Concentration Levels Of Heavy Metals Research Articles

Appraisal of Some Heavy Metals and Elements in Irrigated Vegetables and Fruit Cultivated in College Farm, Maiduguri, Nigeria

This study was conducted to determine concentration levels of heavy metals and element in irrigated leafy vegetables and fruit cultivated at colleges’ farm along river Kumodu Gana bank, Maiduguri. Samples were obtained randomly from five locations and analysed as described by AOAC, (1990). Cadmium, copper, iron, potassium, manganese, nickel, lead and zinc were determined in plant parts of spinach (<i>Amaranthus blitum</i>), jute wallow (<i>Corchurus tridents</i>), roselle (<i>Habiscus sabdariffa</i> variety), and fruits of pepper (<i>Capsicum species</i>). The results revealed mean concentration level of each element determined in the vegetable plants studied; for cadmium had 0.80 - 3.21 µg/g, copper (0.38 - 1.58 µg/g), iron (0.27 - 1.89 µg/g), potassium (6.6 - 27.13 µg/g), manganese (0.26 - 2.42 µg/g), nickel (0.23 - 4.21 µg/g), lead (0.32 µg/g), and 0.13 - 0.74 µg/g for zinc. The magnitude of concentration levels of these elements detected in different irrigated vegetable plant parts materials’ sequential order was K &gt; Ni &gt; Cd &gt; Mn &gt; Fe &gt; Cu &gt; Zn &gt; Pb, the highest was potassium (K), the least was lead (Pb) and Pb was detected in roselle (<i>Habiscus sabdariffa</i> variety) only. No significance differences between the plant parts when compared their concentration levels in term of the elements determined. Their concentrations are below the recommended safe limit proposed by AOAC, EU, FAO and WHO. Hence, irrigated vegetables cultivated in the studied area were found fit, wholesome for consumption and health risk free. Further studies on the same irrigated vegetables and area are recommended.

Spatial Distribution of Some Heavy Metals in Sediments from the River Hadejia Catchment, Nigeria

Heavy metals concentration levels was determined using Instrumental Nitrogen Activation Analysis (INAA) is possible using Nigeria Research Reactor-1 (NIRR) which is a Miniature Neutron Source Reactor (MNSR). It is specifically used for the Neutron Activation Analysis (NAA) technique. The selection of sediment sample is because, overtime, the chemical elements precipitate on the sediment bed; therefore the sediment sample will indicate the true nature of the chemical elements present in the river system. River Hadejia is a perennial river, though the dry season flow is from the upstream regulated flow from the Tiga and Bagauda dams. The sediment samples were collected using stratified random sampling technique based on change in land use activity. Samples were collected during dry and wet seasons and analyzed in the laboratory. The results obtained show the presence of chemical contaminants Chromium (Cr), Zinc (Zn), and Europium (Eu) in concentrations above the permissible limits in the Hadejia river system. For example, Chromium (Cr) has mean concentration of 432.86 mg/l as against the permissible limit for both WHO, (2011) and NSDWQ, (2007) of 0.05mg/l. Anthropogenic and natural geology of the area are the key determinants of the presence of these chemical elements in the area. It is recommended among others that there is need for routing the actual sources of these contaminants in our river catchment areas.

THE RESEARCH OF THE AMOUNT OF HEAVY METALS AND NITROSO COMPOUNDS IN CONCENTRATED TOMATO PRODUCTS

The constant selling race results in need for improving the quality of nutrition products among in-house food and pharmaceutical processing industries, which is an all-important key to success on the consumer market. This requires constant improvement of the product producing technologies. The topical problem of quality is the presence of heavy metals and nitroso compounds in the products. The research aimed at studying the changes in the heavy metal concentration levels (including Zn, Cu, Pb) in tomato products at their thickening has been conducted at the national University of Food Technologies. On the basis of the received results the relationship between the lead, copper, zinc, nitrosocompounds and the solid substances’ amount has been established. The conducted research allowed us to ascertain the fact that the amount of heavy metals and nitroso compounds in raw materials for the concentrated tomato products to be ofhigh quality must not exceed the values of 18…35 % of the limiting concentration.

