Trace Metals In Soils Research Articles

Physicochemical Properties, Total Concentration, Geochemical Fractions, and Health Risks of Trace Metals in Oil-Bearing Soils of Akwa Ibom State, Nigeria

The physicochemical properties, total metal, metal fractions, and related human health problems of metals in oil-bearing soils of Akwa Ibom State were appraised using standard procedures. The study aimed at assessing the effects of crude oil and related activities on the properties of soil including metals (Cd, Cr, Ni, Pb and V), their fractions and associated health problems. Results showed that, levels of parameters were higher in the soils examined than in the control. The entire metals examined, apart from Cd, were within their acceptable limits however; higher than the limits for agricultural soils. Cd and Cr existed mainly in the readily available fraction, while Ni, Pb, and V occurred mainly in the reducible fraction in the studied soils. Conversely, these metals, except Cd, occurred principally in the inert fraction in the control. V/Ni ratio confirmed the soils as oil-forming continents and of organic matter origin. The natural factor, crude oil, and oil-related activities were major sources of soil contaminants. Anthropogenic proportions of metals were more in the soils investigated than in the background soil. The locations were contaminated with metals. Daily intake rates of metals were within their recommended doses except for Pb. The pollution status of the oil-bearing soils and the related human health risks have been revealed.

Environmental assessment of soil contamination by trace metals

The main purpose. The purpose of this research is to develop a method for determining the level of heavy metal contamination in the soil. For this end, the following tasks are set: - to develop a method for the integrated assessment of heavy metal contamination in the soil at the regional and local levels; - to identify the most heavy metal contaminated regions of Ukraine; - to estimate the level of hazard of heavy metal contamination in the soil for territories with different types of land use; - to assess the pollution of soils with heavy metals as a result of hostilities in Donetsk and Luhansk regions. Methodology. The method takes into account the soil morphology, genezises, trace metals background concentrations and based on the development of the self-purification index for various soils in different regions of Ukraine. According to the proposed method soils have been classified by trace metals contamination. Results. At the local level, trace metals in soils were assessed for urban recreational areas, highways and roads, landfills and industrial zones. The soils in recreational areas were classified as ‘good’, highways and roads are classified as ‘satisfactory’ and ‘poor’, industrial and landfill was classified as ‘very poor’ according to the trace metals contamination. At the regional level, the highest contamination Class was given to the soils of Donetsk and Luhansk regions due to the highest density of industrial areas and performed military activities. The environmental assessment of trace metals contamination in soils due to the military activity was performed for these regions. The results of trace metals determination in Kharkiv according to this method indicate that the most dangerous areas are domestic waste landfills and facilities of the industrial companies. Recreation zones are ranked in Class 2. and the territory near the highways are assessed in quality Class 2 and 3. Assessment of the hazard level of trace metal contamination in the soil by the proposed method will allow making a scientifically substantiated decision on the priority of implementation of environmental measures. Scientific novelty. The paper presents a new method of assessing soil contamination with heavy metals at the regional and local level. The advantage of this method is taking into account the hazard class of pollutants and the self-cleaning index. A new classification of the level of danger of soil contamination with heavy metals has been developed. Practical significance. The use of the proposed methodological approach will contribute to obtaining comparable data when assessing the level of soil contamination by heavy metals and determining the priority of implementing environmental protection measures and increasing the level of environmental safety, which is especially relevant for the post-war recovery of our country.

A comprehensive framework for identifying contributing factors of soil trace metal pollution using Geodetector and spatial bivariate analysis

The accurate identification of pollution sources is important for controlling soil pollution. However, the widely used Positive matrix factorization (PMF) model generally relies on knowledge and experience to accurately identify pollution sources; thus, this method faces significant challenges in objectively identifying soil pollution sources. Herein, we established a comprehensive source analysis framework using factor identification and geospatial analysis, and revealed the factors contributing to trace metal(loid) (TM) pollution in soil in the Pearl River Delta (PRD), China. Using the PMF model, we initially considered that the PRD may be affected by natural, atmospheric, traffic and industrial, and agricultural sources. Moreover, Geodetector model detected the relationship between TMs and 12 environmental variables based on the strong spatial “source–sink” relationship of pollutants. The parent material and digital elevation model were the key factors predicting the accumulation of Cr, Ni, and Cu. Industries and roads were the most important determinants of Pb, Zn, and Cd, whereas atmospheric deposition was more important for Hg accumulation. The accumulation of As was found to be closely related to agricultural activities such as the application of chemical fertilizers and pesticides. The spatial autocorrelation between soil TM pollution and environmental variables further supports this hypothesis. Overall, the obtained results showed that proposed approach improved the accuracy of source apportionment and provided a basis for soil pollution control.

