United States Environmental Protection Agency Robert S. Kerr Environmental Research Laboratory Ada OK 74820 Research and Development EPA-600/S2-84-162 Dec. 1984 &EPA Project Summary Closure Evaluation for Petroleum Residue Land Treatment Leale E. Streebin, James M. Robertson, Alistair B. Callender, Lynne Doty, and K. Bagawandoss Three oily residue land treatment sites to which no waste applications had been made for six months, nine months, and six years, respectively, were sampled to define existing condi- tions. Runoff, zone of incorporation (0- 25 cm), and unsaturated zone (26-152 cm) samples were collected at each site during the 15-month study period. A considerable variation in residual oil content existed at the three sites. Site 2, a well-managed operating site which had received no waste for six years, had a residual oil concentration of 2-3 wt.% in the zone of incorporation. Sites 1 and 3, which had received waste applica- tions within the 12 months previous to this study, contained 5-6 and 8-9 wt.% residual oil, respectively-, Oil concentra- tions greater than background were detected as deep as 45-50 cm at all sites with the highest concentrations being found at site 3. Average concen- trations of oil in soil remained relatively constant at each site during the study period; however, large variations in oil content of individual core samples were found within each site. Possible con- tributing factors to this apparent lack of degradation were extended periods of extremely wet or dry soil, low available soil nitrogen levels giving extremely high carbon-to-nitrogen ratios, and the presence of persistent hydrocarbons. Thirteen or more organic priority pollut- ants were identified in samples collected at each site; however, only trace quan- tities were found below the zone of incorporation. Several of these priority pollutants also were identified in ad- jacent soil backqround samples. Metals were immobilized in the top 25 cm of soil at all sites. Soil and soil pore water at each site contained high chloride levels. Site 2 supported a lush growth of vegetation while sites 1 and 3 supported little or no vegetative growth. Vegetation studies revealed that grass- es were more tolerant than tree seed- lings when planted in areas having an oil content of 5-6 wt.%. Root development was inhibited at levels of 4-5 wt.%. In areas having an oil content of 9-13 wt.%, survival rates for both were very low. This Project Summary was developed by EPA's Robert S. Kerr Environmental Research Laboratory, Ada, OK, to an- nounce key findings of the research project that is fully documented in a separate report of the same title (see Project Report ordering information at back). Introduction Land treatment as a disposal method for petroleum residues from oil refinery operations has become popular in recent years, although the technique has been in use for 15 to 20 years. Several studies have been performed to determine the fate of the oil and metals at active land treatment sites. However, few studies have been carried out at closed sites to see if a long-term threat to ground water exists. The purpose of this study was to identify the potential long-term environ- mental impacts of immobilized metals and persistent organics at closed land treatment sites to which previous appli- ------- cations of petroleum residues had been made. Both the zone of incorporation (0-25 cm) and the unsaturated zone (to a depth of 152 centimeters) were monitored for contaminants at each site selected for study. Soil and runoff samples from each site were analyzed for oil content, metals, and selected organic pollutants. Other parameters monitored included: pH, cat- ion exchange capacity, soil texture, soil permeability, soil structure, nitrate and phosphate levels, and chloride ion con- centrations. A revegetation study was carried out at one of the sites to identify grasses or trees which would grow at land treatment sites and possibly aid in site recovery. Experimental Procedures Approach Three oil refinery land treatment sites in Oklahoma were selected for this study. Inactive land treatment areas to which no waste had been applied for six months (site 3), nine months (site 1), and sixyears (site 2) were studied. Soil samples from depths from 0-25 cm