National Water-Quality Assessment (NAWQA) (public)
National Analysis of Trace Elements (public)
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Understanding Trace Elements in Ground Water--
Objectives

"Management" needs for process studies

There's currently great interest in occurrence of trace elements. Health agencies are studying links between common cancers and metals in drinking water; regulatory agencies are dealing with new maximum contaminant levels for arsenic, uranium, and radiochemicals (and resultant lawsuits); and water use and supply interests are looking into alternate water supplies, cost of water treatment, and conjunctive use issues. (CalFed considers arsenic in ground water the #1 barrier to conjunctive water use in California.)

At the same time, process (understanding) studies are needed for several purposes:

• To model likely concentrations in areas and aquifers without data
• To show where human activities create conditions leading to high trace-element concentrations. (For example, in in Wisconsin's Fox Valley, population pressure and water use patterns are rapidly lowering the water table into the sulfide-rich upper St. Peter sandstone, resulting in arsenic concentrations as high as 15,000 ug/L.)
• To help communities site new public and private drinking-water wells
• To help communities select appropriate water treatments based on basic water chemistry & speciation-- the building blocks of process studies. (For example, we know that arsenic co-occurring with iron can decrease treatment costs; on the other hand, either occurrence of arsenite, or arsenic co-occurring with sulfate, can increase treatment costs.)

Most process studies will likely focus on three areas:

• Natural sources of trace elements
• Conditions under which trace elements are mobilized into ground water
• Anthropogenic sources and/or mobilizers of trace elements

The understanding of where and how trace elements move into drinking water supplies, provided by the results of these studies, will vastly improve our ability to predict and portray concentrations moving to supply waters at local, regional and national scales.

Trace Elements National Synthesis internal homepage
National Analysis of Trace Elements (public)
National Water-Quality Assessment (NAWQA) (public)