\ I/ United States Environmental Protection Agency Robert S. Kerr Environmental Research Laboratory Ada OK 74820 Research and Development EPA/600/S6-86/003 Feb. 1987 Project Summary Waste-Soil Treatability Studies for Four Complex Industrial Wastes: Methodologies and Results, Volumes 1 and 2 R. C. Sims, J. L. Sims, D. L. Sorensen, W. J. Doucette, and L. L. Hastings The full two-volume report presents In- formation pertaining to quantitative evalu- ation of the soil treatment potential re- sulting from waste-soil interaction studies for four specific wastes listed under Sec- tion 3001 of the Resource Conservation and Recovery Act (RCRA). Volume 1 con- tains information from literature assess- ment, waste-soil characterization, and treatability screening studies for each selected waste. Volume 2 contains results from bench-scale waste-soil interaction studies; degradation, transformation, and immobilization data are presented for four specific wastes: API separator sludge, slop oil emulsion solids, pentachlorophenol wood preserving waste, and creosote wood preserving waste. The scope of the study involved assessment of the poten- tial for treatment of these hazardous wastes using soil as the treatment medium. The experimental approach used in this study was designed to characterize de- gradation, transformation, and immobiliza- tion potentials for hazardous constituents contained in each candidate waste. For each waste and soil type, treatment was evaluated as a function of waste loading rate, soil moisture, and time. Combinations of selected chemical analyses and bio- assays were used as endpoints to char- acterize treatment. Methodologies were developed for the measurement of specific soil treatment parameters including "volatilization- corrected" degradation rates and for measurement of partition coefficients among waste, water, and air phases of a waste-soil matrix. Partitioning between the water soluble extract of the waste-water- air mixture and soil was evaluated by con- ducting soil isotherm studies using the water soluble extract. These parameters provide input to the proposed U.S. En- vironmental Protection Agency (EPA) Reg- ulatory and Investigative Treatment Zone (RITZ) model developed to assess treat- ment potential for potentially hazardous organic constituents in soil. This Project Summary was developed by EPA's Robert S. Kerr Environmental Research Laboratory (RSKERL), Ada, OK, to announce key findings of the research project that is fully documented in a separate two-volume report of the same title (see Project Report ordering informa- tion at back). Introduction Land treatment (LT) is defined in RCRA as the hazardous waste management technology pertaining to application/incor- poration of waste into upper layers of the soil for the purpose of degrading, trans- forming, and/or immobilizing hazardous constituents contained in the applied waste (40 CFR Part 264). Soil systems for treatment of a variety of industrial wastes have been utilized for many years; al- though, application of hazardous industrial waste to soil utilizing a controlled engine- ering design and management approach has not been widely practiced. This is due, in part, to the lack of a comprehensive technical information base concerning the behavior of hazardous constituents in the soil treatment zone as specifically related ------- to current regulatory requirements (40 CFR Part 264) concerning treatability, i.e., degradation, transformation, and immobil- ization of such constituents. Soil treat- ment systems that are designed and managed based on knowledge of waste- soil interactions may represent a signifi- cant technology for simultaneous treat- ment and ultimate disposal of selected hazardous wastes in an environmentally acceptable manner. This treatment con- cept also may be useful during remedial activities at certain contaminated soil sites. In this research project, representative hazardous wastes from two industrial categories, wood preserving and petro- leum refining, were evaluated as to the potential for treatment in soil systems. A literature assessment for each waste cat- egory was conducted as an aid in the pre- diction of soil treatment potential. The literature review also was used as a guide for design of an experimental approach for obtaining specific information pertaining to degradation, transformation, and im- mobilization of hazardous waste constit- uents in soil. Standards were promulgated in 40 CFR Part 264.272 for demonstrating treatment of hazardous wastes in soil. These stand- ards require demonstration of degradation, transformation, and/or