大宝山矿区长期重金属污染暴露人群的内暴露水平

目的 了解大宝山矿区重金属污染地区人群重金属内暴露情况.方法 于2006年采用横断面调查方法,按比例分层多级随机抽样,选择翁源县1205名居民,用微波消解和石墨炉原子吸收光谱法检测人群全血中镉、铅、铜、锌含量.结果 高暴露区人群(n=563)全血中镉、铅、铜、锌的几何均数分别为24.10μg/L、389.10μg/L、0.82 mg/L、8.38 mg/L.低暴露区人群(n=642)全血中镉、铅、铜、锌的几何均数分别为1.93 μg/L、35.20μg/L、0.82 mg/L、6.85 mg/L.高暴露区男女全血镉、铅、铜、锌暴露水平高于低暴露区和我国一般人群参考值.年长者、曾吸烟和曾饮酒者血镉、铅、锌暴露水平较高.高暴露区人群吸烟、饮酒对血中重金属含量的影响无统计学意义.结论 本次调查的人群重金属内暴露情况比较严重,健康可能受到危害.     

ICP-OES法同时测定螺旋藻中11种矿物元素的含量

目的建立电感耦合等离子体原子发射光谱(ICP-OES)法同时测定螺旋藻中11种矿物元素含量的方法。方法螺旋藻经消解后,采用ICP-OES法测定消解液中11种矿物元素的含量。结果钾、钠、钙、镁、铁、锌、铜、锰、铬、镉、铅11种元素的检出限分别为1.32 mg/L、0.85 mg/L、0.10 mg/L、0.01 mg/L、0.11 mg/L、0.18 mg/L、0.001 mg/L、0.001 mg/L、1.36μg/L、0.85μg/L、6.47μg/L,线性关系良好(r≥0.999),相对标准偏差(RSD)均≤5.25%,加标回收率为95.6%~105.4%。结论本方法准确、灵敏、简便,适用于螺旋藻中矿物元素含量的检测。     

微波消解-石墨炉原子吸收光谱法测定软体类海产品中的铜、镉、镍、铬

目的建立微波消解-石墨炉原子吸收光谱法测定软体类海产品中铜、镉、镍、铬含量的方法。方法样品经微波消解后,以硝酸钯-磷酸二氢铵混合溶液为基体改进剂,石墨炉原子吸收法测定铜、镉、镍、铬的含量。结果铜、镉、镍、铬的线性范围分别在0μg/L~40.0μg/L、0μg/L~2.0μg/L、0μg/L~40.0μg/L、0μg/L~20.0μg/L,相关系数均0.999;方法检出限分别为0.217μg/L、0.022μg/L、0.187μg/L和0.156μg/L,相对标准偏差为1.28%~4.32%,加标回收率为98.60%~105.0%。71份软体类海产品中,铜检出率为95.8%,超标率为4.2%,含量为ND~65 mg/kg;镉检出率为100.0%,超标率为2.8%,含量为0.021 mg/kg~2.3 mg/kg;镍检出率为98.6%,超标率为0.0%,含量为ND~1.3 mg/kg;铬检出率为100.0%,超标率为1.4%,含量为0.011 mg/kg~2.9 mg/kg。结论该方法精密度高,回收率好,可作为软体类海产品中铜、镉、镍、铬含量的检测。     

锡箔纸生产地区重金属负荷水平调查

目的了解锡箔纸生产地区环境和人群中重金属的负荷水平,评估当地重金属污染对人群健康的影响。方法采集环境样品土壤10份、水25份、稻米10份、蔬菜25份和儿童静脉血、尿液各272份,采用电感耦合等离子体质谱法测定全血和尿液中镉、铅、铬、砷、汞的含量。结果水样中重金属含量均符合《生活饮用水标准》;稻米、蔬菜中各重金属含量未超出有关限值;土壤镉含量略偏高,属于三级土壤环境质量标准。小学生血液中汞、镉、砷、铅、铬的中位数为0.508μg/L、1.120μg/L、1.345μg/L、42.850μg/L、1.387μg/L,尿液中5种重金属的中位数分别为0.10μg/g·Cr,1.02μg/g·Cr,43.96μg/g·Cr,1.74μg/g·Cr,2.28μg/g·Cr。结论该地区水、稻米、蔬菜、土壤中的重金属污染程度整体较低,本次调查地区总体未出现明显的健康危害。     

