Polycyclic aromatic hydrocarbons (PAHs) in multimedia environment of Heshan coal district, Guangxi: distribution, source diagnosis and health risk assessment.

Mining activities are among the major culprits of the wide occurrences of soil and water pollution by PAHs in coal district, which have resulted in ecological fragilities and health risk for local residents. Sixteen PAHs in multimedia environment from the Heshan coal district of Guangxi, South China, were measured, aiming to investigate the contamination level, distribution and possible sources and to estimate the potential health risks of PAHs. The average concentrations of 16 PAHs in the coal, coal gangue, soil, surface water and groundwater were 5114.56, 4551.10, 1280.12 ng g(-1), 426.98 and 381.20 ng L(-1), respectively. Additionally, higher soil and water PAH concentrations were detected in the vicinities of coal or coal gangue dump. Composition analysis, isomeric ratio, Pearson correlation analysis and principal component analysis were performed to diagnose the potential sources of PAHs in different environmental matrices, suggesting the dominant inputs of PAHs from coal/coal combustion and coal gangue in the soil and water. Soil and water guidelines and the incremental lifetime risk (ICLR) were used to assess the health risk, showing that soil and water were heavily contaminated by PAHs, and mean ICLRcoal/coal-gangue and mean ICLRsoil were both significantly higher than the acceptable levels (1 × 10(-4)), posing high potential carcinogenic risk to residents, especially coal workers. This study highlights the environmental pollution problems and public health concerns of coal mining, particularly the potential occupational health hazards of coal miners exposed in Heshan.

Distribution Characteristics, Concentrations, and Sources of Cd and Pb in Laoxiawan Channel Sediments from Zhuzhou, China.

Twenty sediment cores encompassing surface (0-20 cm) and deeper (50-60 cm) sediment layers were retrieved from the 3000 m-long Laoxiawan Channel, which receives industrial effluents from Zhuzhou City (China). Analytical results showed that cadmium (Cd) concentrations ranged between 115.7-1126.7 and 108.8-2059.3 mg/kg while lead (Pb) values ranged between 234-3000 and 145-4292 mg/kg in the surface and bottom sediments, respectively. The results also indicated that high levels of Cd and Pb were present in the vicinity of the channel mouth and confluence area. Indices for potential ecological risk and geo-accumulation were used to evaluate the environmental effects and intensity of heavy metal pollution over time. High concentrations of Cd and Pb in the bottom sediments of Laoxiawan Channel were mainly associated with wastewater discharge (10(6) m(3)/year). Thus, the Laoxiawan Channel may be an important metal contaminant source for the Xiang River.

[Occurrence and Risk Assessment of N-nitrosamines and Their Precursors in Qingjiang River Basin].

N-nitrosamines are a type of nitrogen-containing organic pollutant with high carcinogenicity and mutagenicity. In the main drinking water sources of small and medium-sized towns in China, the contamination levels of N-nitrosamines remain unclear. In addition, there is still lack of research on the concentration of N-nitrosamines and their precursors in tributary rivers. In this study, eight N-nitrosamines and their formation potentials （FPs） were investigated in the Qingjiang River, which is a primary tributary of the Yangtze River. The sewage discharge sites were also monitored, and the environmental influencing factors, carcinogenic and ecological risks caused by N-nitrosamines, and their precursors were evaluated. The results showed that six N-nitrosamines were detected in water samples of the Qingjiang River, among which NDMA [（10 ±15） ng·L-1], NDEA [（9.3 ±9.3） ng·L-1], and NDBA [（14 ±7.8） ng·L-1] were the dominant N-nitrosamines, whereas seven N-nitrosamines were detected in chloraminated water samples, among which NDMA-FP [（46 ±21） ng·L-1], NDEA-FP [（26 ±8.3） ng·L-1], and NDBA-FP [（22 ±13） ng·L-1] were the dominant N-nitrosamine FPs. The concentrations of N-nitrosamines in the middle reaches of the Qingjiang River were higher than those in the upper and lower reaches. Furthermore, the concentrations of N-nitrosamines in the sample sites of sewage discharge and tributaries were significantly higher than those in other sampling sites. The monitoring results at the direct sewage discharge points indicated that the main source of N-nitrosamines in river water was the sewage carrying N-nitrosamines and their precursors. In addition, the concentrations of the three dominant N-nitrosamines including NDMA, NDBA, and NDEA were positively correlated with each other, mainly because of their similar sewage sources. The average carcinogenic risk to residents due to N-nitrosamine in drinking water sources was 2.4×10-5, indicating a potential carcinogenic risk. Moreover, due to the high concentrations of N-nitrosamine formation potentials in the Qingjiang River, the carcinogenic risk of drinking water may be even higher. The ecological risk assessment showed that the ecological risk quotient values of N-nitrosamines in the Qingjiang River watershed were lower than 0.002, which was negligible.

[Residues of Organochlorine Pesticides (OCPs) in Water and Sediments from Nansha Mangrove Wetland].

Mangrove wetland plays an important role in coastal environment. A total of 10 surface water samples and 7 surface sediments samples were collected in March, 2015 from Nansha mangrove wetland, and 8 compounds of organochlorine pesticides (OCPs) were determined by GC-ECD to investigate residues level, source, and ecological risk of these compounds in the study region. The result showed concentrations of OCPs in water ranged from 1.89 to 90.19 ng·L-1 (mean 30.16 ng·L-1), and concentrations of OCPs in sediments varied from 3.10 to 16.02 ng·g-1 (average 8.58 ng·g-1). Compared with other estuaries and harbors around the world, concentrations of OCPs in this study stayed at a median pollution level. The mean values of distribution coefficient of HCHs and DDTs between water and sediments were 857 and 368, respectively. Sediments in some parts of the area, whose distribution coefficient was relatively high, may bring water the secondary pollution. Source analysis indicated that HCHs mainly originated from the application of Lindane, and DDTs originated from mixed sources of dicofol and technical DDT. Compared with OCPs in water, OCPs in sediments might contain more historical residual components. OCPs in water had light ecological risk, but OCPs in sediments posed a potential high risk to mangrove ecosystem.

