活性炭吸附重金属离子的影响因素分析

在参考众多资料的基础上,从活性炭对重金属离子吸附机理的观点出发,分析活性炭吸附对重金属离子的主要影响因素--活性炭颗粒粒径、孔隙的大小,温度,pH值,以及水中其他粒子的相互作用等,并在该分析的基础上探讨提高活性炭吸附能力的一些措施。     

Effects of 5-year application of municipal solid waste compost on the distribution and mobility of heavy metals in a Tunisian calcareous soil

It is obvious that the application of solid waste compost improves the soil fertility. These wastes, however, may also have some negative effects on the agricultural environment due to their metal content. This research aimed at evaluating the influence of Tunisian municipal solid waste compost and farmyard manure on some chemical properties and the distribution of heavy metals in a calcareous Tunisian soil (clayey–loamy soil). A field plot experiment, without vegetation, was installed since 1999 at the experimental farm of the Agronomic National Institute of Tunis (INAT) in the region of Mornag (20 km south of Tunis, Tunisia). During 5 years, the field received yearly the following treatments: 0, 40, 80 and 120 t/ha of municipal solid waste compost and 0, 40 and 120 t/ha of manure. The fractionation of heavy metals in the soil was evaluated after 5 years using a sequential extraction procedure. The application of the two amendments was found to increase the content of organic matter, the total nitrogen content and the electrical conductivity, whereas it slightly decreased the soil pH. The addition of manure did not have a significant effect on the accumulation of heavy metals in the soil, whereas compost application increased the total concentration of heavy metals in the soil. The distribution of heavy metals between the different fractions in untreated and treated soils showed the residual fraction to be dominant, followed by the fraction bound to Fe and Mn oxides. The amount of Cu bound to the organic fraction increased with the application rate, which is probably caused by the formation of organic complexes. For the other metals, the increase of the association with organic matter is very limited. The application of compost moreover increases the amount of Zn associated with Fe and Mn oxides. The “Mobility Factor (MF)” was quite low and did not change after the 5-year application of the two organic amendments. It always remained lower than 10%, although for Cd it amounted to 17%.     

Effects of heavy metal pollution of highway origin on soil nematode guilds in North Shenyang, China

Soil samples were collected with distance at 5, 20, 40, 80, 160 and 320 m from the Shen-Ha Highway, Northeast China, to investigate the effect of heavy metals of highway origin on soil nematode guilds. The contents of soil Pb, Cu and Zn and the nematode community structure in this investigation were analyzed. The results showed that the contents of total and available Pb, Cu and Zn varied significantly with the different distances from the highway. Pb was the main pollutant in the soils in the vicinity of Shen-Ha Highway and the zone from 20 to 40 m away from the highway was the most polluted area. The highest abundance of soil nematodes was found at 5 m while the lowest at 20 m away from the highway. Thirty six genera of nematodes belonging to 23 families were identified. Nematode guilds having different responses to soil heavy metals were classified into four types. Soil nematode guilds may act as a prominent indicator to heavy metal pollution of highway origin.     

Concentrations and chemical forms of potentially toxic metals in road-deposited sediments from di erent zones of Hangzhou, China

The 25 road-deposited sediments were collected from five di erent land-use zones (industrial, residential, commercial, park, and countryside) in Hangzhou, China. The concentrations of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in these samples were determined using ICP-AES after digestion with the mixture of HNO3-HF-HCl (aqua regia), and chemically fractionated according to the modified BCR (the European Community Bureau of Reference) sequential extraction procedure. The high metal concentration levels were detected in the sample from industrial zone and commercial zone having heavy tra c. While the low metal levels were noted in the street dust sample from residential zone, park, and countryside zone. The mobility sequence based on the sum of the BCR sequential extraction stages was: Zn (80.28%), Pb (78.68%), Cd (77.66%) > Cu (73.34%) > Mn (67.92%) > Co (41.66%) > Ni (30.36%) > Cr (21.56%), Fe (20.86%). Correlation analysis and principal component analysis were applied to the data matrix to evaluate the analytical results and to identify the possible pollution sources of metals. Factor analysis showed that these areas were mainly contaminated by three sources, namely lithology, tra c, and industry.     