深圳市母乳中矿物质含量及重金属负荷水平研究

目的了解深圳市初产、顺产妇的乳汁中8种矿物质(钙、钾、钠、镁和微量元素锌、铁、硒、铜)含量和3种有毒元素(铅、砷、镉)负荷水平,以评估该地婴儿8种常量元素和微量元素的营养状况和3种有毒元素污染水平。方法于2007年7～10月采集在深圳生活5年以上20～35岁的初产妇产后3周～2月龄的母乳共60份,采用电感耦合等离子体质谱法及电感耦合等离子体发射光谱法测定母乳中的常量元素钙、钾、钠、镁和微量元素锌、铁、硒、铜及有毒元素铅、砷、镉的含量。结果所测母乳的8种矿物质和重金属中,常量元素钙、钾、钠、镁的平均含量分别是280.22、498.61、188.65和28.31mg/L,微量元素锌、铁、硒、铜的平均含量分别是2.29mg/L、358.88μg/L、8.28μg/L和339.16μg/L,铅的平均含量是2.13μg/L。砷和镉的含量均小于0.005μg/L。结论与国际原子能机构的标准及国内的一些地区调查结果比较,深圳地区母乳中常量元素钙、钾、钠、镁和锌、铁、铜7种矿物质的平均含量基本合理,砷、镉的污染水平低,但是存在微量元素硒的缺乏和重金属铅的污染。     

电子垃圾处理环境中居民体内重金属水平及其影响因素的研究

目的 分析暴露于电子垃圾处理环境的人群重金属内暴露水平及其影响因素.方法 于2005年8-12月在我国南方某有十余年历史的电子垃圾集散地及无明显工业污染的农业区随机选取调查对象各59名(暴露组)和79名(对照组).用原子吸收光谱法测定研究对象血和尿中铅、镉、铜水平,并分析研究对象体内的重金属水平及其相关影响因素.结果 暴露组和对照组人群血铅、血镉及尿铅的差异均无统计学意义.但暴露组的尿铜水平(中位数:38.06 μg/g Cr)却高于对照组(中位数:23.69μg/g Cr),差异有统计学意义(P＜0.01);而对照组血清铜水平(中位数:0.86 mg/L)和尿镉水平(中位数:1.96 μg/g Cr)则高于暴露组(血清铜中位数:0.76 mg/L;尿镉中位数:1.04 μg/g Cr),差异均有统计学意义(P＜0.01).此外,电子垃圾回收拆解从业史是血铅的危险因素(OR=3.2,P＜0.05),性别和吸烟是血镉升高的危险因素(性别:OR=7.4,P＜0.05;吸烟:OR=18.4,P＜0.05).结论 电子垃圾处理环境中的铜污染可能危及当地居民健康.对照区未知的镉和铜潜在污染源暴露可能与当地居民尿镉和血清铜水平有关.     

南方某重金属暴露区儿童血和尿中铅、镉水平及影响因素调查

目的了解南方某工业区儿童重金属内暴露水平,为环境重金属污染综合防治提供科学依据。方法采用环境流行病学方法进行横断面调查,共招募530名儿童,包括暴露区266名和对照区264名,调查问卷的同时采集儿童血、尿样本,用ICP-MS方法进行铅、镉含量检测。结果暴露区儿童血、尿中铅、镉含量几何均数分别为65.89,1.93μg/L和4.04,1.43μg/L,显著高于对照区儿童(P0.05),其对应含量分别为37.21,1.07μg/L和2.14,1.02μg/L。暴露区儿童血铅随着年龄的增长有波动样升高趋势,对照区儿童血镉、尿镉水平随着年龄增加有轻微增加趋势,同时无论暴露区还是对照区,男孩重金属内暴露水平比女孩高,存在显著性的性别差异(P0.05)。结论环境重金属暴露区儿童重金属内暴露水平显著高于非暴露区,且随着年龄增长呈现轻微的增长趋势,同时存在显著的性别差异。     