immobilization of a candidate waste in the treatment zone soil. For the purposes of this research, demonstration of degradation of waste constituents was based on the loss of parent hazardous organic compounds within the waste-soil matrix as opposed to "complete" degradation, which is the term used to describe the process where- by waste constituents are mineralized completely to inorganic end products, i.e., carbon dioxide, water, and inorganic species of nitrogen, phosphorus, and sulfur. Rates of degradation were estab- lished by measuring the loss of parent compounds from the waste-soil matrix with time. Transformation refers to partial alteration of hazardous compounds in the soil, thereby converting a problem waste or substances into innocuous or environ- mentally safe forms. In this context, trans- formation refers to formation of inter- mediate products during waste-soil inter- actions (i.e., physical, chemical, and/or biological mechanisms); some intermedi- ate products may become refractory com- pounds in the soil matrix. Immobilization refers to the extent of retardation of the downward transport (leaching potential) and upward transport (volatilization poten- tial) of waste constituents. The transport potential for waste constituents from the waste to water, air, and soil phases is af- fected by the relative affinity of the waste constituents for each phase, and in this project was characterized in column and batch reactors. Therefore, an acceptable demonstration of soil treatment involves an evaluation/quantification of degrada- tion, transformation, and immobilization processes, in order to obtain an integrated assessment of design and management requirements for successful assimilation of a waste in a soil system. Demonstration of the potential for treat- ment of a particular hazardous waste in soil can be addressed using several ap- proaches. Information can be obtained from several sources, including literature data, field tests, laboratory analyses and studies, theoretical parameter estimation methods, or, in the case of existing land treatment units, operating data. In this pro- ject, specific information obtained from literature sources included quantitative degradation, transformation, and immobi- lization data for identified waste-specific hazardous constituents in soil systems. Due to the current lack of a comprehen- sive technical information base, the U.S. EPA considers the use of literature infor- mation only as insufficient to support demonstration of treatment of hazardous wastes in soil at the present time. Specific objectives of this research pro- ject were to: (1) Conduct a literature assessment for each candidate hazardous waste (API separator sludge, slop oil emul- sion solids, creosote wood preserv- ing waste, and pentachlorophenol (PCP) wood preserving waste) to obtain specific information pertain- ing to degradation, transformation, and immobilization in soil of hazar- dous constituents identified in each waste. (2) Characterize candidate wastes for identification of specific constitu- ents of concern; and characterize experimental soils for assessment of specific parameters that influence soil treatability potential. (3) Conduct laboratory screening ex- periments using a battery of bio- assays to determine waste loading rates (mg waste/kg soil) to be used in subsequent longer term experi- ments designed to assess potential for treatment of each selected waste in soil. (4) Develop degradation, transforma- tion, and immobilization information for each candidate hazardous waste^ in the two soils selected for study. 1 (5) Develop methodologies for mea- surement of "volatilization-correct- ed" degradation rates and partition coefficients; use the methodologies developed to generate degradation kinetics/partition coefficients for a subset of waste-soil combinations and for those constituents common to all wastes. Objectives 1, 2, and 3 are addressed in Volume 1 of this report; objectives 4 and 5 are addressed in Volume 2. Research Approach Four listed hazardous wastes were selected for study (Table 1). The wastes chosen are produced in high volume, con- tain numerous organic and inorganic con- stituents, and represent a broad spectrum of physical, chemical, and toxicological characteristics. API separator sludge—(K051) This waste is generated from primary settling of wastewaters that enter the oily water sewer and typically consists of water, oil, and solids. Solids are largely sand and coarse silt, but also may contain significant quantities of hazardous metals, i.e., chromium and lead. Heavy