixat10n of Incinerator Ash ttt '3,596,000 '899,000 Backfill and R~v~getate $585,000 GROUNDRATER ~ON!TORIN6 tt '58,000 ---------- CONSTRUCTION SUBTOTALS " '53,293,000 BID CONTIN6ENCIES 1151) '7,994,000 - SCOPE CONTIN5ENCIES (251) $13,323",000 ---------- CONSTRUCTION TOTALS '74,610,000 PE~~ITTING AND LE6AL SERVICES DURING CONSTRUCTION (51) '3,731,000 BONDING AND INSURANCE (101) '7,461,000 SERVICES DURING CONSTRUCTION (71) S~122~,OOO ADDITIDNAL ITE~S (51) '3,731,000 TOTAL I"PLE"ENTATION COST '94,756,000 ENGINEERING DESIGN COST (101) $7,461,000 ------- TOTAL CAPITAL COST $102,217,000 t Annual 0 L " for 5.0 Years tf Annual 0 L " for 30 Years ttt Annual 0 ~ " for 4 Years '1,127,000 '379,000 '1,625,000 '6;,000 '881,000 '30,811,000 '25,000 '2,a50,~00 '585,000 '41,000 '445,000 ---------- $41 ,000 $44,385,000 $7,994,000 '13,323,000 ---------- '65,702,000 '3,731,000 $7,461,000 '5,223,000 '3,731,000 $85,848,000 $7,461,000 ---------- ------- 34 Alternative 6 (FS Alternative 12 - Cap and slurry wall for sludges, soil fixation) was eliminated because adequate protection of public health and the environment could not be assured. The same reasoning as outlined for alternatives 2 and 3 applies here for soil fixation. In addition to this is the nearly impossible requirement of maintaining the integrity of a cap in an extremely flood prone area. This' alternative was eliminated for these reasons. Consequently, Alternative 5 (FS Alternative 10 - Incineration on-site of sludges and soils) complies with all applicable and relevant Federal environmental laws and regulations. Furthermore, it is the lowest cost permanent remedy that mitigates short and long term threats to public health and the environment. The greater protection afforded by this remedy justifies the additional cost. Operation and Maintenance Operation and maintenance will consist of post closure monitoring of the upper and lower aquifers as well as surficial maintenance of the site once closure is complete. Surficial maintenance includes such items as: o Fence repair o Fill replacement and regrading. Besides the aforementioned, costs also include purchased services such as sampling and laboratory analysis for groundwater monitoring, administrative costs, taxes, insurance, labor, and materials. The State of Texas will assume responsibility for operation and maintenance of the site for a period of 29 years, commencing one year after the post closure period begins. Annual operation and maintenance costs for the recommended alternative is estimated to be $41,000 and the present worth is estimated to be $445,000. Schedule The schedule for the remedial design and construction of the remedy at the Sikes Disposal Pits site is currently dependent upon re-authorization of Superfund. The design phase of the project will begin as soon as funding becomes available, either through re-authorization or a continuing resolution. When funding is available, the design of the remedy will take an estimated 18 to 24 months to complete. Remedial construction will begin as soon as possible after completion of the design, and take ------- TEXAS WATER COMMISSION Paul Hopkins, Chairman Ralph Romins. Commissioner John O. Houchins, Commissioner /.~,;.~ror-A II;" . ~~..' /,1:..:"'. "'Jt;\ I'~ \ )" ',\ ,~ 'rt:' ,..', \~~~~~:~~. ii'~:) Larry R. Soward, Executive Director Mary Ann Hefner, Chief Clerk James K. Rourke, Jr., Genera! Co-..nse: september 15, 1986 Mr. Dick Whittington u. S. Environmental Protection Reqion VI 1201 Elm Street Dallas, Texas 75270 Aqency Re: Draft Recor6 of Decision Sikes Disposal Pits Superfund Site Dear Mr. whittington: We have reviewed the proposed Draft Record of Decision (ROD) and responsiveness summary for the Sikes D1sposal Pits Superfund Site. We have no objection to the issuance of a ROD by the Environmental Protection Agenoy (EPA). Before the State of Texas can concur by providing its 10\ share of the cost for the selected remedial alternative, the fiscal impact of this action must be evaluated and SUbsequently coordinated with state's budgetary process. On a related matter, we would like to comment on the obligation of State monies for a period of 30 years after the remedial construction activities are complete. Such a commitment by the State of ~exas may be a violation of Article VIII, Section 6 of the Texas Constitution which addresses the appropriation of money beyond a two year period. Sincerely yours, ~~ Larry R. Soward Executive Director . ------- COMMUNITY RELATIONS RESPONSIVENESS SUMMARY ON PREFERRED REMEDIAL ALTERNATIVE SIKES DISPOSAL PITS, CROSBY, TEXAS This community relations responsiveness summary is divided into the following sections: I. Overview - This section discusses EPA's preferred alternative for remedial action, and likely public reaction to this