Polybrominated diphenyl ethers and polychlorinated biphenyls in sediments of southwest Taiwan: regional characteristics and potential sources

Very little information is available on the contamination of coastal sediments of Taiwan by PBDEs and PCBs. In this study, we determined the concentrations of 19 PBDE and 209 PCB congeners in 57 surface sediment samples to identify the possible sources of PBDEs and PCBs. The total PBDE and PCB concentrations ranged from below detection limit to 7.73 ng/g and 0.88-7.13 ng/g, respectively; these values are within the ranges observed for most coastal sediments worldwide. The PBDE congeners were dominated by BDE-209 (50.7-99.7%), with minor contributions from penta- and octa-BDEs. The signatures of PCB congeners suggested that PCB residues in Kaohsiung coast may be the legacy of past use or the result of ongoing inputs from the maintenance, repair and salvage of old ships. Principal component analysis of the congener-specific composition of PBDEs and PCBs revealed distinct regional patterns that are related to the use of commercial products.     

江西省兴源冲铜矿床同位素地球化学特征及成矿机制探讨

兴源冲铜矿床地处九岭南缘铜多金属大型矿集区西段的黄茅地区。文章在成矿地质特征的基础上,通过对矿石进行稳定同位素地球化学研究,重点分析了成矿物质来源,探讨了矿床成矿机制。碳、氧同位素分析结果表明,矿区碳酸盐岩δ13CVPDB为-5·4‰～1·9‰,平均为0·6‰,δ18OSMOW变化范围为9·0‰～13·9‰,平均为10·9‰,主要为海相碳酸盐岩,碳、氧同位素图解表明碳可能主要来源于深部,且受高温变质作用和低温蚀变作用明显;矿石硫化物硫同位素δ34S变化范围主要在1·0‰～6·2‰之间,个别样品同位素比值偏大,对比相似矿床,表明该矿床具有海底喷流沉积和后期岩浆热液叠加作用的特征。上述同位素地球化学特征表明,兴源冲铜矿床是在中元古代海底火山沉积基础上,经新元古代晋宁造山期岩浆热液、动力变质叠加成矿作用所形成。     

北京市表层土壤中PAHs含量特征及来源分析

土壤,作为城市中最重要的环境介质,承担了较高多环芳烃(PAHs)的环境负荷,开展土壤PAHs分布特征及来源分析研究,可以为污染风险防控、环保政策制定提供支撑.为研究北京市不同功能区土壤环境中PAHs的含量、组成及来源,本文在北京市主城区进行了大范围采样,同时针对工业区、农业种植区、水源保护区及居民区等不同功能区进行了分...     

基于污染足迹模型的湖州市农业污染评估

太湖流域的水环境质量呈现严重恶化趋势,农业污染物的排放是太湖流域水体环境恶化的主要原因之一。农业污染物主要来源于种植业、畜禽养殖业和水产养殖业的生产过程,不同于以往分开论述三者对水环境的影响,本文基于全国第一次污染普查数据,运用污染足迹模型定量分析了湖州市农业面源(种植业、畜禽养殖业和水产养殖业)对水环境的影响。研究结果表明:(1)农业生产产生的污染物对水环境的影响排序为:磷>氮>有机物;(2)各农业生产类型对水环境的影响排序为:水产养殖业>种植业>畜禽养殖业;(3)湖州市各区县对水环境的影响也存在着明显的空间差异。通过对湖州市农业污染足迹评估,可以明确地提出哪种污染物类型、农业生产类型和区域是湖州市农业面源污染治理的重点。研究结果可以为太湖流域农业的可持续发展和水资源的可持续利用提供一定的参考价值。     

Monitoring of toxic substances in the Hong Kong marine environment

A long-term programme for monitoring toxic substances in the marine environment was established in Hong Kong in 2004, focusing on chemicals of potential ecological and health concern. The programme ran on 3-year cycles, with the first two years monitoring marine water, sediment, biota, and the third year monitoring pollution sources. Twenty-four priority chemicals were measured, including dioxins/furans, dioxin-like PCBs, total PCBs, PAHs, DDTs, HCHs, TBTs, phenol, nonylphenol (NP), NP ethoxylates, PBDEs and metals. Results from the first three years of monitoring indicate that toxic substances in the Hong Kong marine environment were within the range reported for the coastal waters in China and other regions, but generally lower than in the Pearl River Estuary. The levels met the standards for protecting aquatic life and human consumption. Sewage effluent, stormwater and river water were possible sources of phenolic compounds; whereas air deposition or regional pollution, rather than local discharges, may contribute to the dioxins/furans, PAHs and PCBs found in the marine environment.     