母乳中重金属等微量元素状况分析

目的:调查和比较厦门市与保定市母乳中微量元素(铅、镉、锌、铜、锰)含量,分析其影响因素。方法:2008年6~10月间采用简单随机方法抽取厦门市妇幼保健院和保定市妇幼保健院的产妇各200名,填写孕期健康影响因素调查问卷,对母乳中微量元素含量进行分析检测。结果:厦门市和保定市母乳中铅、镉、锌、铜、锰、汞中位数水平分别为7.98μg/L、0.43μg/L、7 163.00μg/L、614.75μg/L、23.81μg/L、2.18μg/L和4.42μg/L、0.26μg/L、6 341.00μg/L、450.25μg/L、27.93μg/L、1.92μg/L。除锰外,厦门市母亲初乳中铅、镉、锌、铜元素含量均显著高于保定市(P<0.01),z值分别为:铅-5.916,镉-4.507,锌-3.047,铜-6.105;保定市母乳中锰显著高于厦门市(z=-2.090,P<0.05)。应用多元Lo-gistic回归发现,产妇食用海鱼均进入了铅、汞、镉、锌、铜的回归方程;乳汁铅与孕期食用鸡蛋、海鱼及身高矮小有关;乳汁镉与食用海鱼多有关;乳汁汞与食用海鱼及蟹类多有关;近3年有过装修、食用海鱼多及阴道分娩乳汁锌含量高;乳汁铜与食用海鱼多、婴儿出生体重大、产妇身高矮小及婴儿出生身长短有关;锰则与家庭附近有污染厂,妊娠期间使用口红,食用豆类产品有关。结论:厦门和保定两市产妇初乳中各种微量元素含量存在差异,与饮食习惯和环境污染等因素有关。     

藏药蕨麻中重金属元素的含量分析

为了考察甘肃临夏产藏药蕨麻被汞铅砷镉铜 (重金属 )污染的程度 ,采用冷原子吸收法测定了汞元素的含量 ,石墨炉原子吸收法测定了铅砷镉铜含量。结果分别为 :Hg 0 0 2 6μg/g、Pb 0 13 μg/g、As 0 0 8μg/g、Cd 0 0 4μg/g、Cu 4 19μg/g ,符合我国绿色行业标准规定。为藏药蕨麻的进一步研究开发提供了科学的依据     

铅、镉、砷污染地区人群免疫功能检测分析

目的 探讨铅锌矿矿区铅镉砷混合接触对不同暴露人群机体免疫状况的影响.方法 选择铅锌矿矿区矿工、矿区居民和无污染地区居民3组人群共96人作为研究对象,对3组人群所处环境中的铅、镉、砷含量,人体血液和尿液的铅、镉、砷含量以及人体免疫学指标进行分析.结果 矿工组血中铅、镉、砷含量几何均数分别为216.57,5.04,58.65μg/L,矿区居民组血中铅、镉、砷含量几何均数分别为143.62,2.42,33.24μg/L,均高于对照人群,几何均数分别为81.54,1.18,11.50μg/L(P<0.01).3组人群尿液中的各种毒物差异有统计学意义(P<0.01).矿工和矿区居民的免疫功能相对于对照组均有不同程度的下降(P<0.01).结论 接触铅、镉和砷的矿区矿工和居民免疫功能受到了不同程度的损害.     

Heavy metals in wetland plants and soil of Lake Taihu, China

Properties of vertical distribution of soil near water bodies are vary considerably from those of land and may greatly affect the transportation of heavy metals in wetlands. Vertical distributions of heavy metals (Cr, Cd, Cu, Pb, and Zn) in the soil of aquatic-terrestrial ecotone (ATE) of Lake Taihu, China, and in wetland plant tissues were studied. Generally, concentrations of heavy metals decreased with increasing depth in the top 40-cm cores and then increased slightly with increasing depth. This investigation indicated that concentrations of Cd, Cr, Pb, and Zn exceeded the geochemical background values in the Taihu Lake area. Concentrations of Cd at all depth soil columns exceeded the Environment Quality Standard for Soils of China. Correlation analysis showed that concentrations of Zn, Cr, Cd, and Pb correlated significantly with one another, suggesting that they had the same origin. The concentration of Cu was negatively correlated with root biomass, which may explain the lower concentration of copper in the soil cores. The dominant plants of the wetland were Phragmites australis and Ludwigia prostrata, and heavy metal accumulated primarily in the root tissue. The general order was root > rhizome > stem > leaf, whereas in L. prostrata, leaf was the main tissue for Cr accumulation. Both P. australis and L. prostrata had the highest concentration factor (CF) to Cu, and CF was 20.3 and 15.8, respectively. Aquatic-terrestrial ecotone plants are more effective in controlling Cu pollution than other heavy metals. This will be very significant for ATE reestablishment near Cu-polluted sites.     