Using geostatistical modeling methods to assess concentration and spatial variability of trace metals in soils of the abandoned gold mining district of Bindiba (East Cameroon)

Using geostatistical modeling methods to assess concentration and spatial variability of trace metals in soils of the abandoned gold mining district of Bindiba (East Cameroon)

ASSESSMENT OF HEAVY METAL CONTAMINATION IN SOIL SAMPLE NEAR INDUSTRIAL AREA OF MORBI, GUJARAT

The quantities of toxic trace metals in soil have a significant impact on soil quality and its usage in food production, particularly in an industrial Area. Toxic elements such as copper, zinc, and iron, as well as Manganese, are investigated in representative soil samples from Morbi, Gujarat's industrial sector. Sample were taken from five different location near industrial area it were compared to the Gujarat government's test range, most of the industrial region is significantly contaminated bycopper, and zinc, with partial contamination by manganese and iron.

Effects of soil trace metals, organic carbon load and physicochemical stressors on active oxygen species metabolism in Scylla serrata sampled along the Bay of Bengal in Odisha state, India

Studies on the synergetic effects of soil and water parameters on Oxidative Stress (OS) physiology systems of the edible mud crab Scylla serrata sampled from different parts of East India are unknown. This study aimed to evaluate the effects of soil Ca, Mg, and organic carbon load and water physicochemical stressors induced spatio-temporal variation of tissue-specific OS and antioxidant parameters in S. serrata along the Bay of Bengal in Odisha. Spectrophotometric or Fourier-transform infrared spectroscopy methods were employed to measure the OS physiology and physicochemical parameters. Pedological and physicochemical factors of water were varied significantly in summer (38–42°C), rainy (25–35°C), and winter (12–20°C) seasons. Activities of antioxidant enzymes (AE) such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and the level of lipid peroxidation (LPx) were found to be higher in hepatopancreas as compared to other tissues irrespective of seasonal variation. Considering the impact of dry seasons, an average of 13.23% enhanced activities of AE were noticed in different tissues of S. serrata in response to temperature, salinity, organic carbon, Mg, and Ca load of sampling sites. However, about 11.26% decrease in the activities of AEs, including GR and GST in most of the tissues were recorded, along with a 21% alleviated level of LPx observed in the rainy season compared to other seasons. Among three coastal zones of the Bay of Bengal, the AEs in crabs sampled from Chandipur were elevated by 5.43% in winter, whereas a 7.05% enhanced level of LPx was found in summer compared to crabs sampled from Chilika and Jagatsinghpur. Overall, the levels of LPx, total antioxidant, and activities of AEs (CAT, GST, GPx, and GR) have shown a positive correlation, whereas ascorbic acid and GSH negatively correlate with habitat water pH, temperature, and salinity of soil and water. The results can be used for ecotoxic and environmental biomonitoring purposes using crabs as model organisms across tropical coastal regions.

Pollution profile, ecological and health risk assessment of trace metals in soils of auto mechanic workshops at Gombe metropolis, Gombe State, Northeastern Nigeria

Pollution profile, ecological and health risk assessment of trace metals in soils of auto mechanic workshops at Gombe metropolis, Gombe State, Northeastern Nigeria

Validation of microwave-assisted digestion and Inductive coupled plasma -mass spectrometer for the determination of trace metals in the soil around Darvill sludgeland and their environmental complications

