Ecological Risk Characterization in a Military Heavy Metals– and Explosives-Contaminated Site

ABSTRACT

Potential ecological risks of two heavy metals (Cu, Pb) and three explosives (TNT, RDX, HMX) were determined for a military gunnery range. Since a portion of the site will be submerged after the construction of a flood control reservoir, risk assessment of the site was conducted over two time points: at the current state and after the construction of the flood control reservoir. Terrestrial plants, terrestrial invertebrates, birds, mammals, and aquatic invertebrates were selected as affected ecological receptors at the study site. Potential noncarcinogenic risk was found only in one terrestrial site for Cu and RDX at both time points: For terrestrial plants, ecological hazard quotient (EHQ) by Cu was 1.22. For terrestrial invertebrates, EHQs for Cu and RDX were 1.38 and 6.47, respectively. EHQs in the aquatic environment increased to some extents after the reservoir construction, but the values were less than 1.0. A comparison between EHQs before and after the construction for the same site shows that the reservoir construction would not significantly increase the overall ecological risk, suggesting that the reservoir construction influenced the potential ecological risks at the study site, but the changes were acceptable. Uncertainties involved in the assessment process were identified and discussed.

Key Words:

• ecological risk assessment
• flood control reservoir
• heavy metals
• explosives
• military gunnery range

ACKNOWLEDGMENTS

This project was supported by the Korea Ministry of Environment as the GAIA (Geo-Advanced Innovative Action) Project and the 2006 Core Construction Technology Development Project (06KSHS-B01) through ECORIVER21 Research Center in KICTEP of MLTM KOREA. An additional support was made by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (grant number, 2010-0001448). The authors thank the Engineering Research Institute of Seoul National University for technical assistance.

Notes

¹Syracuse Research Corporation (2006)

²USACHPPM (2000; 2001; 2002)

¹95% percentile concentrations

²ND: Not detected

³Region B soil concentrations were used as submerged region B sediment concentrations

¹USEPA (1993); Sample et al. (1997)

²Nagy (1987); Calder and Braun (1983); Harestad and Bunnell (1979)

¹mg/kg biota for heavy metals and mg/kg soil for explosives

²Accumulated concentration data from Spurgeon et al. (1994)

³Accumulated concentration data from Bengtsson et al. (1986)

⁴NA: Not available. The TRVs could not be found in the literature.

¹The risks for terrestrial plant were determined according to the indicator plant recommended by Eco-SSL of USEPA (2006).

²NA: Not applicable. The region B was supposed to be submerged after the reservoir construction so that terrestrial risks were not applicable.

¹ND: Not detected. Explosives were not found.

²NA: Not available. For aquatic environment, exposure concentration is calculated using BSAF (biota-sediment accumulation factor). But the values were not available for the explosives.

¹The risks before and after the reservoir construction should be the same.

²After the reservoir construction, region B will be submerged and thus the risks at region B will not present for the bird and the mammal.

³NA, Not available. The pollutant was not found.