Soil Heavy Metal Concentrations Research Articles

Using multispectral variables to estimate heavy metals content in agricultural soils: A case of suburban area in Tianjin, China

Efficient estimation and mapping of soil heavy metal concentrations based on rapid and environmentally friendly multispectral data can provide a reference for the prevention and control of non-point source pollution and safety in ecosystems. In this study, the spatial variation of soil heavy metals (As, Cd, Cr, Cu, Ni, and Zn) in Wuqing was analyzed with 394 and 57 soil samples gathered in 2005 and 2019. Based on these samples, as well as multispectral variables (raw bands and their respective vegetation index and derivative transformation), random forest-ordinary kriging (RFOK) and artificial neural network-ordinary kriging (ANNOK) were combined to predict spatial variations of heavy metal content. Results indicated that the mean values of soil As, Cd, Cr, Cu, and Zn in 2019 exceeded their respective concentrations in 2005 by 1.40, 1.36, 1.12, 1.12, and 1.35 times, and exceeded the standard rate of background values (BGV) in 2019 for all soil heavy metals (except for Ni). Compared to RF, ANN, and RFOK, the ANNOK method exhibited the best estimation performance for As (R20052= 69.47% andR20192= 65.03%), Cd (R20052= 64.48% andR20192= 64.20%), Cr (R20052= 72.02% andR20192= 70.65%), Cu (R20052= 72.05% andR20192= 70.53%), Ni (R20052= 69.37% andR20192= 66.03%), and Zn (R20052= 71.16% andR20192= 67.11%) in the validation dataset. Mapping of heavy metals derived from ANNOK revealed a similar distribution in 2005 and 2019, where the high concentrations of all soil heavy metals were in the southern part of the study area. The effects of multispectral bands as indicated by vegetation index and derivative transformation exhibited sensitivity for predicting soil heavy metals based on hybrid geostatistical methods. Overall, greater efficiency of spatial estimation for the content of soil heavy metals is important for the prevention and control of non-point source pollution.

Determination of Heavy Metals Concentration in Water and Soil at Various Locations in Lahore and their Harmful Impacts on Human and Plants life

Heavy metals poisoning of soil and water has resulted from industrial expansion in Lahore, Pakistan, creating a significant environmental hazard. As a result, monitoring the contamination of soil and water around industrial sites is critical. The fact that higher concentrations of heavy metals have a negative influence on both plants and human life and this cannot be ignored. Higher heavy metal concentrations have a direct impact on human health due to their presence in drinking water. Consumable plants and vegetables cultivated in these polluted areas may collect higher concentrations of heavy metals from soil and water via the phytoremediation process. Its worth mentioning that the accumulation of toxic metals in edible plants and vegetables also has a direct negative impact on human and animal health. The purpose of this study is to find the heavy metals concentration in the soil and ground water in the Lahore area. Five industrial zones were evaluated for water and soil throughout the research period of December 2021 to January 2022 (pre-monsoon). pH and heavy metals content measurements were performed on the collected soil and water samples. We discovered that the water had a higher pH and that the soil was heavily contaminated with significantly higher concentrations of toxic heavy metals. According to the research, there is a gangrenous influence of pollution caused by industrial waste and the surrounding environment on soil and water resources, which affects living creatures. Keywords: Environmental Pollution, Heavy Metal, Pollution, Water pollution, Soil pollution

Determination of Heavy Metals Concentration in Soil and Leafy Vegetables in Urban Expressway and Peri-urban Road Farms of Lagos State, Nigeria