Identification and quantification of mixed sources of oil spills based on distributions and isotope profiles of long-chain n-alkanes

Combined with quantitative determination of concentration and isotopic composition of petroleum hydrocarbons, weathering simulation experiments on artificially mixed oils and their two end-member oils are performed for identification and quantification of mixed sources. The >C₁₈n-alkanes show no appreciable losses during a short-term weathering process. An approach based on distribution of long-chain n-alkanes (>C₁₈) is suggested for estimating the contribution proportion of each source in mixed oils. Stable carbon isotope profile of individual n-alkanes is a powerful tool to differentiate sources of oil spills, but unavailable to accurately allocate each contribution due to a relatively large analytical error.     

Curie point depth from spectral analysis of aeromagnetic data from Cerro Prieto geothermal area,Baja California,México

Using aeromagnetic data acquired in the area from the Cerro Prieto geothermal field, we estimated the depth to the Curie point isotherm, interpreted as the base of the magnetic sources, following statistical spectral-based techniques. According to our results the Curie point isotherm is located at a depths ranging from 14 to 17 km. Our result is somewhat deeper than that obtained previously based only in 2-D and 3-D forward modeling of previous low-quality data. However, our results are supported by independent information comprising geothermal gradients, seismicity distribution in the crust, and gravity determined crustal thickness. Our results imply a high thermal gradient (ranging between 33 and 38 °C/km) and high heat flow (of about 100 mW/m²) for the study area. The thermal regime for the area is inferred to be similar to that from the Salton trough.     

Modern pollen rain in the Lake Qinghai basin,China

Lake Qinghai is the largest inland brackish lake in China and lies within the NE Tibetan Plateau. Our study shows that pollen assemblages in each vegetation belt are significantly correlated with the vegetation types of this area. Among the herbaceous and shrubby pollen assemblages, Artemisia is over-represented, while Poaceae, Cyperaceae and Polygonaceae are under-represented. Artemisia/ Chenopodiaceae (A/C) ratios with the regional vegetation characteristic can be used as a proper index to reconstruct the...     

长江宜昌段水系沉积物镉高值带成因

应用贡献因子和富集因子等方法对长江宜昌段水系沉积物Cd的来源进行研究,结果表明：研究区内地层对宜昌段水系沉积物Cd的贡献由大到小依次为：震旦系>二叠系>泥盆系>志留系;前震旦系、寒武系、奥陶系、三叠系、侏罗系和白垩系地层则对长江宜昌段Cd高值带的形成有一定的削弱作用。利用贡献因子、富集因子和MapGIS空间分析综合研究表明,震旦系和二叠系含矿富Cd地层的风化产物是长江宜昌段Cd高值带的主要自然来源。区内锌矿、煤矿和磷矿开采过程中的尾砂、废水的堆积和排放是长江宜昌段Cd高值带的重要人为污染源。     

松辽盆地南部黑帝庙地区油气成藏模式

应用生物标记化合物m/z191萜烷、藿烷系列和m/z217甾烷系列进行了油源对比,证实下白垩统姚家组葡萄花油层油气来源于上覆地层嫩江组一段,嫩一段烃源岩生成的油气通过断裂运移到该油层。属于上生下储的组合型式,断裂是油气藏形成的主控因素,形成构造-岩性油气藏类型是其主要的成藏模式,该层是黑帝庙地区今后勘探的主要目的层。精细研究姚家组的断裂、低幅度构造与砂体间的配置关系,是今后突破该油层油气勘探的关键。