淇澳岛红树林生态系统中重金属含量相关性

采集珠海淇澳岛北部大围湾的红树林区潮间带沉积物和植物组织样品若干,测定各样品中Cu、Zn、Cd和Pb的含量,四种重金属含量在各沉积物中、各植物组织中以及沉积物和植物组织之间的相关性。研究表明,沉积物中Pb和Zn含量呈极强正相关,Pb、Zn与Cd含量之间呈强正相关,其他各类重金属之间的相关性不显著。四种重金属与沉积物颗粒形态相关性均不显著。红树植物各组织对四种重金属的富集系数范围为0.001~0.72,0.006~0.39,0.053~1.97和0.004~0.24,富集能力与林龄正相关,其中对Zn、Cd和Pb的富集系数与土壤中含量呈负相关,表明在过高重金属污染胁迫的环境中红树植物有自行降低富集能力以避免被伤害的趋势。     

模拟中性和酸性降雨及垃圾渗滤液浸泡粉煤灰及渣重金属浸出特征

采用EPA Method 3051和微波消解以及模拟中性和酸性降雨及垃圾渗滤液对燃煤电厂F类3个等级的粉煤灰和渣开展浸泡实验,并使用电感耦合等离子体质谱法(ICP-MS)测定了其重金属的含量,分析粉煤灰和渣中重金属的分布特征及不同酸碱度下的浸出毒性.结果表明,3个等级的灰中Cr、Mn、Ni、Cu、Zn和Pb的平均含量分...     

Heavy metals of natural and reclaimed tidal riparian wetlands in south estuary, China

The concentrations of Cd, Cr, Cu, Ni, Pb, and Zn in two plant species (Scirpus tripueter Linn. and Cyperus malaccensis Lam.), water, and soils sampled from the reclaimed tidal riparian wetlands (RTRWs) and the natural riparian wetlands (NRWs) in the Pearl River estuary (PRE), were analyzed to investigate and compare their distribution and accumulation. The results show that the concentrations of the six studied heavy metals in soils exceed the eco-toxic threshold recommended by USEPA. The concentrations of Cd, Cr, and Zn in plants may lead to toxic effects compared to others.The hydraulic conditions and the degree of human disturbances can affect the heavy metal accumulation in RTRWs and NRWs. The heavy metal concentrations in water are higher whereas they are lower in soils of RTRWs Compared with that in the NRWs. The accumulation of heavy metals in the roots of plants is higher in NRWs than those in RTRWs while the opposite result is found for heavy metal accumulation in shoots. Based on the bioaccumulation and translocation factors, the plants in NRWs have the higher capacity to accumulate heavy metals, while higher abilities to transport heavy metals from roots to shoots are observed in RTRWs. Heavy metal contaminations in RTRWs are dominated by anthropogenic sources from both side uplands and river water, whereas in NRWs, the metal accumulations are simultaneously affected by anthropogenic and natural factors.     

重金属镉在土壤中的迁移及形态分布研究

通过动态淋溶实验,研究了外源可溶性重金属镉(Cd)在土壤中的迁移,结果表明,淋溶液pH=2.0时,Cd迅速移出土柱,500 mL时即达到最大值。pH=6.0时,镉移出缓慢,1 300 mL时才达到最大值。且81.3%的外源Cd吸附在0~10 cm土层。形态分布研究表明:黄石土壤中镉的存在形态主要是铁锰结合态和残渣态,分别占全量的74.6%、66.1%。随土壤中Cd负荷提高,土壤中交换态、有机态、碳酸盐结合态镉的比例增大。     

珠江口狮子洋海域表层沉积物重金属污染及其生态风险评价

采用污染指数法和生态风险指数法对珠江口狮子洋海域表层沉积物中Hg、Cu、Cd、Pb、As等污染要素进行分析和评价。结果表明:该海域的总体污染程度为低污染水平,污染程度由大到小依次为As>Cu>Pb>Hg>Cd;该海域的总体生态风险性为低,生态风险性由高到低依次为Hg>As>Cd>Cu>Pb,Hg为该海域的主要潜在生态风险因子。     

闽江口及敖江口海域缢蛏养殖质量状况分析与评价

2009年6月至2010年7月对闽江口及敖江口海域养殖缢蛏中的重金属(Cu,Hg,Pb,As,Cd)、有机污染物(TPH,DDTs,PCBs,HCHs)、麻痹性贝毒、腹泻性贝毒和微生物(大肠杆菌、沙门氏菌、单核细胞增生李斯特氏菌、细菌总数)指标进行检测。结果表明:闽江口及敖江口海域养殖缢蛏中的Cu、Pb、Cd、Hg、DDTs、HCHs、PCBs、DSP、PSP、沙门氏菌、单核细胞增生李斯特氏菌、大肠杆菌含量都符合食品卫生安全要求;部分海区缢蛏体内As、细菌总数的含量超标;部分缢蛏养殖区中的TPH超标严重。