Radionuclides (210Po and 210Pb) and Some Heavy Metals in Fish and Sediments in Lake Bafa, Turkey, and the Contribution of 210Po to the Radiation Dose.

The pollution level of Lake Bafa was investigated by collecting fish samples {Dicentrarchus labrax (sea bass), Liza ramada (mullet) and Anguilla anguilla (eel)}, surface sediment, and core samples. In all these samples, 210Po and 210Pb concentrations were estimated, and total annual dose rates were obtained for each species. Some heavy metal (Cr, Ni, Pb, Cd, Mn, Fe, and Zn) concentration levels were obtained for the fish and a core sample. The sediment mass accumulation rate was found to be 3.27 g·m−2·day−1 (0.119 g·cm−2·y−1) from a core sample. The heavy metal concentrations in the vertical profile of samples from the core were also observed. The measured concentration of Zn, Pb, Cd, and Cr were between the ERL (effects range low) and ERM (effects range median) limits, while Ni concentrations were higher than the ERM limit. The observed concentrations of Cd, Pb, and Zn in fish samples did not exceed the limits in accordance with Turkish Food Regulations. Further, the maximum effective dose equivalent of 210Po in the area was found to be 1.169 µSv·y−1.

Analysis of heavy metals in the re-suspended road dusts from different functional areas in Xi’an, China

A study on heavy metal pollution was undertaken in the re-suspended road dusts from different functional areas in Xi'an City of China to investigate the impacts of human activities and land uses on urban environment. The concentrations of Co, Cr, Cu, Mn, Ni, Pb, V, and Zn were determined using X-ray fluorescence spectrometry, and their accumulations were analyzed using enrichment factor. Correlation analysis, principal component analysis, and cluster analysis, combined with the concentration property and enrichment factor, were used to identify the possible sources of heavy metals investigated. The investigated re-suspended road dusts had Co, Cr, Cu, Pb, and Zn concentrations higher than background levels. Samples from different functional areas had diverse heavy metal concentration levels. Co, Cr, Cu, Pb, and Zn presented moderate/significant enrichment in the samples. The source analyses indicated that Mn, Ni, V, Pb, and Zn had the mixed sources of nature and traffic, Cr and Cu mainly originated from traffic source, while Co was primarily derived from construction source. Traffic and construction activities had a significant impact on urban environment. This preliminary research provides a valuable basis for urban environment protection and management.

Occurrences and toxicological risk assessment of eight heavy metals in agricultural soils from Kenya, Eastern Africa.

The concentration distribution and toxicological assessment of eight heavy metals including lead (Pb), cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), mercury (Hg), arsenic (As), and zinc (Zn) in agricultural soils from Kenya, Eastern Africa, were investigated in this study. The results showed mean concentrations of eight heavy metals of Zn, Pb, Cr, Cu, As, Ni, Hg, and Cd in agricultural soils as 247.39, 26.87, 59.69, 88.59, 8.93, 12.56, 8.06, and 0.42mgkg(-1), respectively. These mean values of eight heavy metals were close to the toxicity threshold limit of USEPA standard values of agricultural soils, indicating potential toxicological risk to the food chain. Pollution index values revealed that eight heavy metals severely decreased in the order Hg > Cd > As > Cu > Pb > Zn > Ni > Cr and the mean value of the overall pollution index of Hg and Cd was 20.31, indicating severe agriculture ecological risk. Potential pollution sources of eight heavy metals in agricultural soils were mainly from anthropogenic activities and natural dissolution. The intensification of human agricultural activities, the growing industrialization, and the rapid urbanization largely influenced the concentration levels of heavy metals in Kenya, Eastern Africa. Moreover, the lack of agricultural normalization management and poor enforcement of environmental laws and regulations further intensified the widespread pollution of agricultural soils in Kenya.

