SMALL-SCALE RETROSPECTIVE GROUND-WATER MONITORING STUDY FOR SIMAZINE IN DIFFERENT HYDROGEOLOGICAL SETTINGS, 1991, Roux P. H. , Hall R. L. , Ross R. H. ,

A ground water monitoring study was conducted for the triazine herbicide simazine at 11 sites in the United States. The study used carefully selected, small-scale sites (average size: about 33 acres) with documented product use and sensitive hydrogeological settings. The sites selected were Tulare County, California (two sites); Fresno County, California; Sussex County, Delaware; Hardee and Palm Beach counties, Florida; Winnebago County, Illinois; Jackson County, Indiana; Van Buren and Berrien counties, Michigan; and Jefferson County, West Virginia. These sites satisfied the following criteria: a history of simazine use, including the year prior to the start of the study; permeable soil and vadose zone; shallow depth to water; no restrictive soil layers above the water table; and gentle slopes not exceeding 2 percent. A variety of crop types, climates, and irrigation practices were included. Monitoring well clusters (shallow and deep) were installed at each site except in California and West Virginia, where only shallow wells were installed. Simazine was monitored at these sites at quarterly intervals for a two-year period during 1986-1988. The results of the study showed that out of 153 samples analyzed, 45 samples showed simazine detections. A substantial majority of the detections (32 out of 45) occurred in Tulare, Fresno, and Jefferson counties. The detections in these areas were attributed to mechanisms other than leaching, such as drainage wells, karst areas, surface water recharge, or point source problems. An additional 11 detections in Van Buren County were apparently due to an unknown upgradient source. Only one detection (in Palm Beach County, Florida) near the screening level of 0.1 ppb was attributed to possible leaching. The results of this investigation support the hypothesis that simazine does not leach significantly under field use conditions

Herbicides in karst groundwater in southeast West Virginia, 1996, Pasquarell G. C. , Boyer D. G. ,

A field study was conducted to determine the karst groundwater impact of herbicide application to feed crops in support oil livestock production in southeast West Virginia, Grab samples were taken on a weekly/biweekly schedule at three resurgences for two agriculturally intensive karst watersheds. Two surface water sites were also sampled, The samples were analyzed for the presence of 12 different analytes: atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine), its two metabolites, desethylatrazine (2-chloro-4-ethylamino-6-amino-1,2,5-triazine) and desisopropylatrazine (2-chloro-4-amino-6-isopropylamino-1,3,5-triazine), and nine additional triazine herbicides. Little impact was detected at the two surface water sites. In contrast, 6 of the 10 herbicides were detected in at least two of the three resurgences. Three of them, atrazine (ATR), metolachlor [2-chloro-N(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-acetamide], and simazine [2-chloro-4-6-(ethylamino)-s-triazine], were detected in more than 10% of all samples at all three resurgences, ATR and desethylatrazine (DES) were detected in more than 50% of samples at all three resurgences; median ATR values were 0.060, 0.025, and 0.025 mu g/L. DAR* the ratio of DES to ATR plus DES, was used to differentiate atrazine leaching following storage for long periods in the soil, from transport that bypassed deethylation in the soil through sinkholes and other solutionally developed conduits. DAR* was low (median of <0.5) and highly varied during the periods immediately following ATR application, indicating that significant quantities of ATR were present. In the winter, a release of ATR metabolites from the soil was evidenced by a steadier, and higher DAR* (median of 0.64). The maximum detected ATR concentration was 1.20 mu g/L, which is within the USEPA maximum contaminant level of 3 mu g/L

Agricultural chemicals at the outlet of a shallow carbonate aquifer, 1996, Felton Gk,

A groundwater catchment, located in Woodford and Jessamine Counties in the Inner Bluegrass of Kentucky, was instrumented to develop long-term flow and water quality data. The land uses on this 1 620-ha catchment consist of approximately 59% in grasses consisting of beef farms, horse farms, and a golf course; 16% row crops; 6% orchard; 13% forest; and 6% residential. Water samples were analyzed twice a week for, Ca, Mg, Na, Cl-, HCO3-, SO4=, NO3-, total solids, suspended solids, fecal coliforms, fecal streptococci, and triazines. Flow rate and average ambient temperature were also recorded. No strong linear relationship was developed between chemical concentrations and other parameters. The transient nature of the system was emphasized by one event that drastically deviated from others. Pesticide data were summarized and the ''flushing'' phenomena accredited to karst systems was discussed. The total solids content in the spring was consistent at approximately 2.06 mg/L. Fecal bacteria contamination was well above drinking water limits (fecal coliform and fecal streptococci averages were 1 700 and 4 300 colony-forming-units/100 mL, respectively) and the temporal variation in bacterial contamination was not linked to any other variable

Air monitoring of aldehydes by use of hydrazine reagents with a triazine backbone, 2002, Kempter , Berkhoudt , Tolb ¦l, Egmose , Karst ,