Spatial and seasonal characteristics of river water chemistry in the Taizi River in Northeast China

Anthropogenic activities have led to water quality deterioration in many parts of the world, especially in Northeast China. The current work investigated the spatiotemporal variations of water quality in the Taizi River by multivariate statistical analysis of data from the 67 sampling sites in the mainstream and major tributaries of the river during dry and rainy seasons. One-way analysis of variance indicated that the 20 measured variables (except pH, 5-day biological oxygen demand, permanganate index, and chloride, orthophosphate, and total phosphorus concentrations) showed significant seasonal (p?≤?0.05) and spatial (p?<?0.05) variations among the mainstream and major tributaries of the river. Hierarchical cluster analysis of data from the different seasons classified the mainstream and tributaries of the river into three clusters, namely, less, moderately, and highly polluted clusters. Factor analysis extracted five factors from data in the different seasons, which accounted for the high percentage of the total variance and reflected the integrated characteristics of water chemistry, organic pollution, phosphorous pollution, denitrification effect, and nitrogen pollution. The results indicate that river pollution in Northeast China was mainly from natural and/or anthropogenic sources, e.g., rainfall, domestic wastewater, agricultural runoff, and industrial discharge.     

Fraction characteristics of rare earth elements in the surface sediment of Bohai Bay, North China

Surface sediment samples were collected at 27 stations of Bohai Bay, North China. Sequential extractions were carried out in this study. REE were leached out from four labile fractions: Exchangeable (L1), bound to carbonates (L2), bound to Fe–Mn oxides (L3), bound to organic matter (L4), and the remainder was residual (R5). The total contents of REE fluctuate slightly in Bohai Bay, and are mainly concentrated in the middle region, showing relatively higher levels in the north than that in the south of Bohai Bay. Percentages of L1, L2, L3, L4, and R5 for REE suggest that the residual fraction accounts for the major component of REE, whereas Fe–Mn oxides also play important roles in combining labile REE. As the REE complex is not stabilized, the competition of complex could induce dissociation of the complex and redistribution of the REE in various environments. According to REE patterns and Y/Ho ratios of samples, REE are not anthropogenic or oceanic sources but riverine input, whereas suitable environment varieties can slightly affect the patterns and fractionations of REE. As powerful tracers for the variable of environment, higher anomaly of Eu and Ce in southern regions indicates a greater reduction in the condition of surface sediment in the south than that in the north of Bohai Bay.     

Comparative assessments of VOC emission rates and associated health risks from wastewater treatment processes

With the growing concern regarding emission of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs), the relationship between the VOC emission rates and the associated public health risks has been rarely discussed. The objective of this study was to examine and compare the VOC emission rates and cancer and non-cancer risks by inhalation intake, using a municipal WWTP in China as an example, with respect to the effects of treatment technologies, VOC species, and seasonal variation. Given the treatment technology considered, the emission rates of VOCs in this study were estimated by means of mass balance or calculated on the molecular level. From the viewpoints of both emission rates and cancer and non-cancer risks, sedimentation was the treatment technology with the highest health risks to the workers. Slightly lower VOC emission rates and health risks than those for sedimentation were observed in anaerobic treatment. Although the aeration significantly enhanced the VOC emission rates in the aerobic treatment process, the associated health risks were limited due to the low VOC concentrations in the gas phase, which were likely attributed to the strong mixing and dilution with fresh air by aeration. Amongst the VOCs investigated, benzene was the VOC with both a relatively high emission rate and health risk, while trichloroethylene possessed a high emission rate but the lowest health risk. Without strong interfacial aeration and turbulence between the water and atmosphere, the effects of treatment technology and seasonal variation on the health risks might be connected to the VOC emission rates, while the effect of VOC species depended considerably on the respective cancer slope factors and reference concentrations; the employment of aeration provided a different conclusion in which the emission rates were enhanced without a significant increase in the related cancer risks. These findings can provide insight into future health risk management and reduction strategies for workers in WWTPs.     

