The Toxicity of Produced Water Discharges in the Amazon Basin, - - PowerPoint PPT Presentation

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The Toxicity of Produced Water Discharges in the Amazon Basin, Ecuador

Douglas Beltman, Jennifer Peers, Ann Maest, Michael Carney, Tom Hodgson Stratus Consulting Boulder, CO November 21, 2009

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Texaco’s Oilfield Operations in Ecuador

Texaco drilled and operated 356 oil wells and built 22 production stations from 1967 to 1990 Petroecuador took over operations in 1990 Class action lawsuit brought by residents (including indigenous groups) against Texaco for pollution of the area Court expert recommends damages of $27 billion

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Wells Opened and Operated by Texaco

10 20 30 40 50 60 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 Year Number of wells

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Primary Sources of Contamination

916 unlined, abandoned pits with wastes from wells (oil, drilling muds, other chemicals)

Photo credit:

• L. Dematteis

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Primary Sources of Contamination

Oil spills from pipelines

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Primary Sources of Contamination

Oil poured on roads

Photo credit:

• L. Dematteis, M. Pallares

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Primary Sources of Contamination

Air pollution from open burning of pits, flaring

Photo credit:

• M. Pallares

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Primary Sources of Contamination

Discharge of produced water – Texaco audits show that they discharged ~18 billion gallons from 1972-1990 into streams and rivers

Photo credit:

• M. Pallares

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Oilfield Produced Water

Produced water occurs underground with oil and has to be separated from the oil at the surface

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Texaco Operations

River Station Crude Esmeraldas Well Well Well Well Well Well Well Gas Produced water

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Oilfield Produced Water

U.S. regulations for onshore discharge of produced water date back to the 1920s Onshore produced water is typically reinjected or treated to standards Since Petroecuador took over operations in 1990, produced water is now reinjected What was the toxicity of the water discharged by Texaco?

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20,000 40,000 60,000 80,000 100,000 120,000

A g u a r i c

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u a n t a L a g

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g r i

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e n t L a g

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P a r a h u a c u S a c h a C e n t S a c h a N S a c h a S S h u s h u f i n d i C e n t S h u s h u f i n d i N S h u s h u f i n d i S S h u s h u f i n d i S W Y u c a

Chloride (mg/L)

AGRA,1993 Fugro-McClelland, 1992

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Chloride in Produced Water

Seawater = 19,350 mg/L Seawater = 19,350 mg/L Seawater = 19,350 mg/L Seawater = 19,350 mg/L

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Chloride Toxicity to Aquatic Biota

Chloride disrupts ionoregulatory processes

• f freshwater biota, causing ion imbalances

No data available on toxicity to Amazon Basin aquatic biota Natural waters in the area have low ionic strength (~3 mg/L chloride), may influence susceptibility of aquatic biota to chloride toxicity

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Chloride Toxicity to Aquatic Biota

• Acute LC50s

– Inverts: ~2,000 to 6,000 mg/L Cl – Fish: ~6,000 to 12,000 mg/L Cl

• Chronic effects (growth, reproduction) at

<1,000 mg/L Cl

• USEPA water quality criteria (USEPA, 1988):

– Acute 860 mg/L – Chronic 230 mg/L – Driven by data for invertebrates taxonomically similar to those in the area (Gallo, 2007)

• Hazard Quotient (HQ) = concentration/criterion

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Cl Acute Hazard Quotient for Produced Water

20 40 60 80 100 120 140

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Cl Acute Hazard Quotient

AGRA,1993 Fugro-McClelland, 1992

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Cl Chronic Hazard Quotient for Produced Water

100 200 300 400 500

Aguarico Atacapi Auca Cent Auca S Cononaco Guanta Lago Agrio Cent Lago Agrio N Parahuacu Sacha Cent Sacha N Sacha S Shushufindi Cent Shushufindi N Shushufindi S Shushufindi SW Yuca

Cl Chronic Hazard Quotient

AGRA,1993 Fugro-McClelland, 1992

STATION

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Chloride in Streams Downstream of Stations

5,000 10,000 15,000 20,000 25,000 30,000 35,000 Aguarico Atacpi Auga Auga Sur Cononaco Lago Lago Lago Norte Parahuacu Sacha Sacha Sacha Sacha Sacha Sur Sacha Sur Shushufindi Shushufindi Shushufindi Yuca Yuca

Chloride (mg/L)

Fugro-McClelland, 1992

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Total Petroleum Hydrocarbons in Produced Water

5 10 15 20 25 30

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Total Petroleum Hydrocarbons (mg/L)

AGRA,1993 Fugro-McClelland, 1992

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Total Petroleum Hydrocarbons Most water-soluble TPH from crude

• il is BTEX

From EPA AWQC database (ug/L):

Benzene Toluene Ethylbenzene Xylenes Acute 5,300 17,500 32,000 2,600 Chronic 262 110 1,800 30

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Measured BTEX in Produced Water

20,000 40,000 60,000 80,000 100,000 120,000 140,000 B e n z e n e T

• l

u e n e E t h y l b e n z e n e X y l e n e s ug/L in Produced Water Mean Max

Data source: Villacreces, 2006

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Measured BTEX in Produced Water

500 1000 1500 2000 2500 3000 Sacha Central Shushufindi N Shushufindi S

Concentration (ug/L) Benzene Toluene Ethylbenzene Xylenes Data source: Jocknick et al., 1994

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BTEX Chronic HQ for Toxicity to Aquatic Biota

5 10 15 20 25 Sacha Central Shushufindi N Shushufindi S

Chronic HQ

Benzene Toluene Ethylbenzene Xylenes

Data source: Jocknick et al., 1994

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Toxicity to Humans

Photo credit:

• M. Pallares

BTEX concentrations in produced waters Mean (mg/L) Range (mg/L) Safe Drinking Water Act MCL (mg/L) Benzene 25.1 18.9−36.4 0.005 Toluene 40.7 31.0−61.3 1.0 Ethylbenzene 4.7 1.8−19.9 − p-, m-xylene 30.6 8.8−78.9 10a

• -xylene

9.5 3.7−40.8 10a

• a. Maximum contaminant level for total xylenes.

Sources: Villacreces Carvajal, 2006, Table 2; U.S. EPA, 2007.

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Sediment Contamination

Sediments of rivers and streams downstream of oil operations, including production stations, are contaminated with

• il

Photoactivated toxicity of PAHs in sediment, water column

Photo credit:

• L. Dematteis

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Conclusions

Texaco discharged 18 billion gallons of produced water directly into rainforest streams and rivers used by local people The produced water was acutely toxic to fish and invertebrates – Invertebrates more sensitive – Exposed biota may be susceptible to chloride toxicity The produced water contained benzene at concentrations many times higher than EPA drinking water standard

Photo credit:

• L. Dematteis