Water Quality and Trace Metal Distribution in a Pristine Lake in the Lake Basin in Kenya

Water and surface sediment samples taken from various locations within Lake Kanyaboli in the Lake Victoria basin were analysed to determine the concentration and distribution of heavy metals. There were wide ranges in concentrations of the metals among the sampling points analysed. Sediment concentrations (microg/g dry weight) ranged from n.d.-2.54 (Ag), 0.25-1.08 (Cd), 0.89-1.64 (Co), 3.7-7.73 (Cr), 1.80-30.27 (Cu), 1073-2627 (Mn), 22.61-55.60 (Ni), 11.42-153.9 (Pb), 40.46-154.7 (Sn) and 65.0-146.5 (Zn). Dissolved metal concentrations (microg/L) ranged from n.d.-9.22 (Ag), n.d.-5.54 (Cd), n.d.-8.30 (Co), 5.26-60.82 (Cr), 10.96-43.11 (Cu), 184.7-375.9 (Mn), 1.84-38.3 (Ni), 5.98-47.77 (Pb), n.d.-540.6 (Sn) and 14.5-55.9 (Zn). Compared with WHO standards and other freshwaters worldwide, this lake was found to be unpolluted, with all metals, except Mn, being detected at concentrations lower than the highest desirable levels and maximum permissible levels. Some of the toxic metals, Cu, Zn, Pb and Cd (in sediment) and Ag, Co and Pb (in water) were detected at lower concentrations than those found in the polluted Kisumu Pier in Winam Gulf in the Lake basin, which confirms the anthropogenic influence on the latter.     

Analysis of Heavy Metals in Water and Surface Sediment in Five Rift Valley Lakes in Kenya for Assessment of Recent Increase in Anthropogenic Activities

The concentrations of heavy metals Ag, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sn and Zn were analysed in water and surface sediments of five Rift Valley lakes Nakuru, Elementaita, Naivasha, Bogoria and Baringo in Kenya. The dissolved mean concentration levels (μg/L) in water ranged within 13.0–185.0 (Ag), 2.0–43.0 (Cd), 5.0–316.0 (Co), 25.0–188.0 (Cr), 4.7–100.0 (Cu), 50.0–282.0 (Mn), 19.0–288.0 (Ni), 25.0–563.0 (Pb), 300.0–1050.0 (Sn) and 29.0–235.0 (Zn). The mean sediment concentrations (in μg/g (dry weight)) ranged within 0.1–0.35 (Ag), 0.05–1.18 (Cd), 0.17–1.38 (Co), 1.94–4.91 (Cr), 1.46–20.95 (Cu), 667.7–3946.8 (Mn), 11.69–39.72 (Ni), 10.92–38.98 (Pb), 17.21–56.52 (Sn) and 96.2–229.6 (Zn). The data indicate that some of the sites analysed, especially in Lake Nakuru, had relatively higher concentration levels of heavy metals Cd, Co, Cu, Pb, Ni, and Zn in the water which points to anthropogenic addition. However, potential influence of geochemical processes on the concentration levels in sediment is also shown in Co, Ni, and Cu which were more concentrated in the remote Lake Baringo sediment as well as in Pb and Mn which were more concentrated in the remote Lake Bogoria sediment. Data on some important limnological parameters including pH, salinity, electrical conductivity and temperature are also presented.     

Decennary Variations of Dissolved Heavy Metals in Seawater of Bohai Bay,North China

Characteristics of the spatial and temporal distributions of selected dissolved heavy metals (Cu, Zn, Pb, Hg and Cd) in Bohai Bay, north China was investigated. Water samples from 22 sites were collected and analyzed for the selected metals with atomic absorption spectrometry from the year of 1996 to 2005. Relatively high concentrations of Cu, Zn, Pb and Hg were detected, with maximum concentrations in the 10-year period of 16.30, 422.00, 40.40, 0.23 μg/L respectively. The concentrations of Cd in all samples were quite low, with maximum level of 0.89 μg/L. The spatial distribution of dissolved Cu, Zn and Pb was analogous, where their average concentrations generally descended from the coastline to the central areas of the bay. Differently, for Hg and Cd, relatively high concentrations occurred not only in inshore but also in offshore areas. Measured data of heavy metals were compared with sea water quality standard of China (SWQSC). Cd concentrations in all samples were below SWQSC Grade-I. The percentages of Cu, Zn, Pb, and Hg at Grade-III levels in Bohai Bay were 2.67%, 30.00%, 30.43% and 0.36%, respectively, suggesting the severe contamination of Zn and Pb in this area. Terrestrial inputs via different rivers and sewages may be the important source for the heavy metals contamination.     