Farmers have long considered urban agriculture as a panacea to urban food insecurity. However, growing food in cities is faced with many challenges like food contamination. Past studies on leafy vegetables focused on vegetables cultivated in urban centres. However, this paper aimed to determine and compare the level of heavy metals concentrations in soil and leafy vegetables in Urban Expressway Farms (UEF) and Peri-urban Road Farms (PRF) in Lagos, Nigeria. These two locations were purposefully selected. Soil Auger was used to drill holes to the required soil depth to collect soil samples. Sample of Amaranthus hybridus, Celosia argentea and Corchorus olitorius were collected using “envelope” principle. Pb, Cd and Mn residues in the samples were digested and determined using Atomic Absorption Spectrophotometer. The collected data were analysed using mean, standard deviation and Analysis of Variance. The mean pH value for UEF soil is 6.5 while PRF soil is 6.6. The highest Pb (0.93±0.06) was recorded in Celosia argentea at UEF. The highest mean concentration of Cd (0.51±0.11) was recorded in Amaranthus hybridus at UEF. The highest concentration for Mn was recorded in Amaranthus hybridus (0.98±0.02) at UEF. The concentrations of Pb in Celosia argentea at UEF 5 m from the expressway and Cd concentration in Amaranthus hybridus at 10 m from expressway were above the WHO/FAO permissible levels in vegetables. Level of heavy metal residue observed in soil and vegetables under this study were mostly influenced by the location of the farm-environment and not mainly the vegetable type. The relative concentrations of Pb and Cd in all the three leafy vegetables raise some serious environmental concerns and need to be monitored regularly to prevent consumption of contaminated leafy vegetables. Farmers are encouraged to cultivate in fields far away from expressway.

Characteristics and Assessment of Soil Heavy Metals Pollution in the Xiaohe River Irrigation Area of the Loess Plateau, China

Heavy metals in soil are a potential threat to ecosystems and human well−being. Understanding the characteristics of soil heavy metal pollution and the prediction of ecological risk are crucial for regional eco−environment and agricultural development, especially for irrigation areas. In this study, the Xiaohe River Irrigation Area in the Loess Plateau was taken as the study area, and the concentration, as well as their accumulation degree and ecological risk and distribution of soil heavy metals, were explored based on the geo−accumulation index (Igeo) and Hakanson potential ecological risk index methods. The results showed that the concentrations of soil heavy metals were all lower than the second grade Environmental Quality Standard for Soils of China. However, the average concentrations of Cu, Hg, Cd, Pb, Zn, Ni and As were higher than the above−mentioned standard. Compared with the soil background values of Shanxi Province, eight heavy metals of all samples presented different accumulation degrees, with the highest accumulation degree in Hg, followed by Cd, and the values were 11.3 and 4.0 times more than the background value, respectively. Spatially, the distribution of soil heavy metals in the Xiaohe River irrigation area was quite different, generating diverse pollution patterns with significant regional differences and complex transportation routes. The content of soil heavy metals in the Xiaohe River irrigation area was highly affected by land use types. The pollution degree varied with the distance to an urban area, declining from the urban area to suburban farmland, and the outer suburban farmland. Among these heavy metals, Hg and Cd were the principal contamination elements, and transportation, service industry and agricultural activities were the main potential contamination sources. The potential ecological risk of soil heavy metal positioned as follows: Hg > Cd > Pb > Zn > Cu > As > Ni > Cr. As indicated by the Hakanson potential ecological risk index strategies, except for the Wangwu examining site, the other six sampling sites experienced extremely strong risks, and as a whole, the entire study region was in a condition of incredibly impressive perils. Consequently, these results suggest that improving soil environmental investigation and assessment, setting up soil heavy metal contamination prevention and control innovation framework and reinforcing contamination source control are effective approaches for soil heavy metal contamination anticipation and control in irrigated areas of the Loess Plateau.

Effects of hyperspectral data with different spectral resolutions on the estimation of soil heavy metal content: From ground-based and airborne data to satellite-simulated data

