Build-up Of Metals Research Articles

Characterizing heavy metal build-up on urban road surfaces: Implication for stormwater reuse

Stormwater reuse is increasingly popular in the worldwide. In terms of urban road stormwater, it commonly contains toxic pollutants such as heavy metals, which could undermine the reuse safety. The research study investigated heavy metal build-up characteristics on urban roads in a typical megacity of South China. The research outcomes show the high variability in heavy metal build-up loads among different urban road sites. The degree of traffic congestion and road surface roughness was found to exert a more significant influence on heavy metal build-up rather than traffic volume. Due to relatively higher heavy metal loads, stormwater from roads with more congested traffic conditions or rougher surfaces might be suitable for low-water-quality required activities while the stormwater from by-pass road sections could be appropriate for relatively high-water-quality required purposes since the stormwater could be relatively less polluted. Based on the research outcomes, a decision-making process for heavy metals based urban road stormwater reuse was proposed. The new finding highlights the importance to undertaking a “fit-for-purpose” road stormwater reuse strategy. Additionally, the research results can also contribute to enhancing stormwater reuse safety.

Impact of industrial effluent on growth and yield of rice (Oryza sativa L.) in silty clay loam soil

Degradation of soil and water from discharge of untreated industrial effluent is alarming in Bangladesh. Therefore, buildup of heavy metals in soil from contaminated effluent, their entry into the food chain and effects on rice yield were quantified in a pot experiment. The treatments were comprised of 0, 25%, 50%, 75% and 100% industrial effluents applied as irrigation water. Effluents, initial soil, different parts of rice plants and post-harvest pot soil were analyzed for various elements, including heavy metals. Application of elevated levels of effluent contributed to increased heavy metals in pot soils and rice roots due to translocation effects, which were transferred to rice straw and grain. The results indicated that heavy metal toxicity may develop in soil because of contaminated effluent application. Heavy metals are not biodegradable, rather they accumulate in soils, and transfer of these metals from effluent to soil and plant cells was found to reduce the growth and development of rice plants and thereby contributed to lower yield. Moreover, a higher concentration of effluent caused heavy metal toxicity as well as reduction of growth and yield of rice, and in the long run a more aggravated situation may threaten human lives, which emphasizes the obligatory adoption of effluent treatment before its release to the environment, and regular monitoring by government agencies needs to be ensured.

Assessment of Heavy Metals in Vegetables in Some Rural Areas in Meerut District

The present study was carried out to assess levels of different heavy metals like copper, cadmium, chromium, lead, zinc and iron in vegetables irrigated by ground water and waste water. The results indicated a substantial build-up of heavy metals in vegetables irrigated with water and wastewater. The range of various metals in ground water within permissible limit exept one and two samples while in six samples nitrate was more than permissible limit as prescribed by WHO. Waste water showed Cu, Cr, Pb, Zn and Fe under permissible limit exept some samples while the Cd was more in majority of samples as per recommended by WHO in waste water. The accumulation of heavy metal in vegetables showed wide variation as irrigated by ground water and waste water and palak accumulated high heavy metal as compared to the other vegetables. The present study highlights that both adults and children consuming vegetables grown by wastewater irrigation is not suitable for consumption. However, the vegetables received by the ground water irrigation the values of these metals were below the recommended maximum tolerable levels proposed by the WHO. It is suggested that the regular monitoring of these metals from effluents and sewage, in vegetables and in other food materials is essential to prevent excessive build-up of these metals in the food chain.

Reionisation and High-Redshift Galaxies: The View from Quasar Absorption Lines

AbstractDetermining when and how the first galaxies reionised the intergalactic medium promises to shed light on both the nature of the first objects and the cosmic history of baryons. Towards this goal, quasar absorption lines play a unique role by probing the properties of diffuse gas on galactic and intergalactic scales. In this review, we examine the multiple ways in which absorption lines trace the connection between galaxies and the intergalactic medium near the reionisation epoch. We first describe how the Ly α forest is used to determine the intensity of the ionising ultraviolet background and the global ionising emissivity budget. Critically, these measurements reflect the escaping ionising radiation from all galaxies, including those too faint to detect directly. We then discuss insights from metal absorption lines into reionisation-era galaxies and their surroundings. Current observations suggest a buildup of metals in the circumgalactic environments of galaxies overz~ 6 to 5, although changes in ionisation will also affect the evolution of metal line properties. A substantial fraction of metal absorbers at these redshifts may trace relatively low-mass galaxies. Finally, we review constraints from the Ly α forest and quasar near zones on the timing of reionisation. Along with other probes of the high-redshift Universe, absorption line data are consistent with a relatively late end to reionisation (5.5 ≲z≲ 7); however, the constraints are still fairly week. Significant progress is expected to come through improved analysis techniques, increases in the number of known high-redshift quasars from optical and infrared sky surveys, large gains in sensitivity from next-generation observing facilities, and synergies with other probes of the reionisation era.

