Microfabries of lacustrine sediments to pollutant adsorption from a polluted Eutrophic lake, the Yangtze delta region

Two types of microfabrics relating to pollutant adsorption were studied in the scanning electronic microscope (SEM) in a polluted, eutrophic lake, the Yangtze delta region. Agglutinational texture or the aggregates of small particles are composed of clay minerals and fine organic fragments among the silty grains and the coatings with a thickness about 1 mu m were on the surfaces of the silty grains in the sediments. The chemical constituents of the aggregates and the coatings are K, Na, Ca, Mg, Si, Al, O, Fe, Ti, C, N and P determined in X-ray energy spectrometry connected with the SEM. In some cases, Pb was detected in the aggregates in the top sediment. It is suggested that nutrients and metals are adsorbed to the aggregates, which were formed by electrostatic attraction of physicochemical floes. The coatings on the surface of quartz grains were formed by the interaction of dissociated Al, Si, Fe, etc from silicates with dissolved N, P and C nutrients in interstitial water, which was aroused by human pollution to the lake in recent two decades.

黔西南Au—As—Hg—Tl矿化区毒害金属元素的水地球化学

研究了黔西南典型Ａｕ－Ａｓ－Ｈｇ－Ｔｌ矿化区内毒害金属元素在采矿活动和自然状态影响下的水地球化学特征及其环境效应。结果表明，已开采的Ｈｇ－Ｔｌ矿区地下水和地表水中均有很高的毒害金属元素，煤采区地下水中亦表现出类似的特征，而Ｈｇ－Ｔｌ矿区外围地下水中金属元素保持在较低的水平。Ｈｇ－Ｔｌ矿区地素水中Ａｓ和Ｔｌ的分布模式表明，其含量的变化受矿区地下水排泄和尾矿淋滤作用的控制。在尚未开采的金矿区，浅层地下水中金属元素的含量没有明显的富集，尚未构成环境问题。采矿活动扰动下的地下水和暴露于地表的尾矿及矿山废物是水中毒害金属元素的主要来源，水环境研究对采矿活动造成的环境影响具有良好的指示效果。