Identification of sources of elevated concentrations of polycyclic aromatic hydrocarbons in an industrial area in Tianjin, China

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector in 105 topsoil samples from an industrial area around Bohai Bay, Tianjin in the North of China. Results demonstrated that concentrations of PAHs in 104 soil samples from this area ranged from 68.7 to 5,590 ng g^???1 dry weight with a mean of ∑16PAHs 814 ± 813 ng g^???1, which suggests that there exists mid to high levels of PAH contamination. The concentration of ∑16PAHs in one soil sample from Tianjin Port was exceptionally high (48,700 ng g^???1). Ninety-three of the 105 soil samples were considered to be contaminated with PAHs (>200 ng g^???1), and 25 were heavily polluted (>1,000 ng g^???1). The sites with high PAHs concentration are mainly distributed around chemical industry parks and near highways. Two low molecular weight PAHs, naphthalene and phenanthrene, were the dominant components in the soil samples, which accounted for 22.1% and 10.7% of the ∑16PAHs concentration, respectively. According to the observed molecular indices, house heating in winter, straw stalk combustion in open areas after harvest, and petroleum input were common sources of PAHs in this area, while factory discharge and vehicle exhaust were the major sources around chemical industrial parks and near highways. Biological processes were probably another main source of low molecular weight PAHs.     

Contamination assessment of arsenic and heavy metals in a typical abandoned estuary wetland—a case study of the Yellow River Delta Natural Reserve

Coastal and estuarine areas are often polluted by heavy metals that result from industrial production and agricultural activities. In this study, we investigated the concentration trait and vertical pattern of trace elements, such as As, Cd, Ni, Zn, Pb, Cu, and Cr, and the relationship between those trace elements and the soil properties in coastal wetlands using 28 profiles that were surveyed across the Diaokouhe Nature Reserve (DKHNR). The goal of this study is to investigate profile distribution characteristics of heavy metals in different wetland types and their variations with the soil depth to assess heavy metal pollution using pollution indices and to identify the pollution sources using multivariate analysis and sediment quality guidelines. Principal component analysis, cluster analysis, and pollution level indices were applied to evaluate the contamination conditions due to wetland degradation. The findings indicated that the concentration of trace elements decreased with the soil depth, while Cd increases with soil depth. The As concentrations in reed swamps and Suaeda heteroptera surface layers were slightly higher than those in other land use types. All six heavy metals, i.e., Ni, Cu, As, Zn, Cr, and Pb, were strongly associated with PC1 (positive loading) and could reflect the contribution of natural geological sources of metals into the coastal sediments. PC2 is highly associated with Cd and could represent anthropogenic sources of metal pollution. Most of the heavy metals exhibited significant positive correlations with total concentrations; however, no significant correlations were observed between them and the soil salt and soil organic carbon. Soil organic carbon exhibited a positive linear relationship with Cu, Pb, and Zn in the first soil layer (0–20 cm); As, Cr, Cu, Ni, Pb, and Zn in the second layer (20–40 cm); and As, Cr, Cu, Ni, Pb, and Zn in the third layer (40–60 cm). Soil organic carbon exhibited only a negative correlation with Cd (P?I _geo values), which averaged less than 0 in the three soil layers, this finding indicates that the soils have remained unpolluted by these heavy metals. The mean concentrations of these trace elements were lower than Class I criteria. The degradation wetland restoration suggestions have also been provided in such a way as to restore the reserved flow path of the Yellow River. The results that are associated with trace element contamination would be helpful in providing scientific directions to restore wetlands across the world.     

Occurrence,sources, and ecological risks of PBDEs,PCBs, OCPs,and PAHs in surface sediments of the Yangtze River Delta city cluster,China

Polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) in 25 surface sediments in three cities (Nantong, Wuxi, and Suzhou) in the Yangtze River Delta, eastern China were measured. The mean concentrations were 378, 45.8, 1.98, 4,002 ng/g for PBDEs, OCPs, PCBs, and PAHs, respectively. Their levels in the sediments in the three cities were generally consistent with the city industrialization. PBDEs and OCPs were markedly dominated by deca-BDE (>90 %) and DDTs (>70 %). A principle component analysis of the analytes identified three major factors suggesting different sources of the contaminants in the sediments. PBDEs and the organic carbon in the sediments have common sources from industrial activities; whereas OCPs and PCBs, correlated with the second factor, were mainly from historical sources. The third factor with loadings of PAHs is indicative of various combustion sources. Ecological risk assessment indicated that the potential highest risk is from DDTs, for which 22 sites exceed the effects range low (ERL) values and three sites exceed the effects range median (ERM) value.     