oils that settle and become part of the bottom sludge in an API separator are largely com- posed of heavy tars, large mutiple branched aliphatic compounds (paraffins), polyaromatic hydrocarbons, and coke fines. Proportions of oily material which are tar-like, paraffinic or polyaromatic are largely dependent on the crude source. Slop oil emulsion solids—(K049) This waste is generated from skimming the API separator and typically consists of approximately 40 percent water, 43 per- cent oil, and 12 percent solids. Chromium and lead typically are present in significant concentrations in the solid phase. Table 1. Hazardous Wastes Selected for Evaluation EPA Hazardous Waste Waste No. Petroleum Refinery Wastes API Separator Sludge K051 Slop Oil Emulsion Solids K049 Wood Preserving Wastes Creosote K001 Pentachlorophenol K001 ------- i Creosote wood preserving waste -(K001) Creosote is a distillate from coal tar made by high temperature carbonization of bituminous coal. Creosote alone or in combination with coal tar or petroleum is a major preservative used in wood treat- ment. The principal classes of organic con- stituents present in creosote wastes are polyaromatic hydrocarbons and phenolics. Pentachlorophenol (PCP) wood preserving waste—(K001) Pentachlorophenol is widely used as a wood preservative and also has been used for slime and algae control. The combined PCP-creosote sludge used in this experi- mental investigation contained polyaro- matic hydrocarbons, phenolics, and PCP. An experimental approach was designed to test the hypothesis that treatment would be achieved for each of four listed hazardous wastes in two soil types and to evaluate the effect of selected design and management factors, i.e., waste loading, on treatment. Therefore, the scope of the study involved addressing the demonstra- tion of treatment of hazardous waste us- ing soil as the treatment medium. The soil treatment potential for each candidate waste was evaluated as a function of waste loading rate, soil moisture, and time. A combination of chemical analyses and bioassays was used to characterize end- points for degradation, transformation, and immobilization of waste constituents. Treatment of a hazardous waste refers specifically to treatment of hazardous con- stituents contained in the waste. Stand- ards identified in 40 CFR Part 264.272(c) (i) refer to Appendix VIM constituents listed in part 261. Where waste(s) are from an identified industry with well defined processes, i.e., petroleum refining, it may be acceptable to perform analyses for a subset of Appendix VIII constituents. The subset of organic constituents selected for evaluation in these waste-soil interaction studies included semivolatile polycyclic aromatic hydrocarbon (PAH) compounds and the volatile organic constituents (VOC) benzene, toluene, xylene, ethylben- zene, and naphthalene for each waste, with the addition of pentachlorophenol for the PCP wood preserving sludge. Two soil types were selected as treat- ment media to allow evaluation of the ef- fect of varying soil characteristics on the extent and rate of treatment. Soil types were chosen that (1) represented soils typical of operating land treatment facili- ties and (2) provided a range of specific characteristics for evaluating treatment as a function of soil type. Each soil selected was characterized for specific properties considered to be important in influencing soil treatment processes. The experimental waste loading rate (mass/area/application, or mg waste/kg so- il) was the first design parameter deter- mined. In order to evaluate the extent and rate of treatment, sustained soil microbial activity must be maintained. Therefore, the impact of an applied waste on indige- nous soil microbial populations must be evaluated, especially for any waste con- taining hazardous constituents specifically designed to inhibit biological activity, i.e., wood preserving wastes. In this study, a battery of microbial toxicity screening assays was used to estimate acceptable initial waste application rates for use in subsequent bench-scale waste-soil inter- action studies. A comparative study of the sensitivity of five microbial assays: Microtox, soil respiration, soil dehydrogenase, soil nitrifi- cation, and viable soil microorganism plate counts, to pentachlorophenol (PCP) and slop oil wastes in Kidman sandy loam soil was performed to evaluate response of these commonly used assays to identical waste-soil mixtures. The degradation potential of hazardous organic constituents in any waste applied to soil is critical since biodegradation usually