| Synthetic musks(SMs), as the cheap substitutes to natural musks, are used extensively as fragrant ingredients in a variety of scented household and personal care products. Due to continuous use and incomplete removal during the treatment processes, SMs are steadily introduced into the environment via STP effluent and sludge. Though used at low concentrations, consumption of large volumes and lengthy environmental persistence contribute to SMs detection in almost every environmental compartment. Recently, SMs as emerging persistent organic pollutants are receiving increased concern due to their potential environmental impacts(carcinogenicity, genotoxicity and mutagenicity, physiological ecotoxicity and environment hormone toxicity). A recent screening survey showed that SM concentrations in human blood in Harbin were the highest in China. The monitoring of SMs and determination of their fate in the Songhua River Basin deserves considerable attention. It is of great significance to study the occurrence, fate, transport and risk assessment of SMs in this river. We also simulated the distribution of SMs in multiphase media, and discussed the key scientific problem of single and jointed pollution of SMs and heavy metals.Contamination levels and spatial and temporal distributions of six typical SMs in water of the Songhua River were investigated. Solid phase extraction(SPE) followed by GC-MS assay were used to determine the pollution status of SMs in Songhua River water at 9 sampling points in different hydrological period. Experimental data showed that the Songhua River had been contaminated to different degrees at various sites separately from the river’s source. Total SMs contents in Songhua River surface water of August, 2008(high flow period), October, 2011(normal flow period), January, 2012(low flow period to frozen period) and April, 2012(low flow period to thawing period) were in the range of 0- 1.02, 0- 25.71, 0- 204.18 and 0- 254.44 ng/L, and mean values were 0.02, 2.14, 7.04 and 8.48ng/L, respectively. Concentrations of SMs in low flow period were higher than those in normal flow period and high flow period. Total SMs contents at sampling sites S5(downstream of Harbin City) was maximum. Concentrations of SMs at S5 was in the range of 0- 109.12 ng/L, and mean values was 3.03 ng/L. The second highest contents was found at sampling sites S8(downstream of Jiamusi City). These were directly related to the upstream runoff and municipal wastewater discharges from two city. The polycyclic musks HHCB were found most frequently and at the highest levels in the Songhua River, especially in the frozen period. Preliminary assessment of the impact of HHCB and AHTN, which were introduced by effluent of sewage treatment plant in Harbin City, on the aquatic environment were carried out. Concentrations of SMs of discharged sludge and wastewater in wastewater treatment plants of Harbin city were monitored to study the input properties of Songhua River. In Harbin wastewater treatment plants, 245.5g and 51.8g HHCB and AHTN were disposed through discharged sludge, buried and treated, causing a certain damage to soil environment. 92.8g and 22.5g HHCB and AHTN were eliminated through the wastewater entering Songhua River everyday, leading to the continuous accumulation of SMs in Songhua River, which confirms that drain outlet of the wastewater treatment plants along the river is a typical pollution source to Songhua River.Fate and transformation-transportation processes of two selected SMs(HHCB and AHTN) were also studied in our research. Sorption equilibriums of HHCB and AHTN were achieved in 24.0 h and adsorption process for the kinetics of the whole sorption followed the pseudo-second-order model. Intra-particle diffusion process was used to simulate the initial sorption bahavior, and the correlation coefficients were 0.981 and 0.983 for HHCB and AHTN, respectively. Adsorption and desorption of HHCB and AHTN on the sediment were nonlinear processes. Freundlich model can good fitted the isothermal adsorption and desorption processes. Higher correlation coefficients were HHCB: 0.978 and 0.984, AHTN: 0.982 and 0.966, respectively. Adsorption and desorption process have obvious hysteresis. Studies show that the physical and chemical properties of sediment(ionic strength, p H value and temperature), organic matter and coexisting pollutants(heavy metals, surfactants) could promote or inhibit the adsorption process. The biodegradation half-life period of HHCB and AHTN in Songhua River water varied with the hydrological period. However, the photo degradation under natural light had not changed significantly.A dynamic multimedia fate model was established to stimulate the fate and transport of HHCB in Songhua River. Based on the monitored data, source was evaluated. Simulated data agreed quite well with the survey results and coefficients of cauchy inequality were all below 0.5, therefore, it showed a good fitting. Environmental behavior of HHCB in the mainstream of Songhua River was systematically analyzed, and the HHCB cumulative mass flux in the simulation period was evaluated. Total input and output mass fluxed in all environment phases were 4.32×103 kg and 4.30×103 kg, the relative error is 0.5%. This indicated that HHCB kept mass balance in simulation time.Based on the measured data of SMs in surface water of Songhua River, biotoxicity effects of joint pollution of HHCB and heavy metal(Cd2 +, Cu2 +, Zn2 +) to physiological and biochemical indexes of coontail leaves were explored. Combined pollution of HHCB and heavy metal(Cd2 +, Cu2 +, Zn2 +) showed synergistic effect to the peroxide final product malondialdehyde(MDA) of leaf tissue and antagonistic effect to the concentrations of Chlorophyll. Therefore, content of Chlorophyll and MDA can be used as sensitive indicators for evaluating combined pollution in water environment. |
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