Pollution levels and biomarker responses in zooplankton from three hydrographic regions of southern Brazil: An integrated approach for water quality monitoring

Levels of chemical pollutants [organochlorine pesticides (OCs), current-use pesticides (CUPs), polycyclic aromatic hydrocarbons (PAHs) and trace-metals (Cu, Pb, Zn and Cd)], and biomarkers [metallothioneins (MTs) and lipid peroxidation (LPO)] were assessed in zooplankton of four watersheds belonging to three different hydrographic regions in southern Brazil. Results show that bioaccumulation followed a geographical pattern, as zooplankton from more coastal areas were the less affected. Elevated levels of CUPs (3257-6360 ng/g) and DDTs (1648-3258 ng/g) were found in zooplankton collected in sampling sites located in agricultural areas. In turn, elevated levels of HCHs (419-488 ng/g), endosulfans (108-215 ng/g) and PAHs (82,408-151,400 ng/g) were found in zooplankton collected in areas characterized by agricultural and industrial activities. Importantly, already banned pesticides were also detected, thus raising concerns. Regarding biomarkers, MTs and LPO levels were positively related with pollutant concentration in zooplankton from all assessed areas. This finding points out the suitability of both MTs and LPO as biological tools for environmental monitoring programs. Also, it is important to note that zooplankton is a major component of the first lfevel of consumers in aquatic system food chains. Therefore, chemical pollutants accumulated in zooplankton are likely to be biomagnified along the higher levels of the food chain, thus raising great concern. Therefore, the present study indicates MTs and LPO as suitable tools to predict ecological impacts in aquatic systems, using zooplankton was biomonitor species.

Automated summary

The study found a geographical pattern in the bioaccumulation of chemical pollutants in zooplankton, with higher exposure in agricultural and industrial areas. Biomarkers MTs and LPO were positively related to pollutant concentration, indicating their suitability for environmental monitoring programs. Zooplankton, as a major component of aquatic food chains, can potentially biomagnify chemical pollutants along higher levels, raising concerns for ecological impacts.