Level Of Heavy Metal Pollution Research Articles

Contamination and Ecological Risk Assessment of Heavy Metals in Surface Soils of Esfarayen City, Iran

Background: The urban soil characteristic is very important since numerous people live in cities nowadays. In recent decades, heavy metals enter into the urban environment due to the urbanization and different activities in cities. These metal contaminations can pose serious threats on community health. Contamination factor is a suitable tool for ecological geochemistry assessment. Objectives: The current study aimed to determine the distribution and concentration of heavy metals (Ni, Pb, Zn, Cd, Cu and Cr) in soil from urban soils, assess the pollution level and potential ecological risk of heavy metals. Methods: Forty surface soil samples from different areas with different functions in five districts of Esfarayen, Iran, were collected and transferred to laboratory, after drying the samples at laboratory temperature, they were analysed to measure Ni, Pb, Zn, Cd, Cu and Cr using inductively coupled plasma optical emission spectrometry. Results: The results showed the mean contents of Cd, Cu, Cr, Ni, Pb and Zn in soil of Esfarayen were 0.21, 33.27, 39.9, 32.3, 25.2 and 106 mg/kg, respectively, which were more than the natural background content. The potential ecological risk index ranged from 21.0 to 651 with a mean value of 159. Conclusions: Among different functional areas, the industrial areas had the maximum metal concentrations. According to the potential ecological risk indices, industrial region and city squares in Esfarayen have serious metal contamination and belong to the considerable pollution level. The results of the current study are very important for managers who define development strategies in cities and are also good to source pollution reduction.

Novel assessment method of heavy metal pollution in surface water: A case study of Yangping River in Lingbao City, China

The primary purpose of this research is to understand those elements that define heavy metals contamination and to propose a novel assessment method based on principal component analysis (PCA) in the Yangping River region of Lingbao City, China. This paper makes detailed calculations regarding such factors the single-factor assessment (Pi) and Nemerow’s multi-factor index (PN) of heavy metals found in the surface water of the Yangping River. The maximum values of Pi (Cd) and Pi (Pb) were determined to be 892.000 and 113.800 respectively. The maximum value of PN was calculated to be 639.836. The results of Pearson’s correlation analysis, hierarchical cluster analysis, and PCA indicated heavy metal groupings as follows: Cu, Pb, Zn and As, Hg, Cd. The PCA-based pollution index (Pαn) of samplings was subsequently calculated. The relative coefficient square was valued at 0.996 between Pαn and PN, which indicated that Pαn is able to serve as a new heavy metal pollution index; not only this index able to eliminate the influence of the maximum value of Pi, but further, this index contains the principal component elements needed to evaluate heavy metal pollution levels. Keywords: Heavy metals contamination, Hierarchical cluster analysis (HCA), Pollution evaluation, Principal component analysis (PCA), Yangping River

Assessment of pollution levels and human health risk of heavy metals in dust deposited on Yerevan’s tree leaves (Armenia)

The total concentrations of Cd, As, Pb, Cr, Ni, Co, Zn, Cu, Ag, Hg, and Mo were determined in the atmospheric dust of the city of Yerevan by atomic absorption spectrometry (AAnalyst PE 800). Heavy metal pollution levels were evaluated by calculating geo-accumulation (I geo ) and summary pollution (Zc) indices. Potential human health risk was assessed using the United States Environmental Protection agency’s human health risk assessment model. The results show that mean contents of all elements tested except Ni and Cr were substantially higher than local geochemical background values. According to the I geo , Yerevan territory is strongly-to-extremely polluted by As, Ag, Hg, Mo, and Cd. The Zc assessment indicated that very high pollution was detected in 36 % of samples, high in 32 %, average in 12 %, and low in 20 %. The health risk assessment revealed a non-carcinogenic risk (HI >1) for children at 13 samplings sites and for adults at one sampling site. For children the risk was due to elevated levels of Mo, Cd, Co, and As, while for adults, only Mo. Carcinogenic risk (>1:1,000,000) of As and Cr via ingestion pathway was observed in 25 and 14 samples, respectively. This study, therefore, is the base for further detailed investigations to organize problematic site remediation and risk reduction measures.

