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971.
以三峡库区支流澎溪河回水区为特征区域,研究三峡水库回水区水动力条件对水体富营养化的影响。根据三峡水库的调蓄过程,在175 m高水位、小流量、低污染负荷和145 m低水位、大流量、高污染负荷两种设计条件下模拟澎溪河水体断面平均高锰酸盐指数(CODMn)、总氮(TN)、总磷(TP)浓度和叶绿素a(Chl a)含量。研究表明:澎溪河回水段从上游到下游的CODMn、TN、TP浓度有增加的趋势,在接近河口处有趋同于长江水污染物浓度的趋势。145 m低水位的大流量、高污染负荷设计条件下Chl a含量较高,在弯道下游和河道水面开阔的高阳、双江大桥断面的流速减缓区段,出现Chl a含量峰值。拟合澎溪河水体流速及Chl a含量相关关系,在枯丰两种设计条件下建立水体流速(V)与Chl a含量(S)的相关关系式,分别为S=0186 0〖DK〗·V-0353 6(相关系数r2=0838 0)和S=10844 9〖DK〗·V-0293 9(相关系数r2=0825 4)。模拟结果表明:加大水体流速有利于抑制Chl a含量。通过改变水动力条件控制水体富营养化具有可行性 相似文献
972.
初步研制的汞蒸汽被动式检气管是建立在气体分子扩散和化学吸收原理基础上的,新制备的碘化亚铜沉淀和乙醇、甘油、硝酸混合、研碎,伴入经活化的层析硅胶,填充到检气管中,当汞蒸气进入管内时,发生显色反应,检气管显色长度的平方与汞蒸汽浓度及采样时间的乘积成线性关系,检测下限为0.001ug/mL(1h)。该法集采样与分析于一体,结构简单,不需动力,便于携带,操作方便,实验室模拟运用,其灵敏度和标准偏差令人满意。 相似文献
973.
固定化生物活性炭处理低浓度甲醇废水 总被引:11,自引:0,他引:11
将分离筛选得到的甲醇降解菌固定在颗粒活性炭上,组成固定化生物活性炭反应系统,研究该反应系统处理轻度污染含甲醇废水的最佳运行条件和运行效果,结果表明,固定化生物活性炭处理轻度污染含甲醇放心水的方法明显好于3种树脂和单纯活性炭吸附处理,反应系统的最佳运行条件是水力负荷0.84-0.77m^3(m^2.h),停留时间57-62min,pH7-8,温度20℃-30℃,溶解氧是去除甲醇的主要限制因子,甲醇含量为11.3-23.1mg/L时,去除率大90%,出水CODcr小于12mg/L。此外还研究了生物活性炭生物膜的一些特点,并分析了运行中活性炭吸附性能的变化。 相似文献
974.
Huang DJ Zhang YM Song G Long J Liu JH Ji WH 《Environmental monitoring and assessment》2007,128(1-3):483-488
The Yellow River, the second largest river in China, is the most important resource of water supply in North China. In the
last 40 years, even in the upper Yellow River, with the development of industry and agriculture, more and more contaminants
have been discharged into this river and greatly polluted the water. Although a routine chemical component analysis has been
performed, little is known about the real toxic effects of the polluted water on organisms at environmental level. To explore
whether the pollutants induced oxidative stress and damage to aquatic organisms, malondialdehyde (MDA) level and activities
of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) in hepatopancreas,
kidney and intestine of the field-collected carp Cyprinus carpio from a mixed polluted (Lanzhou Region, LZR) and a relatively unpolluted (Liujiaxia Region, LJXR) sites of the upper Yellow
River were measured. The results showed that when the values of LZR compared with those of LJXR, SOD and GST activities increased
and GPx activity decreased significantly in all the three organs (P < 0.05–0.01); CAT activity decreased but MDA level increased significantly (P < 0.05–0.01) only in kidney and intestine. In conclusion, the results of this study suggest that the pollutants can induce
obvious oxidative damage in the carp, and the SOD, GST and GPx might be better indicators for the oxidative damage in aquatic
organisms. 相似文献
975.
976.
Distinguishing and quantifying anthropogenic trace metals and phosphorus accumulated in sediment is important for the protection
of our aquatic ecosystems. Here, anthropogenic proportion and potential sources of trace metals and phosphorus in surface
sediments of Chaohu Lake were evaluated based on the exhaustive geochemical data. The analysis shows that concentrations of
major and trace metals, and phosphorus, displayed significant spatial diversity and almost all elements were over the pre-industrial
background value, which should be related to the variations of sediment composition partially. Therefore, conservative element
normalization was introduced and calculated enrichment factors (EFs) of the elements were referenced highlighting the human
contamination. EFs of the major and trace metals, except Zn, Pb, and Cu, were all nearly 1.0, indicating the detrital origin.
