To examine the degree of contamination in the Dongting Lake (洞庭湖) area, surface sediments samples were collected and investigated in this study. This lake lies in the south of the middle Yangtze River, and it is ...To examine the degree of contamination in the Dongting Lake (洞庭湖) area, surface sediments samples were collected and investigated in this study. This lake lies in the south of the middle Yangtze River, and it is the second largest fresh-water lake in China. These samples were analyzed for the concentrations of the following 6 elements (CA, Cr, Cn, Ni, Ph and Zn) collected from 46 locations. The index of geo-accumulation was used to assess the degree of contamination of the total trace elements and the assessments showed that the contamination of Cd reached strong to very strong pollution. The speciation of metal in sediments was analyzed using the modified BCR (Community Bureau of Reference) sequential extraction technology and the water column-contamination risk was evaluted by the calculated contamination factors. The results of the speciation of metal indicated that more easily mobilized forms (exchangeable, water soluble, and acid soluble) were predominant for CA, especially in the samples from East Dongting Lake. In contrast, the largest amount of lead was associated with the iron and manganese oxide fractions, and Cn, Zn, Cr, and Ni analyzed were mainly distributed in residual phase at an average percentage higher than 60 % of the total metals. The potential risk to the lake's water contamination was the highest in East Dongting Lake based on the calculated contamination factors. The assessment results using geo-accamnlation index were compared with the information obtained by trace metal speciation and both results were consistent.展开更多
The enrichment of nutrients (Noa-, Noa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The m...The enrichment of nutrients (Noa-, Noa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The mean enrichment factors ([Xi]microlayer/[Xi ]15cm in depth) mostly ranged between 1 . 0 and 2. 0. The dissolved forms were the major forms of the components measured, the enrichment of dissolved organic matter and suspended particles could lead to the changes in the total amount and speciation of nutrients and trace metals. No correlation was observed between sample concentrations, speciation, enrichment factors and sample locations. However, some evidence shows that these parameters are correlated with sea state, indicating the complexity and dynamic nature of the sea surface microlayer.展开更多
Objective Despite the fact that the bioavailability of trace metals indicated by their speciation has been an indispensable parameter in the assessment and treatment of the environmental pollution of trace metals, ma...Objective Despite the fact that the bioavailability of trace metals indicated by their speciation has been an indispensable parameter in the assessment and treatment of the environmental pollution of trace metals, many studies have suggested that the bioavailability of trace metals may change according to the conditions of the environment, and the speciation of trace metals can also transform between some fractions. These transformations are related with these factors such as the compositions, microorganism, time, and other physical-chemical conditions of the system. Our work aims to systematically investigate and probe the factors to affect the transformation aside from analysis at certain time-place. The results of these understanding and investigations can be used for reasonably determining the allocation of financial and technical resources in natural and engineered processes, with bringing about inspirations from the evolution of the speciation of the trace metals on environmental impacts.展开更多
Water contamination by chemical pollutants is increasingly associated with waterborne diseases worldwide. The objective of this study is to assess the chemical health risk associated with drinking water consumption in...Water contamination by chemical pollutants is increasingly associated with waterborne diseases worldwide. The objective of this study is to assess the chemical health risk associated with drinking water consumption in Dakar, Senegal. The methodology adopted in this study is based on the determination of trace metals (Cd, Pb, Fe, Cu and Mn) in human drinking water by flame atomic absorption spectrometry, the estimation of the exposure of populations of the study area on the basis of the quantity of water consumed daily and the determination of the hazard quotient which allows estimating the health risk. The results indicate unacceptable levels of Pb and Cd in the water according to World Health Organization (WHO) guidelines, while the concentrations of Fe, Cu and Mn are below the regulatory values. The hazard quotient (HQ) is in the majority of samples higher than 1 in children and infants for scenario 1 (based on WHO data), reflecting a high risk for this target. In scenario 2 based on consumption data from the populations studied, the HQ is greater than 1 only in heavy consumers. The drinking water consumed by Dakar population presents health risks related to Pb and Cd, particularly for infants, children and heavy consumers, hence the need to strengthen the water treatment system before home consumption.展开更多
This study aims to assess the effective capacity of <i>Panicum</i><span> <i>maximum</i> </span>to accumulate cadmium (Cd), nickel (Ni) and lead (Pb). <i>P</i><span>...This study aims to assess the effective capacity of <i>Panicum</i><span> <i>maximum</i> </span>to accumulate cadmium (Cd), nickel (Ni) and lead (Pb). <i>P</i><span>. <i>maximum</i></span> observed in a greenhouse was subjected to 2 ppm of Cd, 50 ppm of Ni, 100 ppm of Pb contaminated soil and uncontaminated soil, </span></span><span><span><span style="font-family:"">for</span></span></span><span><span><span style="font-family:""> 120 days. Plant growth and biomass produced concentration of trace metals in soil and plant, bioaccumulation and transfer factors, location of potentially toxic elements in tissues and cells of plant ha</span></span></span><span><span><span style="font-family:"">ve</span></span></span><span><span><span style="font-family:""> been determined. Stem length and biomass produced by <i>P</i><span>. <i>maximum</i></span> were higher on the uncontaminated soil followed respectively by those of soil-contaminated by Pb, Cd and Ni. Bioaccumulation factors of trace metals were 8.93 (Pb), 8.47 (Ni) and 3.37 (Cd). Ni was more accumulated in shoot biomass (FT > 1), while Pb and Cd were concentrated in root biomass (FT </span></span></span><span><span><span style="font-family:""><</span></span></span><span><span><span style="font-family:""> 1). Pb is accumulated preferentially in endodermis (roots) and epidermis (leaves). As for Ni and Cd, they are concentrated in central cylinder of roots and in conductive bundles of leaves. At cellular level, Ni and Cd are mainly concentrated in intracellular compartments of leaves and roots, while Pb is strongly detected at cell walls.展开更多
Geochemical background values are the normal concentration of trace metals in the natural environment and sediment cores have been proved to be excellent samples to get these values.The trace metal(Cu,Pb,Zn,Cr,Cd,As,H...Geochemical background values are the normal concentration of trace metals in the natural environment and sediment cores have been proved to be excellent samples to get these values.The trace metal(Cu,Pb,Zn,Cr,Cd,As,Hg,Ni,Li,and Co)concentration profiles along a sediment core are investigated to get the background values and to assess the depositional processes and contamination levels off the southern Shandong Peninsula,China.All the metals,except As and Hg,had similar concentration profiles with the highest average values during the period of 6-3 kyr.The high concentrations of As and Hg occurred before 6ka and during the period of 3-0 kyr.The difference in metal concentrations before and after 6 kyr was mainly attributed to the source of core sediments,which are derived from proximal sediment on the Shandong Peninsula before 6 kyr and the mixture of proximal sediment and Yellow River sediment after 6 kyr.The effects of particle size and human activity were mainly contributed to the metal concentrations since 6 kyr.The average concentrations of trace elements in sediments between 6 and 3 kyr were selected as background values.The principal component factor analysis indicate that the metals were from the natural sources throughout the observed depositional period,with the exception of As and Hg,which may had anthropogenic sources for the sediments from the bottom 2 m of the core.Their geoaccumulation indices indicate that the sediments were not contaminated for Cu,Zn,Cr,Cd,Pb,Ni,Li and Co,whereas they were contaminated recently for As and Hg due to the regional civilization and human activities.展开更多
