Soil-plant-animal relationships and geochemistry of selenium in the Western Phosphate Resource Area (United States): A review

While naturally found in trace quantities, several regions throughout the world have been designated as seleniferous or containing an overabundance of the trace element, selenium (Se), in soil. In particular, portions of the Western Phosphate Resource Area (WPRA) of the United States are considered seleniferous, notably due to past phosphate mining reclamation practices that have promoted Se release and accumulation in soil from weathering overburden waste rock. Concern over Se soil contamination in this region has been attributed to its high levels (ranging from 2.7 to 435 mg Se kg(-1) soil), bioavailability, and subsequent hyperaccumulation in vegetation at toxic concentrations (exceeding 10,000 mg Se kg(-1) plant tissue). The Se hyperaccumulator, western aster (Symphyotrichum ascendens (Lindl.)), is responsible for the vast majority of acute selenium livestock poisonings and fatalities throughout the region. This inherent bioavailability is largely controlled by soil redox chemistry and sorptive processes. The purpose of this review is to integrate information related to the unique site history of the WPRA from onset mining to current Se problems. This review will provide current details and connection of WPRA mining geology, soil Se geochemistry, plant hyperaccumulation, and related livestock fatalities. Soil remediation strategies will also be discussed along with their applicability and viability in this particular anthropogenically-influenced seleniferous region. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This article discusses the selenium contamination issues in the Western Phosphate Resource Area of the United States, focusing on the adverse effects of selenium accumulation in soil on vegetation and livestock, as well as the discussion on soil remediation strategies.