The EFs of Zn, Pb, Cu and phosphorus were 1.0–10.4, 1.0–3.8, 1.0–4.9, and 1.0–7.6, respectively, showing moderate to significant
contamination. Higher EFs of Zn, Pb and Cu occurred in the mouth areas of Nanfei River and Zhegao River, and they decreased
to the lake center in the northwest and northeast lake areas, respectively. We deduced that anthropogenic Zn, Pb, and Cu were
mainly from urban and industrial point sources and the non-point sources of atmospheric deposition contributed little to their
contamination. The EFs of phosphorus showed similar spatial degradation with that of Zn, Pb, and Cu. Moreover, higher EFs
(>1) of phosphorus also occurred in other areas adjacent to the river mouths besides Nanfei River and Zhegao River. This indicated
that the non-point agricultural source may also be responsible for the contamination of phosphorus in Chaohu Lake in addition
to the urban sewage sources. Anthropogenic phosphorus was mainly concentrated in the speciation of NaOH-P, which had higher
potential biological effects than the detrital proportion. Concentrations of Zn, Pb and Cu surpassed the threshold effect
concentrations (TEC) of consensus-based sediment quality guidelines of freshwater ecosystems, especially in the contaminated
northwest area of Chaohu Lake. This highlighted the contributions of anthropogenic contamination to the elevated potential
biological effects of trace metals. Though there had been no obvious human contamination of Cr and Ni in Chaohu Lake, concentrations
were all over the TECs, which may be due to higher background levels in the parent materials of soils and bedrocks in Chaohu
Lake catchment. 相似文献
977.
978.
979.
Anita Érseková Klára Hilscherová Jana Klánová John P. Giesy Jiří Novák 《Environmental monitoring and assessment》2014,186(6):3905-3916
Although passive sampling has been previously used for the monitoring of volatile and semi-volatile contaminants in air, there are limited data on the use of this technique coupled with bioassays based on specific biological responses. Biological responses including those mediated by the aryl hydrocarbon (AhR) receptor as well as (anti-)estrogenicity and (anti-)androgenicity of samples from four Eastern European countries (Lithuania, Slovakia, Romania, and Serbia) were determined. To address the potential differences of specific toxic potencies of pollutant mixtures in ambient air in Eastern Europe, each country was characterized by a single more remote location that served to determine regional background conditions and one location in more urbanized and industrialized locations, which were defined as “impacted” areas. Besides samples from Lithuania, a significant gradient in concentrations of AhR-mediated potency from background and impacted localities was observed. Greatest potencies were measured in samples from impacted locations in Romania and Slovakia. Concentrations of polycyclic aromatic hydrocarbons (PAHs) that were quantified accounted for 3–33 % of the 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents determined by use of the bioassay. No significant estrogenic potency was detected but anti-estrogenic effects were produced by air from two background locations (Lithuania, Slovakia) and three impacted locations (Lithuania, Romania, and Serbia). Anti-androgenic potency was observed in all samples. The greatest anti-estrogenic potency was observed at the background location in Slovakia. Anti-estrogenic and anti-androgenic potencies of studied air samples were probably associated with compounds that are not routinely monitored. The study documents suitability of passive air sampling for the assessment of specific toxic potencies of ambient air pollutants. 相似文献
980.
Assessment and sources of heavy metals in surface sediments of Miyun Reservoir, Beijing 总被引:3,自引:0,他引:3
Xianfang Zhu Hongbing Ji Yan Chen Mingming Qiao Lei Tang 《Environmental monitoring and assessment》2013,185(7):6049-6062
Heavy metals concentrations in surface sediments from Miyun Reservoir were determined to evaluate the pollution and identify the sources. The average content of metals in sediments from Miyun Reservoir followed the order Al>Fe>Ti>Mn>V>Zn>Cr>Ni>Cu>Pb>As>Cd>Hg, and the most mean values were lower than the globe average shale. Heavy metals concentrations at the inflow area of Baihe were higher than those at the inflow area of Chaohe. Heavy metals pollution assessment was carried out by factor enrichment (EF), geoaccumulation index (I geo), and potential ecological risk (RI). The EF values for all heavy metals except Hg, Cd, and Cr at several sites were lower than 3, suggesting low anthropogenic impact on the metals level. The I geo values of Pb indicated that half of the sites were unpolluted to moderately polluted and mainly located in the Baihe area of the reservoir. The RI showed that heavy metals of Miyun Reservoir were low potential risk, however, Hg approached or belonged to moderate ecological risk at sites of M5, M7, and M13. Correlation analysis and principal component suggested that Ni, Cu, V, Zn, Mn, Cr, Ti, and Pb were derived from soil erosion in upper reaches of the reservoir, while Fe, Cd, Hg, As, and partial Pb originated from anthropogenic sources, particularly industrial mining and gold tailings. 相似文献