alternative. II. Background on Community Involvement and Concerns - This section provides a brief history of site background and community interest and concerns raised during remedial planning activities at the Sikes Disposal Pits site. I I I. Summary of Major Comments Received During the Public Comment ------- 2 I. OVERVIEW In the presentation for the public meeting on August 7, 1986, , EPA discussed the remedial alternatives which were examined in the Feasibility Study, for .addressing the contamination at the Sikes Disposal Pits site. After the initial screening of the alternatives a detailed evaluation was performed on the six remaining. Except for the no action alternative, all met basic criteria for protecting public health and the environment and all had common components, including; natural flushing of the upper aquifer as a restoration technique, a perimeter fence, protection of the site against flooding, stormwater and surface water treatment (if necessary), and discharge. The alternatives are: 1. No Action with Monitoring Est. Cost: $ .4 Mill i on 2. Offsite Landfill; Onsite Stabilization of Soil s Est. Cost: $ 56 Mi 11 ion 3. Onsite Incineration of Sludges; Onsite Stabilization of Soils Est. Cost: $ 54 Mill i on 4. Onsite Incineration; Offsite Landfill Est. Cost: $111 Mi 11 ion 5. Onsite Incineration of Sludges and Soil s; Onsite Disposal of Ash Est. Cost: $ 93 Mill ion 6. Cap and Slurry Walls Est. Cost: $ 24 Mill i on The corrective action proposed. by the EPA was Alternative No.5, Onsite Incineration. The estimated cost of $93 Million includes annual operation and maintenance costs of $41,000 ($445,000 over a ten-year time period). Comments from the Crosby, Texas, Chamber of Commerce favored this option, provided that the incinerated wastes were only those generated at the Sikes site and not hazardous wastes brought from other sites. The comments on the options, along with EPAls response to each, are presented later in this document. II. BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS Site Background- The Sikes Disposal Pits site is located on 185 acres, approximately two miles southwest of Crosby, Texas in northeast Harris County. The area surrounding the site is largely undeveloped with numerous active and abandoned sand pits and low-lying swampy areas. The entire site lies within the 100-year floodplain of the San Jacinto River, and portions of the site lie within the 10-and 50-year floodplains. The dike around ------- 3 The Sikes Disposal Pits site began operation as a waste depository in the early 1960s and closed in 1967. During this period, a variety of chemical wastes from area petrochemical i.ndustries were deposited onsite in the sand pits. Numerous drums of wastes were also left on the property. The site was placed on the original National Priorities List in September 1983. Major Concerns and Issues Community involvement relating to the Sikes Disposal Pits site has been relatively low from the time of active operation in the early 1960s to the present. When the French Limited site located across Highway 90 from Sikes began operation in 1966, local attention to the Sikes Disposal Pits and French Limited sites increased. Shortly thereafter, residents in the nearby Riverdale subdivision sent a telegram to then President Lyndon Johnson concerning the waste dumping and their fruitless attempts to halt it. There were fewer community complaints once indiscriminate dumping ceased. In May 1983, the San Jacinto River flooded and inundated the site, and the news media focused attention on the potential environmental hazards caused by the flooding. Local residents telephoned the Texas Department of Water Resources (TDWR) now Texas Water Commission (TWC), District 7 office with their concerns over the possibility of contaminated flood waters flowing through the neighborhood. Other than concerns during flooding, community involvement in the Sikes project has been very low. Activities to Elicit Input and Address Concerns The TDWR (TWC) conducted site investigations through a cooperative agree- ment with the EPA pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). In order to accomplish site investigation activities and to provide safety for the Sikes family who resided on the site, the Texas Department of Emergency Management moved the family i~ March 1983, to travel trailers provided by the Federal Emergency Management Agency (FEMA), which were placed at a location on the property removed from EPA activity. III. SUMMARY OF PUBLIC COMMENTS RECEIVED DURING PUBLIC COMMENT PERIOD AND AGENCY RESPONSES The public comment period on the preferred remedial action alternative for the Sikes Disposal Pits site extended from July 30 to August 20, 1986. A public meeting took place on August 7,1986, in the Crosby High