Groundwater sampling techniques for organic micropollutants: UK experience

Abstract

Sampling for organic micropollutants on a regional scale is from existing public supply or production boreholes. These give good samples for analysis but they will be of mixed waters and may not indicate the true occurrence of organic compounds in the groundwater. The most widely applicable groundwater sampling methods from open observation boreholes in the UK are based on submersible pumps. Several systems are now in use but all have drawbacks when used for organic micropollutant sampling. The present systems, particularly when used in conjunction with straddle-packers, are suitable for studies of inorganic groundwater quality or organic pollution at concentrations above about lmg1 -1 . There are increased difficulties, however, when sampling for trace organic contaminants below concentrations of 1μg1 -1 because of the ease of cross-contamination by the organic materials so prevalent in our environment. Great care has to be taken during sampling to minimize the cross-contamination.

Ground water purging and sampling methods: History vs. hysteria

“…At the same time, further neglect of the unique hydraulic characteristics of monitoring wells led to the use of high-rate pumping devices. The need for more effective and documented sampling methods was driven by the more stringent sampling and analytical data quality objectives, which are placed on micropollutant compliance monitoring programs (Clark and Baxter 1989;Keely and Boateng 1987;Barcelona 1988). In addition, high-flow rate purging resulted in the production of large volumes of potentially contaminated water that required costly handling and treatment.…”

“…It was further recognized that purging was necessary due to in-well water quality changes (Barcelona and Helfrich 1986). The need for more effective and documented sampling methods was driven by the more stringent sampling and analytical data quality objectives, which are placed on micropollutant compliance monitoring programs (Clark and Baxter 1989;Keely and Boateng 1987;Barcelona 1988).…”

Investigation of point source pollution by chlorinated solvents in two different geologies: a multi-layered Carboniferous sandstone-mudstone sequence and the Chalk

“…The best materials to use are stainless steel, Teflon and rigid PVC. Useful information on sampling methods is given by Pohlmann & Hess (1988), Clark & Baxter (1989), Pearsall & Eckhardt (1987), Pettyjohn et al (1981Reynolds et al (1990), Schuller et al (1981 and Sykes et al (1986). Specialized level-determined sampling methods (such as those described in this paper) may be employed where information on solvent distribution with depth is considered important.…”