Soil heavy metal distribution maps can provide decision-making information for pollution control and agricultural management. However, the estimation of heavy metals is sensitive to the resolution of the soil spectra due to their sparse content in soils. The purposes of this study were to test the sensitivity of Ni, Zn and Pb prediction results to variations in spectral resolution, then to map their spatial distributions over a large area. In addition, the effectiveness of spectral feature extraction was investigated. In total, 92 soil samples and corresponding field soil spectra were obtained from the Tongwei-Zhuanglang area in Gansu Province, China. Airborne HyMap hyperspectral image of this area was acquired simultaneously. Three satellite image spectra (AHSIGF-5, Hyperion, AHSIZY-1 02D) were simulated using the field spectra which were measured under real environmental conditions rather than laboratory conditions. The combination of genetic algorithm and partial least squares regression (GA-PLSR) was used as prediction algorithm. The models calibrated by HyMap image full spectral bands had the highest accuracies (RP2 = 0.8558, 0.8002, and 0.8592 for Ni, Zn, and Pb, respectively) because of high consistency. For field spectra and three simulated satellite spectra, models calibrated by simulated AHSIGF-5 spectra performed best because of appropriate resolution (5 nm in the visible near-infrared [VNIR] and 10 nm in the short-wave infrared [SWIR]). The spectral feature extraction method only improved prediction accuracy of the field spectra, indicating that this method benefited from higher spectral resolution. The mapping of the spatial distribution of soil heavy metals over a large area was realized based on HyMap image. According to the results of the satellite simulation spectra, this study proposes to use GF-5 hyperspectral image to estimate heavy metals content. The outcomes provide a reference for the utilization of aerial and satellite hyperspectral images in prediction of soil heavy metal concentrations.

Heavy metals in soils of Mayabeque, Cuba: multifaceted and hardly discernable contributions from pedogenic and anthropogenic sources

Cuba is a country with considerable potential for economic growth, and special efforts are made to increase the agricultural output. As food production depends on the quality of soils, heavy metal concentrations were measured in 39 soils in the province of Mayabeque, Cuba, and interpreted in light of anthropogenic activities and pedogenic conditions (soil type and properties). With median concentrations of 1.8 Cd, 60.3 Cr, 48.1 Cu, 36.2 Ni, 16.7 Pb, 55.0 Zn, and 0.1 mg/kg Hg, soils of Mayabeque were mostly below Cuban quality reference values (QRV) representing benchmarks of quality standards but no official threshold values. Only Cd concentrations were in many cases above the QRV of 0.6 mg/kg and some Cu concentrations above the one of 83 mg/kg. While Cd, Cr, and Ni concentrations were rather pedogenically driven, Cu, Pb, Zn, and Hg contents were rather anthropogenically influenced. When evaluated statistically, Cd and Cr showed most times a significant influence of both sources. In contrast, Ni and Zn could not be significantly related with the origins investigated in this study. Hence, the allocation of heavy metal concentrations to pedogenic or anthropogenic contamination or pollution sources is tentative and needs further investigations. Nevertheless, the present data adds information on soil heavy metal concentrations in the Caribbean region, serves as reference before further industrial development, and sets the ground for adaptation of the QRV for Cd and possibly future national environmental standards.

Assessment of Soil Contamination Using GIS and Multi-Variate Analysis: A Case Study in El-Minia Governorate, Egypt

The issue of soil contamination is one of the most important subjects that interests decision-makers all over the world. It is also related to soil fertility and food security. The soils adjacent to the drains in Egypt suffer from increasing concentration of heavy metals, which negatively affects soil and crop quality. Precise spatial distribution maps of heavy metals are an essential key to mitigating the negative impacts on the ecosystem. Sixty random soil locations adjacent to the El-Moheet drainage were chosen on the west side of the Nile River, El-Minia governorate, Egypt. Six heavy metals (Cr, Co, Cu, Cd, Pb, and Zn) were selected to generate their spatial pattern maps using ordinary Kriging (OK). Principal component analysis (PCA) and contamination factors (CF) were applied to evaluate soil contamination levels in the study area. The results showed that the Gaussiang model was a high fit for soil pH, and Pb, the Exponential model was fit for EC, Stable model was fit for OC, Co, Cu, and Cd. In addition, the Spherical model was fit for both Cr and Zn. The MSE values were close to zero in all selected metals, while the values of RMSSE were close to one. The results showed that the soil heavy metal concentrations were grouped into two clusters using PCA. Furthermore, three contamination degrees were obtained (moderate, considerable, and very high), with about 70.7% of the study area characterized by considerable heavy metals concentration, where the average heavy metals concentration (mg kg−1) in this degree was 91.23 ± 19.5, 29.44 ± 5.2, 53.83 ± 10.2, 1.12 ± 0.3, 36.04 ± 18.0, and 101.29 ± 35 for Cr, Co, Cu, Cd, Pb, and Zn, respectively. The current results reflect the mismanagement and use of low-quality water for irrigation in the study area, which increased the toxic element concentration in soil surface layers. In the end, the results of spatial distribution maps of pollutants and their degrees could support decision-makers as a basis for developing appropriate mitigation plans for heavy metals.