School, Crosby, Texas. Approximately one-hundred thirty (130) people were in attendance with twenty-two (22) people making oral statements or asking questions. Eight written statements were received during the comment ------- 4 In addition to the public meeting, a briefing was held for local officials, primarily composed of the Crosby Chamber of Commerce, on August 7, 1986. The preferred remedial alternative was presented, and appeared to be acceptable, provided no wastes, other than those generated at Sikes, be incinerated at the site. Comment 1 Will wastes from other Houston area hazardous waste sites be incinerated at Sikes? EPA Response No. This alternative was not a part of the Remedial Investigation and Feasibility Study (RIfFS), and therefore, no waste from any other site was considered for incineration or disposal at Sikes. Comment 2 Opposition to incineration onsite was stated. Citizens were concerned about adequate protection of their health and safety, and whether the incinerator would be a permanent fixture. Questions were also asked about .the type of incinerator and operating parameters. EPA Response The design of the incinerator and operating parameters will be established during the remedial design phase, which is the next step after remedy selection. The incinerator will be designed to meet all applicable Resource Conservation and Recovery Act (RCRA) and Toxic Subs~ances Control Act (TSCA) requirements. The contract for construction and operation will require the incinerator to meet technical requirements for permitting, although the incinerator will not have to be permitted. The requirements include, at a minimum, that a trial burn be conducted to confirm that the wastes, including PCBs, can be destroyed to required levels. While in . operation the incinerator will be continuously monitored to ensure compliance with these criteria. The incinerator will also be designed with built-in controls, which will shut down the facility automatically should any burn parameter, such as feed rate, temperature, or emissions, move out of the optimal operation range. By designing the incinerator in this way the chances of an uncontrolled hazardous emission will be minimized. The incinerator will be a temporary facility and will be removed at the completion of the Sikes remedial action. Comment 3 Fumes from an incinerator would be held down by heavy fogs causing local ------- 5 EPA Response The operation contract for the incinerator will be written such that during any atmospheric event that would prevent dispersion, feed to the incinerator will be stopped. Comment 4 The property values around Sikes will be depressed by incineration at the site. EPA Response Property values around Sikes are already depressed due the presence of an uncontrolled hazardous waste site. By cleaning up the site permanently this will no longer be the case. It is hoped that once remedial action is completed at Sikes the surrounding property values will return to normal. Comment 5 Several local residents and three Potentially Responsible Parties (PRP's) questioned why Alternative 12 (cap and slurry wall for sludges, fixation of .soil) was not preferred by EPA since it appears to cost much less than the preferred alternative ($23.4 million versus $92.9 million). EPA Response Alternative 12 does not meet the criteria of Section 300.68(i) of the National Contingency Plan which states that "the appropriate extent of remedy shall be determined by the lead agency's selection of a cost- effective remedial alternative that effectively mitigates and minimizes threats to and provides adequate protection of public health and welfare and the environment." A cap is not a viable long term remedy because the area is extremely flood prone. The application of soil fixation at this site also poses several problems. For one, the effectiveness of soil fixing in preventing contaminant leaching is questionable when organics relatively high in solvents, such as those present at Sikes, are involved. In addition, the water table (only 2 to 10 feet below the surface) and inundation from frequent flooding increases the risk of leaching contaminants. The above considerations reduce the long term integrity of this remedy. Also, because of the high levels of contaminants remaining onsite, this ------- 6 On the other hand, Alternative 10 complies with all applicable and relevant Federal environmental laws and regulations. It is also the lowest cost permanent remedy that mitigates short and long term threats to public health and the environment. The greater protection afforded by this remedy over Alternative 12 justifies the additional cost, and is therefore, the most cost-effective alternative. Comment 6 There have been 12 cases of meningitis in the area within a month when the river flooded. Are