In the present study, the two lakes, Vengaiah lake (Lake A-Sewage polluted receiving discharge from storm water drain) and Yellamallappa Chetty lake (Lake B-Industrially polluted) situated near Krishnarajpuram-Hoskote...In the present study, the two lakes, Vengaiah lake (Lake A-Sewage polluted receiving discharge from storm water drain) and Yellamallappa Chetty lake (Lake B-Industrially polluted) situated near Krishnarajpuram-Hoskote taluk, Bangalore, Karnataka were selected for analysis of trace metals viz., arsenic, aluminium, cadmium, lead, mercury, iron, copper and zinc in water samples. Muscle and gill tissues of freshwater fish Labeo rohita reared in these water bodies were analysed for bioaccumulation of trace metals. Hebbal fish farm was considered as a reference site (Control site) for water and fish samples. Trace metals were analysed by atomic absorption spectroscopy and values were compared with those recommended by FAO/WHO in water and fish samples. Trace metals such as Al, As and Hg were detected in the water sampled from lake B which is attributed to the differences in the sources of pollutants. Fish tissues viz., muscle and gills sampled from Lake B exhibited high concentration of Al, Pb and Cd content showing a positive correlation with their concentration in water samples. The remaining metals as Cu, Zn and Fe were detected in water sampled from all water bodies and also in the fish tissues. Gills exhibited higher concentration of metals in fish from lake B. Bioaccumulation of these trace metals in fish tissues may cause potential danger to human health when consumed on regular basis. Thus necessary remedial measures are required to combat water contamination and its management keeping in view the aquatic ecosystem and public health. Values were statistically significant at P < 0.0001.展开更多
The paper analyzed the concentrations of trace metals in fine and respirable particulates (fine-PM<sub>1</sub> and PM<sub>2.5</sub>;respirable-PM<sub>10</sub>) to determine baseline...The paper analyzed the concentrations of trace metals in fine and respirable particulates (fine-PM<sub>1</sub> and PM<sub>2.5</sub>;respirable-PM<sub>10</sub>) to determine baseline concentrations in the ambient air and the factors impacting its distribution such as land use and time of year when levels may be concerning to public health. Measurements of particulates along with meteorological parameters were made at four sites over the heavily populated west coast of Trinidad (10<span style="font-size:10.0pt;font-family:;" "=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">°</span></span>32'N, 61<span style="font-size:10.0pt;font-family:;" "=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">°</span></span>18'W) during March ’15-May ’16, representing rural, urban, mixed background and industrial land uses. The study found mean levels of trace metals to be highest at the industrial and urban stations. Public health exceedances (referenced to the Canadian AAQ public health standards <a href="#ref23">(Ontario-MoE, 2012)</a>) were measured for beryllium, cadmium, chromium, iron, manganese and nickel (in PM<sub>10</sub>). Iron, manganese and nickel, most associated with particulates at the industrial station, were in frequent exceedance. Beryllium—concentrated in coarse PM (PM<sub>2.5-10</sub>) with only a single measured exceedance at the mixed background station likely poses minimal threat to the health of the nearby population. Cadmium—concentrated in fine PM which peaked once only at the rural station was likely due to an irregular event within a narrow timeframe during the time of sampling. Iron and manganese were frequently above the Canadian public health threshold, but predominated in the coarse PM fraction, suggesting localised sources. Nickel, concentrated in the fine PM fraction, was frequently in exceedance particularly at the industrial station. Cadmium and nickel are genotoxic and should be regulated in order to reduce the burden of toxic carcinogens to which the population can be exposed.展开更多
This study was conducted on the Ngaoundaba Crater Lake sediments to infer provenance,weathering conditions,organic matter accumulation,and trace metal concentrations.Ngaoundaba Lake sediments were collected using a ma...This study was conducted on the Ngaoundaba Crater Lake sediments to infer provenance,weathering conditions,organic matter accumulation,and trace metal concentrations.Ngaoundaba Lake sediments were collected using a manual core sampler at 5 to 8 m water depth.Two sediment cores from the littoral and center of the lake were analyzed for grain size distribution,water content(WC),organic matter content,mineralogy,and major and trace element concentrations.The Ngaoundaba sediments were classified as silt and sandy silt.Sediments show high content in organic matter,which is more to the littoral than to the center of the lake,varying from 14.6%to 24%and21.2%to 40.8%,respectively.The grain surface features identified by Scanning Electron Microscopy(SEM)show both chemical and mechanical microtextures with subrounded to angular shape suggesting both proximal and distal sources.The lake sediments are composed of quartz,kaolinite,and hematite,with low amounts of feldspars,rutile,calcite,illite,and ilmenite.Weathering indices such as the chemical index of alteration(CIA),chemical index of weathering(CIW),and index of compositional variability(ICV)indicate moderate to intense chemical weathering in the source area and immature to mature sediments.The geochemical composition indicates that the sediments were derived from felsic to intermediate igneous rocks,such as granitoids,and mafic alkali lavas like basanites.The environmental risk assessment of trace metals obtained by enrichment factor(EF)and geo-accumulation index(I-geo)shows low contamination of the lake sediments.展开更多
Large-scale metal contamination across the food web is an intractable problem due to increasing pollutant emissions,atmospheric transport,and dry and wet deposition of elements.The present study focus on several trace...Large-scale metal contamination across the food web is an intractable problem due to increasing pollutant emissions,atmospheric transport,and dry and wet deposition of elements.The present study focus on several trace metals that are rarely studied but have special toxicity,including tin(Sn),antimony(Sb),gold(Au),hafnium(Hf),palladium(Pd),platinum(Pt),ruthenium(Ru),tellurium(Te)and iridium(Ir).We investigated trace metals residues and distribution characteristics,and further evaluated the potential health risks from major daily food intakes in 33 cities in China.Sn,Sb,Ir,Hf,and Au were frequently detected in food samples with the concentrations ranged from ND(not detected)to 24.78μg/kg ww(wet weight).Eggs exhibited the highest residual level of all detected metals(13.70±14.70μg/kg ww in sum),while the lowest concentrations were observed in vegetables(0.53±0.17μg/kg ww in sum).Sn accounting for more than 50%of the total trace metals concentration in both terrestrial and aquatic animal origin foods.In terrestrial plant origin foods,Sn and Ir were the most abundant elements.Hf and Au were the most abundant elements in egg samples.In addition,Sb and Ir showed a clear trophic dilution effect in terrestrial environments,while in aquatic ecosystems,Sn,Hf,and Au exhibited obvious trophic amplification effects.The calculated average estimated daily intake(EDI)via food consumption in five regions of China was 0.09μg/(kg·day),implying the health risk of aforementioned elements was acceptable.展开更多