Assessment of vegetation, soil nutrient dynamics and heavy metals in the Prosopis juliflora invaded lands at semi-arid regions of Southern India

Prosopis juliflora is one among the dominant invasive plant species widely distributed in arid and semi-arid regions of the world. The invasion inflicts varying degrees of ecological implications, albeit certain socio-economic benefits are being derived by the local community. In Southern India, the vast semi-arid plains lying east of the Western Ghats mountain range, has ideally favored extensive invasion of P.juliflora. In last three decades, the invasion had spread to the pasture and arable lands that are lying disconnected from the mainstream irrigation system. Therefore, in the context of worsening food security, ecological imbalance, increasing soil degradation and the climate change, the prospects of converting the P.juliflora invaded lands to silivicultural/agricultural activity has been envisaged as a viable alternative. In this scenario, present study is an imperative attempt to understand the coexisting vegetation, soil nutrient profile and heavy metal concentrations in the P.juliflora invaded lands at Tiruchirappalli and Pudukkottai regions of Southern India. Composite soil samples were collected from 60 sites (spread across 4800 km2 including urban–rural gradient) at the depths 0 – 10, 10 – 20, and 20–30 cm. The influence of P.juliflora stand density, litter fall, species diversity, soil texture on the soil physico-chemical properties including soil pH, electrical conductivity (EC), available macro nutrients (N, P and K), organic carbon and heavy metals [Fe, Cu, Cd, Cr, Ni, and Pb] were investigated. The results revealed considerable enrichment of macronutrients in the invaded lands, in contrast to non-invaded lands (p < 0.001***). Of the observed attributes, step wise regression indicated stand density and litter fall as prominent factors (R = 0.7903 and 0.6479 respectively) augmenting soil macro nutrients. In the case of heavy metals, observations along the urban–rural gradient indicated comparatively lower concentrations of heavy metals in the P.juliflora invaded lands of urban areas, hinting the possible of bio-sorption capacity of P.juliflora. Overall, the results infer an optimistic note for potential conversion of the P.juliflora invaded lands to silivicultural maneuvers, prioritizing the native flora.

Multi-Temporal Landsat-8 Images for Retrieval and Broad Scale Mapping of Soil Copper Concentration Using Empirical Models

Mapping soil heavy metal concentration using machine learning models based on readily available satellite remote sensing images is highly desirable. Accurate mapping relies on appropriate data, feature extraction, and model selection. To this end, a data processing pipeline for soil copper (Cu) concentration estimation has been designed. First, instead of using single Landsat scenes, the utilization of multiple Landsat scenes of the same location over time is considered. Second, to generate a preferred feature set as input to a regression model, a number of feature extraction methods are motivated and compared. Third, to find a preferred regression model, a variety of approaches are implemented and compared for accuracy. In this research, 11 Landsat-8 images from 2013 to 2017 of Gulin County, Sichuan China, and 138 soil samples with lab-measured Cu concentrations collected from the area in 2015 are used. A variety a metrics under cross-validation are used for comparison. The results indicate that multi-temporal images increase accuracy compared to single Landsat images. The preferred feature extraction varies based on the regression model used; however, the best results are obtained using support vector regression and the original data. The final soil Cu map generated using the recommended data processing pipeline shows a consistent spatial pattern with a ground-truth land cover classification map. These results indicate that machine learning has the ability to perform large-scale soil heavy metal mapping from widely available satellite remote sensing images.