represents the primary removal mechanism for such constituents. Degra- dation coefficient measurements involve determination of soil concentrations of specific organic constituents as a function of time. Degradation was characterized as a first order kinetic rate process for all con- stituents evaluated; the first order reaction rate constant was then used to calculate half-lives for each constituent. These calculated half-lives provided quantitative information for evaluating the extent and rate of treatment, and for comparing treat- ment effectiveness for each waste-soil combination as a function of design and management factors. Conversion of hazardous constituents to less toxic intermediates within the soil treatment medium also was evaluated. In- formation concerning the toxicity reduc- tion of the waste-soil mixture over time was evaluated using an acute toxicity assay (Microtox test), and a mutagenicity assay (Ames Salmonella typhimurium test). Evaluation of treatment also involved in- vestigation of the extent of migration of hazardous constituents contained in each hazardous waste. A loading rate based on degradation potential was selected for each waste-soil combination; leaching potential was subsequently characterized for these loading rates in laboratory column studies. Partition coefficients among waste (oil), water, and air for a subset of organic constituents also were determined for use as input parameters to the proposed Regulatory and Investigative Treatment Zone (RITZ) model that has been developed by the U.S. EPA Robert S. Kerr Environmental Research Laboratory (RSKERL). Results and Discussion Characterization and Loading Rate Selection Each waste was characterized for poly- cyclic aromatic hydrocarbons (PAH), vola- tile organic constituents (VOC), and poly- chlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) using GC/MS, HPLC, and GC instrumenta- tion. Concentrations of individual PAH compounds in the waste as determined by HPLC are presented in Table 2. Results from VOC analyses for all wastes identi- fied naphthalene as the prominent peak. No TCDD was detected (detection limit 10 ppb) in the PCP waste, although other PCDDs as well as PCDFs were identified. The highest loading rate for each waste- soil combination was evaluated for muta- genic potential using the Ames test with and without microsomal (S9) activation. With activation all four wastes exhibited a positive mutagenic potential in Durant clay loam soil. Slop oil emulsion solids and creosote wood preserving waste exhibited a positive mutagenic potential in Kidman sandy loam soil; API separator sludge and PCP wood preserving waste did not exhibit a mutagenic potential in Kidman soil. None of the wastes exhibited a muta- genic potential as measured by the Ames test without microsomal (S9) activation. All wastes exhibited a high degree of water soluble fraction (WSF) toxicity as measured by the Microtox toxicity test. Important differences in soil properties between the two experimental soils in- cluded organic carbon content (2.88%, 0.5%), pH (6.6, 7.9), and moisture at -1/3 bar (41.6%, 20%) for the Durant clay loam and Kidman sandy loam, respectively. Waste loading rates in soil as selected based on results of Microtox and soil respiration assays are presented in Table 3. The wood preserving wastes used in this project exhibited greater levels of tox- icity than the petroleum refining wastes used. Loading rates selected were gen- erally higher for the Durant clay loam than ------- Table 2. Concentration of Individual PAH Compounds in Wastes Determined by HPLC Concentration in Waste (mg/kg) * Compound Naphthalene Acenaphthalene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Benzofa)anthracene Chrysene Benzo(b)fluoranthene Benzo (k) fluoran thene Benzotaipyrene Benzo (ghi)pyrene Dibenz(a,h)anthracene Indenod, 2, 3-cd)pyrene API Separator Sludge 580 ± 87 (15%) 480 ± 100 (21%) <12 29 ± 33 (1 14%) 810 ± 140 (17%) 110 ± 27 (25%) 5,500 ± 230 (5%) 6,000 ± 440 (7%) 1,400 ± 58 (4%) 570 ± 310 (54%) <3 310 ± 62 (20%) 170 ± 73(43%) <10 40 ± 11 (28%) 61 ± 25 (41%) Slop Oil 2,500 ± 700 (28%) <15 <10 440 ± 300 (68%) 3,600 ± 2,100(58%) 480 ± 93 (19%) 18,000 ± 5,000 (28%) 23,000 ± 6,700(29%) 2,000 ± 1, 100 (55%) 1,100 ± 150(14%) 340 ± 140 (41%) 160 ± 42 (26%) 260 ± 200 (77%) 59 ± 18 (31%) 15 ± 1 (7%) 88 ± 19 (22%) Creosote 28,000 ± 1,200 (4%) 3,600 ± 1,000 (28%) 180,000 ± 40,000 (22%) 23,000 ± 5,900 (26%) 76,000 ± 15,000 (20%) 15,000 ± 6,800 (45%) 72,OOO ± 17,000(24%) 64,000 ± 12,000 (19%) 7,400 ± 1,600 (22%) 8,300 ± 2, 100 (25%) 3,OOO ± 700 (23%) 2,400 ± 460 (19%) 