[Distribution, sources and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Yangtze estuary and Zhejiang coastal areas].

PAHs contents of surface sediments were tested from 62 sampling sites of the Yangtze River estuary and Zhejiang coastal zone in 2013. The results showed that: 16 kinds of PAHs,which are listed as priority pollutants by EPA,were found in all the samples. The total PAHs level( dry weight) reached 31. 8-384 μg·kg- 1and the average amount was 131. 1 μg·kg- 1. The distribution of PAHs was affected by terrigenous input and point source pollution,the high-value zones were found at 2 # sampling site of the Yangtze River estuary and 21 # sampling site of Ningbo. Compared with other sea areas,the survey sea area was at a low PAHs pollution level. PAHs were primarily tetracyclic or tricyclic,and source analysis showed that most of PAHs were originated from combustion of wood and coal. Based on the Sediment Quality Guidelines( SQGs),the assessment result showed that the PAHs content of surface sediments from survey sea area was at a relatively low level of ecological risk; While according to the assessment result of the Sediment Quality Standards( SQSs),PAHs pollution of surface sediments from survey sea area displayed an "Obviously negative ecological effect"to some extent,and some countermeasures are required to control and eliminate pollutions.