these cases linked to pollutants from the Sikes site? EPA Response No. Carl Hickam of the Centers for Disease Control (CDC) contacted Mark Canfield of the Harris County Health Department on meningitis cases in the county. Although meningitis cases are elevated in Harris County, data do not suggest an excessive number of cases for Crosby. Those cases that have been reported (there have been three in Crosby this year) appear to be linked to virus/vector borne routes, not flooding of the Sikes site. Comment 7 Local residents wanted to know if any contaminated sand from the Love Sand Pit (adjacent to the site) had been sold. EPA Response To the Agency's knowledge no contaminated sand has ~een sold. The owners of the Love Sand Pit have been requested not to sell any sand from an area in the pit that showed evidence of leaching of contaminants. Mr. Love agreed verbally with the request and there is no evidence to show that he has not been complying with this. The Texas Water Commission sampled sand thought to be bought from this company and found no evidence of contamination. Comment 8 " 0""'0; Why doesn't EPA require the county to condemn the land, making access difficult, and making it unnecessary to remove or treat the waste? EPA Response This essentially implies a no action response, which does not adequately protect human health and the environment. Although direct contact with contaminants may be minimized for a short while. the long term security of the site is still questionable. Furthermore. by not removing the waste you risk further contamination of the groundwater as well as migration of ------- 7 Comment 9 Several commentors stated a strong preference for biodegradation and wanted to know why it was not considered as an alternative. EPA Response Biodegradation techniques were eliminated as a remedial technology for active consideration in the Feasibility Study's initial screening of technologies. Biodegradation poses several problems at this site. Heavy metals present in the waste could prove toxic to the microorganisms. It is also likely that the desired final soil concentration of 10 ppm of benzene or 1,2-dichloroethane may be well below the minimum concentration required to sustain a specialized microbal population. If this were the case, the soil would not be decontaminated to the necessary level. Landfarming or in situ treatment may not be applicable because of the siting requirements for-treatment units set forth in RCRA (40 CFR 264.271(c)). According to the regulations the maximum depth of the treatment zone must be more than three feet above the seasonal high water table, as required by RCRA regulations. Data indicates that the groundwater levels for the upper aquifer ranges from 2 to 10 feet below the ground surface. tomment 10 Where does Sikes stand on the priority list to get funds? EPA Response The inclusion of Sikes on the National Priorities Ltst allows for funding of all remedial activities. Once Superfund is reauthorized EPA will proceed with the design and construction phases. Comment 11 Have the synergistic effects of the different pollutants in East Harris County or Sikes been studied by EPA? Have the cummulative health effects of these pollutants on East Harris County residents been studied? EPA Response No. Because of the variety of different pollutants present at Sikes and in East Harris County it would be very difficult to assess the synergistic effects. Studies of a similar nature to the ones proposed in the comment have proven to be inconclusive. Instead, what EPA attempts to do is to assess the health impacts of individual sites on the nearby populace. Also, EPA's Office of Research and Development and CDC/ATSDR have begun studies on the health effects of many individual compounds present at ------- Comment 12 8 The remedial objectives proposed in the Feasibility Study appear to be . appropriate for the site, but several criteria to achieve those objectives require clarification and/or modification: A. The definition of waste is proposed as 100 ppm of polynuclear aromatic hydrocarbons (PAH), based upon clean-up criteria for a residential area. A site-specific objective for nonresidential areas (e.g. 1000 ppm PAH) would be more appropriate for the Sikes site. B. The surface water quality criteria are "average quality" requirements, and should apply to ambient water quality in the receiving streams (San Jacinto River and Jackson Bayou). The alluvial aquifer is not an appropriate drinking water supply even in the absence of the Sikes Pits, and the criterion for Objective 5 (prevent use of contaminated groundwater, upper aquifer) should be to eliminate the use of that zone as a potable water supply. c. D. The criteria to satisfy Objective 9 (minimize the potential of a~ adverse air discharge) should