吹扫捕集-气相色谱联用同时测定水中致嗅挥发性有机硫化物

建立了一种利用吹扫捕集(PT)-气相色谱(GC)/火焰光度检测器(FPD)同时测定水中16种致嗅类有机硫化物的分析方法。研究并优化了捕集阱类型、吹扫温度、吹扫时间,解吸温度以及解吸时间对PT的影响。实验表明:大部分硫醚类和硫醇类化合物分别在1~100 ng/L和3~300 ng/L范围内线性良好,线性相关系数大于0.99;相对标准偏差小于9.47%(n=6);加标回收率为81.68%~115.18%。定量下限(10倍信噪比)范围从0.19 ng/L(二乙基二硫醚)到2.67 ng/L(2-甲基-1-丙硫醇)。采用此方法对北京市3条河流水样进行了检测,除1-丙基二硫醚和2-甲基-2-丙硫醇外,其他14种有机硫化物都有检出,质量浓度为1.95~1 282.35 ng/L。     

Hg-CEMS系统中元素汞发生器的溯源和质控方法研究

参考借鉴美国IEMGTP元素汞溯源协议中规定的4个溯源传递层级以及4种常用的成熟溯源质控方法,研究了在中国现有技术条件下,各种质控方法针对Hg-CEMS中元素汞发生器User generator进行质控的适用性。通过对不同质控方法的测试,显示通过可吸附元素汞的活性炭吸附管采样分析（美国EPA 30B方法）和通过汞渗透源两种对元素汞发生器进行质控的方法在中国目前是可行且科学、可靠的。同时对建立和完善中国的元素汞溯源协议和元素汞发生器质控方法提出了建议。     

吹扫捕集-气相色谱/质谱法测定水中的乙醛、丙烯醛、丙烯腈和吡啶

水中的乙醛、丙烯醛、丙烯腈和吡啶经吹扫捕集、解吸后,用HP-VOC毛细管色谱柱进行GC分离,用GC-MS法选择离子模式(SIM)下进行检测,外标法定量。结果表明,选择取样量25 m L,吹扫流量为40 m L/min,吹扫温度为40℃,吹扫时间为15 min,解吸时间为2 min,解吸温度为200℃,烘焙时间20 min,乙醛和吡啶质量浓度在0.025~0.60 mg/L之间,丙烯醛和丙烯腈质量浓度在0.002 5~0.10 mg/L之间时,校准曲线呈线性关系,相关系数r0.995,乙醛、丙烯醛、丙烯腈和吡啶的方法检出限分别为0.001 6,0.001 3,0.000 5和0.002 1 mg/L。对3个不同浓度样品进行空白加标实验,测量的回收率为87.8%~114.3%,相对标准偏差(n=6)为2.51%~10.4%。对3批实际水样进行分析,其中一个废水水样加标回收率为79.2%~103.8%,相对标准偏差(n=6)为3.04%~6.39%。     

碱熔浸取-离子选择电极法测定沉积物中总氟

采用氢氧化钠高温熔融浸取沉积物,用离子选择电极法测定浸取液中的总氟,通过试验确定最佳浸取条件,使方法在5.00μg~500μg范围内线性良好。当取样量为0.2 g时,方法检出限为12.4 mg/kg。用该方法测定沉积物有证标准物质,结果均在标准值范围内,测定3个沉积物实际样品,总氟质量比为254 mg/kg~1 389 mg/kg,6次测定结果的RSD为4.1%~4.8%,3个质量比水平加标回收率为99.2%~101%。     

环境因子对长江宜宾段底泥吸附磷的影响

本文主要研究模拟长江底泥对富营养化水体磷的吸附,分析环境因子对底泥吸附磷的影响。结果显示：（1）在25℃时,底泥对磷的吸附在碱性条件时的吸附速率小于酸性和中性条件,中性条件下的吸附速率最大;（2）在控制上覆水温度时,温度越高底泥对磷的吸附量越小,20℃时底泥的吸附量是30℃吸附量的1.5倍;（3）上覆水中溶解氧的浓度越高,吸附速率越高。     