Heavy metal deposition through rainfall in Chinese natural terrestrial ecosystems: Evidences from national-scale network monitoring

Industrialization and urbanization have led to increasingly serious levels of atmospheric heavy metal pollution, which is one of the main sources of heavy metals to terrestrial ecosystems. Therefore, it is essential to quantify atmospheric fluxes and explore their potential effects on natural ecosystems and human welfare. We monitored water-soluble heavy metals (lead (Pb), cadmium (Cd), and chromium (Cr)) in rainfalls on a monthly basis in 2013 and 2014, at 31 field stations located in typical natural Chinese ecosystems. The average soluble Pb, Cd, and Cr deposition was 1.90 ± 1.54, 0.28 ± 0.25, and 0.96 ± 0.48 mg m−2 yr−1, respectively, with a large variation among the different sites. Generally, the atmospheric deposition of soluble Pb, Cd, and Cr was higher in the southwest, central, south, and north China than in the northwest and northeast China, Inner Mongolia, and Qinghai-Tibet. As expected, the atmospheric heavy soluble metal deposition fluxes were significantly correlated with the number of vehicles (Ps < 0.1). The wet deposition of soluble Pb and Cr was positively correlated with oil and coal consumption, unlike Cd deposition. Moreover, soluble Pb and Cd in atmospheric wet deposition were positively correlated with the contents of Pb and Cd in soil at different regions. In this study, atmospheric heavy metal deposition through rainfall in typical natural ecosystems in China is assessed at the national scale, alerting potential ecological hazards resulting from an increasing atmospheric heavy metal deposition and providing a basis for future studies.

Assessment of physiochemical, heavy metal and indicator bacterial groups in water and soil samples of different oil contaminated regions, Tiruchirappalli city

The levels of physiochemical, heavy metal and microbiological pollution in different oil contaminated regions of Tiruchirappalli city were reported in the study. The water and sediment samples from four different oil contaminated regions in Tiruchirappalli city were collected during monsoon 2015. The sampling regions were divided into two category such as heavy oil contaminated regions (oil shed / oil washed regions) and bus stand regions. In oil contaminated water sample, counts of TVC, TC, TS, FC, FS, VC, SAC, SHC and PC were in the range of 21300 126000, 1620 13200, 240 1050, 250 1130, 100 250, 120 180, 80 160, 130 200 and 260 560 CFU/mL, respectively. In soil sample, the TVC, TC, TS, FC, FS, VLO, SC and PC ranges were 56000 218000, 3100 14800, 350 1260, 330 1420, 150 300, 110 240, 120 200, 160 260 and 410 1060 CFU/g, respectively. The results of this study indicated that oil shed regions gor higher pollutions tha bus stand regions. This study gave a special emphasis on the determination of the levels of pollution and also identified the vulnerable regions. Hence, throughout impoundment and continuous monitoring is needed.

Pollution characteristics and ecological risk assessment of heavy metals in the surface sediments from a source water reservoir

