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131.
Min Xiao Fengchang Wu Runyu Zhang Liying Wang Xinqing Li Rongsheng Huang 《环境科学学报(英文版)》2011,23(8):1249-1256
Low-molecular-weight organic acids (LMWOAs) in eutrophic lake water of Dianchi, Southwestern China Plateau were investigated
diurnally and vertically using ion chromatography. Two profiles (P1 and P2) were studied due to the difference of hydrochemical
features. Lactic, formic, pyruvic and oxalic acid were detected as major components at P1 and P2 which were on average 7.98 and
6.53 mol/L, respectively, corresponding to their proportions of 2.68% and 2.48% relative to DOC. Pyruvic acid was regarded as the
uppermost species at P1 and P2, reaching up to 3.82 and 3.35 mol/L and accounting for 47.9% and 51.3%, respectively, in individual
TOA. Although humus were of biogenetic production at both sites, the significant negative correlation between diurnal variations
of TOAs, fluorescence intensity (FI) of protein-like components and humic-like components at P1 indicated LMWOAs were greatly
originated from bacterioplankton excretion and degradation. However, correlations between diurnal variations of humic-like FI and
physicochemical parameters demonstrated algal origination of LMWOAs at P2. Although content of humus was high, TOA at P2 was
1.45 mol/L lower than that at P1, due to the co-influence of more intense photo-oxidation and aggregation at P2. Therefore, TOAs
exhibited quite opposite diurnal variation trends of increasing-decreasing and decreasing-increasing at P1 and P2, respectively. Except
for impact of solar radiation, bacterial decomposition and assimilation rendered shifts of maximal LMWOAs along water column at
P1. Covering with massive algae, UV rays penetrated shallower depth that LMWOAs assembled in surface layer water before 18:00 at
P2 and represented decreasing profiles. 相似文献
132.
133.
黔西南滥木厂铊矿化区河流沉积物中重金属污染及其潜在生态危害 总被引:3,自引:2,他引:3
黔西南滥木厂铊矿化区河流沉积物中重金属元素的含量很高,其环境污染和生态危害值得关注。本文采用地质累积指数(Igeo)和潜在生态危害指数(RI)对重金属污染及其潜在生态危害进行了评价。结果表明,滥木厂河流沉积物中重金属存在较强程度的污染,并具有较强程度的潜在生态危害。主要的污染元素为Tl、As和Cd,而Cr、Zn、Pb、Cu基本上处于无污染或轻微污染的水平。河流沉积物重金属的污染在上游河段较下游河段严重。重金属平均潜在生态危害的排序为:矿山影响区Tl>Cd>As>Pb>Cr>Cu>Zn;矿山未影响区Cd>Tl>Pb>Cr>As>Cu>Zn。 相似文献