2,700 ± 380 (14%) 1,100 ± 280(25%) <1,200 820 ± 76 (9%) Pen tachlorophenol 42,000 ± 28,OOO (67%) <2,000 < 13,000 <22,000 52,000 ± 6,200 (12%) 1 1,000 ± 6.800 (62%) 46,000 ± 6,200 (13%) 56,000 ± 13,000 (23%) 16,000 ± 2,400 (15%) 6,900 ± 2,200 (32%) 10,100 ± 5,100 (51%) <300 <280 <100 <250 <60 ^Average concentration of three replicate analyses ± one standard deviation (coefficient of variation %). Table 3. Waste V. jste-Soil Loading Rates Selected Based on Microtox and Soil Respiration Test Results Loading Rates Kidman Sandy Loam Durant Clay Loam Low Medium High Low Medium High (% waste wet weight/soil dry weight) Creosote Pentachlorophenol API Separator Sludge Slop Oil 0.4 0.075 6 6 0.7 0.15 9 8 1.0 0.3 12 12 0.7 O.3 6 8 1.0 0.5 9 12 1.3 0.7 12 14 the Kidman sandy loam, thus indicating a difference with respect to the effect of soil type on waste-soil interactions. Results from a battery of microbial as- says conducted using PCP and slop oil wastes indicated a good correlation be- tween the Microtox, soil nitrification, and soil dehydrogenase assays. Highly variable results were obtained with soil respiration (carbon dioxide evolution) and viable plate count assays. The latter two assays ap- peared to be much less sensitive to the waste loadings used. A series of experiments were conducted to evaluate the PAH extraction procedure using the Tekmar Tissumizer. Results for spiked recoveries of 16 PAH compounds from Durant clay loam and Kidman sandy loam soils are presented in Table 4. Four concentration levels were used to bracket the range of PAH concentrations in waste- soil mixtures from the beginning (high concentration) to the termination (low concentration) of the degradation experiments. Information presented in Table 4 indi- cates consistent and generally high re- coveries for all 16 PAH compounds from both soil types. Also, recoveries did not vary greatly and were relatively high through a three-log change in soil PAH concentrations. Thus, the soil extraction procedure used in this project appeared to provide consistent and relatively high ex- traction efficiencies for both soils over the range of concentrations of concern. Treatment Results Results of degradation studies for all four wastes in both soils generally indi- cated an increase in PAH half-life with in- creasing molecular weight or compound size. This observation is generally consis- tent with results obtained in other studies for the PAH class of compounds in soil systems. However, soil half-lives for some higher molecular weight PAH compounds in these complex wastes were observed to be lower than half-lives reported in the literature for PAH compounds only, i.e., without the waste matrix. The observed variation in degradation rates and half-lives obtained for PAH constituents in these studies may be due, in part, to the diffi- culty in accurately analyzing individual constituents in soil mixed with complex environmental mixtures. These degrada- tion rates and half-lives observed in these studies may be lower, however, as a result of cooxidation/cometabolism or other matrix-induced phenomena. An increase in soil moisture content from -2 to -4 bars to -1/3 to -1 bars gen- erally was associated with a decrease in PAH compound half-life for waste-soil mixtures. Results also indicate that half-life values for constituents in each petroleum waste were similar for some compounds even though waste loading rates were different. These results would be expected if de- gradation followed first order kinetics. Half-life values for waste constituents in each wood preserving waste also were similar even though loading rates were dif- ferent. These results are similar to those observed for the petroleum wastes, and are expected if degradation processes follow first order kinetics. After the first experimental period of ap- proximately 280 days, wastes were reap- plied to the soil according to the follow- ing schedule: 1) waste originally loaded at the medium rate was reloaded at the medi- um rate (M/M); 2) waste originally loaded at the low rate was reloaded at the high rate (L/H); 3) nonacclimated soil was loaded at the high rate of waste applica- tion (N/H); and 4) waste-soil mixtures originally loaded at the high loading rate, but not reloaded (H/NR). Results from reapplication experiments were converted to first order reaction rate constants and half-life values. A subset of waste-soil mix- tures for each soil and waste type was ------- Table 4. Tissumizer Extraction Recovery Results for PAH Compounds in Kidman and Durant Soils' Kidman Sandy Loam Soil concentration in mg/kg Compound Durant Clay Loam Soil concentration in mg/kg 1000 1OO 10 1 7000 700 70 Napthalene Acenaphthalene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Benzofalanthracene Chrysene Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(a)pyrene Dibenz(ah)anthracene Benzo(ghi)pyrene lndeno(1,2,3-cdlpyrene 92.3 13.8) 89.7 14.7) 82.3 13.2) 98.0 11.01 98.7 (1.5) 98.7 1 1.5) 95.0 12.7) 106.3 13. 