Role of ground water on hexachlorocyclohexane (lindane) detections in surface water in western Canada

Abstract

AbstractInterrelationships between surface water and groundwater dynamics of α‐ and γ‐hexachlorocyclohexane (HCH) were investigated by determining their detection frequency and concentrations in surface water that originated primarily from surface runoff of snow and rain and in surface water that originated from ground water. In the prairie ecozone in Saskatchewan, where lindane (γ‐HCH) is currently used, lindane and α‐HCH were detected in about 50% of water samples taken from lakes and ponds that are recharged primarily by surface runoff (N = 43 sites). Maximum concentrations for lindane and α‐HCH were 0.011 and 0.004 μg/L, respectively. Isomers of HCH were not detected in any of the eight prairie springs that were examined (N = 10 samples). These springs originate from ground water located beneath agricultural lands. In the montane ecozone of Alberta where lindane is not used for agricultural purposes, only α‐HCH was detected frequently in the Waterton and Athabasca rivers. From 1976 to 1992, α‐HCH was detected in 81% of water samples from the Waterton River with no significant difference in detection frequency through the year (χ2 for 12 months = 14.6, d.f. = 11, p = 0.20, N = 163 samples). The site on the Waterton River is located downstream from a series of large lakes with multiyear storage of surface water. In contrast, discharge for the Athabasca River originates primarily from surface water during summer and ground water during winter. Detection frequency for α‐HCH during these seasons was 53% and 2%, respectively, with the annual pattern a normal distribution. These results indicate that HCH isomers were not detected frequently in surface waters that originate from ground water.