Pesticides and Water Quality - Texas Center for Policy Studies

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TABLE 1.SUMMARY OF REVIEWDATA SOURCESURFACE WATER / DRINKING WATER1996 State Water Quality Inventory and STORETWater Quality Data Base (1984 – 1997)TNRCC, March 1998 § 303 (d) list of WatersFailing to meet Aquatic life use (1990 – 1994 data)Texas Department of Health, Fish Advisories andBans, 1997.Texas Department of Health, Fish Tissue SamplingData (1970 – 1997).Public Drinking Water Sampling Database, TNRCC(1/93 – 3/98); includes quarterly sampling data forapproximately 5000 systems.TNRCC, March 1998, § 303 (d) threatened list ofwaters.SUMMARY10 years of limited data on about 38 pesticides inwater, sediment and fish tissue. Most frequentlydetected pesticides include banned products such aschlordane, dieldrin, silvex and DDT and itsbreakdown products and currently used pesticidessuch as diazinon and 2,4-D. There were no resultsabove the detection limit for 22 of the 32 pesticidestested in water samples. There are no data for manyof the most widely used pesticides. TNRCC hasidentified twelve water body segments “of concern”due to pesticides in sediments and three “ofconcern” for pesticides in fish (mostly chlordane,DDT and breakdown products).Three river segments not meeting aquatic life usedue to elevated diazinon levels.Eleven river segments / lakes have fish consumptionadvisories or bans due to high pesticide levels infish tissue (primarily banned pesticides such aschlordane, toxaphene and DDT breakdownproducts).Limited and sporadic fish tissue sampling datashows several pesticides detected in fish tissueabove detection limits in water bodies across thestate – primarily, but not exclusively, highlypersistent banned pesticides (chlordane, DDT &breakdown products, toxaphene, dieldrin, endrin).Nine Public Water Systems (PWS) exceededatrazine maximum contaminant level (MCL)standards for drinking water at least once sincemonitoring began in 1993. One of these systemswas in violation of standard (average of quarterlysamples above MCL). In 1997, sixty four systemshad 107 detections of atrazine in finished water.Pesticides were detected in over 90 PWS systems,including simazine, alachlor, metolachlor, andothers. (Appendix B)Nine lakes / reservoirs listed because atrazine foundin drinking water from these water bodies.4
1992, 1994 and 1996 Clean Rivers ProgramsAssessments for Texas (15 River Basins and 8Bays).U.S. Geological Survey National Water QualityAssessment Program (NADWA)(1993 – 1995).U.S. Geological Survey Special StudiesCorpus Christi Bay N.E.P.Galveston Bay N.E.P.Texas Parks & Wildlife Spills and Kills – analysisof fish & wildlife investigation reports from 1960 -presentTable 1. SUMMARY OF REVIEW, CONT.Virtually all of the assessments note a lack ofsufficient pesticide water quality data, even thoughland use patterns in some basins indicated potentialconcerns. Clean Rivers Program targetedmonitoring does not generally include pesticides,due to limited resources. Basin assessmentsidentifying potential pesticide concerns included:Upper Neches River (1994); Brazos River fromLake Whitney to Possum Kingdom (endosulfan –1994); Canadian River basin playa lakes (triazineherbicides, aldicarb – 1993); Lower Neches (TaylorBayou – mosquito control program, 1992); Nueces /Rio Grande Coastal Basins (1987 study by NOAAindicating Nueces coastal basins at “high risk” forcontamination); Rio Grande (Arroyo Colorado,mainstem of Rio Grande); Sabine River (1994-malathion in one segment); San AntonioRiver(Medina River below Medina Lake – aldrin,1994); Trinity (chlordane, endrin, 2,45 TP (silvex),2,4D-1994).Trinity River studies found urban and agriculturaluse pesticides (atrazine, metolachlor, prometon,simazine, diazinon); Trinity River coastal prairiearea studies found atrazine, metolachlor, molinateand 26 other pesticides; peak concentrationscoinciding with peak use periods.Rio Grande sediments (1997) – DDT, DDE, andchlordane found frequently in historical data (1970s– 1994); Comal Springs (diazinon, 1993 – 1994);Lake Texana (picloram, 2,4-D and methyl parathionmost frequently detected of the sixteen pesticidesanalyzed for during 1992 – 1997 period.)Lack of water quality data for pesticides; somesediment data available.Lack of sufficient data for analysis; urban land usesestimated to contribute 50% of annual pesticideloadings to the Bay; agriculture (mainly ricefarming) thought to be relatively smallercontributor.Estimated 11% of fish and wildlife kills over last 15years due to pesticides, resulting in over 2.5 millionfish killed.GROUNDWATERTexas Groundwater Protection Committee, 1996Annual ReportTexas Department of Agriculture, Howard & MartinCounties Study, 1988Texas Department of Agriculture – West Texas andSouth Texas Counties Study, 1988 - 1990Thirteen confirmed cases of groundwatercontamination due to pesticides.Arsenic contamination of water wells in theOgallala aquifer, related to arsenic-based pesticideuse on cotton and poor management of cotton ginwaste.Pesticides confirmed in ground water includedarsenic, atrazine, dicamba, prometon, bromacil,picloram, metolachlor, 2,4,5-T and 2,4-D.5
Page 1 and 2: I. INTRODUCTION AND SUMMARYA. Effec
Page 3: courses, parks, highway right-of-wa
Page 8 and 9: The TNRCC has also issued “statew
Page 10 and 11: elated monitoring waivers under the
Page 12 and 13: II. PESTICIDES IN SURFACE WATERThis
Page 15 and 16: whether Texas water bodies are expe
Page 17 and 18: screening levels) for fish tissue a
Page 19 and 20: detected pesticides have been banne
Page 21 and 22: section of a segment was considered
Page 23 and 24: which examines the liver and reprod
Page 25 and 26: Water Body Year of Sample Pesticide
Page 27 and 28: Water Body Year of Sample Pesticide
Page 29 and 30: een detected in Texas public drinki
Page 31 and 32: E. Summary of Statewide DataThe fai
Page 33 and 34: The Clean Rivers Program also has a
Page 35 and 36: Brazos/Colorado Coastal BasinDuring
Page 37 and 38: mosquito control program conducted
Page 39 and 40: San Antonio River BasinThe 1994 Ass
Page 41 and 42: • Cibolo Creek Municipal Authorit
Page 43 and 44: Compound No. of Sites Detections No
Page 45 and 46: urban land use areas were the main
Page 47 and 48: These rural landowners are reported
Page 49 and 50: water include the Tulia and Friona
Page 51 and 52: IV. ENHANCING WATER QUALITY PROTECT
Page 53 and 54: 3. A determination of the public wa
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use, the source water assessments c
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V. CONCLUSION:TEXAS NEEDS A PESTICI
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DRINKING WATER MONITORING WAIVERS F
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At the time this report was being p
Page 63 and 64:
Proposed CMR 162 Alternative Monito
Page 65 and 66:
The need for reasonably location-sp
Page 67 and 68:
Table B-3. Pesticide Analysis Costs
Page 69 and 70:
application and treatment rates, al
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Pesticides and Water Quality - Texas Center for Policy Studies

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