1) 97.0 (2.0) 95.6 (1.5) - - - - 96.0 (0.0) 82.0 (4.4) 80.0(1.7) 96.7 (0.6) 99.3 (0.6) 89.3 (1.5) 99.3 (1.2) 107.7 (0.6) 97.3 (1.2) 97.0 (1.0) 61.0 (0.0) 104.0(1.0) 75.3 (2.5) 101.7 (2.1) 91.0(0.0) 97.0 (1.0) 86.3 (14.6) 41.7 68.7 96.0 99.3 82.0 97.0 103.0 97.3 96.7 64.0 103.7 66.3 103.3 90.7 98.3 (25.5) 13.2) (1.7) (2.1) (3.0) (0.0) (1.0) (2.3) (2.1) (1.0) (1.5) (4.7) (6.4) 10.6) (1.5) - - 103.5 (5.0) 110.0 (0.0) 57.7 (2.5) 85.3 (2. 1) 73.7 (4.0) 96.3 15. 1) 94. 7 (3. 1) 87.7 (1.5) 105.0(2.7) 61.7 (3.1) 78.0 (8.5) 102.0(2.7) 100.0 (2.0) 99.0 87.3 86.7 98.7 99.0 94.3 96.0 107.0 97.3 96.7 - - - - - - (3.0) (7.2) (3.1) (0.6) (1.0) (7.2) (0.0) (2.7) (1.2) 10.6) 111.7 89.3 86.3 97.7 99.0 93.0 100.3 108.0 98.7 86.3 61.3 104.3 79.3 103.3 92.7 98.3 (5.0) (8.1) (11.2) (1.5) (1.0) (2.7) (2.3) (3.6) (1.2) (0.6) (0.6) (1.5) (0.6) (3.2) (1.2) (0.6) 158.3 (8. 1) 78.5 (5.0) 77.5 (5.0) 94.3 (4.0) 98.7 (2.5) 86.7 (3.5) 98.7 (1.5) 105.0 (5.3) 99.0(1.7) 98.0 (1.0) 63.3 (1.2) 105.0 (2.0) 61.7 (2.1) 101.3 (4.0) 90.3 (2.5) 98.3 (1.2) . - - 94.5 (7.8) 115.3 (7.2) 65.0 (5.3) 88.0 (16.5) 80.0 (24.3) 100.0 (1.4) 97.0 (1.7) 86.7 (2.1) 99.7 (2.5) 68.3 (10.0) 86.3 (2.3) 111.0 (4.6) 108.0 (0.0) * Table values represent average recoveries of triplicate extractions at each loading level with standard deviations in parentheses. selected for detailed characterization of degradation. The subset was evaluated for approximately an additional 100 days. For the petroleum wastes, reapplication did not appear to alter the half-life values for PAH constituents. Neither an inhibiting nor stimulating effect was observed. For the wood preserving wastes, there is no trend that would suggest a change in half- life with one reapplication. PAH degradation results for wastes in- cubated in Kidman sandy loam soil gener- ally followed the trend observed for waste treatment in Durant clay loam soil. PAH degradation generally appeared to be in- fluenced by molecular weight or com- pound ring size. Variation in the data ob- tained for degradation increased when waste was reloaded. Pentachlorophenol degradation also was evaluated for the PCP wood preserving waste. Kinetic information is presented in Tables 5 and 6 for PCP waste in Durant clay loam soil and Kidman sandy loam soil, respectively. Half-life values are similar (257 days and 204 days) for PCP initially loaded at the high rate in both soils and not reapplied. Acclimation of Kidman sandy loam soil to PCP may have occur- red as indicated by comparing results in Table 6 for experiments N/H and H/NR in Kidman soils. Both sets of experiments received PCP waste at the high loading rate (0.3%). However, PCP in mixtures in- cubated for 400 days (H/NR) had a half- life of 204 days, while PCP in mixtures in- cubated for 164 days (N/H) had a half-life of 330 days. Evidence for acclimation is also indicated in the experimental set (L/H) initially receiving the low loading rate (0.075%) and reloaded at the high rate Table 5. Degradation Kinetic Information for Pentachlorophenol in Pen- tachlorophenol Wood Preserving Waste Reapplied to Durant Clay Loam Soil at -1 Bar Soil Moisture Loading Rate M/M+ H/NR* r * °0 (mg/kg) 4.0E2 2.3E2 k (day- 1) 0.0016 0.0027 tl/2 (days) 433 257 after waste incorporation into soil. + M/M = originally loaded at medium rate (0.5%), reloaded at medium rate. *H/NR = originally loaded at high rate (0.7%), not reloaded. Table 6. Degradation Kinetic Information for Pentachlorophenol in Pen- tachlorophenol Wood Preserving Waste Reapplied to Kidman Sandy Loam Soil at -1/3 Bar Soil Moisture Loading Rate M/M+ L/H* N/H*" H/NR** r * °0 (mg/kg) 2.7E2 1.6E2 _ + + 1.8E2 k . (day~ 1) 0.0024 0.0046 0.0021 0.0034 t,/2 (days) 289 151 330 204 after waste incorporation into soil. +M/M = originally loaded at medium rate (0.15%), reloaded at medium rate. *L/H - originally loaded at low rate (0.075%), reloaded at high rate (0.3%). * *N/H = nonacclimated soil loaded at high rate (0.3%). + + = not analyzed. **H/NR = originally loaded at high rate (0.3%), not reloaded. (0.3%). The half-life for PCP in this soil was 151 days. Acclimation of soil micro- organisms to PCP would be expected to result in lower half-life values when waste is reapplied. Transformation