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气相色谱法测定地下水中六六六结果的不确定度评定 总被引:7,自引:4,他引:3
依照《测量不确定度评定与表示》,对气相色谱法测定地下水中六六六(HCH)四种单体结果进行了不确定度评定。分析了测量过程中引入的不确定度来源,包括提取液体积的量取、样品提取溶液的定容体积、分析仪器的进样量、标准系列溶液的测量以及仪器重复测定等分量引入不确定度及其各参数的采集和计算方法,最后合成标准不确定度,通过乘以95%概率下的扩展因子2,获得测量结果的扩展不确定度。 相似文献
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有机农药六六六对胶州湾海域水质的影响Ⅰ.含量的年份变化 总被引:1,自引:1,他引:0
根据1979~1984年(缺少1980年)的胶州湾水域调查资料,分析有机农药六六六(HCH)在胶州湾水域的含量大小、年份变化和季节变化。研究结果表明:在1979~1984年(缺1980年)期间,在胶州湾水体中HCH的含量逐年都在减少。在1983年,中国禁止HCH的使用,在禁用后,水体中HCH的含量全部低于一类海水的水质标准。在禁用后,水体中HCH的含量很低,几乎没有季节变化。因此,中国禁止HCH的使用对环境的改善取得显著的成效。 相似文献
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This paper reports the concentrations of 137 Cs, hexachlorocyclohexane(HCH), dichlorodiphenyltrichloroethanes(DDT) and its main degradation products, δ13C, and organic carbon in pond sediments(0-210 cm, sectioned by 2-20 cm interval) and surface soils(the 0-3 cm horizon) collected in 2010 from Chenjia catchment, which is located in Yanting county in the hilly central Sichuan of China. α-, δ-, and γ-HCH, DDT, and DDD were not detected throughout the sediment profile. Trace concentrations of δ-HCH(0.89-29.31 ng g-1) and p,p′-DDE(1.85-6.02 ng g-1) were detected only in top 40 cm sediment. The 137 Cs fallout peak in 1963(corresponding to the 55-60 cm depth), the sedimentary signature left by the last year of HCH use in 1989(an additional indicator at 20-25 cm), and the obvious original channel bed prior to the construction of the pond in 1956 were used as temporal markers to estimate changes in average sedimentation rate between different periods due to changes in land use. Continuous, marked decrease in average sedimentation rate(i.e., 3.79, 1.35 and 1.07 cm year-1 in 1956-1963, 1963-1989, and 1989-2010, respectively)over time was observed, probably due to the reforestation, abandoning of steep sloping farmland for afforestation and natural re-vegetation(implementation of the Grain for Green Program), and the conversion of part of gently sloping farmland terraces to orchard land since the 1980 s, especially since the 1990 s. This was corroborated by the observed decrease(more negative) in δ13C of sediment towards the surface, which indicates increased relative contribution of eroded soil particles coming from slopes with increased tree cover in sediment source area. Combined use of 137 Cs, δ-HCH, and δ13C record in sediments has been demonstrated to be a powerful approach to reconstruction of response in sedimentation rate to historical land use changes. 相似文献
4.
