Integrated Evaluation of Petroleum Impacts to Soil Randy Adams, D. Marín, C. Avila, L. de la Cruz, C. Morales, and V. Domínguez Universidad Juárez Autónoma de Tabasco, Villahermosa, Mexico [email protected] 1.00 0.90 0.80 0.70 0.60 R2 = 0.9626 0.50 0.40 1-IAFcorr 0.30 0.20 0.10 0.00 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 Conc. hidrocarburos (mg/Kg) Actual Modelo BACKGROUND U J A T •Clean-up criteria for petroleum contaminated soils developed in US in 60’s and 70’s on drilling cuttings •1% considered OK – no or only slight damage to crops, only lasts one growing season •Bioassays confirmed low toxicity of residual oil •Subsequenty used as a basis for clean-up criteria for hydrocarbons in soils in many countries does not consider kind of hydrocarbons does not consider kind of soil SISTEMATIC EVALUATION U J A T •Selection of light, medium, heavy and extra-heavy crudes •Selection of 5 soil types common in petroleum producing region of SE Mexico •Contamination of soil at different concentrations •Measurement of acute toxicity (Microtox), and subchronic toxicity (28 d earthworm) •Measurement of impacts to soil fertility: water repellency, soil moisure, compaction, complemented with in situ weathering experiments •Measurement of plant growth: pasture, black beans Crude Petroleum Used in Study U J A T 100% 80% 60% Aliphatics Aromatics 40% Polars + Resins Asphaltenes 20% 0% Light Crude Medium Crude Heavy Crude Extra-heavy Crude 37 ºAPI 27 ºAPI 15 ºAPI 3 ºAPI U J A T FAO: FLUVISOL VERTISOL GLEYSOL ARENOSOL ACRISOL USDA: FLUVENT VERTISOL GLEYSOL PSAMMENT ULTISOL • rich alluvial soil • gilgai microrelief • seasonally flooded •coastal sandy soil • weathered soil from Pleistocene Terrace • medium texture • high clay content • high clay content •very low clay and silt content • good internal • smectite clays: • smectite clays: • sandy-clay texture drainage high shrink-swell high shrink-swell •excessive internal • clays: kaolinites capacity capacity drainage • aerobic and oxides of conditions • poor internal • poor internal Fe/Al, – no shrink drainage drainage swell capacity cacao, maize, pasture, pasture, pasture, coconuts pasture, pineapple, beans, pasture, some maize savannah oak citrus, sugarcane sugarcane, (Macuilís) watermellon, chiles, tomatoes Soils Used in Study Acute Toxicity U J A T •More toxic with lighter crude and in high concentrations •However, at 1% non-toxic in acute test B: baseline (control) L: Light M: Medium Arenosol H: Heavy X: Extraheavy (Psamment) non-toxic indeterminate Toxicity Units Toxicity slight sandy soil toxic H-10 H-10 H-20 H-40 H-80 H-10 H-10 H-20 H-40 H-80 Acute Toxicity U J A T •More toxic with lighter crude and in high concentrations •However, at 1% non-toxic in acute test B: baseline L: Light Acrisol M: Medium H: Heavy (Ultisol) X: Extraheavy A: non-toxic red clay Toxicity Units Units Toxicity Toxicity B:indeterminate soil C: slight B X-10 X-10 X-20 X-40 X-80 H-10 H-10 H-20 H-40 H-80 Acute Toxicity U J A T •High variability with some samples •In general, low-null toxicity in alluvial soils Fluvisol 30,00 L: LigeroLight 25,00 M: Mediano P:M: Pesado Medium 20,00 E:H: ExtrapesadoHeavy Fluvisol X: Extraheavy 15,00 1%: 10,000 ppm (Fluvent) 2%: 20,000 ppm 4%: 40,000 ppm Toxicidad (UT) Toxicidad 10,00 8%: 80,000 ppm Toxicity Units Toxicity 5,00 river levee soil 0,00 L 1% L 2% L 4% L 8% L E 1% E 2% E 4% E 8% E P 1% P 2% P 4% P 8% P M4% X1% X1% X2% X4% X8% H1% H1% H2% H4% H8% M 1% M 2% M 8% M Acute Toxicity U J A T •High variability with some samples •In general, low-null toxicity in alluvial soils Vertisol 20,00 L:L: LightLigero 18,00 M: Mediano 16,00 M:P: PesadoMedium 14,00 H:E: HeavyExtrapesado Vertisol 12,00 X: Extraheavy 10,00 1%: 10,000 ppm 2%: 20,000 ppm 8,00 4%: 40,000 ppm Toxicidad (UT) Toxicidad 6,00 8%: 80,000 ppm brown clay 4,00 soil Toxicity Units Toxicity 2,00 0,00 L 1% L 2% L 4% L 8% L E 1% E 2% E 4% E 8% E P 1% P 2% P 4% P 8% P M4% X1% X1% X2% X4% X8% H1% H1% H2% H4% H8% M 8% M M 1% M 2% M Acute Toxicity U J A T •High variability with some samples •In general, low-null toxicity in alluvial soils Gleysol 25,00 L: Ligero M:L: MedianoLight 20,00 P: Pesado M: Medium E: Extrapesado Gleysol 15,00 H: Heavy 1%: 10,000 ppm 2%:X: Extraheavy 20,000 ppm 10,00 4%: 40,000 ppm Toxicidad (UT) Toxicidad 8%: 80,000 ppm floodable 5,00 brown clay Toxicity Units Toxicity soil 0,00 L 1% L 2% L 4% L 8% L E 1% E 2% E 4% E 8% E P 1% P 2% P 4% P 8% P M4% X1% X1% X2% X4% X8% H1% H1% H2% H4% H8% M 1% M 2% M 8% M Subchronic Toxicity U J A T •Limited toxicity with light crude, greater with medium crude •No toxicity observed in heavy crude until 4 weeks (evasion?) 