English

In this present study, the quality of municipal wastewater used for irrigation of spinach was investigated for its heavy metal build-up. The municipal wastewater used for irrigation and the irrigated spinach samples were collected and analyzed for their heavy metal concentrations. The results indicate that the municipal wastewater used was contaminated with copper (1.90 mg/l), lead (0.09 mg/l) and iron (25 mg/l) and the municipal-irrigated spinach was contaminated with manganese (95 mg/kg) and cadmium (0.03 mg/kg). The results of these investigations were compared with World Health Organization (WHO) and Food and Agriculture Organization (FAO) heavy metal standards for irrigation water quality and permissible levels of metals in food and water. It revealed that the heavy metal concentrations were above the recommended threshold limits. High concentrations of these metals are very detrimental to the health of the inhabitants and crop consumers. Regular monitoring for safe practice is strongly recommended in order to avert terminal diseases in the area.   Key words: Domestic wastewater, irrigation, heavy metals, soil, vegetables.

Heavy metal accumulation in the surficial sediments along southwest coast of India

Concentration and distribution of heavy metals (Cd, Cr, Cu, Hg, Ni, Pb and Zn) in surface sediments collected from five stations located along the southwest coast of India were investigated seasonally to assess whether there is insidious buildup of heavy metals. Spatial variation was in accordance with textural characteristics and organic matter content. The concentration of the metals in sediments of the study area followed the order: Zn > Cr > Ni > Cu > Pb > Cd > Hg. The use of geochemical tools and sediment quality guidelines to account for the magnitude of heavy metal contamination revealed high contamination in monsoon and impoverishment during post-monsoon. Estimated total metal concentrations in the present investigation were comparable with other studies; however, concentrations of Ni and Zn were higher than that of other coastal regions. Concentrations of metals in sediment largely exceed NOAA effects range:low (e.g., Cu, Cr, Hg) or effects range:median (e.g., Ni) values. This means that adverse effects for benthic organisms are highly probable.

Growth and accumulation of heavy metals in turnip (Brassica rapa) irrigated with different concentrations of treated municipal wastewater

The present study has been carried out by irrigating turnip plants with different concentrations of treated municipal wastewater in order to see the effect on heavy metals accumulation and growth of plants. The turnip plants were watered with normal water and the results compared with results obtained by using treated municipal wastewater. The treatments used were: control (tap water) with 0, 25, 50 and 75% wastewater, and 100% wastewater, in three replications. The results indicated a substantial build-up of heavy metals in turnip irrigated with wastewater. The heavy metals content in the dry matter of the plants increased significantly with increase in wastewater concentration. Analysis of plant samples indicated the maximum accumulation of Fe (1,835 mg/kg in roots and 1,247 mg/kg in leaves) followed by Mn, Zn, Ni, Cu and Cd. The findings of this study regarding daily intake of metals suggest that the consumption of plants grown in wastewater is high, compared to consumption of those grown in tap water, but is nearly free of risks.

Trace Metals Characterization in Environmental Media: A Case Study of Cement Production Area Ewekoro, Southwest, Nigeria

Environmental quality deterioration resulting from increase in the level of potentially toxic metals is becoming more pronounced, thus raising the question on safety status of our environment. Impact assessment and characterization of trace metals in the environmental media including groundwater, top soils, and tree barks in the vicinities of West African Portland Cement Company factory mill, Ewekoro, Ogun State, Nigeria was undertaken. The environmental samples were analysed for trace metals employing flame atomic absorption spectrometry (FAAS). The concentration of Cu, Cd and Fe detected in the groundwater ranged between 0.026 - 0.082, 0.0038 - 0.004 and 0.003- 0.035 (mg/L) respectively. A decrease order in the level of metals level observed in the top soil is Fe > Pb >Ni > Cr > Cu > Cd, while that of tree barks samples is Fe > Cu > Cr > Pb > Ni > Cd. The saturated index (SI) obtained (through phreqC model) of the groundwater samples showed saturated to undersaturated with respect to CdSO4 and FeSO4:7H2O, while SI was saturated to supersaturate with respect to CdCO3 and FeCO3. Quality indices employed in analyzing soil data include enrichment factor, contamination factor and pollution load index. There is a buildup of trace metals in the environment (soil) particularly Pb. The levels of metals investigated are within the threshold limit set by the WHO health-based guideline for drinking water. Significant correlations were found to exist between Cd and Ni, Cr and Fe both in the tree bark and top soil samples, suggesting common source

