Detrimental effects of hull cleaning wastewater on oxidative status, life cycle parameters, and population growth of the monogonont rotifer Brachionus manjavacas

Acute and chronic effects of the short-chain chlorinated paraffins on the monogonont rotifer Brachionus manjavacas revealed by multi-biomarker determination

Short-chain chlorinated paraffins (SCCPs) are persistent organic pollutants of global concern. Despite their presence in low concentrations in aquatic environments, the detrimental effects of SCCPs on zooplankton remain limited. In this study, we evaluated the potential effects of acute and chronic exposure (24 h and 10 days) to various concentrations of SCCPs, including 1/10 NOEC, NOEC, and LC10, as retrieved from a 24-h toxicity experiment, using the monogonont rotifer Brachionus manjavacas. A dose-dependent increase in mortality was measured, with an LC50 value of 132 μg L-1 after 24 h. Treatment to the 24h-LC10 value significantly elevated intracellular content of reactive oxygen species, in addition with a marked elevation in malondialdehyde level. Glutathione levels were elevated following exposure to the 24-h LC10 value, along with the induction of enzymatic activities of crucial antioxidant components, including glutathione S-transferase, glutathione peroxidase, glutathione reductase, catalase, and superoxide dismutase. Chronic exposure to the NOEC value over 10 days resulted in hazardous effects on survival, lifespan, reproduction, and population maintenance in B. manjavacas. Taken together, SCCPs induced acute toxicity in rotifers primarily through the induction of oxidative stress. Even at sub-lethal concentrations, consistent exposure can lead to significant detrimental effects throughout the life cycle, indicating that SCCPs pose a serious threat to the sustainability of rotifer populations.

Exposure to hull cleaning wastewater induces mortality through oxidative stress and cholinergic disturbance in the marine polychaete Perinereis aibuhitensis

While wastewater and paint particles discharged from the in-water cleaning process of ship hulls are consistently released into benthic ecosystems, their hazardous effects on non-target animals remain largely unclear. In this study, we provide evidence on acute harmful effects of hull cleaning wastewater in marine polychaete Perinereis aibuhitensis by analyzing physiological and biochemical parameters such as survival, burrowing activity, and oxidative status. Raw wastewater samples were collected during ship hull cleaning processes in the field. Two wastewater samples for the exposure experiment were prepared in the laboratory: 1) mechanically filtered in the in-water cleaning system (MF) and 2) additionally filtered with a 0.45 μm filter in the laboratory (LF). These wastewater samples contained high concentrations of metals (zinc and copper) and metal-based booster biocides (copper pyrithione and zinc pyrithione) compared to those analyzed in seawater. Polycheates were exposed to different concentrations of the two wastewater samples for 96 h. Higher mortality was observed in response to MF compared to LF-exposed polychaetes. Both wastewater samples dose-dependently decreased burrowing activity and AChE activity. Drastic oxidative stress was observed in response to the two wastewater samples. MDA levels were significantly increased by MF and LF samples. Significant GSH depletion was observed with MF exposure, while increased and decreased GSH contents were observed in LF-exposed polychaetes. Enzymatic activities of antioxidant components, catalase, superoxide dismutase, and glutathione S-transferase were significantly modulated by both wastewater samples. These results indicate that even filtered hull cleaning wastewater can have deleterious effects on the health status of polychaetes.