Surface sediment samples were collected from a source water reservoir in Zhejiang Province, East of China to investigate pollution characteristics and potential ecological risk of heavy metals. The BCR sequential extraction method was used to determine the four chemical fractions of heavy metals such as acid soluble, easily reducible, easily oxidizable and residual fractions. The heavy metals pollution and potential ecological risk were evaluated systematically using geoaccumulation index (Igeo) and Hakanson potential ecological risk index (H′). The results showed that the sampling sites from the estuaries of tributary flowing through downtowns and heavy industrial parks showed significantly (p < 0.05) higher average concentrations of heavy metals in the surface sediments, as compared to the other sampling sites. Chemical fractionation showed that Mn existed mainly in acid extractable fraction, Cu and Pb were mainly in reducible fraction, and As existed mainly in residual fraction in the surface sediments despite sampling sites. The sampling sites from the estuary of tributary flowing through downtown showed significantly (p < 0.05) higher proportions of acid extractable and reducible fractions than the other sampling sites, which would pose a potential toxic risk to aquatic organisms as well as a potential threat to drinking water safety. As, Pb, Ni and Cu were at relatively high potential ecological risk with high Igeo values for some sampling locations. Hakanson potential ecological risk index (H′) showed the surface sediments from the tributary estuaries with high population density and rapid industrial development showed significantly (p < 0.05) higher heavy metal pollution levels and potential ecological risk in the surface sediments, as compared to the other sampling sites.

Assessments of levels, potential ecological risk, and human health risk of heavy metals in the soils from a typical county in Shanxi Province, China

A total of 128 surface soil samples were collected, and eight heavy metals, including As, Cd, Cr, Cu, Pb, Ni, Zn, and Hg, were analyzed for their concentrations, potential ecological risks, and human health risks. The mean concentrations of these eight metals were lower than the soil environmental quality standards in China, while they were slightly higher than the background values in Shanxi Province. The enrichment factor, coefficient variation, and potential ecological risk index were used to assess the pollution and eco-risk level of heavy metals, among which, Cd and Hg showed higher pollution levels and potential risks than the others in the studied area. Moreover, multivariate geostatistical analysis suggested that Hg originated mainly from point sources such as industrial emissions, while agricultural activity is the predominant factor for Cd. The human health risk assessment indicated that non-carcinogenic values were below the threshold values. The total carcinogenic risks due to As, Cr, and Ni were within the acceptable range for adults, while for children, they were higher than the threshold value (1.0E-04), indicating that children are facing higher threat to heavy metals in soils. These results provide basic information on heavy metal pollution control and human health risk assessment management in the study regions.

Urban bat communities are affected by wetland size, quality, and pollution levels.

Wetlands support unique biota and provide important ecosystem services. These services are highly threatened due to the rate of loss and relative rarity of wetlands in most landscapes, an issue that is exacerbated in highly modified urban environments. Despite this, critical ecological knowledge is currently lacking for many wetland‐dependent taxa, such as insectivorous bats, which can persist in urban areas if their habitats are managed appropriately. Here, we use a novel paired landscape approach to investigate the role of wetlands in urban bat conservation and examine local and landscape factors driving bat species richness and activity. We acoustically monitored bat activity at 58 urban wetlands and 35 nonwetland sites (ecologically similar sites without free‐standing water) in the greater Melbourne area, southeastern Australia. We analyzed bat species richness and activity patterns using generalized linear mixed‐effects models. We found that the presence of water in urban Melbourne was an important driver of bat species richness and activity at a landscape scale. Increasing distance to bushland and increasing levels of heavy metal pollution within the waterbody also negatively influenced bat richness and individual species activity. Areas with high levels of artificial night light had reduced bat species richness, and reduced activity for all species except those adapted to urban areas, such as the White‐striped free‐tailed bat (Austronomus australis). Increased surrounding tree cover and wetland size had a positive effect on bat species richness. Our findings indicate that wetlands form critical habitats for insectivorous bats in urban environments. Large, unlit, and unpolluted wetlands flanked by high tree cover in close proximity to bushland contribute most to the richness of the bat community. Our findings clarify the role of wetlands for insectivorous bats in urban areas and will also allow for the preservation, construction, and management of wetlands that maximize conservation outcomes for urban bats and possibly other wetland‐dependent and nocturnal fauna.