Plants take up a wide range of trace metals/metalloids(hereinafter referred to as trace metals)from the soil,some of which are essential but become toxic at high concentrations(e.g.,Cu,Zn,Ni,Co),while others are non-e...Plants take up a wide range of trace metals/metalloids(hereinafter referred to as trace metals)from the soil,some of which are essential but become toxic at high concentrations(e.g.,Cu,Zn,Ni,Co),while others are non-essential and toxic even at relatively low concentrations(e.g.,As,Cd,Cr,Pb,and Hg).Soil contamination of trace metals is an increasing problem worldwide due to intensifying human activities.Trace metal contamination can cause toxicity and growth inhibition in plants,as well as accumulation in the edible parts to levels that threatens food safety and human health.Understanding the mechanisms of trace metal toxicity and how plants respond to trace metal stress is important for improving plant growth and food safety in contaminated soils.The accumulation of excess trace metals in plants can cause oxidative stress,genotoxicity,programmed cell death,and disturbance in multiple physiological processes.Plants have evolved various strategies to detoxify trace metals through cell-wall binding,complexation,vacuolar sequestration,efflux,and translocation.Multiple signal transduction pathways and regulatory responses are involved in plants challenged with trace metal stresses.In this review,we discuss the recent progress in understanding the molecular mechanisms involved in trace metal toxicity,detoxification,and regulation,as well as strategies to enhance plant resistance to trace metal stresses and reduce toxic metal accumulation in food crops.展开更多
The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were colle...The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were collected both during off-season agriculture and pluvial agriculture from April to October 2022. The samples were analyzed for trace metals according to the standard methods of the US EPA 2007 with a microwave plasma atomic emission spectrometer (MP-AES), Agilent Model 4210. The pollution level was assessed using contamination factor (Cf) and modified contamination degree (mCd). During the off-season, the concentration of trace metals followed in descending order as Mn > Cr > Cu > Pb > Zn. As, Cd, Co, Hg, Ni, Sb and Se were below the detectable limits. In pluvial season, the concentration of traces of metal follows the order Mn > Cr > Zn > Cu > Ni > Pb > Hg > As. Cd, Co, Sb and Se remain below the detectable limits. The concentrations of Cr, Mn and Zn were lower in the off-season agriculture than in pluvial agriculture. For Cu and Pb, the concentrations were higher in the off-season than in pluvial agriculture. The Cf ranges from 0.24 to 11.70 depending on the considered trace metal. The Cf values of As, Ni, Pb, Zn and Mn indicated that the agricultural study soil was lowery contaminated by these trace metals. The agricultural study soil was moderately contaminated by Cr and Cu, and highly contaminated by Hg. Globally the agricultural study soil presents a moderate degree of contamination (mCd 2.25) by the eight trace metals studied. This result provides information on understanding the risks of trace metal contamination of agricultural soil. It is important to anticipate the control of soil contamination through regular monitoring of toxic metals in agricultural soils, control the quality of chemicals used in agriculture and regulate their use.展开更多
This study aimed to investigate the pollution characteristics, source apportionment, and health risks associated with trace metal(loid)s(TMs) in the major agricultural producing areas in Chongqing, China. We analyzed ...This study aimed to investigate the pollution characteristics, source apportionment, and health risks associated with trace metal(loid)s(TMs) in the major agricultural producing areas in Chongqing, China. We analyzed the source apportionment and assessed the health risk of TMs in agricultural soils by using positive matrix factorization(PMF) model and health risk assessment(HRA) model based on Monte Carlo simulation. Meanwhile, we combined PMF and HRA models to explore the health risks of TMs in agricultural soils by different pollution sources to determine the priority control factors. Results showed that the average contents of cadmium(Cd), arsenic (As), lead(Pb), chromium(Cr), copper(Cu), nickel(Ni), and zinc(Zn) in the soil were found to be 0.26, 5.93, 27.14, 61.32, 23.81, 32.45, and 78.65 mg/kg, respectively. Spatial analysis and source apportionment analysis revealed that urban and industrial sources, agricultural sources, and natural sources accounted for 33.0%, 27.7%, and 39.3% of TM accumulation in the soil, respectively. In the HRA model based on Monte Carlo simulation, noncarcinogenic risks were deemed negligible(hazard index <1), the carcinogenic risks were at acceptable level(10^(-6)<total carcinogenic risk ≤ 10^(-4)), with higher risks observed for children compared to adults. The relationship between TMs, their sources, and health risks indicated that urban and industrial sources were primarily associated with As, contributing to 75.1% of carcinogenic risks and 55.7% of non-carcinogenic risks, making them the primary control factors. Meanwhile, agricultural sources were primarily linked to Cd and Pb, contributing to 13.1% of carcinogenic risks and 21.8% of non-carcinogenic risks, designating them as secondary control factors.展开更多
Based on the study of Beijing PM10 bioreactivity with the newly developed plasmid DNA assay method, and analysis for trace elements of PM10, the cause of plasmid DNA damage by PM10 was investigated. The study showed t...Based on the study of Beijing PM10 bioreactivity with the newly developed plasmid DNA assay method, and analysis for trace elements of PM10, the cause of plasmid DNA damage by PM10 was investigated. The study showed that plasmid DNA oxidative damages by PM10 are of difference in different seasons at various areas. The concentrations of TM50 of PM10 in whole samples respectively collected at urban and comparison sites during winter were 900 μg mL?1 and 74 μg mL?1, while those in their corresponding soluble fractions were 540 μg mL?1 and 86 μg mL?1. In contrast, TM50 contents of PM10 from summer whole samples at urban areas and comparison sites were 116 μg mL?1 and 210 μg mL?1, whereas those in their soluble fractions were 180 μg mL?1 and 306 μg mL?1. The difference of bioreactivity of Beijing PM10 resulted from the variation of trace elements. The oxidative damage of plasmid DNA caused by Pb, Zn, As in PM10 (whole sample) was relatively strong. TM50 and Mn, V, Zn display stronger correlation in the soluble fraction. It implies that Zn could be the major trace element in Beijing PM10 which contributes to oxidative damage to plasmid DNA.展开更多
Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in D...Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in Dongting Lake, China and the human health risks of mussel consumption are largely unknown. We investigated the concentrations of 15 trace metals and metalloids in surface water, sediments, and C. plicata organs(foot, gill, mantle, and visceral mass) and quantified the bioaccumulation and human health risk of these trace metals in specimens collected from Dongting Lake. The concentrations of most metals in surface water exceeded previously published background values. In contrast, the concentrations of most metals in sediments showed a decreasing trend. Overall, the metal concentrations in the gill and visceral masses of C. plicata were higher than those in the foot and mantle, and higher bioaccumulation capacities were observed for essential metals than for nonessential metals. The mean concentrations of the trace elements Zn, Pb, Cd, As, Cu, and Cr in C. plicata foot samples were lower than the threshold values established by international and Chinese organizations. The estimated daily intake(EDI) values of the essential metal Mn in C. plicata foot was higher than the recommended tolerable daily intake(TDI) values for juveniles. Only Mn for juveniles and As for both juveniles and adults may pose noncarcinogenic health risks through foot consumption. The hazard index(HI) values for adults and juveniles were higher than 1, suggesting significant risks of noncarcinogenic effects to humans by exposure to multiple metals.展开更多
