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1.
Mohammad Rasul Jan Mahmood A Khawaja Jasmin Sha Kashif Gul 《中国地球化学学报》2006,25(B08):182-182
Due to the persistent nature of DDT, a persistent organic pollutant and its adverse environmental and health impacts, the present study was undertaken to examine the residual DDT in and around DDT manufacturing factory in Amman Gharh, Nowshera, NWFP. The factory was established in 1963 and remained in operation till 1994. Composite samples of soil, sediments and water were collected in and around the factory area, nearby DDT stores, main factory drain leading to river and nearby villages. Standard procedures were used for the collection, transportation and storage of samples for analysis. Physical parameters for the collected water samples measured were temperature, pH and conductance. Extraction of each sample for DDT analyses was carried out in triplicates using soxhlet extraction apparatus. The extract was transferred to well washed, clean; dry glass vial, sealed and put in the refrigerator. Gas Chromatograph with electron capture detector and capillary column was used for analysis. DDT in the samples was identified on the basis of their retention time and quantified on the basis of peak areas. It is evident from the analytical data obtained in the present study that both water and soil in and around the factory area are still contaminated with DDT, despite the closure of the factory since the past few years. 相似文献
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The distribution and bioaccumulation features of PCBs, DDTs, and HCHs were investigated in the sediments and Manila clams collected from along the Mid-Western coast of Korea. The measured concentrations of ΣPCBs, ΣDDTs and ΣHCHs were 1.08–3.5, 0.12–0.35 and 0.090–0.30 ng g−1 dw in sediment, and 33–390, 7.4–46 and 6.3–27 ng g−1 lipid in Manila clam, respectively. Their levels were found to be relatively lower than those of other contaminated areas and the consumption of Manila clam from these areas seems to be safe for human health according to calculated lifetime cancer risk and hazard indices. The ΣPCBs and ΣDDTs concentrations in sediments showed a significant relationship to those in clams. The significant correlation was observed between BSAF in clams and Kow for each PCB congeners and DDT metabolites. These findings support that the PCBs and DDTs levels, which are highly hydrophobic chemicals, in clam reflect the sediment pollution through bioaccumulation. 相似文献
3.
持久性有机污染物(POPs)具有环境持久性和半挥发性, 可以在区域及全球范围内传输和分布。森林植被和林下土壤富含有机质, 森林生态系统因此成为POPs主要的储存库之一。植被叶片可快速吸附大气POPs, 并通过叶片凋落、雨水冲刷和干沉降等过程加强或加速大气POPs 向地面的沉降, 并使森林土壤成为POPs 的“汇”, 从而形成所谓的“森林过滤效应”, 进而影响POPs 在全球的分布。进入森林的POPs 在森林生态系统中将经历一系列的环境过程。本文简要介绍了森林过滤效应的特征和影响因素, 综述了叶片对大气POPs 的吸附、叶片凋落和干湿沉降、POPs 在土壤中的迁移和损失等3 个主要环境过程的研究进展, 报道了松针、树皮和苔藓作为被动采样器反映的森林POPs空间分布趋势。最后, 提出了森林POPs研究中亟待解决的科学问题, 并指出未来中国森林POPs研究的可能方向。 相似文献
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与季节内振荡-超级云团系统相关的赤道波的识别 总被引：2，自引：0，他引：2
文中重点研究与热带季节内振荡－超级云团系统相关联的赤道波的识别。考虑到赤道波的本质为截获在赤道地区的一般的气候平衡场附近的线性动力过程的固有模态,首先从原理上阐明了ＰＯＰｓ分析技术对于分离各类赤道波动的有效性,以后利用这种分析方法对日本静止气象卫星所观测到的黑体红外辐射温度资料进行了ＰＯＰｓ分析。结果表明,在热带季节内振荡－超级云团系统中,对应于４０ｄ振荡的模态基本表现为Ｋｅｌｖｉｎ波的结构;对应于１０ｄ左右的模态,亦为Ｋｅｌｖｉｎ波,而在２ｄ尺度上,则分别存在经向模态序号ｎ＝１和ｎ＝２的西进和东进惯性重力波。分析中还发现了西进的混合Ｒｏｓｓｂｙ重力波的存在。 相似文献
6.
Xiutang Yuan Xiaolong Yang Anguo Zhang Xindong Ma Hui Gao Guangshui Na Humin Zong Guize Liu Yongguang Sun 《Marine pollution bulletin》2017,114(1):419-427
Spatial distribution, source apportionment, and potential ecological risks of sixteen polycyclic aromatic hydrocarbons (PAHs) and seven endocrine disrupting compounds (EDCs) in the intertidal sediment at the Shuangtaizi Estuary, Bohai Sea of China were analyzed. Results showed that the total PAH concentrations ranged from 28.79 ng g? 1 dw to 281.97 ng g? 1 dw (mean: 115.92 ng g? 1 dw) and the total EDC concentrations from 0.52 ng g? 1 dw to 126.73 ng g? 1 dw (mean: 37.49 ng g? 1 dw). The distribution pattern for the PAHs was generally different from that of the EDCs possibly due to their distinct sources and n-octanol-/water partition coefficients (KOW). Qualitative and quantitative analytical results showed that PAH sources were mainly from a mixture of pyrogenic and petrogenic contributions. The higher levels at the southeast of Geligang indicated that the EDC pollutants may have mainly originated from the plastic industry and other chemical plants located along the Liao River. Ecological risk assessment revealed that PAHs exhibited low ecotoxicological effects, whereas EDCs, especially 4-tert-octylphenol and bisphenol A, had high ecological hazard to the estuarine biota. 相似文献
7.