Impact assessment of heavy metal pollution on soil mite communities (Acari: Mesostigmata) from Zlatna Depression – Transylvania

Abstract The heavy metal pollution level of soil from twelve grasslands and its impact on soil mite communities was assessed. The impact assessment was investigated, taking into account the distance from pollution source, the degree of pollution and the cumulative influence of heavy metals and other environmental variables. These variables were: temperature, humidity, acidity, carbon content, nitrogen total, C/Nt ratio, slope, altitude, vegetation cover, exposition and soil type. The measured concentrations of all heavy metals for the investigated grasslands exceeded the reference values according to the national legislation. In order to make a comparison between investigated grasslands and in order to classify the ecosystems, total metal load was calculated. Three groups of grasslands were established based on different degrees of soil pollution and taking into account the total metal load. In total, 66 Mesostigmata species were identified, with 961 individuals. Mite communities from the most polluted areas were distinguishable from those from less polluted grasslands. Some heavy metals (e.g. As, Cu, Pb and Zn) influenced the soil mites from highly polluted ecosystems, while Mn and other environmental variables (altitude and soil humidity) were strongly correlated with invertebrate communities from the medium polluted areas. Soil temperature was the main factor influencing mites from the less polluted ecosystems.

Determination of Background Value and Potential Ecological Risk Assessment of Heavy Metals in Sediments of the Danjiangkou Reservoir

The aim of this study was to explore the pollution level and potential ecological risk of heavy metals in sediments of the Danjiangkou Reservoir, and the study obtained the background value of heavy metals of the surface sediments using reference element and statistical methods. The results indicated that the background values of Cr, Ni, Cu, Zn, As, Cd, Hg and Pb were 41.18, 34, 32.13, 76.84, 10.46, 0.70, 0.07 and 27.11 mg·kg^-1, respectively. In addition, the potential ecological risks of the eight heavy metals in sediments were assessed using the Hakanson ecological risk index method. The values of RI for these eight metals in surface sediments ranged from 29.49 to 214.11, with the mean value of 118.91, and the pollution level was low. Furthermore, the <i>C</i>fⁱ value was in the order of Cd> Hg> Zn> Cr> Pb> Ni> As=Cu with the mean value of 1.05-1.31, and the pollution level varied from low to intermediate. The <i>C</i>fⁱ values of Cd and Hg were higher than those of other heavy metals with the mean values of 1.31 and 1.24, respectively, which should be paid more attentions.

Landscape Patterns Characteristics of Soil Heavy Metal Pollution in a Town of Southern Jiangsu

It is of great significance to evaluate the soil heavy metal pollution level and to know their spatial distribution characteristics. Taking soil heavy metals As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in a town of southern Jiangsu as research objects, using the single factor evaluation method, Nemerow comprehensive evaluation method, geostatistical analysis method together with the landscape pattern grain effect and the landscape index analysis method, we studied their characteristics of landscape patterns in the study area based on pollution evaluation. The results showed that:① The average value range of single factor pollution index and Nemerow comprehensive evaluation index for soil heavy metals in study area was 0.145-0.893.The overall pollution level was low. The pollution level of south area was lower than that of north area; ② As, Pb, Hg, and Zn elements showed obvious non-point pollution characteristics.As and Pb showed a similar spatial distribution. So were Hg and Zn elements. In contrast, Cd, Cr, Cu and Ni elements showed obvious point pollution characteristics. Cd and Cr showed similar spatial distribution. So were Cu and Ni elements; ③ The suitable grain effect landscape index of nine soil heavy metals pollution landscape was 30-40 m; ④ The low concentration area of soil heavy metals in the study area accounted for the largest proportion. The border of lower concentration area was the most complex part. The distribution of all pollution level areas was relatively concentrated and the comprehensive pollution fragmentation degree was low. The source pollution of soil heavy metals was in concentrated distribution, and its number still counted low, but there was a tendency for further development. As a whole, it was still in the early pollution stage of soil heavy metals.

