气相色谱法测定环境空气中氯化苄和甲苯

用串联的乙醇吸收管收集环境空气中的氯化苄和甲苯,以毛细管柱分离,氢火焰检测器测定,保留时间定性,峰高定量。氯化苄平均浓度在４．２９ｍｇ／Ｌ～２１．４ｍｇ／Ｌ时,相对标准偏差在３．３％～４．６％之间;甲苯平均浓度为４．１８ｍｇ／Ｌ～２０．６ｍｇ／Ｌ时,相对标准差在４．４％～７．８％范围内。方法快速、灵敏度高,有较好的精密度与准确度。     

Genotypic and environmental variation in chromium, cadmium and lead concentrations in rice

Genotypic and environmental variation in Cr, Cd and Pb concentrations of rice grains and the interaction between these metals were investigated by using 138 rice genotypes grown in three contaminated soils. There were significant genotypic differences in the three heavy metal concentrations of rice grains, with the absolute difference among 138 genotypes in grain Cr, Cd and Pb concentrations being 24.5-, 9.1- and 23.8-folds, respectively, under the slightly contaminated soil (containing 4.61mgkg(-1) Cr, 1.09mgkg(-1) Cd and Pb 28.28mgkg(-1), respectively). A highly significant interaction occurred between genotype and environment (soil type) in the heavy metal concentrations of rice grains. Cr concentration in rice grains was not correlated with Cd and Pb concentration. However, there was a significant correlation between Cd and Pb in slightly and highly contaminated soils. The results suggest the possibility to develop the rice cultivars with low Cd and Pb concentrations in grain.     

Distribution and sources of polycyclic aromatic hydrocarbons in surface sediments of rivers and an estuary in Shanghai, China

Concentrations, spatial distribution and sources of 17 polycyclic aromatic hydrocarbons (PAHs) and methylnaphthalene were investigated in surface sediments of rivers and an estuary in Shanghai, China. Total PAH concentrations, excluding perylene, ranged from 107 to 1707 ng/g-dw. Sedimentary PAH concentrations of the Huangpu River were higher than those of the Yangtze Estuary. The concentration of the Suzhou River was close to the average concentration of the Huangpu River. PAHs source analysis suggested that, in the Yangtze Estuary, PAHs at locations far away from cities were mainly from petrogenic sources. At other locations, both petrogenic and pyrogenic inputs were significant. In the Huangpu and Suzhou Rivers, pyrogenic input outweighed other sources. The pyrogenic PAHs in the upper reaches of the Huangpu River were mainly from the incomplete combustion of grass, wood and coal, and those in the middle and lower reaches were from vehicle and vessel exhaust.     

Levels and distribution of polybrominated diphenyl ethers in plant, shellfish and sediment samples from Laizhou Bay in China

Polybrominated diphenyl ethers (PBDEs) are potentially harmful and persistent environmental pollutants. PBDEs concentrations are reported in plant, shellfish and sediment samples collected from Chinese Laizhou Bay. The summation operator(11)PBDE concentrations in plant and shellfish samples from Laizhou Bay were in the range of 70-5900ngg(-1) and 230-720ngg(-1) lipid, respectively. The summation operator(11)PBDEs concentrations in river sediment intervals samples ranged from 1.3 to 1800ng g(-1) dry weight. Pearson correlation analyses were performed on concentrations of PBDEs congeners of different sediment sample intervals. There were significant positive correlations for BDE 28 and BDE 100 (r=0.945, p<0.01), BDE 47 and BDE 99 (r=0.879, p<0.01), BDE 153 and BDE 154 (r=0.934, p<0.01), nona-BDEs and BDE 209 (r>0.934, p<0.01). BDE 209 was the predominant congener in all analyzed samples, consistent with the fact that deca-BDE technical mixtures are the dominant PBDEs product in Laizhou Bay. Data showed that PBDEs should be considered as an increasing pollution problem in the Laizhou Bay region.     

Comparison of receptor models for source apportionment of volatile organic compounds in Beijing, China

Identifying the sources of volatile organic compounds (VOCs) is key to reducing ground-level ozone and secondary organic aerosols (SOAs). Several receptor models have been developed to apportion sources, but an intercomparison of these models had not been performed for VOCs in China. In the present study, we compared VOC sources based on chemical mass balance (CMB), UNMIX, and positive matrix factorization (PMF) models. Gasoline-related sources, petrochemical production, and liquefied petroleum gas (LPG) were identified by all three models as the major contributors, with UNMIX and PMF producing quite similar results. The contributions of gasoline-related sources and LPG estimated by the CMB model were higher, and petrochemical emissions were lower than in the UNMIX and PMF results, possibly because the VOC profiles used in the CMB model were for fresh emissions and the profiles extracted from ambient measurements by the two-factor analysis models were "aged".     

Titanium dioxide mediated photocatalytic degradation of 17beta-estradiol in aqueous solution

Photocatalytic degradation of 17beta-estradiol (E2) in aqueous medium mediated with titanium dioxide (TiO(2)) was studied. Moreover, effect of TiO(2) dosage on the degradation efficiency was investigated. Particular attention was paid to the identification of intermediates and analysis of photocatalytic degradation mechanism of E2 under neutral and alkaline conditions. The degradation efficiency of E2 increased with increasing concentration of TiO(2) but decreased due to light scattering as TiO(2) concentration was greater than 0.5mgml(-1). Several intermediates were formed during photocatalytic degradation of E2. However, only a few of the compounds could be identified and confirmed by LC-MS and LC-MS/MS. Six intermediates were observed by photocatalytic oxidation under alkaline conditions, namely 2-hydroxyestradiol, 10epsilon-17beta-dihydroxy-1,4-estradien-3-one (DEO), 10epsilon-hydroperoxide-17beta-hydroxy-1,4-estradien-3-one and three kinds of dicarboxylic acids formed by the opening of aromatic ring. In addition to the six intermediates mentioned above, 17beta-hydroxy-1,4-estradien-3-one (EO) was observed under neutral conditions and in the presence of methanol. Based on these intermediates, which were hardly degraded even after E2 was fully degraded, the mechanism of E2 degradation by TiO(2) photocatalysis was elucidated.     

