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Orchard arsenic and changing land use in the Great Valley, Virginia and West Virginia

Residential redevelopment of former agricultural lands that may be contaminated by arsenical pesticides is an environmental concern in the rapidly growing northern Virginia-West Virginia region, due to possible increased risk of human exposure to arsenic and other toxic metals, as well as the potential for contamination of the vulnerable karst groundwater aquifer that is extensively used as a drinking water source. (A map of the Great Valley physiographic province is shown in USGS Circular 1166, figure 3.)

The objective of this study is to evaluate whether the use of arsenical pesticides on orchard crops during the 1920s to 1960s in the Great Valley area of Virginia and West Virginia has resulted in significantly elevated concentrations of arsenic and other metals in the soils of former apple orchards, or in stream sediments from drainage basins containing orchards.

The study will conduct a review of existing data and initiate a soil, sediment, water, and biological media sampling project to evaluate the environmental significance of arsenical pesticide residues in the karst environment of the northern Great Valley, Virginia and West Virginia.

This study addresses the following research questions:
1. Do the soils in and adjacent to orchard sites where arsenical pesticide was used contain elevated concentrations of arsenic and other metals relative to likely background conditions?
2. Based on historic land use, agricultural census, and other data, what is the likely extent of potential contamination from arsenical pesticide residues in the region?
3. Using EPA and other risk-based concentration criteria, do the sediments and waters in the region poste a risk to human health or ecosystem function?
4. Does redevelopment of former orchard sites as residential property increase the dipsersal of contaminated sediment and increase the exposure of humans and wildlife to arsenic and other toxic metals?
5. Can periodic cicadas be used as an easily sampled biomonitor measuring bioavailability of pesticide residues in soils?
6. Do the concentration levels of arsenical pesticide residues in periodic cicadas emerging from contaminated orchard sites pose a dietary threat to birds and other wildlife that preferentially feed upon cicadas during emergence events?