of hazardous wastes in all waste-soil combinations was evaluated by measuring changes in the toxicity of the water soluble fraction (WSF) of waste- soil mixtures as indicated by the Microtox test. An increase in WSF toxicity was observed for all waste-soil mixtures evalu- ated during the first experimental period, and a decrease in WSF toxicity was gen- erally observed during the second experi- mental period. These results were consid- ered to be indicative of the formation and subsequent degradation of toxic interme- diate constituents. The Microtox assay proved to be an ex- tremely sensitive assay that did not corre- late with gross degradation indicators such as soil respiration studies, and there- fore could not be used to positively iden- tify the level at which soil biodegradation was inhibited. The WSF toxicity results did indicate, however, that transformation of the waste occurred for all waste-soil com- binations. Since the WSF may contain haz- ardous intermediates, it may be concluded that lower loading rates will be required if the treatment evaluation criterion is com- plete detoxification of the waste-soil mixture. Results of mutagenicity evaluations for soil detoxification of petroleum refinery wastes indicated a reduction from muta- genic to nonmutagenic activity with treat- ment time for API separator sludge in Durant clay loam soil and for slop oil emul- sion solids incubated in Durant clay loam ------- and in Kidman sandy loam soils. Wood preserving wastes, however, were not ren- dered nonmutagenic after 400 days of soil incubation in Durant clay loam soil at waste loading rates of 1.3 percent and 0.7 percent for creosote and PCP wastes, re- spectively. However, no mutagenicity was detected at a loading rate of 0.3 percent PCP waste in Kidman sandy loam soil, and the initial positive mutagenic potential for a loading rate of 1.0 percent creosote waste was reduced to a nonmutagenic level with a treatment time of 400 days. Immobilization of hazardous waste was measured using one bioassay, the Micro- tox test, of laboratory column leachates. Microtox test results indicated the presence of little toxicity in leachates from petroleum wastes incubated at the high loading rates in both Durant clay loam and in Kidman sandy loam soils. Leachates pro- duced from creosote and PCP loaded col- umns exhibited definite toxicity to Micro- tox, thus indicating the potential for leaching of water soluble toxicants that should be considered when defining waste loading rates for these experimental soils. The absence of Microtox test toxicity of some leachates did not conclusively dem- onstrate that leachates were free of toxic constituents. Partition coefficients that were deter- mined for PAH and volatile constituents of all four wastes indicated highest partition- ing of constituents into the oil (waste) phase. Relative concentrations between water and oil (waste) phases for PAH constituents were generally 1:1000 to 1:100,000, with the higher ratios observed for the petroleum wastes. Relative con- centrations among air:water:oil (waste) phases for volatile constituents were generally 1:100:100,000. Conclusions Specific conclusions based on objec- tives and results of this research project include: (1) Literature assessment of specific hazardous constituents experimen- tally identified in each candidate waste indicated a potential for treat- ment in soil systems. (2) Characterization of all candidate wastes by GC/MS, GC, and HPLC identified the PAH class of semi- volatile constituents as common to each waste. In addition, the PCP wood preserving waste contained pentachlorophenol and some dibenzo-p-dioxins and dibenzofur- ans; however, no tetrachlorodiben- zodioxins were detected at a detec- tion limit of 10 ppb. (3) A comparative study of the sen- sitivity of five microbial assays for selection of initial waste loading rates indicated that Microtox, soil dehydrogenase, and soil nitrification assays were the most sensitive to the presence of hazardous wastes, and would result in selecting lower loading rates. Soil respiration and viable soil microorganism plate counts were much less sensitive to hazardous waste application, and would result in selecting higher loading rates. (4) Based on screening assay results, initial loading rates for petroleum refinery wastes were indicated to be an order of magnitude higher than for wood preserving wastes. (5) A methodology was developed for measurement of "volatilization- corrected" degradation rates in soils in order to more accurately evaluate degradation as a treatment mecha- nism. For the