Heavy metal contamination of soil and vegetables in suburban areas of Varanasi, India

Heavy metal contamination of soil resulting from wastewater irrigation is a cause of serious concern due to the potential health impacts of consuming contaminated produce. In this study an assessment is made of the impact of wastewater irrigation on heavy metal contamination of Beta vulgaris (palak); this is a highly nutritious leafy vegetable that is widely cultivated and consumed in urban India, particularly by the poor. A field study was conducted at three major sites that were irrigated by either treated or untreated wastewater in the suburban areas of Varanasi, India according to normal practice. Samples of irrigation water, soil, and the edible portion of the palak (Beta vulgaris L. var All green H1) were collected monthly during the summer and winter seasons and were analyzed for Cd, Cu, Zn, Pb, Cr, Mn, and Ni. Heavy metals in irrigation water were below the internationally recommended (WHO) maximum permissible limits set for agricultural use for all heavy metals except Cd at all the sites. Similarly, the mean heavy metal concentrations in soil were below the Indian standards for all heavy metals, but the maximum value of Cd recorded during January was higher than the standard. However, in the edible portion of B. vulgaris, the Cd concentration was higher than the permissible limits of the Indian standard during summer, whereas Pb and Ni concentrations were higher in both summer and winter seasons. Results of linear regression analysis computed to assess the relationship between individual heavy metal concentration in the vegetable samples and in soil showed that Zn in soil had a positive significant relationship with vegetable contamination during winter. Concentrations of Cd, Cu, and Mn in soil and plant showed significant positive relationships only during summer. Concentration of Cr and Pb during winter season and Zn and Ni during summer season showed significant negative relationships between soil and plant contamination. The study concludes that the use of treated and untreated wastewater for irrigation has increased the contamination of Cd, Pb, and Ni in edible portion of vegetables causing potential health risk in the long term from this practice. The study also points to the fact that adherence to standards for heavy metal contamination of soil and irrigation water does not ensure safe food.     

Interactive Effects of 1,4-Dichlorobenzene and Heavy Metals on Their Sorption Behaviors in Two Chinese Soils

Organic contaminants and toxic heavy metals often coexist in contaminated soils. However, little information concerning the interactive effects of organic contaminants and heavy metals on their sorption behaviors on soils is available. In this study, the competitive sorption effects of 1,4-dichlorobenzene (1,4-DCB) and typical heavy metals, cadmium (Cd) and copper (Cu), on their sorption characteristics on two Chinese soils were examined using a batch equilibration method. The results indicated that the coexistence of Cd and Cu inhibited the sorption of 1,4-DCB on soils and the inhibitive effects increased with increasing concentrations of Cd and Cu. This can be attributed to the inner-sphere complexation of Cd and Cu to form hydration shells of dense water that directly compete for surface sorption sites with 1,4-DCB. Additionally, pore blockage is presumed to be an alternative mechanism for the inhibitive effect. The extent of inhibitive effects depends on not only the relatively chemical characteristics of metals but also on the types of soils. However, the concurrence of 1,4-DCB (50 mg/L) in soils has little effects on the sorption capacity of Cd and Cu due to their higher sorption affinity for the soils than 1,4-DCB. These findings indicated that the coexistence of metals can greatly affect sorption behaviors of hydrophobic organic compounds on soils and thus their fate, transportation, and bioavailability.     

Genotoxicity of heavy metals to the larvae of Chironomus kiiensis Tokunaga after short-term exposure

The genotoxic effects of increasing concentrations (below lethal concentration [LC??]) of cadmium ([Cd] 0.1, 1 and 10 mg/L), copper ([Cu] 0.2, 2 and 20 mg/L) and zinc ([Zn] 0.5, 5 and 50 mg/L) on Chironomus kiiensis were evaluated using alkaline comet assay after exposure for 24 h. Both the tail moment and the olive tail moment showed significant differences between the control and different concentrations of Cd, Cu and Zn (Kruskal-Wallis, p < 0.05). The highest concentration of Cd was associated with higher DNA damage to C. kiiensis larvae compared with Cu and Zn. The potential genotoxicity of these metals to C. kiiensis was Cd > Cu > Zn.     