extend to an assessment of odorous emissions during remedial action. EPA Response The proposed criteria are appropriate for the following reasons (letters of responses match the comment letter): A. The 100 ppm PAH criteria is based on the direct contact hazard at the Sikes site. This level reflects the need to protect the many workers near and around the site and the sports fisherman that frequent the area. B. - The surface water quality criteria is a maximum limit that applies to all surface water, not just major receiving streams. c. Whether the alluvial aquifer is an appropriate drinking water supply is irrelevant and immaterial, since it is currently being used as a drinking water supply. D. Design of the remedy will be such that air emissions are minimized. After remediation the air at the site's border must meet OSHA standards at site boundary, and ------- 9 Comment 13 The volume and characteristics of the wastes at the site have not been sufficiently defined. A. The current waste volume estimates could be low by a factor of ~hree. "Miscellaneous" sludge volume estimates could be signifi- cantly in error, since the aerial extent and depth have not been fully determined, and no data are available regarding PAH concen- trations in underlying soils. Also, further investigation may identify other significant sources of sludge. No current estimates are available for the volume of additional sludge that might be found, leaving additional contingency in the total amount of sludge to be managed under the FS alternatives. B. The Tank Lake and Slough sediments should not have been included in the FS sludge volume because they do not meet the FS definition of either sludges or contaminated soils. EPA Response EPA disagrees. The Remedial Investigation report provides a fully sufficient evaluation of the waste volume and characteristics needed to .decide upon a remedy. A. The FS states, in detail, how waste volumes were calculated. Sludges were identified as waste containing greater than 100 ppm PNAs. The depth of contaminated soils is equal to the depth where a single volatile organic is present at a concen- tration equal to or greater than 10 ppm and where total PNA's are less than 100 ppm. The concern over the determination of aerial extent and depth could have arisen from an inaccurate chemical analysis found in Table 1-2 of the FS. The analysis presented does fit the definition of sludges given in the FS and has led to the impresssion that underlying soils of the main waste pit are really sludges, and that there are addi- tional contaminated soils beneath the sludges that have not been accounted for. However, none of the chemical analyses given in Tables 1-1 and 1-2 representing sludges and contaminated soils were used to estimate waste quantities, therefore this would not have changed the numbers. Sampling and waste quantification were executed on a priority basis related to known or most probable areas of waste deposits. Further sampling was not performed because the size of the site (185 acres) rules out the feasibility of fully determining the compositions and quantities of all site wastes. This would not be a cost effective objective for the RI. However, enough contingency was added into the waste volume estimates that it should fall into the acceptable range for feasibility cost ------- 10 B. The chemical composition of Tank Lake sediments shown in Table 1-1 of the FS indicates as claimed that Tank Lake sediments do not classify as sludges or as contaminated soils. However, this is due to an error made in the FS. The concentration shown for benzene of 1400 ppb was misread as 14 ppm, and not 1.4 ppm as it . really is. For this reason, this analysis was originally shown in Table 1-2, as representing contaminated soils in Tank Lake. None of the chemical analysis for Tank Lake sediments show it satisfies the FS definition of sludge, but based on the analysis for a composite sample, Tank Lake sediments do classify as contaminated soils. Comment 14 The RI and FS documents characterizing the Sikes Disposal Pits do not provide sufficient data to conclude that incineration is technically feasible or cost effective as a remedial action. EPA Response EPA disagrees. Sufficient data was developed in the RI to establish .the technical feasibility of utilizing incineration, either onsite or offsite, as a remedial technology. Incinerator construction costs, operating parameters and efficiency are well documented and the type of waste materials identified have been disposed of by commercial incineration for years. Sufficient data is presented in the FS to determine the feasibility of incineration as part of an overall remedial plan. Additional physical data will be developed during the design phase to provide the specific needs of