and 25-51 cm were analyzed for oil content, metals, TOC, COD, pH, nutrients, chlorides, cation exchange capacity, and selected organic compounds. Soil core samples from the unsaturated zone at depths from 51 -152 cm were analyzed for oil content, metals, and selected organic compounds. Soil pore water samples from a depth of 1.2 m were analyzed for oil content, metals, TOC, COD, and selected organics. The 0-25 cm depths were sampled because the till zone usually extends to a depth of about 25 cm at most operating land treatment facilities. The 25-51 cm depth was sampled because analyses of preliminary samples at these sites showed the presence of oil in some areas. Soil samples from the deeper unsatu- rated zone were analyzed to determine if any migration of pollutants had occurred. Samples of soil pore water were analyzed as a part of the unsaturated zone monitor- ing program to identify any pollutants which might pass through the unsaturat- ed zone. Oil content of the 0-25 cm and 25-51 cm zone samples was determined at selected intervals during the 15-month sampling period in an attempt to deter- mine rates of degradation of residual oil following site closure. In addition, a part of each site was tilled to see if tilling Table 1. Organic Compounds Identified in Soil at Land Treatment Sites Site 1 Site 2 Site 3 Anthracene Phenanthrene Fluoranthene Pyrene Naphthalene Chrysene Benzo(b)fluoranltiene Benzo(a)anthracene Benzo(a)pyrene Dibenzofa. hjanthracene Benzofg, h, ilperylene Isophorone Bis(2 -ethylhexyl)phthalate Butylbenzylphthalate 1,2- diphen ylhydrazine Phenol Pentachlorophenol 4-Nitrophenol 2-Nitrophenol 2. 6-dinitrotoluene Benzene Toluene Ethylbenzene Bromoform X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X "x" denotes compound which was present. enhanced the rate of degradation. No nutrients were added to the site soils during the study, except in those areas used for the revegetation study. The revegetation study was conducted to identify trees or grasses that would grow in oily soil to aid in the recovery of land treatment sites. The revegetation study was conducted only at research site 3. The growth characteristics of five tree species and four grass species were observed for one growth season. Site Characteristics The site soils were tested for selected priority pollutants. The compounds ident- ified at each site are listed in Table 1. The priority pollutants present were primarily polynuclear aromatics and phenolics. The soil at each site was sampled periodically over a 15-month period. A subarea at each site was tilled so that the rate of residual oil degradation in the tilled and the unfilled sections could be compared and evaluated. Oil concentra- tions present in different core samples at each site indicated that a considerable variation in the oil content occurred across the site. The mean oil content concentration in the top (0-25 cm) and bottom (25-51 cm) layers of soil at the three sites is shown in Table 2. The residual oil content at site 2 (2-3 wt.%) was significantly less than that at site 1 (5-6 wt.%) which was significantly less than site 3 (8-9 wt.%). Waste had not been applied at site 2 for approximately six years while sites 1 and 3 had received waste applications within the previous 12 months. No apparent degradation of residual oil occurred at any of the sites during the 15-month study period, which might be attributable to several noticeable factors: (1) the large variation in oil content for sajnples collected within any one site indicate poor application, mixing and/or sampling techniques; (2) during the project period, no nitrogen fertilizer was added to produce a carbon-to-nitro- gen ratio more favorable for sustained microbial activity; (3) adverse weather during the project produced long periods ------- Table 2. Oil Content Data— Means Site 1 Date *Background Top * Background Bottom 4/8/82 Top Bottom 12/1/82 Top Bottom Site 2 'Background Top 'Background Bottom 4/6/82 Top, tilled Bottom, tilled Top, unfilled Bottom, unfilled 7/8/82 Top, tilled Bottom, tilled Top. unfilled Bottom, unfilled 11/19/82 Top, tilled Bottom, tilled Top, unfilled Bottom, unfilled 2/16/83 Top, tilled Site 3 "Background Top "Background Bottom 3/26/82 Top Bottom 6/7/83 Top Bottom "Mean of all background concentrations. of saturated or dry soil conditions either of which might have inhibited microbial activity; and (4) the residual oil at each site contained a relatively high content of high-molecular-weight organic corn- Mean Std Dev. % 0.56 0.13 4.90 0.64 5.62 1.85 0.43 0.40 2.63 0.78 2.95 " 2.58 1.08 2-60 1.17 2.93 1.46 2.65 1.08 2.97 0.57 0.10 8.7 2.7 9.03 5.1? 