Trace metals in PM2.5 were measured at one industrial site and one urban site during September, 2010 in Ji'nan, eastern China. Individual aerosol particles and PM2.5 samples were collected concurrently at both sites....Trace metals in PM2.5 were measured at one industrial site and one urban site during September, 2010 in Ji'nan, eastern China. Individual aerosol particles and PM2.5 samples were collected concurrently at both sites. Mass concentrations of eleven trace metals (i.e., Al, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Ba, and Pb) and one metalloid (i.e., As) were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The result shows that mass concentrations of PM2.5 (130μg/m3) and trace metals (4.03 μg/m3) at the industrial site were 1.3 times and 1.7 times higher than those at the urban site, respectively, indicating that industrial activities nearby the city can emit trace metals into the surrounding atmosphere. Fe concentrations were the highest among all the measured trace metals at both sites, with concentrations of 1.04 ixg/m 3 at the urban site and 2.41 Itg/m3 at the industrial site, respectively. In addition, Pb showed the highest enrichment factors at both sites, suggesting the emissions from anthropogenic activities existed around the city. Correlation coefficient analysis and principal component analysis revealed that Cu, Fe, Mn, Pb, and Zn were originated from vehicular traffic and industrial emissions at both sites; As, Cr, and part of Pb from coal-fired power plant; Ba and Ti from natural soil. Based on the transmission electron microscopy analysis, we found that most of the trace metals were internally mixed with secondary sulfate/organic particles. These internally mixed trace metals in the urban air may have different toxic abilities compared with externally mixed trace metals.展开更多
The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigat...The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigate the concentration of trace metals in atmospheric and lake water samples during the rainy season (before and after precipitation) between November and December 2015. Typical methods of sample preparation for trace metal determination such as cloud point extraction, solid phase extraction and dispersive liquid- liquid micro-extraction are time-consuming and difficult to perform; therefore, there is a crucial need for development of more effective sample preparation procedure. A convection microwave assisted digestion procedure for extraction of trace metals was developed for use prior to inductively couple plasma-mass spectrometric determination. The result showed that metals like zinc (133.50-419.30 μg/m3) and aluminum (53.58-378.93 μg/m3) had higher concentrations in atmospheric samples as compared to lake samples before precipitation. On the other hand, the concentrations of zinc, aluminum, chromium and arsenic were significantly higher in lake samples after precipitation and lower in atmospheric samples. The relationship between physicochemical parameters (pH and turbidity) and heavy metal concentrations was investigated as well. Furthermore, enrichment factor analysis indicated that anthropogenic sources such as soil dust, biomass burning and fuel combustion influenced the metal concentrations in the atmosphere.展开更多
The suitability of two common and ubiquitously distributed and exotic ornamental plant species in Nigeria-Delonix regia and Casuarina equisetifolia as biomonitors and as effective bioaccumulators of atmospheric trace ...The suitability of two common and ubiquitously distributed and exotic ornamental plant species in Nigeria-Delonix regia and Casuarina equisetifolia as biomonitors and as effective bioaccumulators of atmospheric trace metals (Cd, Pb, Zn and Cu) has been evaluated. Bark and leaf samples from these plant species were collected in June and July 2006 at five locations in Benin City. Four of the sampling sites were in areas of high traffic density and commercial activities, the fifth site is a remote site, selected to act as a control and also to provide background information for the metals. The plant samples were collected and processed using standard procedures and trace metals were determined using atomic absorption spectrometer. The bark of the plants was able to bioaccumulate the trace metals, especially Pb which originates from anthropogenic contributions in the city. The Pb range of 20.00-70.00 μg/g measured for the bark samples ofD. regia, exceeded the normal plant Pb concentration of 0.2-20.0 μg/g and most Pb data available in literature. The bark of the plants was observed to accumulate more metals compared to the leave, while D. regia was found to be slightly better than C. equisetifolia in trace metal uptake efficiency. Spatial variations in the distributions of Pb and Zn were significant (p 〈 0.05), and the continuous use of leaded fuel in Nigeria was identified as the predominant source of Pb in the atmosphere.展开更多
Trace metals associated with PM10 aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested5 PCs,which accounted for 86.8% cu...Trace metals associated with PM10 aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested5 PCs,which accounted for 86.8% cumulative variance. PC1 accounted for 30% with a significant loading of metals of anthropogenic origin,while PC2 showed 28% variance with the loading of metals of crustal origin. These trace metals showed seasonal distinct day and night time characteristics. The concentrations of Cu,Pb,and Cd were found to be higher during nighttime in all the seasons. Only Fe was observed with significantly higher mean concentrations during daytime of all seasons except monsoon. The highest mean values of Cu,Cd,Zn,and Pb during post-monsoon might be attributed to winds advection over the regions of waste/biomass burning and industrial activities in Punjab and Haryana regions.Furthermore,concentration weighted trajectory analysis suggested that metals of crustal origin were contributed by long-range transport while metals of anthropogenic and industrial activities were contributed by regional/local source regions.展开更多
The trace metals analysis in synodontis membranaceus (head and tail), bottom sediments, Asystasia Gangetica and Platostoma Africanium were carried out using atomic absorption spectrometer of model Perkin Elmer 3110. ...The trace metals analysis in synodontis membranaceus (head and tail), bottom sediments, Asystasia Gangetica and Platostoma Africanium were carried out using atomic absorption spectrometer of model Perkin Elmer 3110. Metals analysed were copper, nickel, mangenese, chromium, iron lead and cobalt. These metals were detected in the above samples. Vegetation samples concentration in copper, manganese, chromium, iron and cobalt were higher than those obtained in bottom sediments. The tail part of the fish contents of trace metals were also higher than those of the head. The results obtained in this work exceeded the results of water analysis carried out by Omoregha on the same river. Metals such as copper, nickel, manganese and chromium were below detection limit in the water from the same river. The bioaccumulation of these trace metals in these samples were traced to activities of Delta Glass Factory.展开更多
基金This paper is supported by the China Geological Survey(No200314200021).
