Biomarker-enhanced assessment of reproductive disorders in Monoporeia affinis exposed to contaminated sediment in the Baltic Sea
(English)Manuscript (preprint) (Other academic)
We evaluated the relationship between the general toxicity biomarkers (acetylcholinesterase [AChE], lysosomal membrane stability [LMS], antioxidant status measured as oxygen radical absorbance capacity [ORAC]) and embryo aberrations used as bioindicators of contamination in the amphipod Monoporeia affinis. Biomarkers and embryo aberrations were assayed in gravid M. affinis females collected in ten sites located in the Bothnian Sea and Bothnian Bay, together with sediments that were analyzed for PCBs, PAHs and metals. Female antioxidant capacity (ORAC) was positively related to the occurrence of females carrying malformed and membrane-damaged embryos and to the percentage of malformed and/or membrane-damaged embryos in their broods. Moreover, AChE inhibition was observed in concert with increased frequencies of membrane-damaged embryos in the brood, whereas high AChE activity coincided with percentage of embryos with arrested development. Positive relationships were also found between female ORAC levels and number of eggs per female, and between female AChE activity and embryo developmental stage. Also, significant positive correlations were found between AChE activity and ORAC values in the females and concentrations of metals and PAHs in the sediment, while there was a negative correlation between embryo ORAC and some PCB congeners. Partial Linear Square Regression (PLSR) models explained over 80 percent of the variation in the ORAC and AChE values in gravid M. affinis by variation in PCB, PAH and metal concentrations, in combination with environmental variables, such as salinity, depth and TOC. Specifically, ORAC levels were predicted to decrease in response to increased concentrations of CB180 and PAM4,9 and conversely to increase as a result of a mixture of PAHs (BAP, BJKF, BEP, PYRM1, BBF, CHR and FLU) and metals (Cr and V). AChE activity was predicted to increase by exposure to metals (Co, Zn, Ni, Cr and V) and the PAH COR, while inhibition of AChE activity was predicted by increased concentrations of two PCB congeners (CB138 and CB118). PLSR models also showed a positive relationship between salinity and ORAC and AChE in females, while AChE activity was negatively related to total organic carbon content in the sediment. Moreover, bottom depth was included in the AChE model to explain variation in AChE activity from the above mentioned set of explanatory variables. The data set for LMS, being substantially shorter, was analyzed for differences between four sampling sites. The differences found did not reflect variations in sediment concentrations of PAH, PCB and metals. Linking subcellular responses to the reproduction effects facilitates environmental stress assessment and understanding of the response mechanisms.
Biomarkers, AChE, ORAC, LMS, Contaminated sediment, Bioindicators, Reproduction, Embryo aberrations, In situ effects, Monoporeia affinis, Baltic Sea, Gulf of Bothnia
Natural Sciences Environmental Sciences
Research subject Applied Environmental Science; Ecotoxicology
IdentifiersURN: urn:nbn:se:su:diva-102843OAI: oai:DiVA.org:su-102843DiVA: diva2:713538
FunderEU, FP7, Seventh Framework Programme, 217246Swedish Environmental Protection Agency