《Marine pollution bulletin》2013,77(1-2):52-60
Thirty-five surface sediment samples collected from Beibu Gulf and its tributary rivers, China were analyzed for DDTs, HCHs and chlordanes. Total concentrations of DDTs, HCHs and chlordanes in sediments ranged from 0.59 to 126 ng g−1, ND to 2.65 ng g−1 and 0.27 to 3.41 ng g−1 based on dry weight (dw), respectively. Concentrations of DDTs were higher than those reported in the sediments from other regions of the world, while concentrations of HCHs and chlordanes were relatively low. High concentrations of DDTs were observed in the harbor region and aquaculture bases and high concentrations of HCHs were found in the Qin River Estuary. The ratios of (DDE + DDD)/DDTs reflected a mixed input of weathered and fresh DDTs. The predominant β-HCH indicated that HCHs in the study area mainly originated from the historical usage of technical HCH. The residues of DDTs would pose adverse biological effects on the study area. 相似文献
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通过分析测试吉林省中部农业土壤中α-HCH、β-HCH、γ-HCH、δ-HCH 4种异构体和HCB的含量,对该地区HCH和HCB的残留情况进行了讨论。结果表明,在吉林省中部农业土壤中HCH4种异构体均有不同程度的检出,其中β-HCH和γ-HCH为主要的残留物。ΣHCH残留量介于0.42~44.96 ng/g之间,平均值为5.09 ng/g;ΣHCH残留量在不同类型土壤和不同利用方式下土壤中差异不明显。农业土壤中α-HCH/γ-HCH比值均接近于1,指示该地区土壤环境已经发生变化,也可能有新的污染源存在。土壤中HCB平均值为5.51 ng/g,总体残留水平比较低,且在水田中的残留量高于在旱田中的残留量。 相似文献
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胶州湾水域有机农药六六六春、夏季的含量及分布 总被引:2,自引:2,他引:0
根据1981年的胶州湾水域调查资料,分析了有机农药六六六(HCH)在胶州湾水域的分布、迁移和季节变化.结果表明,胶州湾水域在夏季HCH的污染较重,而春季较轻.在时间分布上,在整个胶州湾夏季的表层和底层水体中的HCH含量几乎都高于春季.在空间分布上,胶州湾的东北部水域海泊河、李村河和娄山河的入海口,为湾的东北部近岸水域提供了河流输送的HCH.因此认为,污染源是面污染源,由入湾河流形成的.通过HCH的陆地迁移过程和水域迁移过程的分析发现,HCH的表层含量高,经沉降,HCH的底层含量就高,而且,HCH入海后沉降较快.根据HCH的表、底层的垂直分布和水平分布,提出了在春、夏季的HCH在胶州湾水域迁移过程的模型框图,表明了HCH的运动轨迹,清楚的展现了HCH在春、夏季的表、底层分布规律. 相似文献
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胶州湾水域有机农药六六六的污染源及分布 总被引:1,自引:0,他引:1
根据1982年的胶州湾水域调查资料,分析了有机农药HGH在胶州湾水域的分布、污染源和季节变化。结果表明,胶州湾水域在4月、6月、7月和10月,HCH的污染较轻。在胶州湾水域,4月、6月和7月,HCH的含量变化由近岸向湾中心有梯度形成:从大到小呈下降趋势,10月HCH的梯度变化刚好相反。表层HCH的水平分布状况与底层HCH的水平分布状况一致。HCH含量变化展示HCH通过河流输入近岸水域要比通过地表径流直接输入近岸水域的质量浓度要高。因此,胶州湾水域HCH含量变化证明了HCH的陆地迁移过程。这表明在夏季,输入的胶州湾水域HCH的含量与春季相比,相对较高;HCH表、底层含量变化在时间尺度和空间尺度上证明了HCH的水域迁移过程。这揭示了HCH的表层含量高,通过沉降,HCH的底层含量就高。根据表、底层的HCH含量变化,提出了HCH的水体效应、稀释效应和累积效应,并用模型框图,表明了HCH穿过水体的含量变化,定量描述水体对HCH的作用。 相似文献
8.
胶州湾水域有机农药HCH的分布和残留量 总被引:2,自引:0,他引:2
根据1984年7月、8月和10月的胶州湾水域调查资料,对有机农药HCH在胶州湾水域的分布、来源和季节变化进行了分析,研究结果表明,胶州湾水域没有受到HCH污染。通过7月,HCH含量变化的水平分布,发现土壤中残留的HCH通过地表径流方式汇入近岸水域,并且HCH的含量很低,HCH来源是面来源。通过10月,HCH含量变化的水平分布,发现胶州湾水域输入的HCH只有通过外海的海流输送。HCH含量的季节变化展示了:HCH含量在7月比较高,在10月比较低。这揭示了在7月,HCH的表层含量高,通过沉降,在10月,HCH的表层含量变低。7月和10月,胶州湾水域水体中表层以及胶州湾的湾口水域水体中表、底层HCH含量水平分布表明:表层的HCH的含量减少完全依赖胶州湾潮流的稀释。在禁止HCH农药的使用后,海水中HCH含量大幅减少,这表明陆地残留量的衰减引起水域HCH的减少。而且,海水中HCH含量的快速下降,说明陆地HCH残留量的衰减也较快,下降了38.14%~212.17%。 相似文献
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