文摘To examine the degree of contamination in the Dongting Lake (洞庭湖) area, surface sediments samples were collected and investigated in this study. This lake lies in the south of the middle Yangtze River, and it is the second largest fresh-water lake in China. These samples were analyzed for the concentrations of the following 6 elements (CA, Cr, Cn, Ni, Ph and Zn) collected from 46 locations. The index of geo-accumulation was used to assess the degree of contamination of the total trace elements and the assessments showed that the contamination of Cd reached strong to very strong pollution. The speciation of metal in sediments was analyzed using the modified BCR (Community Bureau of Reference) sequential extraction technology and the water column-contamination risk was evaluted by the calculated contamination factors. The results of the speciation of metal indicated that more easily mobilized forms (exchangeable, water soluble, and acid soluble) were predominant for CA, especially in the samples from East Dongting Lake. In contrast, the largest amount of lead was associated with the iron and manganese oxide fractions, and Cn, Zn, Cr, and Ni analyzed were mainly distributed in residual phase at an average percentage higher than 60 % of the total metals. The potential risk to the lake's water contamination was the highest in East Dongting Lake based on the calculated contamination factors. The assessment results using geo-accamnlation index were compared with the information obtained by trace metal speciation and both results were consistent.
文摘The enrichment of nutrients (Noa-, Noa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The mean enrichment factors ([Xi]microlayer/[Xi ]15cm in depth) mostly ranged between 1 . 0 and 2. 0. The dissolved forms were the major forms of the components measured, the enrichment of dissolved organic matter and suspended particles could lead to the changes in the total amount and speciation of nutrients and trace metals. No correlation was observed between sample concentrations, speciation, enrichment factors and sample locations. However, some evidence shows that these parameters are correlated with sea state, indicating the complexity and dynamic nature of the sea surface microlayer.
基金funded by the National Natural Science Foundation of China(grant No.41572329)
文摘Objective Despite the fact that the bioavailability of trace metals indicated by their speciation has been an indispensable parameter in the assessment and treatment of the environmental pollution of trace metals, many studies have suggested that the bioavailability of trace metals may change according to the conditions of the environment, and the speciation of trace metals can also transform between some fractions. These transformations are related with these factors such as the compositions, microorganism, time, and other physical-chemical conditions of the system. Our work aims to systematically investigate and probe the factors to affect the transformation aside from analysis at certain time-place. The results of these understanding and investigations can be used for reasonably determining the allocation of financial and technical resources in natural and engineered processes, with bringing about inspirations from the evolution of the speciation of the trace metals on environmental impacts.
文摘Water contamination by chemical pollutants is increasingly associated with waterborne diseases worldwide. The objective of this study is to assess the chemical health risk associated with drinking water consumption in Dakar, Senegal. The methodology adopted in this study is based on the determination of trace metals (Cd, Pb, Fe, Cu and Mn) in human drinking water by flame atomic absorption spectrometry, the estimation of the exposure of populations of the study area on the basis of the quantity of water consumed daily and the determination of the hazard quotient which allows estimating the health risk. The results indicate unacceptable levels of Pb and Cd in the water according to World Health Organization (WHO) guidelines, while the concentrations of Fe, Cu and Mn are below the regulatory values. The hazard quotient (HQ) is in the majority of samples higher than 1 in children and infants for scenario 1 (based on WHO data), reflecting a high risk for this target. In scenario 2 based on consumption data from the populations studied, the HQ is greater than 1 only in heavy consumers. The drinking water consumed by Dakar population presents health risks related to Pb and Cd, particularly for infants, children and heavy consumers, hence the need to strengthen the water treatment system before home consumption.
文摘This study aims to assess the effective capacity of <i>Panicum</i><span> <i>maximum</i> </span>to accumulate cadmium (Cd), nickel (Ni) and lead (Pb). <i>P</i><span>. <i>maximum</i></span> observed in a greenhouse was subjected to 2 ppm of Cd, 50 ppm of Ni, 100 ppm of Pb contaminated soil and uncontaminated soil, </span></span><span><span><span style="font-family:"">for</span></span></span><span><span><span style="font-family:""> 120 days. Plant growth and biomass produced concentration of trace metals in soil and plant, bioaccumulation and transfer factors, location of potentially toxic elements in tissues and cells of plant ha</span></span></span><span><span><span style="font-family:"">ve</span></span></span><span><span><span style="font-family:""> been determined. Stem length and biomass produced by <i>P</i><span>. <i>maximum</i></span> were higher on the uncontaminated soil followed respectively by those of soil-contaminated by Pb, Cd and Ni. Bioaccumulation factors of trace metals were 8.93 (Pb), 8.47 (Ni) and 3.37 (Cd). Ni was more accumulated in shoot biomass (FT > 1), while Pb and Cd were concentrated in root biomass (FT </span></span></span><span><span><span style="font-family:""><</span></span></span><span><span><span style="font-family:""> 1). Pb is accumulated preferentially in endodermis (roots) and epidermis (leaves). As for Ni and Cd, they are concentrated in central cylinder of roots and in conductive bundles of leaves. At cellular level, Ni and Cd are mainly concentrated in intracellular compartments of leaves and roots, while Pb is strongly detected at cell walls.
基金This study was financially supported by the Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology(No.MGQNLM201801)the China Geological Survey Projects(Nos.GZH200900501,DD20160145 and DD20190276)and the National Natural Science Foundation of China(No.41706073).
