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491.
This study evaluated variations in heavy metal contamination of stream waters and groundwaters affected by an abandoned lead–zinc mine, where a rockfill dam for water storage will be built 11 km downstream. For these purposes, a total of 10 rounds of stream and groundwater samplings and subsequent chemical analyses were performed during 2002–2003. Results of an exploratory investigation of stream waters in 2000 indicated substantial contamination with heavy metals including zinc (Zn), iron (Fe) and arsenic (As) for at least 6 km downstream from the mine. Stream waters near the mine showed metal contamination as high as arsenic (As) 8,923 μg L−1, copper (Cu) 616 μg L−1, cadmium (Cd) 223 μg L−1 and lead (Pb) 10,590 μg L−1, which greatly exceeded the Korean stream water guidelines. Remediation focused on the mine tailing piles largely improved the stream water qualities. However, there have still been quality problems for the waters containing relatively high concentrations of As (6–174 μg L−1), Cd (1–46 μg L−1) and Pb (2–26 μg L−1). Rainfall infiltration into the mine tailing piles resulted in an increase of heavy metals in the stream waters due to direct discharge of waste effluent, while dilution of the contaminated stream waters improved the water quality due to mixing with metal free rain waters. Levels of As, Cu and chromium (Cr) largely decreased after heavy rain but that of Pb was rather elevated. The stream waters were characterized by high concentrations of calcium (Ca) and sulfate (SO4), which were derived from dissolution and leaching of carbonate and sulfide minerals. It was observed that the proportions of Ca and SO4 increased while those of bicarbonate (HCO3) and sodium and potassium (Na+K) decreased after a light rainfall event. Most interestingly, the reverse was generally detected for the groundwaters. The zinc, being the metal mined, was the most dominant heavy metal in the groundwaters (1758–10,550 μg L−1) near the mine, which far exceeded the Korean standard of 1000 μg L−1 for drinking water. The decreases in the heavy metals contents in the groundwaters associated with reduced rainfall were quite different from the increases observed for the stream waters, which is not clearly understood at this time and warrants further investigation. 相似文献
492.
稻麦轮作田氮素径流流失特征初步研究 总被引:12,自引:0,他引:12
针对近年来氮素化肥施用量大而利用率较低现状,在江苏太湖地区设计田间试验,研究稻麦轮作田全年氮素流失特征。结果表明,在本试验条件下稻季和麦季径流中氮损失量相近,麦季略高,约占施氮量的2%左右。麦稻轮作田径流氮损失中氨态氮较少,以硝态氮和其他形态氮为主,其中氨态氮损失以稻季为主,硝态氮损失稻季和麦季相近,其他形态氮损失麦季较多。不同作物田径流氮组成存在差异,麦季径流氮以硝态氮和其他形态氮为主,氨态氮极少,而稻季在施肥后短时间内径流氮中氨态氮、硝态氮和其他形态氮大致相当,其他时间以硝态氮和其他形态氮为主。 相似文献
493.
Mari S. Golub Carl L. Keen Joel F. Commisso Charles B. Salocks T.R. Hathaway 《Environmental geochemistry and health》1999,21(3):199-209
A potentially high bioavailability of arsenic in gold mine tailings from a site in northern California has been suggested by solubility studies. To help address this issue, an in vivo dosing study was conducted using 12dayold Swiss Webster mouse pups (n=8/group). A sample of sizefractionated mine tailings from the site (<20m particle size, 691g g–1 arsenic) was prepared as an aqueous suspension and administered by gavage in a volume that provided 4mg As/kg body weight. The control group received the same volume of a commercial soil (1g g–1 As) of similar particle size (<60m). No mortality or toxic signs were noted in either group. Tissue samples were collected 1h after gavage, freezedried, microwavedigested and analysed for arsenic by ICP/MS (detection limit 2ng As g–1 dry weight). Arsenic concentrations (ng As g–1 dry weight) in tissues from the pups who received mine tailings were significantly higher than in control tissues. The mean elevation in arsenic concentration was highest in the liver (3364% of control, p<0.0001), followed by blood (818 of control, p<0.0001), skin (207% of control, p=0.07), and brain (143% of control, p<0.0001). The carcass arsenic concentration (excluding the GI tract, liver, brain and skin) was 138 of control (p=0.02). The data indicate uptake of arsenic from weathered mine tailings by the immature mouse pups after oral exposure. 相似文献
494.
The photodegradation of Acid blue 74 in aqueous solution employing a H2O2/ultraviolet system in a photochemical reactor was investigated. The kinetics of decolorization were studied by application of a kinetic model. The results show that the reaction of decolorization followed pseudo-first order kinetics. We demonstrate that there is an optimum H2O2 concentration, at which the rate of the decolorization reaction is maximum. Irradiation at 253.7 nm of the dye solution in the presence of H2O2 results in complete discoloration after ten minutes of treatment. 相似文献
495.
Concentrations of arsenic and heavy metals in vegetation at two abandoned mine tailings in South Korea 总被引:1,自引:0,他引:1
Untreated abandoned mines may result in hazards to ecosystems due to dispersion of various toxic elements such as arsenic
(As) and lead (Pb). Phytoremediation is an alternative of remediation for large scale mine dumps. Plant species were sampled
from two abandoned gold (Au) mines in South Korea. Plant samples were digested following the guidelines of US EPA Method 3050
(US-EPA, 1996) and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Concentrations and bioaccumulation factors
of plants are reported and out-performing species are summarized. Poplar trees (Populus davidiana) growing on the Myoungbong tailings were suggested to be a potential species for revegetation of large scale Au mine tailings.
Arsenic accumulations of bracken ferns (Pteridium aquilinum) sampled from the Duckum tailings were far lower than those of the reported hyperaccumulators, but the possible chronic adverse
effects on residents through daily diet are of concern. 相似文献
496.
497.
498.
火电厂灰场排水除氟与降pH的试验研究 总被引:2,自引:0,他引:2
本文根据湖北荆门热电厂灰场排水水质情况采用硫酸铝-助凝剂的方法进行了除氟与降pH的试验研究.分别通过静态试验、实验室配水动态试验和现场动态试验,使灰场排水中的氟离子含量由18mg/L左右降至10mg/L以下,pH值由9左右降至8以下。灰场排水处理量为每小时5t的现场试验结果表明,降低水中氟离子含量并同时降低其pH值的药品成本费为每吨灰火0.05元左右,只降低pH的药成本费为每吨灰水0.03元以下. 相似文献
499.
500.
“破坏性建设”是煤矿区面临的严重问题,应采取适当的生态环境政策与评价分析,来规划、设计、建设煤矿区的景观生态环境。 相似文献