Acquisition of Instruments for Environmental Science Laboratory

Marymount University, Arlington VA

Investigators

Abstract

A grant has been awarded to Dr. Jason W. Kelsey at Marymount University to purchase an HPLC Chemstation and a Protector fume hood. The equipment will be used to study the bioavailability and toxicity of soil-aged organic pollutants. Important components of the research are the detection and extraction of compounds from soil and organisms that have been exposed to contaminated soil. High Performance Liquid Chromatography (HPLC) is used in the Marymount environmental science laboratory to quantify both recovery of the compound from soil as well as biological uptake. The Chemstation will greatly enhance the analysis of HPLC data. Currently, data are printed onto paper by means of an integrator, making complex analysis difficult. The fume hood will allow work on a wide range of volatile organic pollutants that are otherwise difficult to handle. The absence of a fume hood in the environmental science laboratory makes investigation of volatile compounds difficult and dangerous. The equipment will also be used in the teaching of Integrated Advanced Environmental Laboratory, a course in which upper-division biology undergraduates learn a number of analytical techniques used in experimental environmental science. The bioavailability of phenanthrene, a constituent of petroleum, and atrazine, a widely used herbicide, to earthworms and turtle eggs will be assessed. Of interest is the effect of species differences on the bioavailability of soil-aged pollutants. Sterile soil samples will be amended with phenanthrene or atrazine and allowed to age for a predetermined number of days. The experiments will be designed to yield samples in which the compounds have been aged for different lengths of time (e.g., 120, 60, 30, and 0 days). Organisms will be added to the samples and then extracted to determine the tissue concentration of the compounds. Parallel samples will be extracted to confirm that the unaltered parent compounds (i.e., the added phenanthrene or atrazine) are present in the soil after aging. Extracts will be analyzed using HPLC (with the Chemstation) to quantify uptake and recovery from soil. This work is important for the accurate assessment of the risk of pollutants in soil. Although data reported by the investigator and others demonstrate that many contaminants become progressively less available for uptake as they are aged in soil, estimations of risk of polluted sites are typically based on the total amount of compound present in (i.e., extractable from) soil and not biological availability. Consequently, the risk associated with a particular contaminant in soil is frequently overestimated. This incorrect calculation of risk could lead to the misdirection of resources in an attempt to meet unrealistic and possibly unnecessary clean-up goals. In addition, sites with the highest levels of contamination may not be the sites of highest risk to human and ecological receptors. Exposure assessments that rank environmental and human health risks in a way that appropriately reflects bioavailability will lead to more accurate risk assessments and, ultimately, to more efficient allocation of limited financial and natural resources. Information about species differences will improve predictions of the risk of pollutants in soils as well as further our understanding of the factors that influence bioavailability.