Calorific Value of Festuca rubra Biomass in the Phytostabilization of Soil Contaminated with Nickel, Cobalt and Cadmium Which Disrupt the Microbiological and Biochemical Properties of Soil

The choice of optimal plant species for phytoremediation and organic fertilization plays an important role in stabilizing the functions of soils contaminated with heavy metals. The influence of nickel, cobalt and cadmium on the biomass yield and calorific value of Festuca rubra, heavy metal concentrations in soil and plants and the microbiological, biochemical and physicochemical proprieties of soil were analyzed in a pot experiment. The tolerance index (TI) describing Festuca rubra’s ability to tolerate heavy metals, as well as the translocation (TF), accumulation (AF) and bioaccumulation (BF) factors of heavy metals in Festuca rubra were calculated. The experiment was conducted in two series: In soil fertilized and not fertilized with compost. Nickel and cobalt significantly inhibited the growth and development of Festuca rubra. The experiment demonstrated that this plant species can be grown on soil contaminated with heavy metals. Festuca rubra contained on average 46.05% C, 34.59% O, 5.91% H, 3.49% N, 0.19% S and 9.76% ash. Festuca rubra has a stable calorific value which is not affected by heavy metals; therefore, biomass harvested from heavy metal-polluted soil can be used for energy generation. The calorific value of Festuca rubra ranged from 15.924 to 16.790 MJ kg−1 plant d.m., and the heat of combustion from 17.696 to 18.576 MJ kg−1. It has a stable calorific value which is not affected by heavy metals, therefore biomass harvested from heavy metal-polluted soil can be used for energy generation. Festuca rubra is particularly useful for the phytostabilization of soil contaminated with cadmium and cobalt. Compost minimizes the adverse effects of heavy metal pollution on the microbiological, biochemical and physicochemical properties of soil.

Mining-Related Metal Pollution and Ecological Risk Factors in South-Eastern Georgia

Gold and copper production is important to the Georgian economy, but at the same time, mineral resources are mined in one of the important agricultural areas of the country. This study evaluated water and soil quality in the region. Soil from 18 villages was analyzed. Some of these villages have not been investigated before and previous information about soil quality was unknown. Ecological risk factors and potential ecological risk were determined for the study area. Atomic absorption spectrometry was used to analyze heavy metals concentration in soil and water samples taken from the study area. Integrated water and soil data allowed us to see how these important natural resources influence each other. After the comparison of the four-year period of the study, we observed an increase of heavy metals increase in the soil in 2017 compared to 2014. Higher lead concentration was discovered within a two kilometer radius of the mining area whereas the highest cadmium concentration was observed in the village Ratevani, 15 km away from the nearest mine, where there was an extremely high ecological risk of Cd concentration. Further investigations are recommended to be done in Ratevani village as the people living in this village are at risk of Cd poisoning.

Assessment of heavy metal contamination levels and health risks in environmental media in the northeast region

• Analyze heavy metal contamination levels in soil, water, and air. • Heavy metals from media are hazardous to human health in many ways. • Major pollution is affected by industry and agriculture. • Characterization of human contamination by heavy metals in human hair. • Environment causes health hazards to humans and makes sustainability suggestions. Rapid development in Northeast China has brought serious heavy metal pollution to the environmental media (soil, surface water and air). This paper presents a study on the spatial and temporal distribution, source analysis, potential ecological risk and human health risk assessment of heavy metals in environmental media in Northeast China, aiming to provide a theoretical foundation for controlling and reducing heavy metal pollution. The study shows the following results:1. Developed cities in Jilin Province (Changchun and Jilin) have the most serious heavy metal pollution. 2. The main sources of heavy metals in soil are metallurgical production and agricultural production. The main sources of heavy metals in surface water are industrial production, domestic waste, and sewage. The main sources of heavy metals in the air are vehicle emissions, biomass combustion and coal burning for winter heating. The sources of heavy metals are listed in order of decreasing significance in all three cases above. 3. Soil, surface water and air heavy metal concentrations all have a significant impact on human health. 4. Heavy metals in soil, surface water and air are an ecological risk and already pose a carcinogenic risk to humans.

