Heavy Metals — Soil Communities at Ecological Risk

This article outlines an effect of the different kinds of environmental pollution on the soil nematode communities at two industrial regions (Krompachy and Jelšava) of eastern Slovakia. At the locality Krompachy, soil nematode communities were significantly affected by increased concentrations of As, Cd, Cu, and Zn. At the other location Jelšava, despite low concentrations of heavy metals, long-term emissions of magnesium dust had indirect impact on soil environment through altered soil conditions, mainly by alkaline pH. Pollution effects at the community structure (trophic and c-p groups) of soil nematodes were found to be the highest near the pollution sources, where communities with low population densities consisted mainly of disturbance-tolerant taxa from c-p 1 and c-p 2 groups. With an increasing distance from the pollution sources, the nematode communities were more structured and complex, with higher proportions of sensitive c-p 4 and 5 nematodes, composed mainly of predators and omnivores. Ecological indices (H´, MI2-5, SI) also clearly showed deteriorating environmental conditions towards the pollution sources. The greatest difference in the nematode community structure between the two localities was found in the proportion of c-p 1 and c-p 2 bacteriovorous nematodes. At the locality Krompachy characterised by critical heavy metal load, c-p 2 nematodes dominated, while c-p 1 nematode group prevailed at under extremely alkaline soil conditions in Jelšava. Results also showed that the free-living nematodes are useful tools for bioindication of industrial contamination and could be used as an additional source of information to the common approaches based on chemical methods

Ecological Risk and Distribution of Polychlorinated Biphenyls in Fish

The distribution and concentrations of polychrolinated biphenyls (PCBs) were determined in nine freshwater fish species and the parasite Acanthocephalus lucii in Zemplínska šírava, a heavily polluted water reservoir in Slovakia. The study performed at two different time points five years apart (2004 and 2009) revealed excessive PCB contamination of the fish muscle tissue and significant interspecies as well as tissue-specific differences in PCB uptake by fish. Total PCBs broadly correlated with the trophic position of individual fish species within a food chain (P adipose tissue > muscles > hard roe > bones > brain. Maximum concentrations of PCBs were recorded in the liver of northern pike (214.0 mg.kg-1 lipid wt) and the hepatopancreas of freshwater bream (163.0 mg.kg-1 lipid wt). Individual congeners were not distributed homogeneously within the investigated organs and the adipose tissue. PCB 153 was present in the higher concentrations than other congeners in all fish organs as well as the adipose tissue. Acanthocephalans absorbed significantly higher concentrations of PCBs (P<0.001) than the muscles, liver, kidney, brain and adipose tissue of their host. About 20-fold lower PCB levels was detected in the liver and almost three times in the muscles of infected perch. Data on PCB accumulation in perch infected with acanthocephalans demonstrated a decline of PCB values in all organs as well as the adipose tissue compared to uninfected fish. The study has shown that the fish species, its feeding habit and specific conditions of the habitat are mutually interrelated factors that are responsible for significant variations in fish body burdens