Heavy metals in aquatic organisms of different trophic levels and their potential human health risk in Bohai Bay, China.

Fourteen aquatic organism samples were collected from Bohai Bay, and concentrations of five heavy metals were measured to evaluate the pollution levels in aquatic organisms and the potential risk to human health. The concentrations of Zn and Cu were much higher than those of Cd, Cr, and Pb in all the organisms. In general, the heavy metal concentration levels were in the order phytoplankton < zooplankton < fish < shrimp < shellfish. Heavy metal concentrations in higher trophic-level aquatic organisms in Bohai Bay were compared to those in the organisms from other worldwide coastal waters. The concentration levels of most heavy metals were higher than the 75th percentile, except that Pb concentration was between the 25th and 50th percentiles. The calculated bioconcentration factors (BCF) of Cr, Cu, and Pb for phytoplankton were less than 100, indicating no accumulation in primary producers. The bioaccumulation factor (BAF) of Pb for zooplankton was the highest, indicating significant Pb accumulation in zooplankton. For higher trophic-level aquatic organisms, the order of BAF values was fish < shrimp < shellfish for most metals except for Pb. The human health risk assessment suggests that strict abatement measures of heavy metals must be taken to decrease the health risk caused by consuming aquatic products.

Study of Heavy Metal Contaminations in Green Leafy Vegetables and Fruits of Kitwe District, Zambia

The heavy metal concentrations of Cu, Ni, Zn, Co, Pb and Fe in fruits – Eggplant (Solanum melongena), Lemon (Citrus limon), Tomato (solanum lycopersicum) and Green Leafy Vegetables (GLV) – Pumpkin Leaves (telfairia occidentalis), Rape (brasicca napus), were analyzed. GLV and fruits were purchased from four different market locations (Chamboli, Chisokone, Chimwemwe and Chipata markets) located in and around Kitwe District, Zambia. The heavy metal concentrations in GLV and fruits were determined using the Perkin-Elmer 2380 Atomic Absorption Spectrophotometer (AAS). Most of the results obtained from the analysis showed high levels of heavy metal concentrations as compared to standards permissible by World Health Organization (WHO) and Food and Agriculture Organization (FAO). The levels of heavy metal concentrations in GLV ranged from 1.40 to 7.80 mg/kg Fe; 0.50 to 4.10 mg/kg Cu; 0.35 to 4.0 mg/kg Co; 2.00 to 9.00 mg/kg Ni; 0.70 to 5.05 mg/kg Zn; 0.40 to 1.10 mg/kg Pb, while for fruits the levels ranged from 1.30 to 7.50 mg/kg Fe; 0.50 to 3.20 mg/kg Cu; 0.50 to 4.00 Co; 1.17 to 5.10 mg/kg Ni; 0.20 to 1.25 mg/kg Zn and 0.18 to 0.50 mg/kg Pb. The high levels of heavy metal concentrations in most of the GLV and fruits could be attributed to the various anthropogenic activities taking place in the four locations, with mining activities being the most common contributor. However, if not controlled or monitored by local authorities, the health effects that come with consuming contaminated food may be fatal.

Removal of Heavy Metals from Pharmaceutical Industrial Wastewater Effluent by Combination of Adsorption and Chemical Precipitation Methods