0.30 0.06 1.52 0.35 2.33 1.40 .152 0.10 0.96 0.37 0.52 " 0.95 .33 1.72 0.58 1.46 1.31 1.67 1.14 1.70 0.50 0.0 2.90 4.57 4.85 4.62 pounds which are more Variance 0.090 0.003 2.30 0.12 5.45 1.96 .023 0.01 0.92 .14 0.28 " 0.902 0.11 2.97 0.34 2.14 1.72 2.79 1.29 2.89 0.25 0.00 8.42 20.85 23.56 21.42 resistant to biotransformation. The effect of degradation was tilling on evaluated the rate of at site 2. A statistically significant change in the oil content of the tilled vs. unfilled sections could not be detected over a 14-month period. Potential degradation might have been inhibited by low nitrogen levels. Waste had not been applied to this site for over six years. Oil was still present in some locations at concentrations above background; however, the site soil sup- ported a dense growth of lush vegetation. The concentration of selected heavy metals in the soil at the sites was compared to background concentrations. At all sites, metals were present at levels above background. There was consider- able variability in the metal concentration across the sites, as with the oil content concentrations. The actual concentra- tions of metals were low. The metals were concentrated in the top 25 cm of soil, with little or no vertical migration. Soil acidity at the top (0-25 cm) and the bottom (25-51 cm) of site soil was deter- mined to indicate the potential for solubil- ization of metals. The range of pH was from 7.1 to 7.5 at all sites. The chloride ion concentrations of the site soils were higher than background at all three sites (Table 3). Only one set of determinations were made, so variation over time could not be observed. However, since the chloride ion concentration of the soil pore water decreased with time. the same trend could be expected for soil chloride ion concentration. Total Organic Carbon (TOC) values for the sites are given in Table 4. The TOC values in the top (0-25 cm) of soil at all the sites were greater than background. The bottom (25-51 cm) sample at site 3 had greater TOC values than background. At site 2 the top sample had a higher TOC than background. Sites with the higher oil contents had correspondingly higher TOC values. The oil at site 3 extended well below the zone of incorporation. This correlated with the high TOC values of the bottom sample at site 3. The unsaturated zone at each of the three sites was monitored for pollutants by core sampling below the zone of incorporation at depths between 51 cm and 1 52 cm, and by collecting pore water passing through the unsaturated zone. Water passing through the unsaturated zone contained amounts of chloride (from 1 2 mg/l to 5,000 mg/l), and extractable oil and grease. Some metals appeared to be solubilized under the existing condi- tions at these sites. Even though the pH of the soil pore water and the soil in the top 51 cm was usually above 7.0, barium. zinc, iron, and manganese were all at fairly high concentrations in the soil pore water. 3 ------- Table 3. Soil Chloride Concentration Date Top Mean CT Concentration (mg/kg) Bottom Bkg T Bkg B Site 1 6/30/82 Site 2 7/8/82 Site 3 11/4/82 119.6 28.0 72.6 103.3 33.1 101.5* 17.6 137 19.8 *Mean of 2 determinations Table 4. Soil TOC Date Top Mean TOC % Bottom Bkg T Site 1 11/10/81 Site 2 7/21/81 11/12/81 Site 3 11/17/81 10.4 3.6 5.2 11.2 1.5' 2.6 0.9 6.7 2.0 1 1 0.8 1.4 *Mean of 2 values. Table 5. Organics Present in Unsaturated Zone Cores Compound Site 1 Site 2 Acenaphthene 1,2-Diphenylhydrazine 2,4 Dinitrotoluene Anthracene Bis(2-ethylhexyl)phthalate Isophorone A cenaphthylene Fluorene Diethylphthalate Butylbenzylphthalate 2-Nitrophenol 4-Nitrophenol 2.4-Dichlorophenol Phenol Phenanthrene Pyrene Chrysene Benzo(a)anthracene Benzo(b)fluoranthene Benzo(k)fluoranthene Benzofa)pyrene 2.6-Dinitrotoluene Di-n-butylphthalate 15.4 2.9 7.3 BkgB 1.3 0.5 0.3 0.3 Site 3 x x x x x x x x x The soil pore water also contained high levels of TOC and