ABSTRACT This study presents the optimization, validation, and application of microwave-assisted digestion and inductively coupled plasma mass spectrometry (ICP-MS) for the simultaneous determination of trace metals (B, Cd, Co, Cr, Cu, Mo, Ni, Pb, Se, V, Zn, and As) in soils from sludgeland. This analytical method was validated according to the requirements of ISO standards for new methods, which include parameters such as linearity, sensitivity and range, accuracy, precision, selectivity, the limit of detection (LOD), the limit of quantification (LOQ), and recoveries. The method demonstrated good linearity with a correlation coefficient greater than 0.999 for all 12 metals of interest. The limit of detection (LOD) was found to be between 0.001 and 0.006 µg/L and the Limit of Quantification (LOQ) was between 5 and 200 µg/L. The method was then applied to soil samples from 28 sites where sludge is disposed to assess the presence of trace metals and their concentrations were compared with background concentrations of metals in South Africa. The Cr with the value ranging from 83.5 mg/kg to 480 mg/kg exceeded the limits in all sites while Zn, Co, Ni, As exceeded in some sites. Geo accumulation was then used to categorize the contamination level of soil by trace metals and observed to be strongly contaminated by Zn with values between 1.2 and 3.5 while moderately contaminated by Pb, Ni, Cu, and As with values between 1.3 and 2.7 which poses their environmental risk.

Identification of pollution sources and spatial distribution of trace metals in soils of the industrial area El Hadjar (Annaba, Algeria)

ABSTRACT The purpose of this study is to investigate trace metal contents in soils, to determine their spatial distribution, and to identify their potential natural either anthropogenic sources using multivariate statistical approaches. Soils were taken in the industrial area of El Hadjar (NE-Algeria) at 0-10 and 10-20 cm. The results revealed an order of Fe > Zn > Pb > Cu > Cr, whatever the depth. Mean concentrations of Fe, Zn, Pb, Cu and Cr were 31191, 219.87, 96.76, 47.87, 28.27 µg/g, respectively, at 0-10 cm, and 29,792, 304.09, 115.45, 49.08, 28.16 µg/g, at 10-20 cm. Cr and Fe mean concentrations were below or close to soils worldwide backgrounds. These metals perhaps principally derive from natural sources. The percentages of sites with Zn, Pb and Cu contents over the background values were: 88.23% (Zn) > 82.35% (Pb) > 52.94% (Cu) at 0-10 cm, and 94.11% (Zn) > 88.23% (Pb) > 41.17% (Cu) at 10-20 cm. Hotspot areas of metal contamination were mainly concentrated around the Arcelor Mittal complex which seems to be the strongest effect factor influencing the spatial distributions of these metals. Results of this study suggest that Cr and Fe are predominantly derived from natural sources; Pb and Zn from industrial sources; and Cu from agricultural and industrial ones.

Immobilization of trace elements and lettuce growth in soil amended with activated dolomite phosphate rock fertilizers

Activation of low-grade phosphate rocks such as dolomite phosphate rock (DPR) with organic molecules of humic acid (HA) and sodium lignosulfonate (SLS) holds promise for developing slow release P fertilizers. Consequently, activated DPR fertilizers also contains multiple essential plant elements, including P, Ca, Mg, Zn, and Fe, while minimizing leaching losses of nutrients and heavy metals. Greenhouse experiments were conducted to examine the availability of Ca, Mg, and trace metals in soils applied with activated DPR fertilizers and subsequent response of lettuce (Lactuca Sativa L.) as compared with original DPR and water-soluble P fertilizers including superphosphates (SP) and diammonium phosphates (DAP). Application of activated DPR fertilizers stimulated the uptake of Ca, Mg, Zn, Fe, B by lettuce plants relative to original DPR and DAP. Potential toxic elements such as Cr, Cd, Ni, Pb, and Cu were mostly immobilized in soil without uptake by lettuce when applied with activated DPRs primarily due to increased soil pH, as compared with water soluble fertilizers such as DAP and SPs. Apparently, the activated DPR fertilizers offer advantages over original DPR materials and water-soluble P fertilizers in providing multiple nutrients with minimal adverse effects on soil and environmental quality.