a detailed assessment of incineration. Whether incineration is cost effective or not doesn't depend only on collecting more waste samples for physical character- ization, but is determined by blending many factors into a comparative analysis of alternate technologies. . Comment 15 The soil decontamination criterion for Objective 1 (prevent human contact with contaminated soils and wastes) based upon 100 ppm Polynuclear Aromatic Hydrocarbons will provide more than adequate protection to human health and the environment for the area. Additional criteria for soil decontamination based upon the simplified model in Appendix D of the FS are unnecessary. EPA Response The goal of the 10 ppm benzene or 1,2-dichloroethane decontamination criteria is necessary to restore the upper aquifer to drinking water quality within 30 years following the completion of remedial action. Using the site characteristics ~o develop the model, it was determined that the 10 ppm criteria was the level of cleanup required to attain the 30 year objective.. If the site were not cleaned-up to this level, then it is highly feasible that a groundwater remediation would be ------- 11 Comment 16 A 100-year flood protection dike surrounding the entire site, as . suggested in the FS, is unnecessary and would cost $5 million. The flood protection dike need only protect the areas of the site in which a remedial program could be significantly impacted due to flooding which results in equipment damage or contaminant dispersal. EPA Response Total protection of the area used during remediation is necessary due to frequent flooding of the site. However, the dike cost estimated in the FS is approximately $1.5 million, not $5 million. The costs used to calculate this amount were taken from Average Low Bid Unit Costs published monthly by the State Department of Highways and Public Transportation. Costs for District 12, Houston and surrounding area, in the January 1986 issue were used. Comment 17 The wastewater treatment system is under-sized for those alternatives which require excavation of the pits without groundwater migration .controls. The basis for this argument is a calculated flow rate of 350 gpm for groundwater. The flow rate in the FS is 80 gpm. If alternative 12 (cap and slurry wall) were performed less groundwater would need to be treated, making this method even more economical. EPA Response EPA disagrees. The expected flow rate of groundwater into Tank Lake during excavation of sediments was the basis for sizing the water treatment system. This flow was estimated by two methods. First, the flow rate was calculated from permeability, differential head, and side wall area. This method produced a flow rate of 80 gpm. The second method was to use the flow of groundwater infiltrating Lovels large sand pit south of the slough (the wall area and depth of this pit was estimated as being equal to or greater than that of Tank Lake). The discharge of water from this pit was estimated to be less than 50 gpm. The 80 gpm flow rate was used so that the worst case cost estimate would be produced. The difference between the 350 gpm flow rate mentioned in the comment and the 80 gpm flow rate calculated in the FS is due to the permeability values used. The permeability used for the 350 gpm calculation (2.5X10-3 cm/sec) represents a single point value from a well located upgradient and in a clean area. An average of well permeabilities located close to Tank Lake would have yielded a more realistic flow ------- 12 The same volume of contaminated groundwater was used for costing all alternatives. Although the volume of water to be treated would probably be less for Alternative 12 than for the preferred alternative, this would not make Alternative 12 more cost effective. Comment 18 The time allocated to environmental permitting, design, procurement, and construction of incineration facilities in the FS (i.e. one year) is insufficient. EPA Response If the above comment were accurate it would be true. However, implementation time referred to accounts for only the construction period, as defined in the FS. It is anticipated that mobilization of the incinerator would be completed during the one year time period required for dike construction. The design of the incinerator will have occurred previous to this. Also, according to CERCLA, 40 CFR Part 300.68 (a) (3), Federal, State, and local permits are not required for fund financed remedial action or remedial actions taken pursuant to Federal action under Section 106 of CERCLA. "Comment 19 In the event substantial volumes of additional sludge are found, the onsite incineration option could include two subcategories. These sub- categories include: increasing the incinerator size (or number of incineration trains) to incinerate all sludges