Distribution and potential ecological risk of heavy metals in the typical eco-units of Haihe River Basin

The distribution and characteristics of seven heavy metals in sediments located in the typical ecological units （eco-units） （e.g., rivers, lakes, and estuaries） of Haihe River Basin were analyzed. The Hakanson potential ecological risk index was used for ecological risk assessment. The results indicated that the concentration scales of As, Hg, Cr, Cd, Pb, Cu, and Zn in the eco-units were 2.08 to 24.80 mg·g-1, 0.01 to 1135.50 mg·g-1, 28.70 to 152.73mg·g-1, 0.03 to 195765.83mg·g-1, 8.65 to 157.82mg·g-1, 6.47 to 178.61mg·g-1, and 21.09 to 1076.25 mg·g-1, respectively. The maximum concentra- tions of Hg, Cd, and Zn showed higher levels than other water bodies around the world. Hg and Cd have high concentrations in Zhangweinanhe River （1135.50 and 195765.83mg·g-1, respectively） and Haihe Estuary （790.50 and 548.47 mg·g-1, respectively）. According to the ecological factor, Cd and Hg showed very strong ecological risks. The seven heavy metals, namely, Cd, Hg, As, Cr, Pb, Cu, and Zn, exhibited ecological risk levels in descending order. Based on the potential ecological risk index, Luanhe River and Baiyangdian Lake had moderate ecological risks, whereas every site in Zhangweinanhe River and Haihe Estuary had substantial risk levels. The risk order of the typical eco-units are as follows： Zhangweinan River （2278345.68） 〉 Estuary （161914.74） 〉 Luanhe River （191.54）〉Baiyangdian Lake （120.95）. These results provided a scientific basis for water environment improve- ment and risk management of the Haihe River Basin.

Biologic risk and source diagnose of 16 PAHs from Haihe River Basin, China

Surface sediments of rivers can exhibit spatial and temporal variations in contaminant concentrations that may significantly affect risk evaluations. As to pollution control and remediation of watershed, large-scale and further background data on PAHs in China were required urgently. Spatial distribution and compositional character- istics of 16 polycyclic aromatic hydrocarbons （PAHs） in surface sediments from Haihe River Basin were investi- gated. A method based on effects range （ER） was used to assess ecosystem risk of ZPAHs （the total of 16 PAH） sensitively and accurately. The results indicated that ∑PAHs content levels ranged from 257 to 16901 μg·kg-1 dry weight. The lower tings predominated in the samples, and 2-, 3-, 4-, 5- and 6-ring PAHs accounted for 12%, 21%, 30%, 30%, and 7% respectively in total PAHs. The ratio of F1 / （F1 ＋ Py） uniformly distributed in the interval 0.20- 0.80, indicating that it may be affected by petroleum origin, oil combustion, biomass and coal combustion jointly. ∑PAHs in Cetian （S6）, Dongwushi （S19）, Handan （S20）, Aixinzhuang （S21） and Tianjin （S37） exceeded effects range low （ERL）, in which biologic effects were in a medium level with an adverse effect on biologic organisms. Thus, it is necessary to strengthen the PAHs monitoring and research of the Haihe River Basin.