Glutathione-S-Transferase Production in Earthworm as Tool for Assessment of Heavy Metal Pollution in Abattoir Soil

The use of direct response of animals to environmental challenges by production of biomarkers is a better tool to assess environmental pollution than the conventional methods. This study aimed to measure Glutathione-S-transferase (GST) in earthworms as tools for assessing heavy metal pollution in abattoir soil. Five (5) replicates each of earthworm species (Libyodrilus violaceous, Eudrilus eugeniae and Alma millsoni), soil and rumen waste samples were collected from three (3) abattoir sites (Lafenwa, Gbonogun and Madojutimi abattoirs), and a control site located within Federal University of Agriculture Abeokuta, beside an undisturbed stream with no rumen waste. Heavy metal (Cu, Zn, Pb, Cd, Co, Cr, Ni and Mn) concentrations in rumen waste, abattoir soils and earthworm tissues were determined using Atomic Absorption Spectrophotometer. The pH and organic matter (OM) concentrations of the rumen waste and abattoir soils were determined by standard methods. GST activities in the earthworm tissues were determined through the conjugation of 1 mM reduced glutathione (GSH) with 1 mM 1-chloro-2,4-dinitrobenzene (CDNB). The rumen waste recorded significantly higher (p ≤ 0.05) % OM, heavy metal concentrations and pH level than in their respective abattoir soils. The mean heavy metal concentrations of Cu, Zn, Pb, Cd and Mn were highest in the tissue of earthworm species obtained from Lafenwa abattoir. A significantly (p ≤ 0.05) higher GST activities were recorded in the tissue of earthworm species obtained from Lafenwa and Gbonogun abattoirs. Libyodrilous violaceus obtained from Lafenwa abattoir recorded the highest GST activity (8.47±1.39) in their tissue followed by the ones from Gbonogun abattoir (8.21±0.85). A significant (p ≤ 0.05) positive correlations was observed between GST activities in earthworm tissues and heavy metal concentrations. GST activities can therefore be used to assess the level of heavy metal pollution in abattoir soils.

Heavy metal levels in kiwifruit orchard soils and trees and its potential health risk assessment in Shaanxi, China.

Concentrations of five heavy metals (Cr, Cu, Cd, Hg, and Pb) in orchard soils and kiwifruit tissues (root, twig, leave, fruit) collected from Shaanxi province in China were measured, and the potential health risk for human through the fruit consumption was assessed. The orchard soils were in no pollution for Cr, Cu, Hg, and Pb, with their pollution index (PI) ≤1, while 10.0% of the soil samples were under Cd contamination. Furthermore, kiwifruit tended to have a higher Cd and Hg accumulation (as indicated by Biological Accumulation Coefficient) from soil and have a higher Cu and Hg translocation (as reflected by Biological Transfer Coefficient) to aboveground parts. From the human health point of view, the DIM and HRI values for all the fruit samples were within the safe limits, while for Cr, Cu, Cd, Hg, and Pb, about 22.5, 12.5, 52.5, 15.0, and 47.5% of the fruit samples exceeded the national maximum permissible levels, respectively. These results showed that, although there was no possible health risk to consumers due to intake of studied kiwifruit fruits under the current consumption rate, the regular survey of heavy metal pollution levels should be performed for the kiwifruit in Shaanxi province and a strict management program should be established to reduce the amount of chemical fertilizers and pesticides used in fruit production in order to prevent the potential health risk.

Heavy metal pollution and Pb isotopic tracing in the intertidal surface sediments of Quanzhou Bay, southeast coast of China

Concentrations of 16 heavy metals and Pb isotopic ratios in the intertidal surface sediments of Quanzhou Bay were determined to study the pollution level of heavy metals and the sources of Pb. The results showed that most concentrations of Cd, Sn, Mn, Cu, Zn, Cr, Pb, Hg, Ni, Co, Cs, Fe and V were higher than the background values, while most concentrations of Ti, Sb and Sr were lower than the background values. The mean concentrations of Cu, Zn, Pb, Cr and Cd exceeded the first-grade criteria of Chinese marine sediment quality. The geo-accumulation indexes revealed that the sediments had been polluted by some heavy metals. The results of Pb isotopic tracing indicated that the total Pb in the sediments were mainly from parent material, industrial emission and vehicle exhaust with the mean contributions of 38.2%, 51.3% and 10.5%, respectively, calculated by a three-end-member model of Pb isotopic ratios.

