Scientists and regulators in the United States began emphasizing the study of pesticides in ground water in 1979 and 1980. The scientific community began to emphasize the study of nitrates in ground water as a result of fertilization in the mid to late 1970s. By the mid 1980s. tens of thousands of wells were found to contain elevated nitrate concentrations and detectable concentrations of pesticides. Few, if any, of the data were collected from wells associated with the nation's 13,000 golf courses.
Golf is popular on Cape Cod, an area that depends on a hydrogeologically vulnerable aquifer system as its principal source of drinking water. Pesticides and fertilizers are applied to golf courses, often at high rates on greens and tees. Therefore the EPA, the Barnstable County government, and several local golf course superintendents collaborated on a study of the impact of golf course turf management on ground water quality.
Nineteen monitoring wells were installed upgradient and in greens, tees, and fairways on four golf courses. Selected soil core samples were collected and analyzed. Four to six rounds of ground water samples were collected over one and a half years and analyzed for 17 pesticides and related chemicals; nitrate‐N samples were collected at least monthly. Seven of the 17 chemicals were never detected. The most frequently detected chemical‐dichlorobenzoic acid ‐ probably had been an impurity in herbicide formulations. Chlordane was detected in several wells at concentrations exceeding the health advisory level, perhaps due either to repeated heavy applications coupled with preferential flow of the bound/particulate phase and /or cross contamination during well installation. The results show no cause for concern about use of these currently registered pesticides.
Nitrate‐N concentrations were generally below the 10 ppm federal MCL, with some exceptions. Overall, nitrate‐N concentrations decreased in response to lower application rates and use of slow‐release fertilizer formulations.
Two watersheds were treated with one application of 2,4,5,T + picloram (1:1) at 1.12 kg/ha while one other watershed was treated for 2 consecutive years at the same herbicide rates. Residues of 2,4,5‐T were reduced to trace levels [<10 parts per billion (ppb)] in soils 7 days after application at one location, after 28 days at the second, and after 56 days at the third. Residues of 2,4,5‐T were not detected below 15 cm and usually remained in the surface 2.5 cm of soil. Picloram was reduced to trace levels within 56 to 112 days after application, was not detected deeper than 60 cm, and was usually restricted to the surface 15 cm of soil. There was no evidence of subsurface lateral movement of either herbicide. Surface runoff water contained trace amounts of residue following storms for about 30 days after application. There was no evidence of residue carry over into the second year after treatment in water, soils, or vegetation. Monitoring of cumulative residues in water, soils, and vegetation showed that about 75% of the picloram was dissipated from the ecosystem within 28 days after application and over 90% was lost after 112 days.
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