Towards sustainable and efficient land development: Risk of soil heavy metal(loid)s in abandoned gold mines with short‐term rehabilitation and potential value for targeted remediation

AbstractRecently sustainable and efficient land development and the potential reutilization values of abandoned mines (i.e., industrial, arable, and tourism) have been attracting worldwide attention. However, environmental impacts after rehabilitation practices are often ignored and field data are lacking. What remains unknown is an understanding how the risk of soil trace metal(loid)s (TMs) respond to short‐term rehabilitation of abandoned gold mines and the potential value for following targeted remediation. We found that a high level of TM cadmium (Cd) and arsenic (As)] contamination and significant health risk to humans, limited land reutilization in rehabilitation scenarios. Feedback from soil TMs to rehabilitation is of potential value for following targeted remediation. Specifically, (1) the major pollutants we studied were Cd and As. Cadmium poses a considerable ecological risk as evidenced by Igeo, contamination factor, and risk assessment code, and a much higher bioavailability evidenced by non‐residual fractions (42.42%). Arsenic has the lowest environmental availability with 90.99% in residual fraction; (2) spatial distributions of TMs were similar. Sites with serious contamination were mainly located in the southwest of the study area, close to the abandoned mine; Results of principal component analysis suggested that mining activities were the main anthropogenic pollution sources; (3) there was no non‐carcinogenic risk and a higher carcinogenic risk was found in adults than in children. Targeted remediation techniques are needed to mitigate carcinogenic risks posed by As and Cr. This study emphasized the necessity of assessment of soil TMs risk in abandoned gold mines with short‐term rehabilitation and offered crucial data utilized to optimize time parameters (short‐term) towards sustainable and efficient land development.

Plague and Trace Metals in Natural Systems.

All pathogenic organisms are exposed to abiotic influences such as the microclimates and chemical constituents of their environments. Even those pathogens that exist primarily within their hosts or vectors can be influenced directly or indirectly. Yersinia pestis, the flea-borne bacterium causing plague, is influenced by climate and its survival in soil suggests a potentially strong influence of soil chemistry. We summarize a series of controlled studies conducted over four decades in Russia by Dr. Evgeny Rotshild and his colleagues that investigated correlations between trace metals in soils, plants, and insects, and the detection of plague in free-ranging small mammals. Trace metal concentrations in plots where plague was detected were up to 20-fold higher or lower compared to associated control plots, and these differences were >2-fold in 22 of 38 comparisons. The results were statistically supported in eight studies involving seven host species in three families and two orders of small mammals. Plague tended to be positively associated with manganese and cobalt, and the plague association was negative for copper, zinc, and molybdenum. In additional studies, these investigators detected similar connections between pasturellosis and concentrations of some chemical elements. A One Health narrative should recognize that the chemistry of soil and water may facilitate or impede epidemics in humans and epizootics in non-human animals.

Biowaste-derived, nanohybrid-reinforced double-function slow-release fertilizer with metal-adsorptive function

Bio-based slow-release fertilizers (SRFs) have drawn significant attention in resolving food scarcity issues, improving nutrient utilization efficiencies, and preventing environmental pollution. However, current SRFs still need to improve their release profile, reduce the bioresource cost, and resolve multiple environmental issues e.g., different types of soil/water contamination. In this study, we propose an original concept to fabricate double-function and environmentally friendly SRFs with a controllable fertilizer release function and strong adsorption capability of trace metals in soils. The hypothesis is that a hydrophobic nanohybrid synthesized from the low-cost lignin biowaste and clay allows the well-dispersion in the bio-based polyurethane matrix derived from readily available agriculture byproducts. The exfoliation of nanohybrid in the biopolymer membrane not only blocks the path of hydrophobic fertilizer release but also possesses cationic ions absorption function. The results show that the nanohybrid has a strong metal adsorption capability and the synthesized nanohybrid-based controlled-release fertilizers (CRFs) exhibit excellent N release longevity (more than one month). These multiple-function CRFs promote plant growth in trace-metal contaminant soil in a cherry radish matrix study. This work also provides a detailed examination of the synthesis of lignin clay hybrid biocomposite, the encapsulation of fertilizers by the biocomposite membrane, the study of the nutrient release profile, and the metal adsorption mechanism. For the first time, biobased and low-cost CRFs provide multiple functions including controllable fertilizer release, strong metal adsorption capability for soil remediation, or trace metal re-utilization, which is expected to open a new door for large-scale utilization of CRFs in a nutrient contaminant soil environment.