Heavy Metals Contaminants in Watercress (Nasturtium officinale R. BR.): Toxicity and Risk Assessment for Humans along the Swat River Basin, Khyber Pakhtunkhwa, Pakistan

This research aimed to investigate the bioaccumulation and health risk associated with absorption of the selected heavy metals (HMs) i.e., lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu) in a wild leafy vegetable Nasturtium officinale that grows along the Swat River in swampy areas. The areas were categorized using the ecological risk index (RI), which indicates how heavy metal concentrations in soil and plants change over time. The bioaccumulation factor was greater than that at the 400 ≤ RI sites, indicating a probable health risk of these metals from N. officinale consumption. Furthermore, the health risk index for Cd and Pb was more significant, i.e., greater than one in the majority of the samples, indicating health concerns associated with consuming N. officinale from the study site. However, Zn and Cu levels were lower than the nutritionally needed levels, raising the risk of deficiency in the population. Plants cultivated in Pb and Cd-polluted sites were nutrient deficient in Cu and Zn. Intake of such plants can expose people to HM contamination and nutritional deficiencies. The results concluded that the plants accumulated significant HM contents and may have health concerns but are safe for consumption in children and adults.

Heavy Metals Concentration and Arthropod Population in Some Selected Dumpsites from Calabar, Cross River State, Nigeria

The aim of this research is to investigate the influence of refuse dumping on arthropods population and heavy metals concentration in Calabar Cross River state, Nigeria. Soil, and arthropod samples were collected from Lemna, Nassarawa, University of Calabar female hostel and Goldie market dumpsites which were labeled S1, S2, S3, and S4, respectively while same samples were picked from a plot of land labeled PC as a control. Arthropods were identified using light microscope and identification guide while heavy metals Cd, Pb, Cr, Ni, Co, As and Hg were analysed in soil and arthropods using Atomic absorption spectrophotometer (AAS). The results obtained showed 8363 arthropod individuals consisting of 19 species dominated by Muscidae (flies) family which constitutes about 20.39% whose presence indicates high level of pollution of the dumpsite and a possible health implication on people living around the dumpsites because these organisms are vectors for diseases such as yellow fever, malaria, Heavycholera and typhoid fever. Cadmium was the highest occurring heavy metal in dumpsites soil with a concentration of 1.457±0.493 mg/kg in S4 while As was the lowest with a concentration of 0.001 ± 0.000 mg/kg in S1 and Hg was below detection limit in all dumpsites. In arthropods, Cd had the highest occurrence with a concentration of 0.020 ± 0.001 mg/kg in S4 while Pb in S2 and Co in S1 with concentration of 0.001 ± 0.000 each were the lowest occurring metals. Heavy metals concentration in soil and arthropods from the dumpsites was higher than that of the control which shows the influences of refuse dumping and strong (&gt; 5) positive correlation between mean metal concentrations in soil and arthropods suggests that these arthropods can be used as bio-indicators of heavy metals contamination and accumulation. It is therefore recommended that wastes be segregated and proper disposal methods should be adopted.

The Effect of Pelletized Lime Kiln Dust Combined with Biomass Combustion Ash on Soil Properties and Plant Yield in a Three-Year Field Study

Extensive application of mineral fertilizers resulted in high soil acidity, which is one of the major problems for crop production and soil degradation. Industrial solid waste, such as lime kiln dust and wood ash, can be used as alternative liming materials to benefit sustainable agricultural development. In this work, pelletized lime kiln dust with and without wood ash was utilized as liming material and the results of the three-year field study were compared with conventional mineral-based liming materials. It was determined that pelletized lime kiln dust satisfies the requirements posed by the recent European Union regulations to qualify as liming materials. The application of 2000 kg/ha Ca equivalent pelletized lime kiln dust increased soil pHKCl by ~0.55 pH units. Moreover, pelletized lime kiln dust significantly increased spring wheat grain yields ranging from 33.6% to 40.4%, depending on the pellet size. The usage of these liming materials not only increased crop yield but also decreased heavy metal concentration in soil. Due to high alkalinity, carbonate content, easy handling, and the transportation of pelletized lime kiln dust with and without wood ash, the materials have the potential to be used in agriculture as liming materials to reduce soil acidification and increase crop productivity or be used as soil amendments.