with)n the designated 3 years; or, extending the implementation schedule to accomodate larger waste vo 1 umes. EPA Response EPA does not feel there will be a substantial volume change from that estimated in the FS, for the reasons stated in the response to Comment 11. However, if greater. amounts"....of waste are found, it would be the Agency's choice to bring in more incineration trains to accomplish the cleanup in the given amount of time. Comment 20 The implementation schedules for all alternatives considered (except the no action alternative) should be adjusted to reflect realistic time requirements. These adjustments to schedule will have a significant impact upon present value costs of implementing the various alternatives. EPA Response The assumption that the time reQuirements are unrealistic is based on the statements in Comments 13 and 18 regarding volume of wastes and time allocated for permitting~ design, procurement, and construction of ------- . . 13 drastically underestimated, and the comment regarding construction time was invalid, no adjustment to the schedule is required. Comment 21 The Feasibility Study states that there appear to be trace quantities of one or more vac's, including benzene, chlorobenzene, 1,1-dichloroethane, 1,2-dichloroethane, and vinyl chloride in the lower aquifer; however, Table 1-9 of the FS indicates that none of these substances were detectable in the lower aquifer. There is also a statement that polynuclear aromatics (PNA's) are at two times the concentration in the main waste pit as in the small pit. Analytical results in table 1-1 do not support this statement. EPA Response The data in Table 1-1 of the FS does show that for most individual PNA's, the ratio is about two times the concentration in the main waste pit as in the small waste pit. The analysis listed in Table 1-9 of the FS represents an upgradient water sample, taken in July 1985, for setting background water quality criteria. The contamination mentioned in the comment has been detected intermittently in the lower aquifer in concen- .trations below the Human Health Standards (10-5 risk level) in wells both upgradient and downgradient of the site. This data indicated the trace contamination was not from the site, and therefore, was not be considered in the remedy. Comment 22 There has not been a consistent approach in assessing feasible remedies throughout the FS. For example, among the objectives for remediation established by EPA are: to minimize site-related degradation of the San Jacinto River and the Jackson Bayou. Another objective is to prevent use of contaminated groundwater from the upper aquifer. The.Feasibility Study states in numerous places that there is no evidence of any degradation of the San Jacinto River and Jackson Bayou from the site and there is also no evidence of any contaminated groundwater offsite in the upper aquifer. EPA Response EPA disagrees. There is currently no evidence of migration of contaminants offsite that would lead to the stated degradation. However, this migration will occur if appropriate actions are not taken to meet the objectives. Comment 23 An alternate water supply can be provided for the Riverdale subdivision; this would eliminate human exposure to potentially contaminated ground- water in the vicinity of the Sikes site. This means the lower aquifer would not have to be cleaned up and a less stringent soil removal criteria ------- 14 EPA Response Even if an alternate water supply were provided, there would be no way to prevent continued use of the upper aquifer. With some of the wastes still in place the upper aquifer would continue to be contaminated, possibly leading to contamination of the lower aquifer. Also, the State of Texas may not have institutional controls that could prevent the use of the upper aquifer. Comment 24 Natural and enhanced soil degassing are proven remediation techniques, but these alternatives were not thoroughly tested and evaluated for the Sikes site. EPA Response Natural and enhanced soil degassing were not considered because they are not viable technologies for remediation of the Sikes site. Soil degassing is usually effective when used on sandy soils that have been contaminated with volatile organics, such as the case with the Sikes Disposal Pits site. However, this technology is not effective when water saturated soils are involved, which is also the case at this site. This method •cannot be used on sludges, and does nothing to remedy heavy metal contamination. If this technology were used on the contaminated soils in spite of the high water table, a separate remedy would still have to be designed for disposing Qf the sludges and soils contaminated with inorganics and non-volatiles. This makes it a very impractical remediation technique ------- |