Investigating Heavy Metal Pollution in Mining Brownfield and Its Policy Implications: A Case Study of the Bayan Obo Rare Earth Mine, Inner Mongolia, China.

The rapid urbanization of China and associated demand for land resources necessitates remediation, redevelopment, and reclamation of contaminated soil. Before these measures are taken, a basic investigation and inventory of heavy metal (HM) pollution levels in contaminated soil is necessary for establishing and implementing the redevelopment plan. In the present study, to identify the policy implications of inventorying and mapping HM pollution of soil in brownfields throughout China, the Bayan Obo giant rare earth element (REE)-Nb-Fe ore deposit of Baotou in Inner Mongolia, China, which is the largest REE mineral deposit in the world, was taken as a case study. Soil samples from 24 sites in Bayan Obo mining area (MA) and 76 sites in mine tailing area (TA) were collected for determining contents of soil HMs (Cr, Cd, Pb, Cu, and Zn). The results showed that the average concentrations of Cr, Cd, Pb, Cu, and Zn in both MA and TA were all higher than their corresponding background values for Inner Mongolia but lower than the Class II criteria of the National Soil Quality Standards of China (GB 15618-1995). Enrichment factor (EF) analysis of the soil samples indicated that the soil in the brownfield sites was highly enriched with Cr, Cd, Pb, Cu, and Zn compared to the corresponding background values. In MA, the EF for Cd was the highest among the studied elements, while in TA, the EF for Cr (3.45) was the highest, closely followed by the EF for Cd (3.34). The potential ecological risk index (RI) indicated a moderate potential ecological risk from the studied HMs in MA and a low potential ecological risk in TA, and the results of RI also suggested that the soil was most heavily polluted by Cd. According to the spatial distribution maps of HM, contamination hot-spots were primarily located near mining-related high-pollution plants. Based on the results, policy recommendations are proposed related to brownfield management in urban planning.

Comparison on Different Evaluation Methods of Heavy Metal Pollution----- A Case for K1 Columnar Samples of Yalu River Estuary Watercourse

Heavy metals were determined in columnar sediment samples of the Yalu River estuary watercourse. The environmental status was assessed by using the pollution load index, geologic cumulative index, potential ecological harm index and Nemerow index. It is shown that the geologic cumulative index and Nemerow index show a low level of heavy metal pollution indicating that the pollution of K1 columnar samples is not serious. The results of the ecological risk index and the pollution load index are consistent by indicating a medium pollution degree of columnar sediments of the Yalu River estuary watercourse.

Heavy metal concentrations of selected public parks of Istanbul City

Many cities, especially larger metropolises, parks are very important recreational areas where people usually have closer contact with flora. Therefore, the pollution level in the parks can have a greater effect on human health. Heavy metals are ubiquitous with the environment, as a result of both natural and anthropogenic activities, and humans are exposed to them through various pathways. Essentially, these areas are assumed to be less exposed to routine contaminants, but especially in metropolises, this assumption could prove false considering these areas are stuck within the confines of a city full of pollutant activity such as intense traffic. In this study; the relationships between heavy metal pollution levels (Cd, Cr, Cu, Ni, Pb, Zn) and the pH and electrical conductivity (EC) of soil samples were investigated from the parks on the Asian side of Istanbul. For this purpose, the most frequently visited 16 parks were selected as sampling sites. In the second part of the study, linear correlation is used for the data analysis.

Multivariate analysis combined with GIS to source identification of heavy metals in soils around an abandoned industrial area, Eastern China.