Comparing resistome profiles from anthropogenically impacted and non-impacted areas of two South Shetland Islands – Maritime Antarctica

Whalers Bay, in Deception Island, has one of the most anthropogenically impacted areas in Maritime Antarctica. However, considering the volcanic nature (high concentrations of heavy metals) of Deception Island's soils, this putative anthropogenic impact should be carefully investigated. In this context, the objective of this study was to compare resistome profiles of impacted and non-impacted areas in Deception Island (Whalers Bay, Crater Lake, and Fumarole Bay) and Livingston Island (Hannah Point) in order to investigate the microbiome tolerance/resistance mechanisms selected as a function of environmental drivers. Metagenomics was used to search for genes conferring resistance/tolerance to antibiotics, biocides, and heavy metals. Whalers Bay has a greater diversity of antibiotic, biocide, and heavy metal resistance classes found in its microbiomes. However, Hannah Point, at Livingston Island, has a greater abundance of antibiotic and biocide resistance/tolerance genes. The microbiome of Deception Island's non-impacted areas (Crater Lake and Fumarole Bay) showed resistance/tolerance genes almost entirely to heavy metals. Pb was found in higher concentrations in Whalers Bay soil in comparison to the other areas, indicating human contamination. The non-metric multidimensional scaling (NMDS) analysis revealed that Pb concentrations influenced resistome profiles in Whalers Bay soil. Despite the effect of Pb on the microbial communities of Whalers Bay, most heavy metal concentrations did not have a significant impact on resistome genes, suggesting that the volcanic soil heavy metal concentration of Deception Island has little biological influence.

UTILIZING INDUCED MUTAGENESIS IN KAZAKHSTANI WHEAT BREEDING

Mutagenic effect of physical factors and chemical substances (aziridine or ethylene imine, nitrosoethylurea, nitrosoethyleneurea) leads to increase of the spectrum of hereditary variability for breeding purposes, which however is not studied in full extent. Ecological study of anthropogenic factors action leading to disruption of certain links between chemical elements and their combinations, raise of heavy metals concentration in soil, facilitate examination of mutagenic and toxic properties of heavy metals. Increase in wheat yields by improving its genotype is one of the most urgent problems of agriculture and economy. At present, using traditional methods of selection and genetic studies, such as backcross selection, distant hybridization, and experimental mutagenesis, increased efficiency of obtaining genetically modified and improved forms of wheat [1-5]. Heavy metals are defined as metals having a density higher than 5 g/cm3. Of the total 90 naturally occurring elements divided into three classes by the degree of their threat, 53 are considered heavy metals and few are of biological importance. Accumulation of heavy metals such as cadmium (Cd) in the environment is now becoming a major cause of environmental pollution. Toxic metals can inactivate proteins, shifting metal cofactors, blocking active centers or causing allosteric changes. Besides, large number of those possesses ability of inducing mutagenic changes, tumors and causing macroscopic changes. Molecular mechanism of heavy metals toxicity is not completely understood. Cd is non-essential element that negatively affects plant growth and development, released into the environment by power stations, heating systems, metal working industries or urban traffic, which has high cumulative effect with almost no biodegradation. In plants it affects such processes as stomata opening, transpiration and photosynthesis, consequently chlorosis, leaf rolls and stunting are the main symptoms of Cd toxicity in plants accompanied by root browning, leaf red-brownish discoloration. It can also reduce the absorption of nitrate from root to shoot by inhibiting the nitrate reductase activity in shoots. The negative effect of Cd on plant growth was accompanied by an increase in dry to fresh mass ratio in all organs. Several researches have suggested that an oxidative stress could be involved in cadmium toxicity, by either inducing oxygen free radical production, or by decreasing enzymatic and non-enzymatic antioxidants [6-9]. On the other hand, the use of induced mutagenesis showed high efficiency in the production of forms with high yield, quality bakery, lodging resistance, modified plant height and resistance. And, this paper is an attempt of summarizing results performed by our group in this direction.