The removal of heavy metals from our environment especially industrial effluents is now shifting from the use of conventional adsorbents to the use of chemical precipitation. The presence of heavy metals in the environment is a major concern because of their toxicity, bioaccumulating tendency, and threat to human life and the environment. The main objective of this research is to study the effectiveness of the combination of hydrogen peroxide and activated bentonite clay in the removal of heavy metal ions from pharmaceutical industrial effluent. About 13.790 mg/l of Fe, 1.650 mg/l of Zn and 2.000 mg/l of Ni were detected in the digested sample and batch removal of heavy metals such as Fe, Zn and Ni from industrial wastewater effluent under different experimental conditions using hydrogen peroxide as precipitating agent in combination with activated bentonite clay as adsorbent. Appreciable differences in the level of heavy metals concentration were observed based on pH effect. The result shows higher effectiveness relatives to other treatments formulated for the effluent treatment such as Alum precipitation effect, effect of hydrogen peroxide concentration dose, contact time effect and temperature effect. Removal of heavy metals in effluent was optimum at pH 10 for zinc (Zn) and nickel (Ni) and at pH 8 for iron (Fe), at temperature of 50°C, 0.75% hydrogen peroxide concentration dose and 100 mins holding time, reducing the amounts from 13.790 to 1.436 mg/l of Fe, while 1.650 to 0.127 mg/l of Zn and 2.000 to 0.115 mg/l of Ni respectively. The percentage differences in concentration for the heavy metals removal in industrial wastewater are as follows: Fe (89.58%), Zn (92.30%) and Ni (94.22%). The result showed high level of Zn and Ni generated from this pharmaceutical industry is above 1 mg/l FEPA and WHO standard but only Fe showed low level concentration compared to 20 mg/l FEPA and WHO standard in this study. This study reveals the need for enforcing adequate effluent treatment methods before their discharge to surface water to reduce their potential environmental hazards.

Assessment of Heavy Metals and Radionuclide Concentrations in Mafikeng Waste Water Treatment Plant

A study was carried out to assess the heavy metal and radionuclide concentrations of water from the waste water treatment plant in Mafikeng Local Municipality. Ten water samples were collected from various stages of water treatment (n = 2 per stage) which included sewage delivered to the plant, the two treatment stages, the effluent and the community water. Samples were analyzed for heavy metal content using Inductive Coupled Plasma Mass Spectrometer. Gross α/β activity concentrations in water samples were evaluated by Liquid Scintillation Counting whereas the concentration of individual radionuclides was measured by gamma spectroscopy. The results showed marked reduction in the levels of heavy metal concentration from 3 μg/L (As) - 670 μg/L (Na) in sewage into the plant to 2 μg/L (As) - 170 μg/L (Fe) in the effluent. The gross α activity in all the water samples (7.7 - 8.02 Bq/L) exceeded the 0.1 Bq/L limit set by World Health Organization (WHO). Gamma spectroscopy revealed very high concentrations of 235U and 226Ra in water samples, with the lowest concentrations (9.35 and 5.44 Bq/L, respectively) in the in-coming sewage and highest concentrations (73.8 and 47 Bq/L, respectively) in the community water. All the values were considerably higher than the limits of South Africa Target Water Quality Range and WHO. However, the estimated total doses of the two radionuclides for the analyzed water samples (10.62 - 45.40 μSv·yr-1) were all well below the reference level of the committed effective dose of 100 μSv·yr-1 recommended by WHO.

MAPS OF HEAVY METALS IN CLUJ COUNTY SOILS DEVELOPED USING THE REGRESSION-KRIGING METHOD

Knowledge of the basic levels of heavy metal concentrations in soil and their spatial disposition, on a certain area, is particularly important for economic activities, but especially for preventing and stopping pollution. The spatial distribution maps, obtained by measurements performed (of a certain density), cover the entire studied area and are very useful. According to the literature several methods are known for building such maps, most of them based on a simple mathematical interpolation. The Regression-Kriging method used in this paper is one of the best ways to solve this problem, because its algorithm takes into account the influence of physicochemical characteristics of the soil and also the deviations among the calculated values using mathematical models and the ones measured in the field. This method was used to perform the maps of the spatial distribution for eight heavy metals concentrations (Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in the Cluj County soils. The use of the nonlinear mathematical models and the maps for predictors (previously achieved) have provided a high precision for these spatial distributions, that can be now successfully applied in preventing and combating of soil pollution.

Relationship between Heavy Metal Exposure and Bone Mineral Density in Korean Adult.

