Multiple biomarker responses in caged benthic gastropods Bellamya aeruginosa after in situ exposure to Taihu Lake in China

Qian Li,Markus Hecker,Lingling Wu,Åke Bergman,Lei Duan,Taowu Ma,Meng Wang,Ling Chen,Jianfu Zhao,Yanling Qiu,Magnus Breitholtz

doi:10.1186/s12302-018-0164-y

Abstract

BackgroundFreshwater sediments have been recognized as a long-term sink and potential source for environmental pollutants released into the aquatic ecosystems. In this study, the sediment quality of Taihu Lake, which is susceptible to anthropogenic contamination, was assessed by a combination of chemical analytical and biological end points. Specifically, the snail Bellamya aeruginosa was caged in situ at two locations representing different pollution levels for different exposure times (7, 14 and 21 days). At each of these time points, biochemical parameters, i.e., phase I biotransformation enzymes ethoxyresorufin-O-deethylase (EROD), the antioxidant enzymes superoxide dismutase and catalase, reactive oxygen species, protein carbonyl content and lipid peroxidation, were evaluated in the hepatopancreas of snails. In addition, surface sediments were collected for analysis of contaminants of concern, including inorganic pollutants, organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers.ResultsChemical analyses revealed that sediments from Taihu Lake were contaminated with trace elements and organic pollutants. Concentrations of trace elements (Cu, Ni and As) and organochlorinated pesticides (4,4′-DDE) exceeded their corresponding threshold effect level according to the sediment quality assessment values for freshwater ecosystems in Canada, indicating that adverse biological effects may occur. All biomarkers, except EROD activity, were induced in snails during all exposure times. The integrated biomarker response index (IBR) indicated that during the initial exposure phase (7 days), B. aeruginosa were subjected to significant environmental stress, which diminished during later sampling time points.ConclusionsResults showed that IBR correlated well with the levels of environmental contaminants, demonstrating the applicability of this biomonitoring approach to complex environmental exposure scenarios.

Highlights

Freshwater sediments have been recognized as a long-term sink and potential source for environmental pollutants released into the aquatic ecosystems
Physical and chemical analysis of water and sediments There were no differences in water quality between the two sampling sites, with water temperatures of 26.8– 33.1 °C, pH of 8.2–8.7 and dissolved oxygen (DO) concentrations of 6.57–9.16 mg/L
With the exception of polybrominated biphenyl ethers (PBDEs), concentrations of metals and other organic pollutants were markedly greater at site A when compared to site B

Summary

Introduction

Freshwater sediments have been recognized as a long-term sink and potential source for environmental pollutants released into the aquatic ecosystems. The snail Bellamya aeruginosa was caged in situ at two locations representing different pollution levels for different exposure times (7, 14 and 21 days). At each of these time points, biochemical parameters, i.e., phase I biotransformation enzymes ethoxyresorufin-O-deethylase (EROD), the antioxidant enzymes superoxide dismutase and catalase, reactive oxygen species, protein carbonyl content and lipid peroxidation, were evaluated in the hepatopancreas of snails. Compared with studies of native populations, the use of caged organisms affords numerous advantages such as the ability to select specific species and developmental stages, to control exposure duration and to focus on specific locations as animals are prevented from moving into or out of sites [20]. The use of caged organisms can minimize the influence of adaptive mechanisms, which may have evolved in resident organisms over time under long-term chronic exposure conditions and would lead to the underestimation of pollution [14]

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Results

Conclusion