Heavy metal toxicity monitoring in sediments of Jinhae bay, Korea.

Abstract

Sediments in the enclosed Jinhae Bay area surrounded by a large heavy industrial complex in Korea are becoming a reservoir for a wide range of chemicals, especially heavy metals (Lee et al. 1990). Inorganic toxicants such as heavy metals can be transferred through the food chain and also affect biota directly. Metal toxicity associated with solids in the environment is of particular concern since they can be released into the water column and adversely affect the biota. Direct uptake from sediment particles can be an important additional source of sedimentbound contaminants for sediment feeding animals (Landrum and Robbins 1990). Monitoring programs often rely on total metal concentrations in sediments. These chemical analyses do not give information on metal availability to the biota. A vast array of toxicity tests has been employed for assessing the toxicity of freshwater and marine sediments (Burton and Scott 1992). The tests include the use of biochemicals or organisms such as enzymes, bacteria, phytoplankton, zooplankton, benthic invertebrates, macrophytes or fish (Kong et al. 1995). In many such tests, water or solvents are added to elute the toxicants from the solid matrix, leading to toxicant dilution. The newly proposed solid-phase microbioassays include the Microtox solid-phase test (Tung et al. 1990) and the direct solid-phase toxicity testing (DSTT) using the Toxi-Chromotest kit (Kwan 1993). However, these tests respond to both organic and inorganic toxicants present in a sediment sample and are not specific for heavy metal toxicity. The purpose of the present study was to investigate the use of a solid-phase enzymatic test, MetPLATE , and to determine toxicity in sediment samples collected from Jinhae Bay (South Korea) which are highly contaminated with heavy metals. The test is based on the specific inhibition by heavy metals of β galactosidase of a mutant strain of Escherichia coli (Bitton et al. 1994). This test was previously applied to test heavy metal toxicity in soils (Bitton et al. 1996; Boularbah et al. 1996) and sediments (Bitton et al. 1992).