BackgroundExposure to heavy metals from environmental and industrial sources remains a concern of serious public health risk. This study was conducted to analysis the relationship between heavy metal concentrations and bone density.MethodsThis study used data from a nation-based sample of Koreans (n=2,429) from 2008 to 2011 Korea National Health and Nutrition Examination Survey. We were obtained heavy metals (lead, mercury and cadmium), socioeconomic and demographic factors and bone mineral density (BMD) measured by T-score.ResultsMenopausal women, current smoker or the frequent alcohol drinking, low educational level and low family income were greater in the osteopenia or osteoporosis groups than normal group, and were associated with an increased blood heavy metal concentration levels. The highest quartile group in blood lead had a 1.47 times (95% confidence interval [CI] 1.16-1.87) risk of osteopenia or osteoporosis. In case of blood cadmium, the risk for osteopenia or osteoporosis increased 2.1 times (95% CI 1.64-2.68).ConclusionsWe observed a significant association between blood heavy metals (lead and cadmium) levels and low BMD. Our findings suggest that heavy metal exposure may be a risk factor for osteoporosis.

Effect of Irrigation by Waste Water on Accumulation of Heavy Metals in Soil and Plant

A pot experiment was carried out to determine the effect of using waste water irrigation on the concentrations of (Pb, Cd, Cu and Zn) in soil and their subsequent accumulation in plant. Waste water was diluted to give four treatments: T1 (waste water), T2 (1:1), T3 (2:1) well water: waste water and T4 (well water) as control. Higher concentrations of Pb, Cd, Cu and Zn were observed in soil of T1 compared toT4. Pb and Cd in (tops and roots) of chard were above the maximum permissible level in vegetables (WHO,1984). The results also showed a decrease in microbial density caused by high level of heavy metals concentration and an increase in aggregate stability.

Soil Contamination with Heavy Metals around Jinja Steel Rolling Mills in Jinja Municipality, Uganda.

Soil contamination with heavy metals has severely increased over the last few decades, mainly from industrial wastes and human activities. Soil pollution is a source of danger to the health of people globally. To assess the level of soil contamination with heavy metals around steel rolling mills in Jinja municipality, Uganda. Four composite soil samples were collected from each of the sides of the Jinja steel rolling mills, dried and digested. The digested solution samples were analyzed in triplicates for the levels of lead (Pb), zinc (Zn), cadmium (Cd), chromium (Cr), copper (Cu), and nickel (Ni), using a flame atomic absorption spectrometer (Savant AA model 2009); the analytical process was monitored using analytical standard solutions. Data analysis was performed using Statistical Package for the Social Sciences (SPSS) software version 19 and Excel. Mean metal concentrations, standard deviations, medians, and skewness were obtained to describe heavy metal concentrations in the soil. Pollution load index and geo-accumulation indices were calculated to determine the level and extent of heavy metal contamination in the soil. The mean concentration loads of the heavy metals in soils around the Jinja steel rolling mills were 43.15 mg/kg for Pb, 28.16 mg/kg for Zn, 0.93 mg/kg for Cd, 0.22 mg/kg for Cr, 80.96 mg/kg for Cu, and 9.40 mg/kg for Ni. The metal load distribution around the industry was in descending order: Left-hand side > Downwind side > Right-hand side > Upwind side. Results for the geo-accumulation index were 1.30 for Pb, -1.31 for Zn, 2.63 for Cd, -7.25 for Cr, 2.99 for Cu, and -1.19 for Ni. The overall pollution load index was 1.08. The concentration levels of heavy metals around the steel rolling mills did not appear to be of serious concern, except for copper and cadmium, which showed moderate pollution and moderate to strong pollution, respectively. All heavy metals were within the limits of the United States Environmental Protection Agency (USEPA) residential soil standards and the Dutch intervention soil standards. Overall, soils around the Jinja steel rolling mills were slightly polluted with heavy metals, and measures therefore need to be taken to prevent further soil contamination with heavy metals.