COD. The average COD/TOC ratio ranged from 3.2 to 3.5. At site 1 the COD values ranged from 400 to 2420 mg/l initially, then decreased with time. The COD at site 2 ranged from 335 to 990 mg/l initially and also decreased with time. An exception which did not follow the typical trend occurred at site 3, where the COD values first decreased and increased again toward the end of the research period. Evidence for significant migration of oil or metals into the soil of the unsaturated zone (below 50 cm) was not found. Indications are that there was movement of trace quantities of organic priority pollutants into the unsaturated zone. The soil cores samples from the unsaturated zone contained some priority pollutants at concentrations in the low ppb range. More priority pollutants were present in the soil cores than in the soil pore water at sites 2 and 3, but not at site 1. The compounds identified in deeper soil cores and the soil pore water were generally different compounds and are listed in Tables 5 and 6. Several of these same compounds also were identified in back- ground samples. The site soils were characterized for texture, permeability, X-ray diffraction, and cation exchange capacity. Composite samples from each site and from areas adjacent to the sites were analyzed. Grain size distribution for the soils were determined in accordance with ASTM designation 0422-63(72) or AASHTO designationT-88-78. Site 1 was a silty loam, site 2 a sandy loam, and site 3 a clay. Standard laboratory permeability tests were performed on samples of the top 25 cm of soil. No significant difference between the permeability of the back- ground soil and site soil was observed at any of the sites. The X-ray diffraction analysis showed some changes in the soil structure. There was a masking of the montmorillonite and chlorite peaks. One explanation is that the oily residues penetrated the interplanar structures of the clays. There were changes in the intensities of the calcite, feldspar, dolomite, and quartz peaks. Generally, the major peaks either remained the same or diminished in intensity with increasing oil content. The exception to this trend was the calcite peaks which generally increased in in- tensity with increasing oil content. The cation exchange capacity of both site and background soils was determined using the ammonium saturation method. At sites 1 and 2, there was an increase in ------- Table 6. Organics Present in Soil Pore Water Compound Site 1 Site 2 Site 3 Phenol 4-Nitrophenol Pentachlorophenol Chrysene Bisl2-ethylhexyl)phthalate Di-n-butylphthalate Table 7. Characteristics of Site Runoff Site No. 1 2 3 COD (mg/l as Ot) 120 5 540 roc (mg/l as C) 18 <5 495 Oil and Grease (mg/l) 8.4 10.8 35.8 Site 1 - unfilled, no grass cover. Site 2 - unfilled, grass cover. Site3 - tilled. CEC where oil was applied to the soil. However, at site 3, the CgC of site soil was lower than the background soil. Runoff Runoff samples were collected to de- termine if runoff from closed land treat- ment sites contained hazardous constit- uents. A 25-year, 24-hour storm for the region was simulated. The COD, oil, and grease data (Table 7) show that the runoff from tilled areas contained more organic material than unfilled areas. Runoff from the tilled areas was in contact with the oily soil for a longer period because the tilled area was more porous. Aluminum and iron were in runoff from all three sites at higher concentrations than that of applied water. Revegetation The revegetation study involved both field and laboratory (environmental cham- ber) testing. Trees and grasses were planted at site 3 and monitored for growth and development characteristics for one season. The trees planted were black locust (Robinia pseudoacacia), hackberry (Celtis occidentalis), osage orange (Mac- lura pomifera), red cedar (Juniperus virgin/ana), Russian olive (Elaeagnus angustifolia). The grasses planted in the field were: bermuda grass (Cynadon dactylon), colonial bentgrass (Agrostis tenuis). crabgrass (Digitaria sanguinalis), weeping lovegrass (Eragrpstis curvula). The field site was divided into two oil level sections. One contained moderate amounts of oil (5-6%) and the other heavy amounts (9-13%). A control site which contained no oil was also established. Tree