English

Consumption of food crops contaminated with heavy metals is a major food chain route for human exposure. In the present study, vegetables grown in the sewage and tube well water irrigation are Raphanus sativus, Daucus carrota and Brassica rapa. Concentration of Cd, Pb and Ni was significantly higher in sewage irrigated soil at all the four depths (0-15, 15-30, 30-45 and 45-60 cm), respectively. Cadmium, Lead and Nickel concentration are higher at the surface horizons and it decreases sharply with depth in both tube well and sewage irrigated soils. Extent of heavy metal built up in sewage irrigated soils was significant in both 0-15 and 15-30 cm depth. Higher concentration of Pb, Cd and Ni, were observed in the roots of all crops grown in sewage irrigated soils compared to that of crops grown on tube well irrigated soils. Sewage water irrigation has a great potential to contaminate the soil which may lead to the accumulation of heavy metals in crop plants and may cause harmful effect on animals and plants. Results, indicate that, long term and indiscriminate application of sewage water, which contains heavy metals may cause accumulation of heavy metals in surface and sub-surface soils and the buildup of heavy metals on soil profile may prove harmful not only to plants, but also to consumers of the harvested crops. Key words: Crops, heavy metals, water, sewage, tube well.

Mathematical relationships for metal build-up on urban road surfaces based on traffic and land use characteristics

The study investigated the influence of traffic and land use parameters on metal build-up on urban road surfaces. Mathematical relationships were developed to predict metals originating from fuel combustion and vehicle wear. The analysis undertaken found that nickel and chromium originate from exhaust emissions, lead, copper and zinc from vehicle wear, cadmium from both exhaust and wear and manganese from geogenic sources. Land use does not demonstrate a clear pattern in relation to the metal build-up process, though its inherent characteristics such as traffic activities exert influence. The equation derived for fuel related metal load has high cross-validated coefficient of determination (Q2) and low Standard Error of Cross-Validation (SECV) values which indicates that the model is reliable, while the equation derived for wear-related metal load has low Q2 and high SECV values suggesting its use only in preliminary investigations. Relative Prediction Error values for both equations are considered to be well within the error limits for a complex system such as an urban road surface. These equations will be beneficial for developing reliable stormwater treatment strategies in urban areas which specifically focus on mitigation of metal pollution.

Bioimaging of copper deposition in Wilson's diseases mouse liver by laser ablation inductively coupled plasma mass spectrometry imaging (LA-ICP-MSI)

Unbalance of metals play an important role in the development of liver diseases. Wilson's disease for example is an autosomal recessive disorder in which the liver does not release copper into bile and resulting metal buildup leads to organ damage and liver failure. Laser ablation inductively coupled plasma mass spectrometry imaging (LA-ICP-MSI) is an established analytical technique for the determination of trace metals in biological tissue. This work demonstrates a new application of LA-ICP-MSI of trace metal imaging (Mn, Fe, Cu, and Zn) to study Wilson's disease in mouse liver tissue (vs. control sections). The quantification of tissue trace metals was performed using in-house produced tissue standards from murine brain with well-defined element concentrations. The results show that the average concentrations of Mn in control (0.7μgg−1) and Wilson's disease liver samples (0.6μgg−1) were not different. In contrast, Fe, Cu, and Zn in Wilson's disease liver samples (80μgg−1 for Fe, 143μgg−1 for Cu, and 32μgg−1 for Zn) were found significantly higher than in control tissue samples (41μgg−1 for Fe, 4μgg−1 for Cu, and 18μgg−1 for Zn).

