Water quality criteria and ecological risk assessment for ammonia in the Shaying River Basin, China.

Current Chinese surface water environmental quality standard GB3838-2002 for ammonia fails to take water quality factors and native organism distributions in different basins into consideration. In this study, ammonia toxicity tests were performed using three aquatic organisms native to the Shaying River Basin (China). Published ammonia toxicity data with pH and temperature, and toxicity data acquired in this study were used to establish water quality criteria. The final criterion maximum concentration (CMC) and criterion continuous concentration (CCC) for the Shaying River Basin were 5.09 and 1.36 (mg total ammonia nitrogen (TAN))/L (pH 7 and 20 °C), respectively. In addition, based on the corresponding relationship between ammonia toxicity and temperature and pH, the ecological risk assessment of ammonia was conducted in different seasons for the Shaying River using a tiered approach of both hazard quotient (HQ) and the joint probability (JPC) methods. Two methods gave consistent results: the ecological risks of ammonia to aquatic species in the Shaying River Basin were severe and the risk could be ranked as wet season > flat season > dry season. It is therefore indicating that monitoring, evaluation, and early warning of ammonia pollution need to be taken to prevent and control the risks posed by ammonia pollution, especially for wet season (because of high temperatures and pH) or flat season (because of high pH values). We hope the present work could provide valuable information to manage and control ammonia pollution in the Shaying River Basin.

[Sources and Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbons in the Jiaxing River Network].

In order to study the pollution source and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the Jiaxing river network, PAHs were analyzed by GC-MS. The results show that with the influence of rainfall and surface runoff in the wet season, the types and mass concentrations of PAHs in the river network of Jiaxing differ from the dry season. Ten and 16 priority PAHs were detected in the dry season and wet season, respectively. The average mass concentration of PAHs in the dry season was 143.83ng·L-1 and 73.47ng·L-1 in the wet season. The range of mass concentration of PAHs in the dry and wet season was 77.32-283.76ng·L-1 and 13.05-133.02ng·L-1, respectively, and 2-ring and 3-ring PAHs accounted for 79.18% in the dry season and 73.60% in the wet season. PAHs pollution in the river network of Jiaxing was at a low level compared with the domestic and foreign areas. The isomer ratio and principal component analysis found that the PAHs in the Jiaxing river network mainly come from urban non-point source pollution, combustion source, and traffic pollution in the dry season and wet season. The results of the Kalf risk entropy method show that in the dry season, naphthalene(Nap), acenaphthylene(Acy), acenaphthene(Ace), fluorene(Flu), phenanthrene(Phe), anthracene(Ant), fluoranthene(Fla), pyrene(Pyr), and benzo(a)anthracene(BaA) are at moderate ecological risk. In the wet season, Nap, Acy, Flu, Phe, Fla, Pyr, BaA, benzo(b)fluoranthene(BbF), benzo(k)fluoranthene(BkF), benzo(a)pyrene(BaP), indeno(1,2,3-cd)pyrene(InP), and benzo(g,h,i)perylene(BghiP) are at moderate ecological risk. In the dry season, ∑PAHs are at moderate ecological risk, and low in the wet season. On the whole, PAHs pollution in the Jiaxing river network presents moderate ecological risk levels, and measures to reduce the ecological risk of PAHs in the river network should be taken by the Departments concerned.