Ecological risk of trace metals in soil from gold mining region in South Africa

The Witwatersrand basin in South Africa is one of the well-known gold mining regions worldwide. Plausibly, it is one of the sites in South Africa with the highest environmental impact emanating from trace metal contamination. This study assessed the concentration of Fe, S, Cu, Mn, Cr, Zn, Ni, Co, P, Mo using inductively coupled plasma optical emission spectrometry on 21 soil samples that were collected from 9 independently located historical gold mine tailings. The results revealed high mean concentration (mg/kg) for Fe (36,433.39) > S (5,071.83) > Cu (1,717,28) > Mn (612.81) > Cr (74.52) > Zn (68.67) > Ni (40.44) > Co (9.63) > P (3.49) > Mo > (2.74) in the samples investigated. Estimated degree of contamination by using contamination indices calculations showed that the sites surveyed are on average low to moderately contaminated with Co, Cr, Cu, Mn, Ni, S, and Zn. The trace metals that are most likely to cause ecological risk incorporate Mn and Cu, especially at Durban Deep. While the health risk assessment revealed a low ecological risk (Eri) of Cr, Ni, and Zn, the Eri estimates showed that the residents in the study area are prone to health risk mainly from the covetous effects of Cu (320 ≤ Eri). The residents of the study area are low income earners and the possibility that they can relocate is nonexistent. Thus, mitigation strategies are required to avoid eminent health risks and restraining housing developments near the tailing dumps.

Urban soils in a historically industrial city: patterns of trace metals in Pittsburgh, Pennsylvania

The distribution of legacy heavy metals in industrial city soils is not well documented. Therefore, fundamental details such as the ‘background’ (i.e., non-road/non-dripline) concentration of trace metals in urban soils are uncertain. While there has been a strong focus on mapping lead contamination near roads and residences, these studies are generally not placed in the context of the urban background. In this study, ‘background’ distributions of urban relevant trace metals: arsenic, cadmium, copper, lead, and zinc were mapped based on soil samples collected throughout Pittsburgh. Distinct spatial patterns were revealed: contamination is elevated in the eastern portion of the study area, driven by dominant wind patterns and historical coking activities in low-lying areas (paleochannels), areas subject to atmospheric temperature inversions that focus air contamination. The mixing analysis revealed spatial structures in contributions of industrial activities to metal soil contamination. In particular, regions enriched in cadmium relative to zinc (i.e., Zn:Cd<317) were located near historical coking operations, and areas enriched in lead relative to zinc (Pb:Zn>1) were located in areas with historical secondary lead smelters. These results suggest a comprehensive accounting of the trace metals concentrations in background soils has important implications for the assessment of exposure risk in populations residing in historically industrial areas. Relatively sparse sampling of background conditions in urban systems can indicate patterns of legacy contamination and attribute this contamination to historical sources.

Pollution and health risk assessment of trace metal in vegetable field soils in the Eastern Nile Delta, Egypt

The accumulation of trace metals in vegetable field soils is of increasing worry because of the potential health hazards and their detrimental effects on soil ecosystems. To investigate the state of trace metal pollution in vegetable field soils, 60 surface soil samples were collected from vegetable fields across the Eastern Nile Delta region, Egypt. The results concluded that the concentrations of Cu, Mn, and Ni were lesser than their corresponding background values, while the concentrations of Cd, Co, Pb, and Zn were exceeding their background values. The pollution indices showed that the studied soil experienced low to moderate contamination and the Cd and Cr contamination was serious. The hazard index values of nine trace metals signified that there was no adverse non-carcinogenic risk for adults and children. The carcinogenic risk of Cd, Co, Ni, and Pb for both age groups was within acceptable limits, while Cr had critical carcinogenic hazards for children. Overall, the quality of studied soils is relatively safe, although some samples impose serious pollution problems of Cd and Cr. Thus, properly monitored trace metals and soil management action should be applied to reduce further soil pollution in vegetable fields in the Eastern Nile Delta.