文摘Geochemical background values are the normal concentration of trace metals in the natural environment and sediment cores have been proved to be excellent samples to get these values.The trace metal(Cu,Pb,Zn,Cr,Cd,As,Hg,Ni,Li,and Co)concentration profiles along a sediment core are investigated to get the background values and to assess the depositional processes and contamination levels off the southern Shandong Peninsula,China.All the metals,except As and Hg,had similar concentration profiles with the highest average values during the period of 6-3 kyr.The high concentrations of As and Hg occurred before 6ka and during the period of 3-0 kyr.The difference in metal concentrations before and after 6 kyr was mainly attributed to the source of core sediments,which are derived from proximal sediment on the Shandong Peninsula before 6 kyr and the mixture of proximal sediment and Yellow River sediment after 6 kyr.The effects of particle size and human activity were mainly contributed to the metal concentrations since 6 kyr.The average concentrations of trace elements in sediments between 6 and 3 kyr were selected as background values.The principal component factor analysis indicate that the metals were from the natural sources throughout the observed depositional period,with the exception of As and Hg,which may had anthropogenic sources for the sediments from the bottom 2 m of the core.Their geoaccumulation indices indicate that the sediments were not contaminated for Cu,Zn,Cr,Cd,Pb,Ni,Li and Co,whereas they were contaminated recently for As and Hg due to the regional civilization and human activities.
文摘In the present study, the two lakes, Vengaiah lake (Lake A-Sewage polluted receiving discharge from storm water drain) and Yellamallappa Chetty lake (Lake B-Industrially polluted) situated near Krishnarajpuram-Hoskote taluk, Bangalore, Karnataka were selected for analysis of trace metals viz., arsenic, aluminium, cadmium, lead, mercury, iron, copper and zinc in water samples. Muscle and gill tissues of freshwater fish Labeo rohita reared in these water bodies were analysed for bioaccumulation of trace metals. Hebbal fish farm was considered as a reference site (Control site) for water and fish samples. Trace metals were analysed by atomic absorption spectroscopy and values were compared with those recommended by FAO/WHO in water and fish samples. Trace metals such as Al, As and Hg were detected in the water sampled from lake B which is attributed to the differences in the sources of pollutants. Fish tissues viz., muscle and gills sampled from Lake B exhibited high concentration of Al, Pb and Cd content showing a positive correlation with their concentration in water samples. The remaining metals as Cu, Zn and Fe were detected in water sampled from all water bodies and also in the fish tissues. Gills exhibited higher concentration of metals in fish from lake B. Bioaccumulation of these trace metals in fish tissues may cause potential danger to human health when consumed on regular basis. Thus necessary remedial measures are required to combat water contamination and its management keeping in view the aquatic ecosystem and public health. Values were statistically significant at P < 0.0001.
文摘The paper analyzed the concentrations of trace metals in fine and respirable particulates (fine-PM<sub>1</sub> and PM<sub>2.5</sub>;respirable-PM<sub>10</sub>) to determine baseline concentrations in the ambient air and the factors impacting its distribution such as land use and time of year when levels may be concerning to public health. Measurements of particulates along with meteorological parameters were made at four sites over the heavily populated west coast of Trinidad (10<span style="font-size:10.0pt;font-family:;" "=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">°</span></span>32'N, 61<span style="font-size:10.0pt;font-family:;" "=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">°</span></span>18'W) during March ’15-May ’16, representing rural, urban, mixed background and industrial land uses. The study found mean levels of trace metals to be highest at the industrial and urban stations. Public health exceedances (referenced to the Canadian AAQ public health standards <a href="#ref23">(Ontario-MoE, 2012)</a>) were measured for beryllium, cadmium, chromium, iron, manganese and nickel (in PM<sub>10</sub>). Iron, manganese and nickel, most associated with particulates at the industrial station, were in frequent exceedance. Beryllium—concentrated in coarse PM (PM<sub>2.5-10</sub>) with only a single measured exceedance at the mixed background station likely poses minimal threat to the health of the nearby population. Cadmium—concentrated in fine PM which peaked once only at the rural station was likely due to an irregular event within a narrow timeframe during the time of sampling. Iron and manganese were frequently above the Canadian public health threshold, but predominated in the coarse PM fraction, suggesting localised sources. Nickel, concentrated in the fine PM fraction, was frequently in exceedance particularly at the industrial station. Cadmium and nickel are genotoxic and should be regulated in order to reduce the burden of toxic carcinogens to which the population can be exposed.
基金generously sponsored by the German Federal Ministry of Education and Researchsupported by the Alexander von Humboldt Foundation。
文摘This study was conducted on the Ngaoundaba Crater Lake sediments to infer provenance,weathering conditions,organic matter accumulation,and trace metal concentrations.Ngaoundaba Lake sediments were collected using a manual core sampler at 5 to 8 m water depth.Two sediment cores from the littoral and center of the lake were analyzed for grain size distribution,water content(WC),organic matter content,mineralogy,and major and trace element concentrations.The Ngaoundaba sediments were classified as silt and sandy silt.Sediments show high content in organic matter,which is more to the littoral than to the center of the lake,varying from 14.6%to 24%and21.2%to 40.8%,respectively.The grain surface features identified by Scanning Electron Microscopy(SEM)show both chemical and mechanical microtextures with subrounded to angular shape suggesting both proximal and distal sources.The lake sediments are composed of quartz,kaolinite,and hematite,with low amounts of feldspars,rutile,calcite,illite,and ilmenite.Weathering indices such as the chemical index of alteration(CIA),chemical index of weathering(CIW),and index of compositional variability(ICV)indicate moderate to intense chemical weathering in the source area and immature to mature sediments.The geochemical composition indicates that the sediments were derived from felsic to intermediate igneous rocks,such as granitoids,and mafic alkali lavas like basanites.The environmental risk assessment of trace metals obtained by enrichment factor(EF)and geo-accumulation index(I-geo)shows low contamination of the lake sediments.
基金supported by the National Key research and development Program (No.2017YFC1600200)Dalian Science and Technology Innovation Fund (No.2020JJ26SN057)。
文摘Large-scale metal contamination across the food web is an intractable problem due to increasing pollutant emissions,atmospheric transport,and dry and wet deposition of elements.The present study focus on several trace metals that are rarely studied but have special toxicity,including tin(Sn),antimony(Sb),gold(Au),hafnium(Hf),palladium(Pd),platinum(Pt),ruthenium(Ru),tellurium(Te)and iridium(Ir).We investigated trace metals residues and distribution characteristics,and further evaluated the potential health risks from major daily food intakes in 33 cities in China.Sn,Sb,Ir,Hf,and Au were frequently detected in food samples with the concentrations ranged from ND(not detected)to 24.78μg/kg ww(wet weight).Eggs exhibited the highest residual level of all detected metals(13.70±14.70μg/kg ww in sum),while the lowest concentrations were observed in vegetables(0.53±0.17μg/kg ww in sum).Sn accounting for more than 50%of the total trace metals concentration in both terrestrial and aquatic animal origin foods.In terrestrial plant origin foods,Sn and Ir were the most abundant elements.Hf and Au were the most abundant elements in egg samples.In addition,Sb and Ir showed a clear trophic dilution effect in terrestrial environments,while in aquatic ecosystems,Sn,Hf,and Au exhibited obvious trophic amplification effects.The calculated average estimated daily intake(EDI)via food consumption in five regions of China was 0.09μg/(kg·day),implying the health risk of aforementioned elements was acceptable.