广州市居民家庭室内灰尘中传统和新型阻燃剂与塑化剂的污染特征及健康风险评估

近年来,随着阻燃剂多溴联苯醚(PBDEs)和以邻苯二甲酸酯(PAEs)为代表的传统型塑化剂(LPs)的逐步禁用或限用,有机磷系阻燃剂(PFRs)等新型阻燃剂及替代型塑化剂(APs)的生产和使用呈逐年增长的趋势,其环境污染特征和人体暴露健康风险值得引起广泛关注.目前,灰尘已广泛用于室内环境中PBDEs、PFRs和LPs等半挥发性有机污染物(SVOCs)的污染特征评估,而关于室内灰尘中APs的污染特征则鲜有报道.本研究以广州市42户普通居民家庭为研究对象,采集家庭室内灰尘并分析了PFRs、PBDEs、LPs和APs的含量及组成特征.结果表明,PFRs、PBDEs、LPs和APs在室内灰尘中均有广泛检出,其含量分别为593.28～11531.56、13.45～27029.13、40494.83～1154497.16和15365.19～1013352.51 ng·g^-1.大多数家庭中,PFRs和部分APs在灰尘中的含量呈现高于PBDEs和LPs的特征,PFRs和APs等新型污染物的人体暴露健康风险需引起高度关注.采用暴露模型评估人体经灰尘摄入和皮肤接触对目标污染物的日均暴...     

类水滑石对污泥焚烧飞灰浸出液中磷的纯化

采用Mg-Fe型类水滑石（LDH）吸附剂提纯污泥焚烧飞灰（ISSA）浸出液中的磷,探究了吸附剂煅烧对磷吸附效果的影响及磷吸附和脱附机理.研究发现,在高浓度磷溶液（>1000mg/L）中,未煅烧的类水滑石（LDHu）磷吸附容量高于煅烧后的类水滑石（LDHc）.LDHu具有典型的层状结构,磷的吸附与脱附主要通过磷和金属离子沉淀-溶解、静电吸附-排斥、配位作用和离子交换实现.而LDHc层状结构消失,形成双金属氧化物,不存在明显的阴离子交换作用.经LDHu或LDHc吸附和NaOH溶液脱附后,ISSA浸出液均具有良好的磷纯化效果,磷相对纯度从36%分别上升至77%和69%,磷回收率分别为84%和57%.纯化后的溶液适合制备高值含磷产物.     

天津市中心城区集中供应管网末梢水的抗生素耐药基因污染特征研究

为了研究天津市中心城区集中供应管网末梢水的抗生素耐药基因(antibiotic resistance genes,ARGs)污染特征,采集了天津市中心城区6个采样点的管网末梢水样,分别采用微孔滤膜正压过滤法及核酸吸附-洗脱法富集水中细菌和胞外核酸后,利用实时定量PCR技术对15种胞内ARGs和胞外ARGs进行定量检测....     

CASS工艺脱氮影响因素分析

针对CASS工艺脱氮的效果不够理想、效率不高、出水不够稳定的现象，对脱氮的主要影响因素曝气时间、DO、温度、λ进行了生产性试验研究，分析结果表明，曝气时间3h，D02．5mg／L是本污水厂最合理的参数控制值，曝气时间3h时NH3-N和TN的平均去除率分别为89．7％和59．7％，D02．5mg／L时NH3-N和TN的平均去除率分别为94．5％和71．3％，脱氮效果良好；温度对脱氮的效果有很明显的影响，春季的脱氮效果明显好于冬季；脱氮效果随冲水比的增高而降低，但出水均达标说明CASS工艺有良好的抗冲击负荷的能力。     

A New Approach of BioCO2 Fixation by Thermoplastic Processing of Microalgae

Effective sequestration of carbon dioxide (CO₂) by algae reduces greenhouse gases effect on global warming. Algae biomass or residual such as biomeal from algae biofuel processing can be judiciously used for industrial applications such as fertilizer, animal feed, and plastics. Conversion of algae into useful plastic materials can be accomplished by extrusion technology. During algal plastic manufacturing, up to 20% thermoplastic algal blends can be fixated into or encapsulated by a non-biodegradable polymer such as polyolefin, which is known to be resistant to abiotic or biotic degradation. As a result, CO₂ that is captured by algae through photosynthesis is permanently stored in a form of biomass and will not be released back into the atmosphere. The extrusion of microalgae reported in this article is a novel process to sequester CO₂ and at the same time it makes a good use of the algae biomass in plastic manufacturing. Mechanical properties of the thin plastic films containing microalgae are comparable to the neat polyurethane or polyethylene films. Injection molded articles containing microalgae are dimensionally stable. However, a lower tensile strength, especially elongation at break, is observed in comparison to the neat polypropylene.     

新型电极及其电解阳离子染料染色模拟液研究

本文研制了一种可用于废水处理的新型阳极和阴极，研制电极电解处理离子染料色模拟液时，分解电压低，脱色率高，电能消耗少。