| Popis: |
Even though bivalve molluscs are recognized as bioindicators of freshwater quality, their responses to multiple stressors are unpredictable. This study aims to elucidate the inter-population peculiarities of the effect in the sub-chronic environmentally relevant exposure to novel contaminants. The specimens of Unio tumidus from pristine (Pr) and contaminated (Ct) areas were treated with ibuprofen (IBU, 0.8 µg L− 1), microplastic (MP, 1.0 mg L− 1, size 0.1–0.5 mm), or their combination (Mix) for 14 days. Untreated mussels (PrC- and CtC-groups) served as controls. The PrC-group had higher levels of antioxidants Mn-SOD, Cu,Zn-SOD, catalase, and cholinesterase (AChE) as well as lesser levels of oxidative lesions (TBARS and protein carbonyls) in digestive gland than the CtC-group, confirming different quality of life in two populations. However, lysosomal stability was similar in all studied groups. IBU induced antioxidant and AChE responses and lysosomal integrity in the Ct-group, only. MP caused the up-regulation of Mn-SOD and TBARS, and the suppression of Cu,Zn-SOD solely in the Pr-group. Discriminant analyses indicated lesser differences between Pr-groups, demonstrating their resistance across all treatments compared to Ct-groups. Most remarkable response was revealed in the CtIBU-group, and the alleviation of individual effects was established in combined exposures. The qualification of stress-neutral and stress-positive populations were proposed for Pr- and Ct-populations correspondingly. Inter-population peculiarities must be taken into consideration when environmental impact of MP and pharmaceuticals is evaluated. |