Determination of organochlorine pesticide residue in sediment and water from the Densu river basin, Ghana

The distribution of organochlorine pesticides in the aquatic ecosystem from the Densu river revealed varying levels of concentration in water and the sediment samples. Three locations were sampled along the river to evaluate the levels of organochlorine pesticide residue in the river. Sediment and surface water samples were extracted by soxhlet and liquid-liquid extraction respectively and analyzed using Gas Chromatograph coupled with electron capture detector. The detectable organochlorine pesticides were gamma-hexachlorocyclohexane (HCH), delta-hexachlorocyclohexane, heptachlor, aldrin and dieldrin. The other pesticides that were investigated are gamma-chlordane, alpha endosulfan, endosulfan sulfate, p,p′-DDT and its metabolite p,p′-DDE, methoxychlor, endrin and its metabolite endrin aldehyde and endrin ketone. The order of increasing frequency of detection of samples was higher in sediment than water. In sediment, the mean concentration ranged from 0.030 μg kg⁻¹ dry weight (endrin) to 10.98 μg kg⁻¹ dry weight (aldrin). The highest detected concentration of organochlorine in water was endosulfan sulfate with mean concentration of 0.185 μg L⁻¹. Analysis of variance indicated significant differences for most organochlorine pesticide residue in the sediment sampled from the various locations. Some of the levels of organochlorine pesticides detected in water were relatively high compared to guideline values set by World Health Organization and Australia and thus could be harmful if the trend is not checked.     

Sorption and desorption of carbamazepine, naproxen and triclosan in a soil irrigated with raw wastewater: estimation of the sorption parameters by considering the initial mass of the compounds in the soil

The amphipod Hyalella azteca was exposed for 28 d to different combinations of Zn contaminated sediment and food. Sediment exposure (+clean food) resulted in increased Zn body burdens, increased mortality and decreased body mass when the molar concentrations of simultaneously extracted Zn were greater than the molar concentration of Acid Volatile Sulfide (SEM_Zn-AVS > 0), suggesting that dissolved Zn was a dominant route of exposure. No adverse effect was noted in the foodexposure (+clean sediment), suggesting selective feeding or regulation. Combined exposure (sediment + food) significantly increased adverse effects in comparison with sediment exposure, indicating contribution of dietary Zn to toxicity and bioaccumulation. The observed enhanced toxicity also supports the assumption on the presence of an avoidance/selective feeding reaction of the amphipods in the single sediment or food exposures. During 14 d post-exposure in clean medium, the organisms from the same combined exposure history received two feeding regimes, i.e. clean food and Zn spiked food. Elevated Zn bioaccumulation and reduced reproduction were noted in amphipods that were offered Zn spiked food compared to the respective organisms that were fed clean food. This was explained by the failure of avoidance/selective feeding behavior in the absence of an alternative food source (sediment), forcing the amphipods to take up Zn while feeding. Increasing Zn body burdens rejected the assumption that Zn uptake from food was regulated by H. azteca. Our results show that the selective feeding behavior should be accounted for when assessing ecological effects of Zn or other contaminants, especially when contaminated food is a potential exposure route.     

