Toxicological and ecotoxic impact of secondary and tertiary treated sewage effluents
M Petala1, L Kokokiris, P Samaras
1Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Abstract:
Secondary sewage effluents are discharged in significant quantities in aquatic environments delivering pollutants that were not removed during treatment; yet advanced treated effluents are not lacking of contaminants. In this study, biochemical biomarkers were measured in liver and kidney of rainbow trout (Oncorynchus mykiss) exposed to unchlorinated, chlorinated and tertiary treated secondary sewage effluents. In addition, organic matter, nitrogen and suspended solids were assayed, while a common bioassay, Daphnia magna 21d reproduction test was also applied in order to examine potential relation between the performed bioassay and the biomarkers. Processes using oxidative conditions, such as ozonation and chlorination, resulted in significantly increased breeding rate (up to 74%) of the organism. Biomarkers measurements incorporated the determination of total glutathione (GSH), glutathione S-transferases (GST), glutathione peroxidase (GPX), lipid peroxidation (LPO) and an innovative biomarker in such applications, haem peroxidase. In general, the response of biomarkers was dependent upon the treatment method and it was tissue specific. Secondary effluents inhibited liver GST and haem peroxidase, while GSH levels and LPO were significantly provoked in liver. Ozonation provoked hepatic peroxidation, in terms of haem peroxidase and LPO, and GST; while the protective (to Reactive Oxidant Species - ROS) GSH was depleted, suggesting extended ROS attack to the organism. Similar response of biomarkers (but to a lesser extend) was observed after exposure of trout to effluents submitted to both coagulation and ozonation, emphasizing the significance of removing the residual organic matter by other methods than oxidative ones. Ozonation also enhanced renal LPO and GPX; however the former employment of coagulation limited the peroxidation phenomena. Chlorination mainly affected the levels of total GSH in both tissues.
More Related Videos
08:09Wastewater Irrigation Impacts on Soil Hydraulic Conductivity: Coupled Field Sampling and Laboratory Determination of Saturated Hydraulic Conductivity
Published on: August 19, 2018
08:49Vegetated Treatment Systems for Removing Contaminants Associated with Surface Water Toxicity in Agriculture and Urban Runoff
Published on: May 15, 2017
Related Concept Videos
Biological Treatment of Effluent and Waste Water
Microbial Wastewater Treatment
Toxicity Testing in Animals
Toxic Reactions: Overview
Toxicity falls into two primary categories: local and systemic.
Local toxicity appears at the exposure site, such as protein denaturation caused by caustic substances.
In contrast, systemic toxicity requires the toxic agent's absorption and distribution,...
Types of Toxins
Air pollutants, primarily gases, pose significant threats to respiratory health, leading to conditions like hypoxia, lung cancer, and in extreme cases, death.
Environmental pollutants like...
Environmental Applications of Microorganisms