Chemical fractionation of some heavy metals in soils irrigated from El-Saff wastewater drainage canal, Egypt

ABSTRACT Assessment of heavy metals fractions in soils irrigated with wastewater can directly reflect their bioavailability and contamination level in soil depths. The present study was conducted to assess the heavy metals (Cd, Cu, Pb, Mn, and Fe) fractionation in agricultural soils illegally irrigated with El-Saff wastewater drain, southern Giza Governorate, Egypt. Generally, practices of wastewater irrigation increased pH values in the deeper depths of irrigated soils. Results revealed that long-term wastewater irrigation profoundly affected the studied heavy metals fractions in soil depths. Generally, the ranges of studied heavy metals concentrations in soils irrigated with wastewater were apparently different. All fractions were significantly higher in the upper soil depths (0–60 cm and 30–60 cm) than the deeper depths. (60–90 cm and 90–120 cm). Heavy metals concentrations varied in the soils as Fe > Mn > Cu > Pb > Cd after irrigation. The heavy metals fractions were dominant in the residual form followed by oxides bound and organically bound fractions. Lower contents of heavy metals in the soil were obtained in the exchangeable fraction. Wastewater irrigation resulted in the transformation of heavy metals into different fractions as residual > oxide associated > organically bound > carbonate associated > exchangeable form. Monitoring of heavy metals concentration in El-Saff wastewater effluent is periodically required.

Geospatial modeling and ecological and human health risk assessments of heavy metals in contaminated mangrove soils

Heavy metal-contaminated wastes can threaten mangrove forests, one of the most biodiverse ecosystems in the world. The study evaluated the geospatial distribution of heavy metals concentrations in soils, the ecological and human health risks, and metal contents in soil fractions and mangrove organisms in the Botafogo estuary, Brazil, one of the most environmentally impacted estuaries in the country. The metal concentrations exceeded by up to 2.6-fold the geochemical background; 91%, 59%, 64%, 31%, and 82% of the soils were contaminated with Cr, Zn, Pb, Cu, and Ni, respectively. Adverse effects to the biota may occur due to Cr, Cu, Ni and Pb exposures. Contents of clay and organic matter were the main factors governing the distribution of metals in soil, contributing to up to 63% of the total variability. However, the geospatial modeling showed that the predictive ability of these variables varied spatially with the metal and location. The ecological and human health risks assessments indicated that the metal concentrations in soils are safe for the environment and human beings. There was a low transfer of metals from the soil to the biota, with values of sediment-biota accumulation factor (SBAF) and biological accumulation coefficients (BAC) lower than 1.0, except for Zn (SBAF = 13.1). The high Zn bioaccumulation by Crassostrea rhizophorae may be associated with the concentrations of Zn in the bioavailable fractions.

Assessment of elevated CO2 concentrations and heat stress episodes in soybean cultivars growing in heavy metal polluted soils: Crop nutritional quality and food safety

The present study evaluated the interactive effects of global change and heavy metals on the growth and development of three soybean [Glycine max (L.) Merrill] cultivars and the consequences on yield and food safety. Soybean cultivars (Alim 3.14 from Argentina, and ES Mentor and Sigalia, from Germany) were grown until maturity in heavy metals polluted soils from the Rhine Valley, Germany, at two CO2 concentrations (400 and 550 ppm) and heat stress (HS) episodes (9 days with 10 °C higher than maximum regular temperature) during the critical growth period in controlled environmental chambers. Different morpho-physiological parameters, heavy metal concentration in aerial organs, seed quality parameters, and toxicological index were recorded. The results showed that no morphological differences were observed related to CO2. Moreover, Alim 3.14 showed the highest yield under control conditions, but it was more sensitive to climatic conditions than the German cultivars, especially to heat stress which strongly reduces the biomass of the fruits. Heavy metals concentration in soil exceeds the legislation limits for agricultural soils for Cd and Pb, with 1.6 and 487 mg kg−1 respectively. In all cultivars, soybeans accumulated Cd in its aerial organs, and it could be translocated to fruits. Cd concentration in seeds ranged between 0.6 and 2.4 mg kg−1, which exceed legislation limits and with toxicological risk to potential Chinese consumers. Pb levels were lower than Cd in seeds (0.03–0.17 mg kg−1), and the accumulation were concentrated in the vegetative organs, with 93% of the Pb incorporated. Moreover, pods accumulated 11 times more Pb than seeds, which suggests that they act as a barrier to the passage of Pb to their offspring. These results evidence that soybean can easily translocate Cd, but not Pb, to reproductive organs. No regular patterns were observed in relation to climatic influence on heavy metal uptake.