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C25H34O7, monoclinic, P21 (no. 4), a = 9.24730(10) Å, b = 9.9061(2) Å, c = 12.5907(2) Å, β = 101.264(2)°, V = 1131.15(3) Å3, Z = 2, Rgt(F) = 0.0380, wRref(F2) = 0.1025, T = 173 K.

C25H34O7, monoclinic, P21 (no. 4), a = 9.24730(10) Å, b = 9.9061(2) Å, c = 12.5907(2) Å, β = 101.264(2)°, V = 1131.15(3) Å3, Z = 2, Rgt(F) = 0.0380, wRref(F2) = 0.1025, T = 173 K. [ABSTRACT FROM AUTHOR]

C25H34O7, monoclinic, P21 (no. 4), a = 9.24730(10) Å, b = 9.9061(2) Å, c = 12.5907(2) Å, β = 101.264(2)°, V = 1131.15(3) Å3, Z = 2, Rgt(F) = 0.0380, wRref(F2) = 0.1025, T = 173 K. [ABSTRACT FROM AUTHOR]

Trace polycyclic aromatic hydrocarbons (PAHs) in drinking water sources have significant harmful effects on human health. Water and sediment samples from water source regions of three water treatment plants in Guangzhou were collected and the distributions of 16 kinds of PAHs were analyzed. The human risk of PAHs in the water samples was also evaluated using the Risk Assessment Guidance for Superfund (RAGS) of the United States Environmental Protection Agency (USEPA). The results showed that PAHs in the samples from the three water source regions did not exceed the corresponding standard limit for water quality, and the content of ΣPAHs in suspended solids and sediments was below the medium level. The non-carcinogenic risks (HQ and HI) of PAHs in the water samples were less than 1, and the non-carcinogenic risk was negligible. In addition, Risk ingest , Risk dermal , and Risk T for the waters were all in range of 5.53×10 -7 to 5.34×10 -6 , indicating that a carcinogen risk was possible but acceptable. The results of the isomer ratio method indicated that the PAHs in the water sources of the three water plants had a mixed input of pollution, including petroleum discharge, petroleum combustion, and incomplete combustion of wood, coal, and biomass. The total organic carbon (TOC) content of the water and sediment samples was positively correlated with the accumulation and enrichment of low-ring PAHs, and there was a significant positive correlation between PAHs and similar molecules in the sediments. The ΣPAHs in the water and sediment samples were also strongly correlated.

The distribution characteristics and pollution degrees of 20 organochlorine pesticides (OCPs) were investigated in surface sediments from Zhelin Bay south of China and the ecological risk of OCPs and integrated ecological risk at the samples stations in sediments were evaluated by risk quotient (RQ) and sediment quality guideline of NOAA. The possible sources of HCHs and DDTs in sediments were preliminarily studied, and the correlation between OCPs and sediment characteristic parameters was discussed. The concentrations of DDTs in surface sediments were found to be higher than those of other OCPs, especially p,p' -DDD, and the concentrations of DDTs were higher than the limited values of Chinese Marine sediment quality criteria. The total concentration of 20 OCPs in surface sediments ranged from 14.14 to 306.88 ng·g -1 , with a mean concentration of 78.37 ng·g -1 , and the highest total concentration was at site 8(S8). There were inevitable adverse biological effects and high ecological risk of p,p' -DDD and p,p' -DDT, high integrated ecological risk at S8 and S10. The possible sources of HCHs in surface sediments of Zhelin Bay were mainly from the application of Lindane pesticides. At S1,S2,S10,S11 there was input of DDT into mariculture area of Zhelin Bay, and at the other sites the sources of DDT were from the early residue in sediments or the long-term weathering sediments of using pesticides. There was a very significant positive correlation between HCHs, endosulfan, chlordane and dieldrin in sediments, while there was a negative relation between the above OCPs and TOC, which indicated that the presence of TOC could promote their biodegradation. There was a significant positive correlation between p, p' -DDD and Ca, which revealed that DDT used in the early period was deposited with biological carbonate. Increasing size of sediment particles discouraged the accumulation and enrichment of OCPs in sediments.