[Distribution Characteristics of Polycyclic Aromatic Hydrocarbons in Different Environmental Media from Qingbang Island, Zhoushan, China].

Eleven soil, three seawater and three passive air samples were collected from Qingbang Island in July, 2013, and 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed. The distribution characteristics, possible sources and ecological risk assessment were investigated. The results showed that the concentrations of total 16 PAHs ranged between 60.30 and 123.34 ng x g(-1) with a mean value of 105.49 ng x g(-1) in soil, 45.96-101.08 ng x L(-1) with a mean value of 66.45 ng x L(-1) in seawater and 5.09-5.41 ng x d(-1) with a mean value of 5.35 ng x d(-1) in air samples, respectively. The PAHls concentrations of soil samples in tidal zone were higher than those in other areas. The highest PAHs concentrations in seawater were detected in complicated hydrological sea area. PAHs concentrations in air were equally distributed around the island. 2-4 rings PAHs were dominant species in soil, water and air samples. Ratio method and factor analysis were used to identify the possible sources of PAHs. The result suggested that PAHs in soil were mainly originated from combustion of coal, wood, diesel and petrol, while the possible sources of PAHls in water and air were mixed. The ecological risk assessment indicated that PAi s in different environment media posed little risk to people.

[Distribution and enrichment characteristics of organochlorine pesticides in water and halobios from Qingbang Island in Zhoushan, China].

A total of 14 biological samples and 3 water samples were collected from the Qingbang Island. The concentrations of OCPs in the samples were determined by GC-ECD to investigate the distribution, composition, source and potential health risks of these compounds in the study area. The results showed that OCPs were detected in all samples. The detection ratios of OCPs were 100%. Concentrations of HCHs and DDTs ranged from 0.09 ng x g(-1) to 11.51 ng x g(-1) and 0. 02 ng x g(-1) to 56.15 ng x g(-1), respectively. Compared with other regions, the pollution of OCPs in Qingbang Island stayed at a low level. Distribution characteristics of OCPs in halobios from Qingbang Island indicated that changes in the upwelling and fronts were the main factors that affected the distribution of OCPs. Source analysis showed that HCHs and DDTs in halobios were mainly originated from the external. In addition, OCPs residues were far below the National Food Safety Standard. The estimated daily intake of OCPs from the halobios tested was also below the acceptable daily intake(ADI) recommended by FAO/WHO, indicating little health risk in halobios consumption for local residents.

[Distribution characteristics and risk assessment of organochlorine pesticides in soil from Jiufeng Mountain Range in Fujian, China].

Totally 81 surface soil samples were collected from Jiufeng Mountain Range, and 8 compounds of organochlorine pesticides (OCPs) were determined by a Ni electron capture detector (GC-ECD) to investigate the distribution, composition, source and potential health risks of these compounds in the study region. The detection ratio of HCHs and DDTs' isomers ranged from 77.78% to 100.00%. Concentrations of HCHs and DDTs in surface soils ranged from 0.97 ng x g(-1) to 247.40 ng x g(-1) (mean 10.17 ng x g(-1)) and 0.01 ng x g(-1) to 384.75 ng x g(-1) (mean 18.91 ng x g(-1)), respectively. Compared with other regions, the pollution of OCPs in Jiufeng Mountain Range stayed at a low level. The residue level in different types of lands was in the order as: paddy field > vegetable land > tea land > woodland. Source analysis indicated that Lindane and dicofol might be used recently in this area. The incremental lifetime, cancer risks (ILCRs) of different age groups (children, youths, and adults) were all within the acceptable risk range of 10(-6) to 10(-4) recommended by USEPA for carcinogenic chemicals. The residue level of OCPs in soil may not cause cancer risk for local residents basically.

[Distribution characteristics of organochlorine pesticides in soil from Daiyun Mountain Range in Fujian, China].

Totally 101 typical surface soil samples were collected from Daiyun Mountain Range, and 20 compounds of OCPs were analyzed by a Ni electron capture detector (GC-ECD) to investigate the horizontal distribution and composition of organochlorine pesticides (OCPs) in the surface soil of Daiyun Mountain Range. The results showed that all OCPs were detected in the soil samples. The detection ratios of OCPs were all over 90%, except for Endrin and beta-HCH. The sum concentration of HCHs, DDTs, Endosulfan and Endosulfan sulfate, accounted for 79.51% of the total OCPs, which were considered to be the dominant OCPs in the Daiyun Mountain Range. The OCPs concentrations in the surface soils ranged from 2.56 to 465.99 ng x g(-1) with a mean value of 38.00 ng x g)(-1). Compared with other regions, the concentrations of HCHs and DDTs in this study stayed in a low pollution level. Endosulfan and Endosulfan sulfate showed a certain degree of risk in the surface soil of the study area. Source analysis showed that new input of lindane and dicofol might occur in the survey region. The historical application was the prime source of Endosulfan. The residue level of OCPs in different lands was in the following order: paddy land > vegetable land > orchard. The OCPs pollution of orchard soil was primarily due to the new input of lindane and dicofol, while the pollution of paddy land was mainly from the usage of Endosulfan.