Ecotoxicological characterization of energetic substances using a soil extraction procedure

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Soil Science

Background:

• Soils at manufacturing facilities are often contaminated with energetic substances.
• Characterizing the ecotoxicity of these contaminated soils is crucial for environmental risk assessment.
• Standardized methods are needed to accurately measure the toxic potential of contaminated soils.

Purpose of the Study:

• To evaluate the ecotoxicity of soils contaminated with energetic substances.
• To assess the effectiveness of the acetonitrile-sonication extraction method (US EPA SW-846 Method 8330) combined with aquatic toxicity tests.
• To determine the influence of soil properties on the extractability and toxicity of 2,4,6-trinitrotoluene (TNT).

Main Methods:

• Acetonitrile-sonication extraction (US EPA SW-846 Method 8330) of laboratory and field soil samples.
• Aquatic toxicity testing using Microtox (Vibrio fischeri) and Selenastrum capricornutum growth inhibition assays.
• Analysis of soil leachates containing TNT, RDX, and HMX from an explosives manufacturing facility.
• Multi-factorial analysis of Microtox data on soils with varying moisture and texture.

Main Results:

• TNT-dependent soil toxicity was measurable in organic extracts and aqueous leachates.
• Toxicity levels in field samples were similar to spiked soil studies, indicating TNT as the primary toxicant.
• Soil moisture content and texture significantly affected TNT extractability and subsequent toxicity measurements.

Conclusions:

• The modified Method 8330 coupled with ecotoxicity tests can effectively assess the toxic potential of soils contaminated with energetic substances.
• TNT is a significant contributor to the ecotoxicity of contaminated soils.
• Soil characteristics play a critical role in the bioavailability and toxicity of energetic contaminants.