Sea cucumbers Isostichopus badionotus and earthworms Eisenia foetida as bioindicators of contamination by 14c-hexachlorobenzene

Abstract

The pollution of different ecosystems is a world problem since some persistent xenobiotics, as hexachlorobenzene (HCB), although had been banned, continue to be generated as by-product of chemical processes, or are utilized in agriculture, and then, continue to be detected worldwide. The chemical or physical transports of these compounds allow that they reach and contaminate several environmental compartments, as soils, sediments and waters, where they can be harmful to the local biota and the food webs. In order to foresee and verify some of these effects, the use of some bioindicators - organisms from the lower trophic levels of different food webs - have been investigated to evaluate the potential hazard of bioaccumulation along the food webs. These bioindicators may be used as sentinel-species, as organisms that are able to bioaccumulate the xenobiotic present in the environment, and thus, indicate the possible contamination of the whole local biota. To evaluate the possibilities of HCB-contamination on different environments and ecological niches, this study will analyze the bioaccumulation and the effects of HCB in the marine organism sea-cucumbers (Holothurian Isostichopus badionotus) and the soil earthworms (Oligochaeta Eisenia foetida), as bioindicators of marine sediment and soil contaminated by treatment with 14C-HCB. The quantitative determination of the contamination and bioaccumulation, as well as the amounts of 14C-HCB present in the environments before and after the presence of the organisms will be done by radiometric and conventional analytical techniques, to determine the radioactivity and the HCB-amounts present in the sediment, water, soil and organisms, and to detect the biomarker contamination parameters. (AU)