Sergey V. Kakareka Tamar I. Kukharchyk 《中国地球化学学报》2006,25(B08):177-178
In the paper the procedure for and results of a test study of a few persistent organic pollutants - polycyclic aromatic hydrocarbon （PAH）, polychlorinated biphenyls （PCB） and hexachlorobenzene （HCB） emission from the open burning of different types of wastes （domestic wastes, agricultural debris, landscape cleating debris, etc.） are discussed. The open burning of agricultural debris and landscape-clearing debris is widely applied in rural areas and small towns and in allotment gardens for the recovery of that part of wastes that can not be utilized for compost preparation. This process is most typical during the autumn season and to a lesser degree during spring. Burning occurs usually in bon fires. Burning modes differ depending on the volume of material burnt, the waste moisture content, the weather conditions, etc. During this process part of domestic wastes （polluted wood, paper, chipboard, films, plastics, etc.） are burned also. Investigations included the collection and preparation of combustible material, the simulation of open burning processes, particulate and gas emission sampling, chemical analysis of sample and data processing. Sampling procedures and sample preparation were agreeable to the emission sampling standards. The aerosol and vapour phases of POPs were collected by ordinary sampling train with pumping of waste gases through filter and solid sorbent （polyurethane foam）. For the measurements of PAH in emission, gas chromatography and mass spectrometry were used which make it possible to identify and determine 16 PAH compounds in the samples; this method was used for HCB determination also. Gas chromatography with ECD detector was used for PCB measurement. It was detected that the levels of PAH emission from wastes uncontrolled burning of wastes vary greatly. Influencing factors are composition and properties of refuse, temperature and mode of burning, level air supply. Generally, the increase of content of wood leads to the increase of PAH in emission. PAH emission also increased with increasing temperature of burning. The highest PAH values are characteristic of emissions from domestic refuse burning. Practically, all naphthalene, acenaphthylene, acenaphthene （from 60% to 100% of their total mass） and fluorene （14%-99%） were emitted in gaseous form. 相似文献
8.
Jehangir Shah Abdur Rahman Mumtaz Khan Khan 《中国地球化学学报》2006,25(B08):187-188
Tobacco is an important cash crop in Pakistan. It is a sensitive plant prone to many bacterial, fungal, and viral diseases. It is also attacked by several species of worms, beetles and moths. Therefore high levels of pesticides are used to grow tobacco. The obvious benefits from the use of the pesticides are so spectacular that some of the problems associated with their use are not recognized. However, many of these pesticides are highly toxic and have impacts on tobacco workers, especially occupational exposures, which are the direct victims of pesticides poisoning. The victims include many children, pregnant women and elders who all participate in tobacco production. Pesticides either cause or exacerbate a number of illnesses in farmers and farm workers when they are exposed to them. So, occupational exposure is probably one of the most important impacts on tobacco farmers, since they and their families are exposed constantly to a large amount of pesticides. This exposure can lead to many serious problems. No study has been done to identify the effects of tobacco pesticides on human health especially on farmers health in Pakistan. The objective of this paper is to establish a correlation of pesticides application on tobacco crop with cancer incidence in the tobacco growing districts of NWFP- Pakistan. 相似文献
9.
The specific geographic location and natural conditions of the Arctic region play a significant role in the global climate change. As a result of perennial low temperature, simple ecological structure, and fragile ecosystem and weak stability in the Arctic, Persistent Organic Pollutants (POPs) accumulating from the region of middle and low latitudes may cause tremendous pressure in the arctic ecological environment. Therefore, the research of POPs in the Arctic region is not only conducive to more in-depth understanding of POPs distribution and transformation process in the global range, but to reasonably assess the harm of human activities on the arctic ecological environment. Thus, in the past 40 years, especially after nine new kinds of emerging organic contaminants being added to the list of Stockholm Convention in 2009, more and more scientific community and general public have pay attention to the research of POPs in the Arctic region. At present, the understanding of legacy POPs in the Arctic is limited, and the research of emerging POPs is in the initial stage. This paper aimed to summarize some conclusions and implications of the research, and focused on the occurrence level, historical evolution, bioaccumulation and source of POPs in atmosphere, waters, sediments and organisms in the Arctic region. Finally, the future changes and key scientific problems of POPs in the Arctic region were proposed. 相似文献
10.
The exposure time is a variable which is usually not incorporated into models for toxicity. However, with persistent organic pollutants (POPs) exhibiting a nonspecific mode of action and lipophilic properties this variable can be modeled by the usage of the internal concentrations as a measure of the toxicity with fish. The bioconcentration process with fish is a relatively well understood and predictable process which allows the calculation of the internal lethal concentration. When the exposure time is relatively short the critical internal lethal concentrations are relatively constant for the group of POPs whereaas the LC50 measured in the ambient water is quite variable. When the exposure time is relatively long, results on the measurement of the critical internal concentration with fish over different exposure times has demonstrated that the internal lethal concentration falls with increasing exposure times in a consistent and predictable manner. This reduction in life expectancy can be described in a model which can be used to estimate the critical internal concentration for any exposure time. It also provides information useful in assessing the risk to fish and potentially other species due to the occurrence of residues of POPs in natural aquatic systems. It is suggested that these relationships can be extended to other groups of organisms and chemicals. 相似文献