Removal of organic toxic chemicals using the spent mushroom compost of Ganoderma lucidum

The removal of the organic toxic chemicals di-n-butyl phthalate (DBP), di-2-ethyl hexyl phthalate (DEHP), nonylphenol (NP), and bisphenol-A (BPA) by laccase obtained from the spent mushroom compost (SMC) of the white rot fungi, Ganoderma lucidum, was investigated. The optimal conditions for the extraction of laccase from SMC required using sodium acetate buffer (pH 5.0, solid : solution ratio 1 : 5), and extraction over 3 h at 4 °C. The removal of NP was enhanced by adding CuSO(4) (1 mM), MnSO(4) (0.5 mM), tartaric acid (20 mM), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS; 1 mM), and 1-hydroxybenzotriazole (HBT; 20 mg L(-1)), with ABTS yielding a higher NP removal efficiency than the other additives. At a concentration of 2 mg L(-1), DBP, DEHP, NP, and BPA were almost entirely removed by laccase after incubation for 1 day. The removal efficiencies, in descending order of magnitude, were DBP > BPA > NP > DEHP. We believe that these findings could provide useful information for improving the efficiency of the removal of organic toxic chemicals in the environment.     

高氯低COD值水样的无汞快速测定法

以硝酸银和硫酸铬钾代替硫酸汞来消除 COD 测定中的氯离子干扰,同时将重铬酸钾溶液的浓度降低为0.100 mol／L,并用硫磷混酸代替硫酸,该方法经过对标准样品和实际样品的测定,表现出对于测定氯离子含量低于25000 mg／L的高氯低 COD 值水样具有较好的准确度和精密度,同时可以实现银盐的回收再利用。     

离子色谱法测定PM_(2.5)中硫酸根离子含量不确定度评议

准确测定大气颗粒物中水溶性组份对分析污染物来源及身体健康具有重要意义。本文采用离子色谱法测定PM2.5中硫酸根离子含量,并对测定的不确定度进行分析。分析过程不确定度来源是样品重复性测量引入不确定度,样品测量准确性引入不确定度和标准曲线的不确定度。应用不确定度评定理论,计算硫酸根离子的合成不确定度。结果表明,滤膜中硫酸根离子本底浓度高低与剪裁滤膜环节是不确定度的主要来源。为了提高分析的准确性,建议使用本底低的滤膜,并取整张滤膜进行分析。     

微波消解和ASD消解ICP-MS测定土壤中重金属元素的比较

采用微波消解和ASD消解2种消解方式对不同土壤样品进行消解,ICP-MS测定其中重金属含量。微波和ASD2种消解方式均能够较好地提取土壤中的Cr、Co、Ni、Mn和V元素,实验结果的相对误差和相对标准偏差均≤10%,符合实验分析的要求。微波消解精密度优于ASD,可作为优先选择的前处理方法。     

Toxicity of propargylic alcohols on green alga--Pseudokirchneriella subcapitata

The present study evaluates the toxicity of 34 propargylic alcohols, including primary, primary homo-, secondary, and tertiary alcohols, based on their effects on phytoplankton. A closed-system algal toxicity test was applied because the closed-system technique presents more realistic concentration-response relationships for the above compounds than the conventional batch tests. The green alga, Pseudokirchneriella subcapitata, was the test organism and final yield and growth rate were chosen as the test endpoints. Among all the propargylic alcohols tested, 1-pentyn-3-ol is the most toxic compound with its EC50 equal to 0.50 mg L(-1), which can be classified as a "R50" compound (very toxic to aquatic organisms, EC50/LC50 < 1 mg L(-1)), following the current practice for classification of chemicals in the European Union (EU). There are several other compounds including 2-decyn-1-ol, 3-decyn-1-ol, 1-hexyn-3-ol, 3-butyn-2-ol, and 3-hexyne-2,5-diol, which deserve more attention for their possible adverse impact on the aquatic environment, because these alcohols can be classified as "R51" compounds (toxic to aquatic organisms, EC50/LC50 between 1 and 10 mg L(-1)). Compared to the base-line toxicity relationship (narcosis QSAR) derived previously, tertiary propargylic alcohols can be identified as nonpolar narcotic chemicals, while secondary alcohols and primary alcohols with low molecular weight generally exhibit obvious excess toxicity in relation to the base-line toxicity. Finally, quantitative structure-activity relationships were established for deriving a preliminary estimation of the toxicity of other propargylic alcohols.