Winter third- to fourth-instar larvae of Chironomus plumosus as bioassay tools for assessment of acute toxicity of metals and their binary combinations

The ecotoxicological effect expressed as mortality of four metal ions (Cd, Cu, Zn, Al) and their associations on winter third- to fourth-instar larvae of Chironomus plumosus was determined. The effect of individual metals was introduced as acute toxicological effect and expressed as LC(50) and LC95 values with 95% intervals of confidence. On the basis of the LC50 values the toxicity of metals after 96 h treatment was ranked Cu>Cd>Zn>Al. Copper was at least 100 times more toxic than other metals tested. When the acute toxic effect of metal pairs was observed, in general, deleterious effects were directly proportional to metal concentrations. The toxicity of metals in combinations was different from that of individual metals, because of either antagonism or synergism. From the results obtained it can be concluded that when in metal pairs in which the original metal (the metal for which the interaction was determined) is at the lower concentration (Cd 10 mg x L(-1), Zn 25 mg x L(-1), Al 25 mg x L(-1), Cu 0.1 mg x L(-1)), the prevailing interaction is synergism (mortality was higher for metal combinations than for individual metals). Except for an overadditive effect (synergism), additivity was also confirmed in some cases (Al25+Cd10; Al25+Cd25; Al25+Cu0.1; Cu0.1+Cd10; Cu0.1+Cd25; Cu0.1+Al50). Synergism, in combinations in which the original metal is at the higher concentration (Cd 25 mg x L(-1), Zn 50 mg x L(-1), Al 50 mg x L(-1), Cu 1.0 mg x L(-1)), was observed only for the pairs Zn50+Al25 and Zn50+Cu1.0. Reciprocal additivity was observed after 96 h of treatment only for the combination Zn50+Al50. For all other binary combinations in which the original metal was at the higher concentration, an antagonistic effect was confirmed.     

Speciation, behavior, and bioavailability of copper downstream of a mine-impacted lake

A combination of Cu speciation analysis and toxicity testwork was conducted to assess the behavior, speciation, and bioavailability of Cu in a stream system rich in dissolved organic carbon (DOC) downstream of a mine-impacted lake (East Lake, ON, Canada). Elevated levels (approximately 50 microg/L) of Cu exist in the lake due to the release of dissolved Cu to the water column from underlying sediments. Most of the Cu present in East Lake and downstream is present as filterable species that represent 74 to 100% of the total. Measurements of labile Cu as measured by diffusive gradients in thin films (DGT) suggest that most of the Cu is unavailable to aquatic biota. The DGT results indicate that 9 to 24% of Cu within the receiving environment is biologically available. Decreases in the labile Cu fraction with distance downstream of East Lake correlate well with increases in the concentration of DOC (r(2) = 0.79-0.95), presumably due to the progressive importance of Cu-organic complexes. The relationship between filterable Cu and SO(4)(2-) downstream of East Lake was linear (r(2) = 0.99) for all sampling periods, suggesting that decreases in filterable Cu concentration downstream of East Lake could be attributed solely to dilution (i.e., conservative behavior). Variations in the filterable Cu concentration resulting in 50% mortality (LC50 = 96-203 microg/L) and the concentration resulting in an inhibition of reproduction by 25% (IC25 = 75-156 microg/L) with respect to Ceriodaphnia dubia (7-d incubation) in Cu-spiked solutions could be explained by differences in labile-Cu concentrations as determined by DGT. The considerable complexation capacity afforded by lake and stream waters can be attributed to complexation of Cu with abundant DOC (7-17 mg/L). The relevance of the toxicity data to water-effect ratio testwork, and the associated development of site-specific water quality objectives, are discussed.     

Levels of Toxic Metals in Multisectoral Samples from Winam Gulf of Lake Victoria

In this study, the distribution and sources of inputs of trace metals including Cd, Cu, Zn and Pb from various sources as well as Fe which is widely used in the construction industry, into Winam Gulf of Lake Victoria were investigated. The sampling sites were located up streams and down streams of four rivers (Sio, Nyamasaria, Nyando and Sondu-Miriu), in four beaches along the lake (Port Victoria, Kisumu Car Wash, Dunga and Hippo point beaches) and in three estates (Nyamasaria, Migosi and Nyawita) in Kisumu city, covering potential agrochemical and industrial sources and drinking water points, respectively. The concentrations (in μg/L) of trace metals analysed in the lake and river waters ranged from <1.79 (Cd), <3.83 (Pb), <1.53–3.86 (Cu), 4.37–11.6 (Zn), 11.8–2,440 (Fe). The sediment concentrations (in μg/kg × 10³) ranged from 0.19 to 1.91 (Cd), 6.86–138 (Pb), 18–100 (Cu), 36.2–443 (Zn) and 960–73,200 (Fe), with highest concentrations of all metals being recorded at Kisumu Car Wash area. The study confirmed that the concentrations of the metals accumulate downstream in the rivers both in water and sediment and these rivers are major sources of the heavy metal load into Winam Gulf of Lake Victoria.