Risk of endocrine disruption to fish in the Yellow River catchment in China assessed using a spatially explicit model

Abstract

The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner.Acc e p ted P r e p r i nt Acc e p ted P r e p r i nt Acc e p ted P r e p r i nt Acc e p ted P r e p r i ntThis article is protected by copyright. All rights reservedAbstract: The GWAVA model, incorporating regional water abstractions and reservoir information, was used to model human-sourced steroid estrogens: estrone (E1) and estradiol (E2) in the Yellow River catchment. The river flows in the main stem were calibrated using gauged flows. Following a review of Chinese data on estrogen discharge from a range of sewage treatment plants, low, median and high discharge rates were identified and used as best, expected and worst case scenarios, respectively. For any given location, the time-variation of modelled estrogens levels was summarized using the mean and upper 90th percentile (90%ile), which is where the model predicts 90% of values would be below this concentration. The predicted means and 90%iles for E1 were comparable with previous E1 measurements reported in the river. For the whole catchment, only 19% (mean value) of the river system by length was predicted to exceed 1 ng/L E2 equivalents (EEQ) using expected estrogen sewage discharge. Only 3% of the network by length was predicted to exceed the dangerously high 10 ng/L EEQ when considering 90%ile concentrations. The highest exposures were in the Fen and Wei tributaries. Endocrine disruption risk from estrogens was predicted to be minimal in the main stem.Only in the worst case discharge scenario and 90%ile predicted concentrations, were the most downstream river reaches of the main stem predicted to be at risk. Reservoirs appeared to be helpful in reducing estrogen concentrations thanks to longer water residence facilitating biodegradation. This article is protected by copyright. All rights reserved