OXIDATIVE STRESS ENZYMES AS BIOMARKERS OF HEAVY METAL POLLUTION IN INTERSTITIAL INVERTEBRATES.

Chemical contamination of fresh and marine water has a strong influence on the metabolic status of aquatic organisms. The expression level and catalytic activity of enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) etc., could be sensitive biomarkers for the oxidative stress induced in aquatic organisms by abnormal levels of biotic and abiotic factors. The present work aimed to study the effect of increasing lead concentration under controlled conditions on the levels of SOD activity in living microinvertebrates and to find the most appropriate class of interstitial invertebrates that respond promptly to the heavy metal contamination. The interstitial water samples were collected at Station Scarisoara on Aries River, during March 2010. The microinvertebrates found have been sorted and identified as belonging to Oligochaeta, Nematoda and Copepoda (Cyclopida) groups. The organisms of each group have been separated and incubated in the presence of lead concentration similar to that determined in the original environment (30 μg Pb/dm³). Biological samples consisting of living microinvertebrates have been analysed for SOD activity at 0 and 24 hours, and after 7 days of incubation, respectively. Our preliminary results suggest a modulation of activity of SOD, by lead ions present in the surroundings of living microinvertebrates tested. [ABSTRACT FROM AUTHOR]