Pesticides and Water Quality - Texas Center for Policy Studies

III. PESTICIDES IN TEXAS GROUND WATERA. IntroductionWhen first introduced into widespread use, pesticides were not deemed to be a threat to ground water.Early pesticides, such as arsenic, and the post-World War II synthetic pesticides, such as DBCP 116 , werethought either to be captured in soils or to degrade quickly. That theory was shattered in the 1960s and1970s, with proof that many pesticides were very persistent in the environment, and that some pesticideswere showing up in aquifers which provided drinking water to rural and urban residents.As in most states with significant agricultural production, Texas has found pesticides in a number of itsaquifers. Unlike some states, such as Ohio and Wisconsin, Texas has not pursued a comprehensiveprocess for detecting or reporting pesticides in ground water or for evaluating the significance of theproblem. Even with the creation of an inter-agency ground water protection committee by the TexasLegislature in 1989, collection of data and the evaluation of risks have been slow.As this inter-agency committee has pointed out, however, “data gaps” (such as the lack of pesticide useand fate data) are barriers to an effective program. 117 As discussed in a previous TCPS report, 118 Texasdoes not have a program for systematic reporting or collecting of pesticide use data, even in areas of thestate with very vulnerable groundwater systems, such as the recharge zone for the Edwards Aquifer.In addition, rural landowners have been reluctant to allow voluntary sampling of their water wells byrepresentatives of state regulatory agencies. Thus, Texas agencies have not been able to evaluate theextent of the contamination problem, even for high-profile pesticides like atrazine. 119 For example, theTexas Groundwater Protection Committee (TGPC) identified an area along the Brazos River Alluvium insoutheast Texas 120 as a region where atrazine is likely used and ground water is vulnerable tocontamination. The TGPC designed a study program for the area, but could not carry it out. Farmers inthe area would not allow their wells to be sampled for atrazine by representatives of the state agencies.While the members of the TGPC have the authority to go on the lands to sample the wells, they arereluctant to do so if farmers or ranchers object. Thus, TGPC only took samples from a few public wells,leaving the study with little scientific value.The Brazos River landowners, like others in Texas, are concerned that if they allow government agenciesto sample their water wells and the tests indicate contamination, these agencies will seek penalties fromthe landowners, even if the landowners have always used the pesticides in accordance with the label.116 Dibromochloropropane was banned in the late 1970s. It had been widely used to kill nematodes in soils. It is suspected tocause sterility in men, as well as cancer. It is also suspected of being a testicular toxin. It has been found in wells in a numberof states and foreign countries. The Leaching Fields: A Non-Point Threat to Groundwater, prepared by the Assembly Office ofResearch for the California Legislature, March 1985, pp. 84-87.117 See, for example, the draft report of the Data Evaluation Task Force of the Texas Groundwater Protection Committee of May6, 1997. The Task Force found “that the current data are insufficient to conclude that all ground water susceptible areas of thestate are unaffected by non-point source contamination by atrazine.... The present data base contains information of variablequality collected for various purposes.”118 Texas Center for Policy Studies, Realm of the Unknown: Pesticide Use in Texas (Texas Center for Policy Studies: Austin1999).119 Id.120 These alluvial or bolson deposits range from one to seven miles wide along 350 miles of the River. They provide asignificant amount of water for irrigation. See, Texas Department of Water Resources, Ground Water Availability In Texas,Report No. 238, (TWDB: Austin, September 1979).35