This study aimed to investigate the pollution degree and human health risk of heavy metals in soil and air samples around electroplating factories. Soil, air and waste gas samples were collected to measure 8 heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in two electroplating factories, located in Baiyun district of Guangzhou city. Geoaccumulation index and USEPA Risk Assessment Guidance for Superfund (RAGS) were respectively carried out. Results showed that concentrations of Hg and Pb in waste gas and Cr in air samples were higher than limits of the corresponding quality standards, and concentrations of Cd, Hg and Zn in soil samples reached the moderate pollution level. The HQ and HI of exposure by heavy metals in air and soil samples were both lower than 1, indicating that there was no non-carcinogen risk. CRAs and CRCr in soil samples were beyond the maximum acceptable level of carcinogen risk (10(-4)), and the contribution rate of CRCr to TCR was over 81%. CRCr, CRNi and TCR in air samples were in range of 10(-6) - 10(-4), indicating there was possibly carcinogen risk but was acceptable risk. CR values for children were higher than adults in soils, but were higher for adults in air samples. Correlation analysis revealed that concentrations of heavy metals in soils were significantly correlated with these in waste gas samples, and PCA data showed pollution sources of Cd, Hg and Zn in soils were different from other metals.

Contents of heavy metals in different sewage sludges were analyzed and the speciation distribution and bioavailability of heavy metals were investigated, and the risk assessment code (RAC) and toxicity characteristic leaching procedure for solid waste were used to evaluate the potential ecological risk and leaching toxicity risk of heavy metals in sludge samples, respectively. The results showed that contents of Cu, Cr, Pb and Zn were high and presented a great difference by different sources in sewage sludges. Most of heavy metals existed in non-residual fractions and percentages of the mobile fraction (acid soluble fraction) of heavy metals in acidic sludge were higher. According to the results of single extraction, 1 mol x L(-1) NaOAc solution (pH 5.0) and 0.02 mol x L(-1) EDTA + 0.5 mol x L(-1) NH4OAc solution (pH 4.6) were suitable for evaluating bioavailable heavy metals in acidic and alkaline sludge, respectively. Percentages of bioavailable heavy metals were higher with the stronger of sludge acidity. The mobile ability of heavy metals resulted in the high ecological risk of sludge samples, and the bioavailability of heavy metals caused acidic sludges with a very high ecological risk but alkaline sludges with the middle ecological risk. Leaching toxicity risk was very high in sludge samples except domestic sewage sludge. After the removal of bioavailable heavy metals, leaching toxicity risk of sludge samples was still high in spite of its decrease; however, part type of sludges could be implemented landfill disposal.

The adsorption behavior of exogenous thorium on soil was studied to evaluate the contaminated risk on soil. The adsorption capacity, equilibrium time, distribution coefficient and desorption ability were investigated by the experiments of static adsorption. The strong adsorption ability of exogenous thorium on soil samples was observed by high adsorption ratio (> 92%) and low desorption ratio (< 5%) in equilibrium, and the biggest distribution coefficient was over 10(4). The adsorption capacity and equilibrium time were related to soil properties. According to the results of adsorption, Freundlich equation (r > or = 0.9167) and Elovich equation (R2 > or = 0.8980) were primely fit for describing the thermodynamics and kinetics of the adsorption of exogenous thorium on soil samples, respectively, which indicated that the adsorption was belonged to the nonlinear adsorption, and was affected by the diffusion of thorium on soil surface and in mineral interbed. Sequential extraction procedure was employed to evaluate the bound fractions of exogenous thorium adsorbed on soil samples. Based on the extracted results of thorium fractions, exogenous thorium was presented in the labile nonresidual fractions (over 58%) at the low initial concentration (10(-7) - 10(-6) mol x L(-1)), and nonresidual fractions enhanced with the increase of the initial amount, meanwhile more exogenous throium was transferred to the stable residual fractions.