Concentration of Heavy Metals in Available Fish Species (Bain, Mastacembelus armatus; Taki, Channa punctatus and Bele, Glossogobius giuris) in the Turag River, Bangladesh

This study was conducted to assess the concentration level of heavy metals in three available fish species (Bain, Mastacembelus armatus; Taki, Channa punctatus and Bele, Glossogobius giuris) of the Turag river, Bangladesh during the months from January to March, 2014. In case of bio-concentration of heavy metals in fish, the levels of Pb, Cd, Cr, Cu and Fe ranged from 0.01-0.13 mg/kg, 0.001-0.02 mg/kg, 0.17-0.48 mg/kg, 0.30-0.74 mg/kg and 4.05-46.86 mg/kg, respectively while Hg was below detection level. These values indicate that the heavy metals were concentrated in fish flesh at a higher level than water. The highest values of Pb, Cd and Cr were found in Bain fish, Fe was found in Taki fish and Cu was found in Bele fish. Most of the heavy metals have crossed the permissible limits in fish, especially for the values of Cr, Cu and Fe. From the results of the present investigation, it can be concluded that the available fish species are harmful for their consumers.

Biosorption studies on copper (II) and cadmium (II) using pretreated rice straw and rice husk.

This study investigated the adsorption and removal behaviour of copper (Cu) (II) and cadmium (Cd) (II) ions using rice husk and rice straw in aqueous solutions. Different parameters were used to investigate their adsorption performance in saline conditions and the optimal level of biosorption at different pH levels. The main parameters were pH (3, 6 and 9), initial concentration level of heavy metals (Cu (II) 5, 10, 20, 40 and 60mg/L and Cd (II) 0.5, 1, 2, 4 and 8mg/L, respectively), salinity (0, 50 and 100mM NaCl) and contact time (ranging from 3 to 60min). Langmuir and Freundlich isotherm models were applied to analyse the removal efficiency and sorption capacity of the pretreated rice husk and rice straw. The removal efficiency and adsorption capacity generally increased with the pH and reached a plateau in alkaline conditions. The percentage removal of Cu (II) by rice husk reached 97% at pH 9 and 95% by rice straw at pH 6. Biosorption performance increased in the absence of NaCl. Kinetic studies for both metals revealed that the biosorption of Cu (II) and Cd (II) onto rice straw and husk was pseudo-second order.

Arbuscular mycorrhizal fungi community structure, abundance and species richness changes in soil by different levels of heavy metal and metalloid concentration.

Arbuscular Mycorrhizal Fungi (AMF) play major roles in ecosystem functioning such as carbon sequestration, nutrient cycling, and plant growth promotion. It is important to know how this ecologically important soil microbial player is affected by soil abiotic factors particularly heavy metal and metalloid (HMM). The objective of this study was to understand the impact of soil HMM concentration on AMF abundance and community structure in the contaminated sites of South Korea. Soil samples were collected from the vicinity of an abandoned smelter and the samples were subjected to three complementary methods such as spore morphology, terminal restriction fragment length polymorphism (T-RFLP) and denaturing gradient gel electrophoresis (DGGE) for diversity analysis. Spore density was found to be significantly higher in highly contaminated soil compared to less contaminated soil. Spore morphological study revealed that Glomeraceae family was more abundant followed by Acaulosporaceae and Gigasporaceae in the vicinity of the smelter. T-RFLP and DGGE analysis confirmed the dominance of Funneliformis mosseae and Rhizophagus intraradices in all the study sites. Claroideoglomus claroideum, Funneliformis caledonium, Rhizophagus clarus and Funneliformis constrictum were found to be sensitive to high concentration of soil HMM. Richness and diversity of Glomeraceae family increased with significant increase in soil arsenic, cadmium and zinc concentrations. Our results revealed that the soil HMM has a vital impact on AMF community structure, especially with Glomeraceae family abundance, richness and diversity.

Assessment of heavy metal contamination in water and sediments of Trepça and Sitnica rivers, Kosovo, using pollution indicators and multivariate cluster analysis.

