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841.
为了研究饲料中铜暴露对吉富罗非鱼幼鱼的毒性作用,将1 080条罗非鱼幼鱼暴露于6个浓度梯度的高铜日粮中,通过60 d的暴露试验,测定罗非鱼血红细胞微核变化和组织中铜的蓄积.结果表明,铜在各组织中积累量的顺序依次为:肝脏>脾脏>肠道>鳃>肌肉,与对照组相比,其中肝脏、脾脏、肠道中铜的含量随着时间和日粮中铜浓度的升高而逐渐升高,而鳃和肌肉中铜含量无显著差异;罗非鱼幼鱼血红细胞微核率、核异常率、总核异常率与日粮中铜的浓度存在一定的剂量—效应关系,并且核异常率高于微核率.  相似文献   
842.
低强度超声波辐射对污泥生物活性的影响机制   总被引:2,自引:0,他引:2  
通过测定超声辐射前后污泥性质的变化,不同处理方式对污泥活性影响以及自由基清除剂NaHCO3加入对超声作用效果影响,初步探讨了低强度超声波辐射对污泥生物活性的影响机制.研究结果表明,低强度超声辐射的机械作用和空化作用,使污泥絮体破碎,强化了固-液对氧的传质,提高了酶活性以及增加了溶液中可利用基质,从而强化了污泥的生物活性;不过,超声辐射同时也产生大量自由基,会对污泥生物活性产生抑制或破坏.因此,低强度超声辐射对污泥活性影响是促进效应和抑制效应共同作用的综合表现.  相似文献   
843.
典型材料屋面积尘重金属形态分布与风险评估   总被引:3,自引:0,他引:3  
李敦柱  管运涛  刘安  李思远 《环境科学》2015,36(9):3269-3277
以华南地区4种典型材料屋面(瓷砖、混凝土、金属和沥青)为研究对象,采用改进式BCR连续提取法对其屋面积尘中10种重金属(Ba、Co、Cr、Cu、Mn、Ni、Pb、Sb、Sr和Zn)进行形态分析与风险评估.结果表明,屋面积尘重金属平均含量明显高于道路积尘.形态分析表明,Zn的酸溶态比例明显高于其他重金属,Pb和Cu主要以可氧化态存在,其余重金属均以残渣态为主;屋面积尘重金属可移动态比例表现为PbZnCuMnCoSrSbNiBaCr,其中Pb、Zn、Cu、Mn和Co可移动态比例均超过50%.环境风险评估发现,污染指数(Cf)与风险评价编码指数(RAC)最大值均为Zn,其生态风险较高.健康风险评估表明,屋面积尘重金属对成人与儿童非致癌风险均表现为:PbCrSbZnMnCuBaNiCoSr,其对成人非致癌风险均小于安全限值,不构成威胁,但Pb对儿童的非致癌风险高于安全限值,形成威胁;屋面积尘中Cr、Co和Ni低于致癌风险阈值,对人体无致癌风险.  相似文献   
844.
通过对大石桥市“九五”期间大气监测资料的分析研究,从中找出该期间大石桥市大气环境质量的变化规律与发展趋势,分析出大气污染的原因与特征,进一步提出综合防治建议。  相似文献   
845.
脱硫设备用有机高分子防腐材料,其性能主要取决于该材料的耐温抗老化性。本文通过机理分析及试验将研究一种有机硅改性的环氧树脂,并加入超细石墨粉和石棉绒,以硅烷偶联剂处理的玻璃布为增强骨架,做成耐温玻璃钢复合防腐材料。由实验发现,该防腐材料随温度的变化具有优良的稳定性和强度保留率,能够满足工业性应用要求。  相似文献   
846.
Increasing evidence confirms that elemental carbon (EC) is not only a light-absorbing constituent that warms the atmosphere but also a significant environmental pollutant. Investigations were conducted to identify carbonaceous pollution signatures in road dusts and urban soils and to evaluate potential sources in Xi'an. Average concentrations of EC, char-EC, and soot-EC in soils were 0.90, 0.51, and 0.39 mg g?1, respectively, a little higher than or comparable to prior studies on the Loess Plateau. Vertical profiles in soils revealed soot-EC concentrations from pre-industrialized samples close to ~0.20 mg g?1, while EC and char-EC varied widely, with no distinct pattern. Enrichment factor analysis indicated that EC, char-EC, and soot-EC in road dusts were all elevated by an order of magnitude. The spatial distribution of total EC, char-EC, and soot-EC in road dusts revealed close correspondence with human activities such as coal combustion and vehicle emissions. The average char-EC/soot-EC ratio was 1.66 for road dusts, suggesting that the main sources of carbonaceous particles are local coal combustion and vehicle emissions. The study demonstrated that EC, char-EC, and soot-EC levels in road dusts are effective indicators of anthropogenic pollution.  相似文献   
847.
