Hinkley GroundwaterContaminationIt’s not over: it’s just the beginning….Masahiro YagiEnvironmental Economics (ECON 360.01)Prof. Diya Mazumder
Erin Brockovich• Erin Brockovich (2000),successfully highlighted theissue of environmentalconflict by depicting the caseof Hinkley GroundwaterContamination.• http://abcnews.go.com/US/erin-brockovich-fighting-neighbors-toxic-drinking-water/story?id=15120603#.ULxMUYNQVnc
History of Hinkley Groundwater Contamination• Pacific Gas & Electric (PG&E)operates a compressor station in thetown of Hinkley in San BernardinoCounty, California• An underground plume of a chemicalcalled Chromium(VI )• Lawsuit led by a lawyer ErinBrockovich to represent 600 Hinkleyresidents against the PG&E• In 1996, PG&E agreed to pay $333million to those who claimed healthissues due to the contamination,which was the largest settlement inthe history of the U.S.
The case has not ended yet!• The area of chromium(VI) contaminations has expanded in recent years.• Currently, Hinkley residents have been offered 5 final cleaning up options.• Regional water board and residents are expected to choose a clean-up option byJanuary 2013.“What is the best clean-up option for the Hinkley?”
No Project 4B 4C-2 4C-3 4C-4 4C-5Years to 50 ppb Cr6 6 6 6 4 3 20Years to 3.1 ppb Cr6 Not Estimated 40 39 36 29 50Years to 1.2 ppb Cr6 Not Estimated 95 90 85 75 95Maximum Agricultural Units* (acres) 182 446 575 575 1394 575Maximum groundwater pumpingrate (gallons per minute, annualaverage)1100 2395 3167 4388 4388 3167Subsurface (in-situ) treatment? Yes Yes Yes Yes Yes YesAvobe-ground (ex-situ) treatment? Not currently No No Yes, 2 locationsplume core andnorthern areaNo Yes, 1 locationnear plume coreKey features PG&E continuesexisting cleanupwithoutexpansion.(Alternativerequired byCEQA). Doesn’taddress fullextent of plume.Expands AUs andin-situ zonesover No Project.Groundwaterextraction is notyear-round.Up to 9 AUs, year-roundgroundwaterextraction usingAUs with wintercrops added.Similar to 4C-2,but year-roundgroundwaterextraction using2 abovegroundtreatmentfacilities insteadof AUs in winter.Up to 25 AUs foryear-roundgroundwaterextraction Mostextensive plumecapture zone,fastest cleanup,but most aquiferdrawdown.Abovegroundtreatment inplume core(instead of in-situ). Number ofAUs similar to 4C-2. Removes allforms ofchromium fromthe highconcentrationplume area.Feasibility Study Estemiated Costs($million)N/A 84.9 118 276 173 171Impact Level (1 is low, 6 is high)Groundwater Drawdown 1 2 4 5 6 3Aquifer Compaction 1 2 4 5 6 3Plume Bulge 1 2 3 5 6 3TDS/Uranium byproducts 1 2 3 5 6 3Mn, As, Fe byproducts 1 4 4 3 4 2Nitrate byproducts 1 2 3 4 4 3Wildlife habitat ot loss 1 2 3 5 6 4EIR AlternativeElement
Groundwater extractioncontaminated groundwater is pumped from thesubsurface (also called the aquifer) to containthe groundwater plume from further migrationand is used in one or more of the followingways:
Agricultural treatment(land treatment or agricultural units)• extracted groundwater is used to irrigatelivestock forage crops, such as alfalfa. Cr(VI) inthe extracted groundwater is hanged to solidtrivalent chromium as it infiltrates through thesoil. Cr(VI) is the toxic form of chromium, whileCr(III) has very low toxicity.
Above-ground treatment(ex-situ treatment)• Where the extracted groundwater isprocessed through a water treatment plant toremove all forms of chromium (trivalent andhexavalent), which is transported off-site fordisposal.
Subsurface treatment(in-situ treatment)• food-grade carbon substances, such asethanol, are injected into the groundwaterwithin the aquifer to turn the hexavalentchromium into trivalent chromium which isleft in solid form at the water table.
Subsurface freshwater injection• this method creates barriers of freshwaterwithin the aquifer to deflect the contaminatedgroundwater towards another direction.
ImpactsWater Supply:• Drawdown - aggressive groundwaterextraction to contain and clean up plume lowersgroundwater levels• Compaction - loss of aquifer water storagecapacity due to groundwater drawdown
Impacts (continued)Water Quality:•Cr plume “bulge” – injection or irrigationcauses temporary bulge during remediation•Byproduct formation - increased in-situtreatment increases manganese, arsenic, iron ingroundwater
Impacts (continued)Biological Resources:• Restricted tortoise movement - AUs may limitdesert tortoise movement through valley• Loss of wildlife - could be disturbed, killedduring construction/operation
Benefit-Cost Analysis• Benefit– Agricultural benefit– Health benefit Cr• Cost– Engineering Cost– Social Cost• Health (Nitrate, Uranium)– Worst case scenario
Focus: Health Risk• Health risk of Cr 6- Lung cancer- Allergic dermatitis- Oral cavity, and intestine tumors• Health risk of bi-products by clean-up– Nitrate– Uranium– Total Dissolved Solids(TDS) Not available– Manganese Not significant– Arsenic Not significant– Iron Not significantHigh Blood Pressure, Diabetes, non-Hodgkin’slymphoma, Birth defects Bone cancer, Kidney damageSocialBenefitSocial Cost
Social BenefitCancer Risk• Current Cr[VI] in Hinkley: 7.8ppb• Objective: 1.2ppb• 1.2ppb = 2 in 1 million has a cancer risk ifhe/she drinks 2 liters of water that containsthis level of Cr[VI] for 70 years.1-2ppb7.8ppb/0.06ppb…130 in 1 million have cancerrisk (when Cr[VI] = 7.8ppb)1.2ppb = 2 in 1 million have acancer risk 130 – 2 = 128 people aresavedSocial Benefit = costs of cancertreatment x 128
Social Benefit• extracted groundwater is used to irrigatelivestock forage crops, such as alfalfa• Benefit-profit for the local farming community and usingthe resource for its current highest productive use-potentially reducing the import of potable waterfor agriculture-job opportunities for local farmers
• Uranium- Increase from 4ppb to app. 80.5ppb (WorstCase Scenario)• Nitrate- Increase from 10ppm to 10.5ppmSocial CostBone Cancer + Kidney damage = Social Cost2.683 in 1 million= cancer / kidney damage risk1.5 in 1 million havehealth risksHigh blood pressure + diabetes + non-Hodgkin’slymphoma = Social Cost