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121.
Status of trace elements in paddy soil and sediment in Taihu Lake region 总被引:14,自引:0,他引:14
Thirteen paddy soil profiles and river sediments which are sources of irrigation water were collected around the Taihu Lake, and the trace elements were estimated. The content of La and Ce in paddy soil and sediment were 39.3 and 68.6 mg/kg soil and 36.9 and 65.1 mg/kg soil, being within the range of background values. The values for Pb, Cu, Ni, Cr, Co, Mn, Zn, Se in paddy soil were 23.3, 27.8, 25.5, 63.5, 10.2, 386, 68.7 and 0.25 mg/kg soil respectively, all below the national permission level. There was a decline of Zn in paddy soil. Some of the river sediments were seriously polluted. The river in Yangjin site was most contaminated with 5.47 g Cu/kg and 7.4 g Zn/kg. The high concentration of Pb and Ni also was observed in this sediment. River in Weitang, Huashi, Xinzhuang and Meiyan were contaminated with Pb, Cu and Ni to some extent. Zn, Cu and Pb were the main pollutants in present experiment sites. The fast development of village/township industries have caused severe environmental pollution in the Taihu Lake region, especially irrigation river sediments. Se content in plant and seed was 0.04 and 0.03 mg/kg respectively, showed Se-deficiency in paddy soil in the Taihu Lake region. 相似文献
122.
123.
A study of using dual membrane technologies, microfiltration (MF) and reverse osmosis (RO), for reclaiming blowdown of the cooling tower was conducted at ZJK power plant, Hebei province, China. The study shows that the combined MF-RO system can effectively reduce water consumption in the power industry. The results indicate that MF process is capable of producing a filtrate suitable for RO treatment and achieving a silt density index (SDI) less than 2, turbidity of 0.2 NTU. The water quality of RO effluent is very good with an average conductivity of about 40 micros/cm and rejection of 98%. The product water is suitable for injection into the cooling tower to counteract with cooling water intrusion. After adopting this system, water-saving effectiveness as expressed in terms of cycles of concentration could be increased from 2.5-2.8 times to 5 times. 相似文献
124.
负载型金催化剂用于室温下CO的消除 总被引:4,自引:0,他引:4
从催化活性、抗潮湿、抗硫中毒、稳定性等方面考察了负载型金催化剂对于CO氧化反应的性能。筛选出的2-3催化剂可在-22℃下完全消除CO,并且在催化活性、抗潮湿、抗硫中毒、稳定性等方面具有现行催化剂无法比拟的优点。 相似文献
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126.
Gia Thanh Nguyen Jian Pu Takayuki Miura Hiroaki Ito Shinobu Kazama Yoshimitsu Konta An Van Le Toru Watanabe 《Food and environmental virology》2018,10(1):61-71
This study investigated the level of norovirus contamination in oysters collected at a lagoon receiving urban drainage from Hue City for 17 months (August 2015–December 2016). We also investigated the genetic diversity of norovirus GI and GII in oyster and wastewater samples by using pyrosequencing to evaluate the effect of urban drainage on norovirus contamination of oysters. A total of 34 oyster samples were collected at two sampling sites (stations A and B) in a lagoon. Norovirus GI was more frequently detected than GII (positive rate 79 vs. 41%). Maximum concentrations of GI and GII were 2.4 × 105 and 2.3 × 104 copies/g, respectively. Co-contamination with GI and GII was observed in 35% of samples. Norovirus GII concentration was higher at station A in the flood season than in the dry season (P = 0.04, Wilcoxon signed-rank test). Six genotypes (GI.2, GI.3, GI.5, GII.2, GII.3, and GII.4) were identified in both wastewater and oyster samples, and genetically similar or identical sequences were obtained from the two types of samples. These observations suggest that urban drainage and seasonal flooding contribute to norovirus contamination of oysters in the study area. 相似文献
127.
为阐明不同植被类型下表层土壤有机碳的分布特征,本文选取北京松山国家级自然保护区内胡桃楸阔叶林、蒙古栎阔叶林、油松针叶林、针阔叶混交林、灌丛和草甸6种典型植物群落作为研究对象,基于野外调查、采样与实验室分析对不同植被类型下表层土壤有机碳含量、密度及周转速率进行了研究。结果表明:草甸表层土壤有机碳含量和密度最高,分别为188.5 g/kg和10.9 kg/m2,周转速率最低,为0.019 6/a;针阔叶混交林表层土壤有机碳含量和密度最低,分别为68.6 g/kg和5.7 kg/m2,周转速率为0.074 9/a;灌丛表层土壤有机碳周转速率为0.077 4/a。土壤有机碳含量整体上随土壤深度增加而逐渐减少。土壤水分的增加和土壤温度的下降使表层土壤有机碳含量及密度呈上升趋势,而使有机碳周转速率呈下降趋势。土壤有机碳密度随海拔升高呈逐渐上升趋势。海拔通过影响不同植被群落土壤水热条件来影响微生物活动及凋落物的分解,进而影响表层土壤有机碳含量、密度和周转速率。本文为松山国家级自然保护区典型植被类型土壤碳储量和周转研究提供了有效参考。 相似文献
128.
以Al-Ferron逐时络合比色法研究有机硅铝复合絮凝剂中铝的形态分布 总被引:5,自引:0,他引:5
以正硅酸乙酯(TEOS)、二乙氧基二甲基硅烷(DEDMS)、?-氢丙基二乙氧基甲基硅烷(APDES)这3种硅烷偶联剂为硅源.合成了新型的有机硅铝复合絮凝剂,利用Al-Ferron逐时络合比色法研究了这3种絮凝剂的铝形态分布.结果表明,3种系列有机硅铝复合絮凝剂中,硅源、碱化度(B)、Si/Al摩尔比对铝形态分布都有影响.其中,碱化度对铝形态的影响较大.3种产品表现出类似的变化趋势.随碱化度的增大,Al,含量呈现下降趋势,而Alh和AIr含量则明显上升.以TEOS为硅源的产品中,Al为主要形态;以DEDMS为硅源的产品中,硅源对铝形态的影响不明显;以APDES为硅源的产品中.Alh则为主要形态,其含量随Si/Al摩尔比的增大而增多. 相似文献
129.
磷矿山清洁生产评价指标体系的构建——以贵阳市磷矿山为例 总被引:1,自引:1,他引:0
通过对磷矿山清洁生产评价指标选取原则和筛选方法的确定。并结合磷矿山的实际情况,经过多次专家咨询,从而筛选出适合磷矿山清洁生产的具体评价指标。并按层次分析法(AHP)的特点确定目标层、准则层、指标层、指标因子层四个层次,其中,目标层有1项;准则层有6项;指标层有28项;指标因子层有9项,最后建立磷矿山清洁生产评价指标体系,这将为磷矿采选业清洁生产评价提供技术支持和导向,从而有助于磷矿企业推行清洁生产技术,实现可持续发展。 相似文献
130.