Kaschin-Beck disease (KBD) could be exogeneous free radical induced endemic osteoarthropathy under conditions of lacking necessary antioxidant defences.especially selenium-cored defence in Chinese eco-en-vironment. Experimental evidences have been provided for the internal relations among previously suggested pathologic factors, i.e., selenium deficiency, organic matters of drinking waterand mycotoxins from contaminated grains, based on the facts that the former is a preventory factor while the others are exogenous freeradical carriers. ESR spectrum shows that these exogenous free radical carriers have a property of semi-quinone compounds and are toxic in in-vitro cartilage cell culture and animal tests in inducing lipid peroxidation process.  相似文献   
848.
讨论了现有的石油类废水的采样器。用分液漏斗和普通玻璃漏斗组装成石油类污水采样器,用CY-2000多功能红外测油仪对模拟水样进行分析。结果表明水样中石油类平均值为11.00mg/L,显著性检验t值为1.476〈t0.05(6)=2.45,无显著性差别。说明设计的采样器更符合实际要求。  相似文献   
849.
The Korean government recently proposed expanding the number of soil-quality standards to 30 by 2015. The objectives of our study were to construct a reasonable protocol for screening priority soil contaminants for inclusion in the planned soil quality standard expansion. The chemical ranking system of soil pollution substances (CROSS) was first developed to serve as an analytical tool in chemical scoring and ranking of possible soil pollution substances. CROSS incorporates important parameters commonly used in several previous chemical ranking and scoring systems and the new soil pollution parameters. CROSS uses soil-related parameters in its algorithm, including information related to the soil environment, such as soil ecotoxicological data, the soil toxic release inventory (TRI), and soil partitioning coefficients. Soil TRI and monitoring data were incorporated as local specific parameters. In addition, CROSS scores the transportability of chemicals in soil because soil contamination may result in groundwater contamination. Dermal toxicity was used in CROSS only to consider contact with soil. CROSS uses a certainty score to incorporate data uncertainty. CROSS scores the importance of each candidate substance and assigns rankings on the basis of total scores. Cadmium was the most highly ranked. Generally, metals were ranked higher than other substances. Pentachlorophenol, phenol, dieldrin, and methyl tert-butyl ether were ranked the highest among chlorinated compounds, aromatic compounds, pesticides, and others, respectively. The priority substance list generated from CROSS will be used in selecting substances for possible inclusion in the Korean soil quality standard expansion; it will also provide important information for designing a soil-environment management scheme.  相似文献   
850.
The impacts of climate change on streamflow and non-point source pollutant loads in the Shitoukoumen reservoir catchment are predicted by combining a general circulation model (HadCM3) with the Soil and Water Assessment Tool (SWAT) hydrological model. A statistical downscaling model was used to generate future local scenarios of meteorological variables such as temperature and precipitation. Then, the downscaled meteorological variables were used as input to the SWAT hydrological model calibrated and validated with observations, and the corresponding changes of future streamflow and non-point source pollutant loads in Shitoukoumen reservoir catchment were simulated and analyzed. Results show that daily temperature increases in three future periods (2010–2039, 2040–2069, and 2070–2099) relative to a baseline of 1961–1990, and the rate of increase is 0.63°C per decade. Annual precipitation also shows an apparent increase of 11 mm per decade. The calibration and validation results showed that the SWAT model was able to simulate well the streamflow and non-point source pollutant loads, with a coefficient of determination of 0.7 and a Nash–Sutcliffe efficiency of about 0.7 for both the calibration and validation periods. The future climate change has a significant impact on streamflow and non-point source pollutant loads. The annual streamflow shows a fluctuating upward trend from 2010 to 2099, with an increase rate of 1.1 m3 s−1 per decade, and a significant upward trend in summer, with an increase rate of 1.32 m3 s−1 per decade. The increase in summer contributes the most to the increase of annual load compared with other seasons. The annual NH4+-N load into Shitoukoumen reservoir shows a significant downward trend with a decrease rate of 40.6 t per decade. The annual TP load shows an insignificant increasing trend, and its change rate is 3.77 t per decade. The results of this analysis provide a scientific basis for effective support of decision makers and strategies of adaptation to climate change.  相似文献   
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