Effect of cadmium and calcium treatments on phytochelatin and glutathione levels in citrus plants

Industry residues, phosphate fertilisers and wastewater as a source of irrigation have considerably increased levels of heavy metals in the soil, mainly cadmium (Cd(2+)). To test the effects of a calcium (Ca(2+)) treatment on Cd(2+) accumulation and plant tolerance to this heavy metal, plants of two citrus genotypes, Cleopatra mandarin (CM) and Carrizo citrange (CC), were watered with increasing concentrations of Cd(2+), and phytochelatin (PC) and glutathione (GSH) content were measured. Both genotypes were able to synthesise PCs in response to heavy metal intoxication, although CM seems to be a better Cd(2+) excluder than CC. However, data indicate that CC plants had a higher capacity for regenerating GSH than CM plants. In this context, the effects of Ca(2+) treatment on Cd(2+) accumulation, plant survival and PC, GSH and oxidised glutathione (GSSG) content were assessed. Data indicate that treatment with Ca(2+) had two positive effects on citrus physiology: it reduced Cd(+2) uptake into roots and also increased GSH content (even in the absence of Cd(2+)). Overall, the data indicate that although Cd(2+) exclusion is a powerful mechanism to avoid heavy metal build-up into photosynthetic organs, the capacity to maintain optimum GSH levels to feed PC biosynthesis could also be an important factor in stress tolerance.

Urban wastewater irrigation and its effect on growth, photosynthesis and yield of chickpea under different doses of potassium

The deficiency of potassium (K) has resulted in decreasing the yield and quality of food grains. Moreover, with decreasing water resources the use of wastewater in agriculture as an alternative source of water and nutrients is being debated. This study was therefore undertaken to test wastewater for its suitability as irrigation water together with uniform basal doses of nitrogen (N) and phosphorus (P) and varying doses of potassium (K0, K20, K40 and K60). It was observed that the plants receiving wastewater as a source of irrigation water performed better with a lower K dose. Potassium at 20 kg ha−1 along with wastewater resulted in better growth, photosynthetic rate (P N), stomatal conductance (g s) and yield of the chickpea (Cicer arietinum L.). Thus fertilizer rates could be lowered with the use of wastewater which can serve not only as the source of water but of nutrients also. However, regular monitoring of wastewater and soil for any buildup of heavy metal is necessary. The physical and chemical parameters of wastewater were also tested and most of them were found to be well within the permissible limits as set by the Food and Agriculture Organization (FAO).

Metal Concentration in Plant Tissues of Jatropha curcas L Grown in Crude Oil Contaminated Soil

This study evaluated the heavy metal concentration in plant tissues of Jatropha curcas grown in crude oil contaminated soil in Asaba, Delta State, Nigeria, in 2010. The soil treatments included 0.0, 2.0 4.0, 6.0, 8.0, and 10.0% w/w oil contamination. The results showed a significant buildup of heavy metals including iron, zinc, cadmium, copper, manganese, lead, chromium, and nickel in contaminated soils when compared to the uncontaminated subplots (p ≤ .05). The amounts of metals observed in this study are below tolerable limits according to the Food and Agriculture Organization of the United Nations and Federal Environmental Protection Agency of Nigeria. A gradual accumulation and biomagnifications of these nonbiodegradable elements in plants can lead to dangerous or lethal levels with inherent health risks for humans and other organisms.

Characterising metal build-up on urban road surfaces

Reliable approaches for predicting pollutant build-up are essential for accurate urban stormwater quality modelling. Based on the in-depth investigation of metal build-up on residential road surfaces, this paper presents empirical models for predicting metal loads on these surfaces. The study investigated metals commonly present in the urban environment. Analysis undertaken found that the build-up process for metals primarily originating from anthropogenic (copper and zinc) and geogenic (aluminium, calcium, iron and manganese) sources were different. Chromium and nickel were below detection limits. Lead was primarily associated with geogenic sources, but also exhibited a significant relationship with anthropogenic sources. The empirical prediction models developed were validated using an independent data set and found to have relative prediction errors of 12–50%, which is generally acceptable for complex systems such as urban road surfaces. Also, the predicted values were very close to the observed values and well within 95% prediction interval.

Effect of treated municipal wastewater on bean growth, soil chemical properties, and chemical fractions of zinc and copper

