[Analysis of Heavy Metal Pollution Characteristics and Potential Ecological Risks of Surface Sediments in Dongjiang Lake].

To understand the pollution characteristics, spatial distribution characteristics, potential ecological risks, and sources of heavy metals in surface sediments of Dongjiang Lake, 12 surface sediment samples were collected from Dongjiang Lake. The contents of 20 heavy metals including Li, Be, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Pb, and U were analyzed in this study. The geo-accumulation index method and potential risk index method were used to evaluate the pollution degree and potential risks of heavy metals in sediments, and the correlation analysis and principal component analysis were used to trace the source of the primary heavy metals. The results showed that the average contents of ω(Cd)(2.25 mg·kg-1) and ω(As)(80.80 mg·kg-1) in heavy metals of Dongjiang Lake sediments were 21.2 times and 5.5 times the background value (0.11 mg·kg-1 and 14.7 mg·kg-1) of Hunan province. The overall spatial distribution of heavy metals was in the order of South>North>Central. The evaluation by the geo-accumulation index method showed that Cd was at the heavy pollution level, As and Se were at the moderate pollution level, Ag and Ga were at the light pollution level, and the other heavy metals were below the pollution standard. The evaluation by the potential risk index showed that all the surface sediments of Dongjiang Lake were at the high-risk level. The main environmental risk factor was Cd, which had an extremely high risk; the second was As, which had a medium risk; and the remaining heavy metals had no ecological risk.

[Distribution Characteristics and Ecological and Health Risk Assessment of Phthalic Acid Esters in Surface Water of Qiandao Lake, China].

In order to reveal the pollution and risk level of phthalic acid esters (PAEs) in Qiandao Lake, six types of PAEs in 17 sampling points (in Qiandao Lake and its inflowing rivers) in dry and wet seasons were detected. The results showed that six types of PAEs were detected in both dry and wet seasons, with the concentrations of 0.98-5.33 µg·L-1 (average concentration 2.63 µg·L-1) in the dry season and 3.22-17.88 µg·L-1 (average concentration 7.99 µg·L-1) in the wet season. In terms of the detection rate and concentration of each monomer PAEs, DiBP, DBP, and DEHP were the main PAEs components in the water body. The measured value of DBP at 10 sampling points and its average mass concentration in the wet season were higher than the national standard (3 µg·L-1). Principal component analysis indicated that the main sources of PAEs were personal care products, plastics, and domestic waste. The pollution level of PAEs in Qiandao Lake was at a high level at home and abroad. The health risk assessment results in Qiandao Lake showed that the non-carcinogenic risk index of PAEs in the study area was less than 1, which would not produce non-carcinogenic risks to the human body. The carcinogenic risk index of children exceeded 10-6 at some points, indicating that it may pose carcinogenic risks to children, to which more attention should be paid.