seedlings were placed in holes with a mixture of peatmoss and soil from the control area. Th is was to buffer the young roots from adverse effects of the waste until they were better established. The grasses were planted by broadcasting seed onto beds of processed cow manure and wheat straw. Bermuda grass was sprigged. Crabgrass seed and bermudagrass sod were used for both environmental cham- ber and field studies. With the exception of one red cedar, all trees in the heavily oiled area failed to survive. The survival rate was greater in the moderately oiled soil; however, the trees that lived were stunted. Red cedar trees showed best tolerance. Their ability to tolerate heat and drought was reflected by a higher survival rate. Crabgrass and bermudagrass grew best in the field. There was a germination delay and, biomass production when compared to the control soil. Oil and volatile waste products in the site soil are suspected to be responsible for the growth abnormalities. Heavy amounts of oil had adverse effects on the vegetation. Drought resist- ant species fared best in the dry, hot climate. In addition to the species planted, a few native plants were observed grow- ing in lightly oiled (1 -5%) sections of the land treatment site. Conclusions 1. Sampling procedures at land treat- ment sites must be carefully de- signed, since there can be consid- erable variability in oil concentra- tions across a site. 2. Management of closed land treat- ment sites, i.e., nutrient addition, etc., should continue following the last waste application until biotrans- formation of all organic hazardous constituents has occurred. 3. Some vertical migration of oil may occur at the land treatment sites, but this migration probably will not extend below 50 cm of the surface. In this study, no oil was present in the soil between 50 and 150 cm at any of the three sites. 4. Persistent organic priority pollut- ants in oily residue land treatment site soils consist primarily of high- weight polynuclear aromatic com- pounds. If management of closed sites is not maintained, movement of these pollutants into the unsatu- rated zone may occur. 5. Reduction of the oil content at land treatment sites to background lev- els may not be possible. One site in this study had been well managed, had no residues applied for six years, and supported profuse vege- tative growth; yet this site still had an average oil content level be- tween 2.5 and 3 percent. Thus, it may be more practical to reduce pollutant levels to the point where inhibition of vegetative growth and leaching, air emissions, or surface runoff of hazardous constituents are no longer problems. 6. If proper pH management is main- tained, metals in land treatment site soils should be immobilized in the top 25 cm of the soil. 7. Volatile hydrocarbons may be emit- ted during the tilling process for an extended period of time after waste application has ceased. 8. Vegetative cover reduces the po- tential for contamination of runoff with site pollutants. Grasses pro- vide the best vegetative cover. A ground cover using grasses can be established at oil concentrations of 4 to 5 wt.%; however, root develop- ------- ment and crop yield may be signifi- cantly inhibited. 9. Closed oily residue land treatment sites should be tilled at frequent intervals and nutrients applied until the oil concentration has decreased to a maximum of 3 percent prior to attempting to establish a ground cover using forage crops (grasses). This report was submitted in fulfillment of Cooperative Agreement No. CR 807- 936010 by the School of Civil Engineering and Environmental Science, University of Oklahoma under the sponsorship of the U.S. Environmental Protection Agency. This report covers a period from November 1980 to July 1983 and work was com- pleted as of June 1983. LealeE. Streebin, JamesM. Robertson. A list air B. Cat'lender, LynneDoty, andK. Bagawandoss are with the University of Oklahoma, Norman, OK 73019. Don H. Kampboll is the EPA Project Officer (see below). The complete report, entitled "Closure Evaluation for Petroleum Residue Land Treatment." (Order No. PB 85-115 822; Cost: $ 19.00. subject to change) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Robert S. 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