semivolatile PAH com- pounds studied, volatilization was important only for naphthalene. (6) A methodology was developed for measurement of partition coeffi- cients for hazardous constituents among waste (oil), water, and air phases. It was not possible to measure the partitioning between the water soluble extract and soil because the very low water solubil- ities of the aromatic hydrocarbons and the very high affinity of these constituents for soil resulted in reduction of constituent concentra- tions in the water soluble extract to below detection limits. The method- ology proved useful for obtaining partition coefficients for waste (oil)/water (K0), air/water (Kh), and air/waste (oil) Koa), for volatile con- stituents and for waste (oil)/water for semivolatile constituents. (7) PAH constituents contained in each of the four wastes investigated were degraded under conditions of initial waste application to nonac- climated soils as well as when wastes were reapplied to soils. In general, PAH degradation did not appear to be influenced by varia- tions in soil type or loading rates used in this study; however, PAH degradation in petroleum refinery wastes generally exhibited higher rates than in wood preserving wastes. (8) All waste-soil mixtures tested ex- hibited an initial increase in WSF toxicity followed by a decrease in * toxicity with incubation time. The I pattern of WSF toxicity with time was considered to be an indication of formation and degradation of toxic intermediates. (9) Partition coefficients determined for PAH and volatile constituents con- tained in each of the wastes eval- uated demonstrated highest parti- tioning of constituents into the oil (waste) phase. Relative concentra- tions between water and oil (waste) phases for PAH constituents were generally 1:1000 to 1:100,000, with the higher ratios observed for the petroleum wastes. Relative concen- trations among air:water:oil (waste) phases for VOCs were generally 1:100:100,000. Recommendations The following recommendations are made in regards to conducting future soil treatability studies for hazardous wastes: (1) The use of chemical analyses alone appears to be insufficient to charac- terize treatability potential of a hazardous waste in soil. Use of chemical analyses alone fails to ac- count for interactions of compo- nents in a waste and the production of toxic/mutagenic metabolites. Use of bioassays to characterize the degradation, transformation and im- mobilization processes should be used to complement chemical analyses information. (2) Careful attention in future soil treatability studies should be given to potential fate, transport and ef- fects of intermediate products formed during waste-soil interac- tions. Information obtained con- cerning degradation, transforma- tion, and immobilization of hazard- ous constituents should be used to aid in selecting waste loading rates to be used in field evaluation study. (3) When determining partition coeffi- cients (K0, Kh, KD, Kao) for evalua- tion of immobilization processes in waste-soil mixtures, several differ- ent ratios of waste:water volumes and several water soluble fraction volumes:soil weights should be used to generate partition iso- therms with several points in order to evaluate the ranges of linearity for the isotherm and partition coef- ficient values. Determination of par- tition coefficients between soil and 6 ------- water soluble extract of the waste (KD) will require larger amounts of waste and water than used in this investigation to generate larger amounts of water soluble fractions. The full report was submitted in fulfill- ment of Cooperative Agreement No. CR-810979 to Utah State University under sponsorship of the U.S. Environmental Pro- tection Agency. R. C. Sims, J. L. Sims, D. L. Sorensen, W. J. Doucette, and L. L Hastings are with Utah State University, Logan, UT 84322. John £. Matthews /s the EPA Project Officer (see below). The complete report consists of two volumes, entitled "Waste/Soil Treatability Studies for Four Complex Industrial Wastes: Methodologies and Results," "Volume 1. Literature Assessment, Waste/Soil Characterization, Loading Rate Selection," (Order No. PB87-111 738/A S; Cost: $ 18.95) "Volume 2. Waste Loading Impacts on Soil Degradation, Transformation, and Immobilization,"(Order No. PB 87-111 746/AS; Cost: $24.95) The above reports will be available only from: (costs subject to change) 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. Kerr Environmental Research Laboratory U.S. Environmental Protection Agency P.O. 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