Overview of POPs and heavy metals in Liao River Basin

The water quality (COD as an index) in the Liao River basin (LRB) has been significantly improved in recent years, but toxic organic pollutants and heavy metals, however, are still present. Due to their bio-accumulative, persistent and poorly biodegradable properties as well as carcinogenic, teratogenic and mutagenic effects, these pollutants have caused severe water environment pollution in the LRB and threatened to human health. This paper reviewed the pollution levels of PAHs, OCPs, PCBs, emerging persistent organic pollutants and heavy metals in the LRB. The quantitative source apportionment methods and their application in LRB were summarized in detail. It was indicated that the organic pollutants and heavy metals in the LRB mainly originated from industrial sources, municipal wastewaters and agricultural nonpoint sources. The main problems and some suggestions for future study were proposed in order to acquire systematic data sets and comprehensive information on water pollution characteristics, which would provide valuable basis for government to establish an efficient strategy on prevention and control of highly toxic organic pollutants and trace heavy metals in the LRB.