基金supported by the National Natural Science Foundation of China(31972500 and 41930758)the Key Research&Development Program of Jiangsu Province(BE2021717)。
文摘Plants take up a wide range of trace metals/metalloids(hereinafter referred to as trace metals)from the soil,some of which are essential but become toxic at high concentrations(e.g.,Cu,Zn,Ni,Co),while others are non-essential and toxic even at relatively low concentrations(e.g.,As,Cd,Cr,Pb,and Hg).Soil contamination of trace metals is an increasing problem worldwide due to intensifying human activities.Trace metal contamination can cause toxicity and growth inhibition in plants,as well as accumulation in the edible parts to levels that threatens food safety and human health.Understanding the mechanisms of trace metal toxicity and how plants respond to trace metal stress is important for improving plant growth and food safety in contaminated soils.The accumulation of excess trace metals in plants can cause oxidative stress,genotoxicity,programmed cell death,and disturbance in multiple physiological processes.Plants have evolved various strategies to detoxify trace metals through cell-wall binding,complexation,vacuolar sequestration,efflux,and translocation.Multiple signal transduction pathways and regulatory responses are involved in plants challenged with trace metal stresses.In this review,we discuss the recent progress in understanding the molecular mechanisms involved in trace metal toxicity,detoxification,and regulation,as well as strategies to enhance plant resistance to trace metal stresses and reduce toxic metal accumulation in food crops.
文摘The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were collected both during off-season agriculture and pluvial agriculture from April to October 2022. The samples were analyzed for trace metals according to the standard methods of the US EPA 2007 with a microwave plasma atomic emission spectrometer (MP-AES), Agilent Model 4210. The pollution level was assessed using contamination factor (Cf) and modified contamination degree (mCd). During the off-season, the concentration of trace metals followed in descending order as Mn > Cr > Cu > Pb > Zn. As, Cd, Co, Hg, Ni, Sb and Se were below the detectable limits. In pluvial season, the concentration of traces of metal follows the order Mn > Cr > Zn > Cu > Ni > Pb > Hg > As. Cd, Co, Sb and Se remain below the detectable limits. The concentrations of Cr, Mn and Zn were lower in the off-season agriculture than in pluvial agriculture. For Cu and Pb, the concentrations were higher in the off-season than in pluvial agriculture. The Cf ranges from 0.24 to 11.70 depending on the considered trace metal. The Cf values of As, Ni, Pb, Zn and Mn indicated that the agricultural study soil was lowery contaminated by these trace metals. The agricultural study soil was moderately contaminated by Cr and Cu, and highly contaminated by Hg. Globally the agricultural study soil presents a moderate degree of contamination (mCd 2.25) by the eight trace metals studied. This result provides information on understanding the risks of trace metal contamination of agricultural soil. It is important to anticipate the control of soil contamination through regular monitoring of toxic metals in agricultural soils, control the quality of chemicals used in agriculture and regulate their use.
基金supported by Project of Chongqing Science and Technology Bureau (cstc2022jxjl0005)。
文摘This study aimed to investigate the pollution characteristics, source apportionment, and health risks associated with trace metal(loid)s(TMs) in the major agricultural producing areas in Chongqing, China. We analyzed the source apportionment and assessed the health risk of TMs in agricultural soils by using positive matrix factorization(PMF) model and health risk assessment(HRA) model based on Monte Carlo simulation. Meanwhile, we combined PMF and HRA models to explore the health risks of TMs in agricultural soils by different pollution sources to determine the priority control factors. Results showed that the average contents of cadmium(Cd), arsenic (As), lead(Pb), chromium(Cr), copper(Cu), nickel(Ni), and zinc(Zn) in the soil were found to be 0.26, 5.93, 27.14, 61.32, 23.81, 32.45, and 78.65 mg/kg, respectively. Spatial analysis and source apportionment analysis revealed that urban and industrial sources, agricultural sources, and natural sources accounted for 33.0%, 27.7%, and 39.3% of TM accumulation in the soil, respectively. In the HRA model based on Monte Carlo simulation, noncarcinogenic risks were deemed negligible(hazard index <1), the carcinogenic risks were at acceptable level(10^(-6)<total carcinogenic risk ≤ 10^(-4)), with higher risks observed for children compared to adults. The relationship between TMs, their sources, and health risks indicated that urban and industrial sources were primarily associated with As, contributing to 75.1% of carcinogenic risks and 55.7% of non-carcinogenic risks, making them the primary control factors. Meanwhile, agricultural sources were primarily linked to Cd and Pb, contributing to 13.1% of carcinogenic risks and 21.8% of non-carcinogenic risks, designating them as secondary control factors.
基金This work was supported by the National Natural Science Foundation of China(Grant No.40275040)Shanghai Leading Academic Disciplines(T0105).
文摘Based on the study of Beijing PM10 bioreactivity with the newly developed plasmid DNA assay method, and analysis for trace elements of PM10, the cause of plasmid DNA damage by PM10 was investigated. The study showed that plasmid DNA oxidative damages by PM10 are of difference in different seasons at various areas. The concentrations of TM50 of PM10 in whole samples respectively collected at urban and comparison sites during winter were 900 μg mL?1 and 74 μg mL?1, while those in their corresponding soluble fractions were 540 μg mL?1 and 86 μg mL?1. In contrast, TM50 contents of PM10 from summer whole samples at urban areas and comparison sites were 116 μg mL?1 and 210 μg mL?1, whereas those in their soluble fractions were 180 μg mL?1 and 306 μg mL?1. The difference of bioreactivity of Beijing PM10 resulted from the variation of trace elements. The oxidative damage of plasmid DNA caused by Pb, Zn, As in PM10 (whole sample) was relatively strong. TM50 and Mn, V, Zn display stronger correlation in the soluble fraction. It implies that Zn could be the major trace element in Beijing PM10 which contributes to oxidative damage to plasmid DNA.