Volatile organic compounds at swine facilities: A critical review

Volatile organic compounds (VOCs) are regulated aerial pollutants that have environmental and health concerns. Swine operations produce and emit a complex mixture of VOCs with a wide range of molecular weights and a variety of physicochemical properties. Significant progress has been made in this area since the first experiment on VOCs at a swine facility in the early 1960s. A total of 47 research institutions in 15 North American, European, and Asian countries contributed to an increasing number of scientific publications. Nearly half of the research papers were published by U.S. institutions.Investigated major VOC sources included air inside swine barns, in headspaces of manure storages and composts, in open atmosphere above swine wastewater, and surrounding swine farms. They also included liquid swine manure and wastewater, and dusts inside and outside swine barns. Most of the sample analyses have been focusing on identification of VOC compounds and their relationship with odors. More than 500 VOCs have been identified. About 60% and 10% of the studies contributed to the quantification of VOC concentrations and emissions, respectively. The largest numbers of VOC compounds with reported concentrations in a single experimental study were 82 in air, 36 in manure, and 34 in dust samples.The relatively abundant VOC compounds that were quantified in at least two independent studies included acetic acid, butanoic acid (butyric acid), dimethyl disulfide, dimethyl sulfide, iso-valeric, p-cresol, propionic acid, skatole, trimethyl amine, and valeric acid in air. They included acetic acid, p-cresol, iso-butyric acid, butyric acid, indole, phenol, propionic acid, iso-valeric acid, and skatole in manure. In dust samples, they were acetic acid, propionic acid, butyric acid, valeric acid, p-cresol, hexanal, and decanal. Swine facility VOCs were preferentially bound to smaller-size dusts.Identification and quantification of VOCs were restricted by using instruments based on gas Chromatography (GC) and liquid chromatography (LC) with different detectors most of which require time-consuming procedures to obtain results. Various methodologies and technologies in sampling, sample preparation, and sample analysis have been used. Only four publications reported using GC based analyzers and PTR-MS (proton-transfer-reaction mass spectrometry) that allowed continuous VOC measurement. Because of this, the majority of experimental studies were only performed on limited numbers of air, manure, or dust samples. Many aerial VOCs had concentrations that were too low to be identified by the GC peaks.Although VOCs emitted from swine facilities have environmental concerns, only a few studies investigated VOC emission rates, which ranged from 3.0 to 176.5 mg d⁻¹ kg⁻¹ pig at swine finishing barns and from 2.3 to 45.2 g d⁻¹ m⁻² at manure storages. Similar to the other pollutants, spatial and temporal variations of aerial VOC concentrations and emissions existed and were significantly affected by manure management systems, barn structural designs, and ventilation rates.Scientific research in this area has been mainly driven by odor nuisance, instead of environment or health concerns. Compared with other aerial pollutants in animal agriculture, the current scientific knowledge about VOCs at swine facilities is still very limited and far from sufficient to develop reliable emission factors.     

What Do the Occurrences of Migratory Fishes in the Upper Mekong Mean?

This paper examines the recent appearance of four migratory species in the Upper Mekong: Dasyatis laosensis, Anguilla bicolor, Anguilla marmorata, and Chitala ornata. Since 2006 these species have been continually sampled in an area below Jinghong Dam in Xishuangbanna, China. This region is far beyond their historical upstream distribution, and the reasons for these appearances and their subsequent impact on river ecosystem are considered.     

Determination of cyclic volatile methylsiloxanes in water,sediment, soil,biota, and biosolid using large-volume injection–gas chromatography–mass spectrometry

Several methods were developed to detect the cyclic volatile methylsiloxanes (cVMSs) including octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) in water, sediment, soil, biota, and biosolid samples. Analytical techniques employed to optimize measurement of this compound class in various matrices included membrane-assisted solvent extraction in water, liquid–solid extraction for sediment, soil, biota, and biosolid samples. A subsequent analysis of the extract was conducted by large-volume injection–gas chromatography−mass spectrometry (LVI−GC−MS). These methods employed no evaporative techniques to avoid potential losses and contamination of the volatile siloxanes. To compensate for the inability to improve detection limits by concentrating final sample extract volumes we used a LVI–GC–MS. Contamination during analysis was minimized by using a septumless GC configuration to avoid cVMS’s associated with septum bleed. These methods performed well achieving good linearity, low limits of detection, good precision, recovery, and a wide dynamic range. In addition, stability of cVMS in water and sediment was assessed under various storage conditions. D4 and D5 in Type-I (Milli-Q) water stored at 4 °C were stable within 29 d; however, significant depletion of D6 (60–70%) occurred only after 3 d. Whereas cVMS in sewage influent and effluent were stable at 4 °C within 21 d. cVMS in sediment sealed in amber glass jars at −20 °C and in pentane extracts in vials at −15 °C were stable during 1 month under both storage conditions.