10000 ppm control light Arenosol medium (Psamment) heavy % % mortality extraheavy sandy soil days Subchronic Toxicity U J A T •Biomass loss in first 2 weeks and then recovery (~2 mo. ?) •Recovery much slower with heavy crude 100 10000 ppm control 80 Arenosol light (Psamment) 60 medium heavy 40 Biomass (%) Biomass extraheavy (normalizaded) 20 sandy soil 0 0 10 20 30 days Subchronic Toxicity U J A T •Limited toxicity with light crude, greater with medium crude •Very low toxicity with heavy crude, but with extraheavy crude after 3 weeks formation of compacted clumps 10000 ppm control light Acrisol % % mortality medium (Ultisol) heavy extraheavy red clay soil days Subchronic Toxicity U J A T •Biomass loss in first 2 weeks, then recovery (~3-8 weeks) •No evidence of recovery for extraheavy crude (clumps) 10000 ppm control light Acrisol medium (Ultisol) heavy extraheavy % biomass, (normalized) biomass,% red clay soil days Subchronic Toxicity U J A T •Very low mortality in alluvial soils (only 4%, in heavy crude) •Bioavailability limited by presence of silts and clays; Clays with shrink-swell capacity no clumping 100 Heavy 80 Crude 60 80,000ppm Fluvisol Mortality (%) Mortality 40 40,000ppm (Fluvent) 20,000ppm 20 10,000ppm 0 river levee 0 7 14 21 soil days Subchronic Toxicity U J A T •Low-nul mortality in alluvial soils (0%, in heavy crude) •Bioavailability limited by presence of silts and clays; Clays with shrink-swell capacity no clumping 100 80 Heavy 60 Crude 80,000ppm Mortality (%) Mortality 40 Vertisol 40,000ppm 20 20,000ppm 0 brown clay 0 7 14 21 soil days Problems with Fertility U J A T •Evidence from US, Canada, SE Mexico indicate potential fertility problems, especially with weathered hydrocarbons: •More weathered HC molecules act as chemical bridges between SOM and non -polar HC •Important in formation of hydrocarbon layers on soil particles: •Water repellency, field capacity •Aglomeration and compaction Model for Soil Water Repellency U J A T Non - or low polarity hydrocarbons Weathered, slighlty polar hydrocarbons Natural organic material (charged/polar/non-polar) Mineral Fraction (negative charge) (From: Litvina et al. 2003) Soil Water Repellency U J A T Soil Water Repellency U J A T • In Fluvisol and Vertisol water repellency could be modeled based on ºAPI and TPH concentration Vertisol In situ Moisture Content U J A T • open air weathering experiments (1 yr) Compaction U J A T • measured with soil penetrometer after weathering expts. (1 yr) • observations from worm assays Type of hydrocarbons Type of soil Conc. of hydrocarbons Recent spill or weathered U J A T Plant Growth in Hydrocarbon Toxicity Fertility Contaminated Soil Type of crop Conceptual or pasture Model Plant development ? and growth Plant Growth U J A T • pasture planted by stolons • cut every 2 mo. and above ground biomass measured Pasture Production 1.00 • catch up? …or • degraded soil conditions? control 0.80 • on-going experiment light 0.60 medium 0.40 heavy Biomass (dry, g) (dry, Biomass 0.20 extraheavy 0.00 Fluvisol1 Vertisol 2 Gleysol 3 Arenosol 4 Acrisol 5 CONCLUSIONS U J A T Impacts of petroleum contamination in soil are affected by: •Type of Petroleum: lighter crudes are more acutely toxic (but temporary) heavier crudes are more likely to impact fertility: •polar groups lead to formation of HC laminates water repellency/soil moisture soil compaction •recovery may be very, very slow CONCLUSIONS U J A T Impacts of petroleum contamination in soil are affected by: •Type and abundance of soil clays: smectites: high surface area, expansive (in brown-grey soils) reduce toxicity (low bioavailability) very little water repellency (lots of reactive surface area) very little compaction (shrink-swell properties) non-smectites: kaolinites, amorphous Fe/Al oxides low surface area, non-expansive (in red-clay soils) med-high toxicity (more bioavailability) med-high water repellency (less reactive surface area) a lot or compaction (no shrink-swell properties) CONCLUSIONS U J A T Impacts of petroleum contamination in soil are affected by: •Type and abundance of soil clays: very sandy soils: practically no clay (<1%) med-high toxicity (almost complete bioavailability) high water repellency (very little reactive surface area) no compaction (absence of clays: basically no aggregates) Thank you for your attention [email protected] non-smectite very clays abundant smectite clays absent PSAMMENT ARENOSOL VERTISOL VERTISOL FLUVISOL FLUVISOL FLUVENT GLEYSOL GLEYSOL ACRISOL ULTISOL CRUDE PETROLEUM CRUDE med-high very low toxicity med-high very water repellency med-high little low soil moisture very high very high little compaction none CRUDE PETROLEUM light type of crude extraheavy med-high toxicity very low water repellency very little low soil moisture high none compaction high ARENOSOL PSAMMENT FLUVISOL FLUVENT toxicity med-high VERTISOL smectite smectite claysVERTISOL absent