基金jointly supported by the National Natural Science Foundation of China (Nos. 51622901 , 51709225 )the Young Scientific Research Innovation Team Project of Xi'an University of Technology (No. 104/256051715 )。
文摘Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in Dongting Lake, China and the human health risks of mussel consumption are largely unknown. We investigated the concentrations of 15 trace metals and metalloids in surface water, sediments, and C. plicata organs(foot, gill, mantle, and visceral mass) and quantified the bioaccumulation and human health risk of these trace metals in specimens collected from Dongting Lake. The concentrations of most metals in surface water exceeded previously published background values. In contrast, the concentrations of most metals in sediments showed a decreasing trend. Overall, the metal concentrations in the gill and visceral masses of C. plicata were higher than those in the foot and mantle, and higher bioaccumulation capacities were observed for essential metals than for nonessential metals. The mean concentrations of the trace elements Zn, Pb, Cd, As, Cu, and Cr in C. plicata foot samples were lower than the threshold values established by international and Chinese organizations. The estimated daily intake(EDI) values of the essential metal Mn in C. plicata foot was higher than the recommended tolerable daily intake(TDI) values for juveniles. Only Mn for juveniles and As for both juveniles and adults may pose noncarcinogenic health risks through foot consumption. The hazard index(HI) values for adults and juveniles were higher than 1, suggesting significant risks of noncarcinogenic effects to humans by exposure to multiple metals.
基金supported by the National Basic Research Program(973)of China(No.2011CB403401)the National Natural Science Foundation of China(No.41105088,41275141)+1 种基金the Natural Science Foundation of Shandong Province(No.ZR2011DQ001)the State Key Laboratory for Coal Resources and Safe Mining(No.SKLCRSM11KFB03)
文摘Trace metals in PM2.5 were measured at one industrial site and one urban site during September, 2010 in Ji'nan, eastern China. Individual aerosol particles and PM2.5 samples were collected concurrently at both sites. Mass concentrations of eleven trace metals (i.e., Al, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Ba, and Pb) and one metalloid (i.e., As) were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The result shows that mass concentrations of PM2.5 (130μg/m3) and trace metals (4.03 μg/m3) at the industrial site were 1.3 times and 1.7 times higher than those at the urban site, respectively, indicating that industrial activities nearby the city can emit trace metals into the surrounding atmosphere. Fe concentrations were the highest among all the measured trace metals at both sites, with concentrations of 1.04 ixg/m 3 at the urban site and 2.41 Itg/m3 at the industrial site, respectively. In addition, Pb showed the highest enrichment factors at both sites, suggesting the emissions from anthropogenic activities existed around the city. Correlation coefficient analysis and principal component analysis revealed that Cu, Fe, Mn, Pb, and Zn were originated from vehicular traffic and industrial emissions at both sites; As, Cr, and part of Pb from coal-fired power plant; Ba and Ti from natural soil. Based on the transmission electron microscopy analysis, we found that most of the trace metals were internally mixed with secondary sulfate/organic particles. These internally mixed trace metals in the urban air may have different toxic abilities compared with externally mixed trace metals.
基金supported by the Universiti Tunku Abdul Rahman under Universiti Research Grant(No.IPSR/RMC/UTARRF/C1-13/G03)
文摘The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigate the concentration of trace metals in atmospheric and lake water samples during the rainy season (before and after precipitation) between November and December 2015. Typical methods of sample preparation for trace metal determination such as cloud point extraction, solid phase extraction and dispersive liquid- liquid micro-extraction are time-consuming and difficult to perform; therefore, there is a crucial need for development of more effective sample preparation procedure. A convection microwave assisted digestion procedure for extraction of trace metals was developed for use prior to inductively couple plasma-mass spectrometric determination. The result showed that metals like zinc (133.50-419.30 μg/m3) and aluminum (53.58-378.93 μg/m3) had higher concentrations in atmospheric samples as compared to lake samples before precipitation. On the other hand, the concentrations of zinc, aluminum, chromium and arsenic were significantly higher in lake samples after precipitation and lower in atmospheric samples. The relationship between physicochemical parameters (pH and turbidity) and heavy metal concentrations was investigated as well. Furthermore, enrichment factor analysis indicated that anthropogenic sources such as soil dust, biomass burning and fuel combustion influenced the metal concentrations in the atmosphere.
文摘The suitability of two common and ubiquitously distributed and exotic ornamental plant species in Nigeria-Delonix regia and Casuarina equisetifolia as biomonitors and as effective bioaccumulators of atmospheric trace metals (Cd, Pb, Zn and Cu) has been evaluated. Bark and leaf samples from these plant species were collected in June and July 2006 at five locations in Benin City. Four of the sampling sites were in areas of high traffic density and commercial activities, the fifth site is a remote site, selected to act as a control and also to provide background information for the metals. The plant samples were collected and processed using standard procedures and trace metals were determined using atomic absorption spectrometer. The bark of the plants was able to bioaccumulate the trace metals, especially Pb which originates from anthropogenic contributions in the city. The Pb range of 20.00-70.00 μg/g measured for the bark samples ofD. regia, exceeded the normal plant Pb concentration of 0.2-20.0 μg/g and most Pb data available in literature. The bark of the plants was observed to accumulate more metals compared to the leave, while D. regia was found to be slightly better than C. equisetifolia in trace metal uptake efficiency. Spatial variations in the distributions of Pb and Zn were significant (p 〈 0.05), and the continuous use of leaded fuel in Nigeria was identified as the predominant source of Pb in the atmosphere.
基金Partial financial support from the CSIR network project(PSC 0112)CSIR fellowship to Subhash Chandra,SRF
文摘Trace metals associated with PM10 aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested5 PCs,which accounted for 86.8% cumulative variance. PC1 accounted for 30% with a significant loading of metals of anthropogenic origin,while PC2 showed 28% variance with the loading of metals of crustal origin. These trace metals showed seasonal distinct day and night time characteristics. The concentrations of Cu,Pb,and Cd were found to be higher during nighttime in all the seasons. Only Fe was observed with significantly higher mean concentrations during daytime of all seasons except monsoon. The highest mean values of Cu,Cd,Zn,and Pb during post-monsoon might be attributed to winds advection over the regions of waste/biomass burning and industrial activities in Punjab and Haryana regions.Furthermore,concentration weighted trajectory analysis suggested that metals of crustal origin were contributed by long-range transport while metals of anthropogenic and industrial activities were contributed by regional/local source regions.
文摘The trace metals analysis in synodontis membranaceus (head and tail), bottom sediments, Asystasia Gangetica and Platostoma Africanium were carried out using atomic absorption spectrometer of model Perkin Elmer 3110. Metals analysed were copper, nickel, mangenese, chromium, iron lead and cobalt. These metals were detected in the above samples. Vegetation samples concentration in copper, manganese, chromium, iron and cobalt were higher than those obtained in bottom sediments. The tail part of the fish contents of trace metals were also higher than those of the head. The results obtained in this work exceeded the results of water analysis carried out by Omoregha on the same river. Metals such as copper, nickel, manganese and chromium were below detection limit in the water from the same river. The bioaccumulation of these trace metals in these samples were traced to activities of Delta Glass Factory.