ANALYSIS OF LEAD IN GROUNDWATER

The feasibility of filtration for use in analysis of lead in groundwater samples is examined. Both colloid material and particulate material can be collected during groundwater sampling and the size of the material overlap in the size range of 1-10 microns. Particulate material collected when sediments are disturbed during sampling can cause elevating levels of lead and consequently unnecessary site investigations.

The low flow purge technique is used to sample monitoring wells for the presence of contaminants. The low flow purge technique minimizes collection of sediment in the well during sampling however it is time consuming and more costly than the use of bailers. A simple protocol for sampling of groundwater with bailers followed by filtration will be developed as a low cost option for removing particulate material from groundwater samples without removing the naturally occurring colloid material. Colloidal material may serve as an important mechanism by which contaminants are transported in subsurface systems and the sampling protocol should not eliminate the presence of this material.

Samples collected with bailers are filtered (filter pore size range 0.45 to 10 microns) and both the filtrate and sediment collected on the filter are analyzed for lead with Inductively Coupled Plasma Atomic Emission Spectrometry(ICP-AES). The lead levels are also compared to lead levels from groundwater samples taken with the low flow purge method. Comparison of the Pb levels with filtration of different pore size ranges will be used to determine if filtration (and the appropriate pore size of filter material) can be used as an alternative low cost method to the low flow purge method.