Probabilistic ecological risk assessment of copper in Chinese offshore marine environments from 2005 to 2012

•PERAs of Cu was conducted in the coastal marine environment of China from 2005 to 2012.•Concentrations of Cu in Chinese offshore marine waters ranged from 0.1 to 43.2μg/L.•The sensitivity of marine taxa to Cu follows as: algae>crustaceans>mollusks>oligochaeta>fish.•Risks posed by Cu to ecological systems in Chinese offshore areas declined from 2005 to 2012. The objective of the present study was to conduct a probabilistic assessment of risk posed by copper found in the coastal marine environment of China from 2005 to 2012. This was achieved by applying a tiered ecological risk assessment (ERA) approach for characterization of risks of concentrations of copper from nationwide marine water monitoring program. The results show that from 2005 to 2012 the overall trend of hazard quotients (HQs) in the coastal marine environment of China the proportion of locations that exceed a HQ of 1.0 decreased from 64% in 2005 to 31% in 2012. While this indicates an overall improvement of the environment, there still have potential ecological risks in the most of the area, especially for the major gulfs of Liaodong and Bohai Bays and Yellow River Estuary. In addition, probabilities of exceeding the toxicity threshold for 5% of species were 27.6%, 5.4%, 4.9%, 0.8%, 0.4%, 1.0%, 1.8% and 0.12% annually between 2005 and 2012, respectively.