Heavy metals in soils polluted by industrial production are a meaningful topic worldwide. The purpose of this study is to understand the pollution status and spatial distribution of heavy metals in soils. The result can help decision-makers apportion possible soil heavy metals sources and formulate effective pollution control policies. In this paper, 155 soil samples (0-20 cm) were collected and analyzed for eight heavy metals (Cd, Hg, As, Cu, Pb, Cr, Zn, and Ni) from an abandoned industrial area of Tong County, located in Jiangsu Province of Eastern China. The multivariate analysis (including I(geo), Ei/RI, EF, PCA, and CA) and geostatistics (GIS) were used to assess the enrichment level and pollution level of soil heavy metals and identify their sources. The results indicated that eight heavy metals in soils had moderate variations, with CVs ranging from 19.63 to 63.34%. The pollution level of I(geo) of soil heavy metals decreased in the order of Cd~Zn > Cu > Hg~As~Pb~Cr~Ni. The enrichment level of soil heavy metals decreased in the order of Cd > Zn > Hg > Cu > Pb > Ni > As > Cr. According to the Ei, except Cd and Hg were in the significant and moderate ecological risk levels respectively, other soil heavy metals were in the clean or light ecological risk levels, the level of potential ecological risk (RI) of the whole industrial area was moderate. Finally, the source identification of soil heavy metals indicated that Cd and Zn were primarily controlled by human activities, and Hg and Cu were controlled by natural and anthropogenic sources, and As, Pb, Cr, and Ni were mainly controlled by soil parent materials.

Water quality characteristics and pollution levels of heavy metals in Lake Haiq, Ethiopia

The main aim of this study was to assess the level of water quality of Lake Haiq, Ethiopia with respect to selected physical parameters and heavy metals. Parameters such as temperature, pH, turbidity, electrical conductivity and total dissolved solids were measured in situ. While total alkalinity, chloride, ammonia, nitrate and sulphate were investigated using standard analytical procedures. the level of the studied heavy metals (Pb, Cd, Cu and Zn) was determined using the inductively coupled plasma-optical emission spectrometry. Sulphate, nitrate, ammonia, chloride, and total dissolved solids were within the recommended levels for a drinking water by the WHO guidelines. In contrast, the total alkalinity, turbidity and pH values were above the recommended limits, indicating the inconveniency to use the water for drinking. While Cd in the water sample was under the method detection limit (< 0.0039 mg/L), the levels of Cu, and Zn were found to be under the respective permitted limits. However, the level of lead throughout the sampling sites ranged from 0.064 to 0.108, which is 6 to 10 times higher than the permitted level in drinking water confirming the awkwardness of using the lake water for drinking. A detailed study of the catchment on the possible sources of pollution is recommended so that appropriate control measures could be taken by the governmental bodies. Keywords: Heavy metals, Lake Haiq, South Wollo, Water pollution

Laboratory tests for the phytoextraction of heavy metals from polluted harbor sediments using aquatic plants

The aim of this study was to investigate the concentrations and pollution levels of heavy metals, organochlorine pesticides, and polycyclic aromatic hydrocarbons in marine sediments from the Leghorn Harbor (Italy) on the Mediterranean Sea. The phytoextraction capacity of three aquatic plants Salvinia natans, Vallisneria spiralis, and Cabomba aquatica was also tested in the removal of lead and copper, present in high concentration in these sediments. The average detectable concentrations of metals accumulated by the plants in the studied area were as follows: >3.328±0.032mg/kg dry weight (DW) of Pb and 2.641±0.014mg/kg DW of Cu for S. natans, >3.107±0.034g/kg DW for V. spiralis, and >2.400±0.029mg/kg DW for C. aquatica. The occurrence of pesticides was also analyzed in the sediment sample by gas chromatography coupled with mass spectrometry (GC/MS).Due to its metal and organic compound accumulation patterns, S. natans is a potential candidate in phytoextraction strategies.