Biomagnification of chlorinated paraffins in amphibians from an e-waste effected ecosystem, South China: evidence from quantitative fatty acid signature analysis

Amphibians are ecologically significant and environmentally sensitive vertebrates, yet the bioaccumulation behavior and trophic transfer of chlorinated paraffins (CPs) in amphibian remain poorly understood. In this study, we examined the concentrations, tissue distribution, and congener profiles of short- and medium-chain chlorinated paraffins (S/MCCPs) in amphibians and their insect prey from an e-waste-contaminated wetland. Quantitative fatty acid signature analysis (QFASA) was applied to determine amphibians’ dietary composition and to refine biomagnification factor (BMF_QFASA) calculations. Median concentrations of the total CPs were ranged from 1.75 to 38.2 μg/g lipid weight (lw) in amphibian tissues, and ranged from 1.45 to 7.14 μg/g lw in eight insect species. Results showed that S/MCCPs were widely distributed in amphibian tissues, with the highest SCCPs levels found in skin, and MCCPs in muscle. Predator–prey relationships and physiological traits influenced tissue-specific accumulation and interspecies differences in three amphibians. Principal component analysis of CP homologue profiles revealed clustering patterns reflecting trophic transfer, particularly between amphibians and insect taxa such as dragonflies. BMFs of S/MCCP congeners ranged from 0.55 to 11.7, 0.12 to 5.27, and 0.26 to 6.49, respectively, exhibited biomagnification along the amphibian food chains, except for SCCPs in the WF food chain. Log BMF_QFASA showed a parabolic relationship with log K_OW and a strong positive correlation with log K_OA, suggesting that K_OA is a better predictor of biomagnification in amphibians. Our findings provide novel insights into the environmental behavior of CPs in amphibian food chains and highlight the need to consider species-specific traits and physicochemical properties in ecological risk assessments.