The current study was carried out in order to investigate the short-term effect of different dilutions of wastewater on soil chemical properties, chemical fractions of zinc (Zn) and copper (Cu), and to assess the chemical buildup of heavy metal on two bean species. The experiment was performed as factorial based on completely randomized design with different dilutions of wastewater on two bean cultivars in two soil textures. The treatments consisted of irrigation with treated wastewater over all growing season, irrigation with wastewater and freshwater in equal proportions, and irrigation with well water only as control. The result showed that soil parameters are significantly affected by application of wastewater irrigation. Irrigation with wastewater increased the concentrations of organic matter, electrical conductivity, N, K, P, Fe, Cu, Zn, Mn, and Ni in soils compared to the control treatment. However, their values were all below international standards. Application of wastewater decreased soil pH and calcium carbonate equivalent. Plant tissue analysis showed increases in N, P, K, Zn, Cu, Zn, and Mn concentrations in grain and frond of beans in wastewater treatment as compared to the control. The concentrations of all elements in plants were lower than the toxic threshold. Chemical fractionations of Zn and Cu indicated that chemical forms of these metals were affected by irrigation with wastewater. Irrigating with wastewater resulted in the movement of Zn from the labile fractions towards the nonlabile fractions. In turn, mobility factor of Cu increased with application of wastewater. Maximum fresh and dry yields of beans were obtained from wastewater treatment compared to the control treatment. This study indicated that wastewater irrigation improves soil properties, plant growth, and yield without any contamination in soil and toxicity in plants.

In Memoriam: Ranga Komanduri

In Memoriam: Ranga Komanduri

Chemical changes in an Oxisol cultivated with maize (Zea mays, L.) after six years disposal of sewage sludge

Sewage sludge is composed of predominantly organic matter and can be used to improve soil characteristics, such as fertility. Therefore, its application in agriculture is an adequate alternative for its final disposal. However, there is a lack of information on its long-term effects on soil changes in tropical areas. Thus, the objectives of this study were to determine: (a) the effect of sewage sludge application on heavy metal build-up in soil and maize grains and (b) the effects of soil amendment with sewage sludge on the chemical properties of a Brazilian Oxisol. Besides the increasing levels of Zn, Cu, Ni, Cd, Pb and Cr, amending soil with sewage sludge also alters the distribution of these metals by increasing the mobile Phases, which correlated significantly with the increase in metal extraction with two single extractants, Mehlich 1 (HCl 0.05 mol L –1 + H2SO4 0.0125 mol L –1 ) and DTPA (Diethylenetriaminepentaacetic acid). Nevertheless, metal build-up in soil and plants was within the allowed limits. The data obtained does not indicate any expressive drawbacks in the use of sewage sludge as a soil amendment, as the heavy metal concentrations observed are unlikely to cause any environmental or health problems, even overestimated loadings.

Biosolids and Distillery Effluent Amendment to IrishMiscanthus×giganteus Plantations: Impacts on Groundwater and Soil

It is necessary to determine the risk of water pollution arising from amendment of organic by-products (OBs) to energy crops under Irish conditions. Therefore, the impact of landspreading two OBs on the quality of groundwater underlying plantations of Miscanthus X giganteus was assessed. Municipal biosolids and distillery effluent (DE) were spread annually (for 4 yr) on six 0.117-ha treatment plots at rates of 100, 50, and 0%. The 100% rate represented a maximum P load of 15 t ha(-1) as per Irish EPA regulation. Groundwater was sampled for 25 mo and tested for pH, electrical conductivity, NO(3)(-), orthophosphate (PO(4)(3-)), total soluble P, K(+), Cu, Cd, Cr, Pb, Ni, and Zn. Assessment of quality was based on comparison with Irish groundwater threshold values (GTVs). The study was limited to within-plot using a "well bottom" approach and did not investigate movement of groundwater plumes or vectors of percolation through the soil profile. Mean groundwater concentrations did not exceed GTVs during the sampling period for any species, with the exception of groundwater PO(4)(3-) in the 100% DE plot, which was almost double the GTV of 0.035 mg L(-1). There was no significant build-up of nutrients or heavy metals in groundwater (or soil) for any plot. Excessive PO(4)(3-) in the 100% DE plot groundwater is likely due to high background soil P, soil characteristics, and the occurrence of macropore/soil pore flow. These factors (particularly background soil P) should be assessed when determining suitable sites for land-spreading OBs.

Assessment of copper and zinc in soils and fruit with the age of an apple orchard

Chemical fractions of copper and zinc in soils were evaluated and, the transfer coefficient of copper and zinc from soil to apples depending on age of apple orchard were determined. The fractions of copper and zinc in surface soil were in decreasing order: residual > organic-bound > Fe−Mn oxides > carbonates and exchangeable > water-soluble fractions. With increasing age of apple orchard, the residual fraction showed the highest residual fractions of copper and zinc, whereas those of water soluble and exchangeable fractions were relatively low. Tc values of copper and zinc did not show significant difference with the age of apple orchard (p >0.05). As our results show that the concentrations of Zn and Cu in soil increase with age of apple orchard, continuous monitoring and pollution control of hazardous material are needed to prevent the excessive build-up of heavy metals in the food chain.