土壤中有机污染物运移模型的对比分析

分别建立了考虑非平衡吸附和生物降解的单区域溶质运移动力学模型(简称单区域模型)和两区域溶质运移动力学模型(简称两区域模型),基于数值模拟方法,对两种模型进行了定量的对比分析.分析结果表明,参与流动的水分的含量、不可动水区的持留释放能力是影响污染物在土壤-水环境中分配规律以及两种模型模拟结果之间差异的重要因素;较大的可动水区和不可动水区之间的质量转移系数,可以通过增加持留释放能力而增强不可动水区对溶质运移的影响能力,因此在模拟过程中不应单纯依据不可动水的含量大小来确定采用何种模型进行模拟,而应同时考虑可动水区和不可动水区之间的质量转移系数对模拟效果的影响.     

气升式内循环蜂窝陶瓷反应器高效快速修复地表水的研究

采用新型蜂窝陶瓷载体气升式内循环反应器(IAL-CHS)对受污染的城市地表水进行生物修复,该反应器能快速有效地修复受污染水体.考查了氨氮的变化历程、HRT与氨氮去除率间的关系,确定了最佳HRT为20 min.在HRT为20 min、接触反应时间仅为14 min条件下,该反应器对氨氮、TP、COD、TOC、浊度、UV254的去除率分别为86.7%～96.2%、4.5%～34.4%、15.5%～63.6%、5.8%～38.1%、9.4%～88.3%、3.8%～48.5%.     

Residues of organochlorine pesticides (OCPs) in aquatic environment and risk assessment along Shaying River,China

Organochlorine pesticides (OCPs) are pesticides with global scale ubiquity, persistence and bioaccumulation, which leave long-term residuals in the water body. OCPs’ high toxicity poses significant threats to human health and aquatic biodiversity, making assessment of OCPs’ impact on aquatic ecology and human health urgently necessary. In this research, the presence of 16 OCPs in surface water and groundwater along Shaying River, China, as well as OCPs concentration correlations, was investigated at 24 selected sampling sites. At the same time, the ecological risk and human carcinogenic risk were also analyzed by risk quotient method and USEPA’s Risk Assessment Guidance, respectively. Results showed that the total concentration of OCPs ranged from 21.0 to 61.4 ng L^?1 in groundwater, and 12.3–77.5 ng L^?1 in surface water. Hexachlorocyclohexane (HCHs) and heptachlor were the prominent contaminants in groundwater, which indicated their use in the recent past and confirmed their persistence. The α-HCH/γ-HCH ratios in groundwater confirmed that γ-HCH (lindane) was used as main substitute of technical HCH in the study area. The correlation analysis illustrated that δ-HCH and γ-HCH played a dominant role in HCHs residue. Heptachlor and α-HCH, as well as endosulfan and heptachlor epoxide, had a strongly significant positive correlation, suggesting an associated usage of the two pair OCPs. An extremely high ecological risk for aquatic organism was observed for γ-HCH, heptachlor and dieldrin, while the carcinogenic risks posed by the selected OCPs in surface water and groundwater were all acceptable.     

4种烟嘧磺隆多元复配除草剂对意大利蜜蜂和玉米螟赤眼蜂的急性毒性及初级风险评估

为明确4种烟嘧磺隆复配除草剂对意大利蜜蜂和玉米螟赤眼蜂的急性毒性影响并评估其初级风险。采用饲喂法、点滴法和玻璃管药膜法,分别测定了8%烟嘧·氯吡嘧磺隆、16%烟嘧·硝磺·氯吡嘧磺隆、36%烟嘧·莠去津和22%烟嘧·氯吡·氯氟吡氧乙酸异辛酯对意大利蜜蜂成年工蜂和玉米螟赤眼蜂的急性毒性,并分别采用危害商值和安全系数进行初级风险评估。结果表明,上述4种制剂对意大利蜜蜂成年工蜂的经口毒性48 h-LD_(50)(半致死剂量,median lethal dose)分别为68.03、1.60×10~2、1.40×10~2和100μg a.i.·蜂-1,接触毒性48 h-LD_(50)分别为18.53、53.01、89.98和100μg a.i.·蜂-1,危害商值均小于50,对意大利蜜蜂均为低毒且低风险。4种制剂对玉米螟赤眼蜂的急性毒性24 h-LR50(半致死用量,median lethal rate)分别为1.88×10~(-4)、5.46×10~(-4)、2.12×10~(-3)和1.68×10~(-3)mg a.i.·cm~(-2),安全系数分别为0.16、0.23、0.59和0.51,其中8%烟嘧·氯吡嘧磺隆和16%烟嘧·硝磺·氯吡嘧磺隆对玉米螟赤眼蜂为高风险性,36%烟嘧·莠去津和22%烟嘧·氯吡·氯氟吡氧乙酸异辛酯为中等风险性。因此,这4种复配制剂对蜜蜂成年工蜂的风险性较低,但对赤眼蜂的风险性较高,所以在喷洒防除期间应与赤眼蜂释放期错开。