The concentrations of As, Cd, Cr, Co, Cu, Ni, Pb, and Zn in water and sediment samples from Trepça and Sitnica rivers were determined to assess the level of contamination. Six water and sediment samples were collected during the period from April to July 2014. Most of the water samples was found within the European and Kosovo permissible limits. The highest concentration of As, Cd, Pb, and Zn originates primarily from anthropogenic sources such discharge of industrial water from mining flotation and from the mine waste eroded from the river banks. Sediment contamination assessment was carried out using the pollution indicators such as contamination factor (CF), degree of contamination (Cd), modified degree of contamination (mCd), pollution load index (PLI), and geo-accumulation index (Igeo). The CF values for the investigated metals indicated a high contaminated nature of sediments, while the Cd values indicated a very high contamination degree of sediments. The mCd values indicate a high degree of contamination of Sitnica river sediment to ultrahigh degree of contamination of Trepça river sediment. The PLI values ranged from 1.89 to 14.1 which indicate that the heavy metal concentration levels in all investigated sites exceeded the background values and sediment quality guidelines. The average values of Igeo revealed the following ranking of intensity of heavy metal contamination of the Trepça and Sitnica river sediments: Cd > As > Pb > Zn > Cu > Co > Cr > Ni. Cluster analysis suggests that As, Cd, Cr, Co, Cu, Ni, Pb, and Zn are derived from anthropogenic sources, particularly discharges from mining flotation and erosion form waste from a zinc mine plant. In order to protect the sediments from further contamination, the designing of a monitoring network and reducing the anthropogenic discharges are suggested.

Compositional and metabolic quotient analysis of heavy metal contaminated soil after electroremediation

Heavy metal soil contamination provides a danger both to human and environmental ecosystem health and is still on the rise in many developing countries. Electroremediation provides an innovative method to remedy contamination of soils by heavy metals. Fundamental to the acceptance of any soil remedial technique is proof that positive benefits outweigh the negative impacts, in terms of soil health. The environmental effect of electroremediation of heavy metals contaminated soil by some biological indicators was evaluated. A soil contaminated with Zn, Pb, Ni, and Cd was used in a laboratory experiment. Treatment was imposed with a constant voltage gradient of 0.83 V/cm for 20 days. Results indicated that the physicochemical changes caused by the electroremidiation process on the soil microbial population (actinomycetes and gram-positive and negative bacteria), soil respiration and microbial biomass were significant (p < 0.01). At the commencement of the study, soil microbial activity was reduced, due to physicochemical changes in pH, amount of moisture and the changes in the levels of heavy metals in the soil. The greatest reduction on the microbial activity was close to the cathode where high levels of heavy metal concentrations and high pH were demonstrated. The metabolic quotient index [qCO2] was used to achieve a more refined evaluation, compared to analysis of soil respiration and microbial biomass alone. Accordingly, high amounts of qCO2 near the cathode show the unfavorable living conditions of such microorganisms in these sections.

Investigation of Heavy Metals (Pb, Cd, Cr, Cu, Hg and Fe) of the Turag River in Bangladesh

The study was conducted to assess the concentration level of heavy metals in water of the Turag river during the months from January to March, 2014. The level of Pb, Cd, Cr, Cu, Hg and Fe ranged from 0.002-0.005 ppm, BDL (Below Detection Level)-0.03 ppm, 0.007-0.024 ppm, 0.03-0.15 ppm, BDL (Below Detection Level)-0.00024 and 0.78-6.33 ppm, respectively. The concentration level of heavy metals in water did not exceed the permissible limit except Fe. This result was obtained because of river water is always flowing and metals cannot be accumulated in flowing water. For this reason a little amount of analyzed heavy metals were traced in water samples. But heavy metals have toxic properties, leading to adverse effects on human and ecosystem health even in small doses. So, the Turag river water is not safe for using different purposes and steps should be undertaken to improve the water quality of the river.DOI: http://dx.doi.org/10.3329/jesnr.v7i2.22221 J. Environ. Sci. &amp; Natural Resources, 7(2): 133-136 2014