Spatial distribution and ecological risk assessment of potentially toxic metals in the Sundarbans mangrove soils of Bangladesh

At present, there are growing concerns over the increasing release of trace metals in the Sundarbans mangrove areas in Bangladesh due to nearby shipbreaking and metallurgical industries, untreated waste discharge, navigation activities, and other natural processes that deposit trace metals into soils. The current study investigated the spatial distribution, contamination level, and ecotoxicity of eight trace metals (Fe, Mn, Cu, Zn, Pb, Cd, Cr, Ni) in Sundarbans soils. Results revealed that all the trace metals except Cr were present in higher concentrations compared to Earth’s shale and/or upper continental crust. Principal component analysis and Pearson correlation showed strong positive correlations (p < 0.05) between Fe, Mn, Cu, and Zn; Ni with Mn and Cr. There were significant associations (p < 0.05) of % clay and total organic carbon (TOC) with Pb-Ni-Cr and negative correlations of pH with all the trace metals. The hierarchical cluster analysis grouped Pb, Ni, and Cd into one distinct cluster, suggesting they are derived from the same sources, possibly from anthropogenic activities. Geo accumulation index (I-geo), enrichment factor (EF), contamination factor (CF), and spatial distribution showed moderately polluted soils with Ni, Pb, and Cd (EF = 3–7.4, CF = 1–2.8, I-geo = 0–0.9) and low pollution by Zn, Cu, Fe, and Mn (EF < 3, CF < 1, I-geo < 0). The ecological risk index (RI) revealed that S-4 (RI = 114.02) and S-5 (RI = 100.04) belonged to moderate risk, and other areas posed a low risk (RI < 95). The individual contribution of Cd (25.9–73.7%), Pb (9.2–29.1%), and Ni (9.6–26.4%) to RI emphasized these metals were the foremost concern in the Sundarbans mangroves due to their long persistence time and high toxicity, even if they were present in low concentrations.

Impact of Seasonal Variations and Oil Activities on the Total Concentrations, Geochemical Fractions, And Human Health Problems of Trace Metals in Soils Within the Oil-Bearing Communities of South-South Region of Nigeria

The impacts of oil activities and seasonal variations on the total concentrations, geochemical fractions, and human health problems of trace metals in soils within oil-bearing communities of Akwa Ibom State, Nigeria were examined. Top soils were obtained from Eket, Onna, Esit Eket, and Ibeno local government areas between January and December, 2017. Samples were also collected from Etinan local government area of the State and used as the Control. The samples and Control were subjected to standard analytical procedures and analysed for their physicochemical properties and total metal concentrations. The modified BCR methods were employed for the speciation of metals. The findings revealed that the pH levels were higher during the dry season while, the electrical conductivity, organic matter, and cation exchange capacity of the studied soils were higher in the rainy season. The total mean concentrations of Pb, As, Cd, Cr, Fe, and V were higher in the dry season whereas, Ni was higher in the wet season. Though, their concentrations were within the acceptable limits. Generally, the concentrations of all the parameters in the studied soils were higher than at the control site. Pb, As, Ni, and V existed predominantly in the reducible fraction, Cd and Cr in acid extractable while, Fe existed mostly in the residual fraction in the studied soils. However, at the control site all the metals except Cd existed mainly in the residual fraction. The study showed that all the studied locations were highly contaminated with these metals and substantial seasonal variations were also recorded for the pollution indices. It was also noted that, seasonal changes and oil activities were the key factors affecting the quality of the studied soils. Daily intake rates for the metals through exposure to soil for both the young and old populations were within their required oral reference doses. The non-carcinogenic risks recorded for both populations were less than one. However, both populations were exposed to high Pb and the younger ones were more susceptible. The study revealed the influence of seasonal change and oil activities on the mobility and toxicity of metals in the studied soils.

Assessment of Trace Metal Content in Soils of Automobile Workshops around Bori Urban Area, Rivers State, Nigeria

This study was designed to assess the concentration of trace metals (Cr, Cd, Mn, Ni, Pb, Zn) in soils of automobile workshops around Bori Urban, Rivers State, Nigeria. Samples were collected from three auto mechanic workshops within the Bori urban area, Rivers State, Nigeria. The soil samples were prepared by standard procedures, and analyzed using the Atomic Absorption Spectrophotometer, AAS (Solaar Thermo Elemental Atomic Absorption Spectrometer-Model SE 71906). Detectable concentrations (mg/kg) of the metals, Zn, Mn, Pb, Cd, Ni and Cr were 4.05 ± 1.02, 9.64 ± 0.71, 13.39 ± 2.28, 2.46 ± 0.42, 2.86 ± 0.79 and 2.76 ± 0.99 respectively. The concentrations and contamination factors (CFs) across the three auto mechanic garages were of the order, Pb &gt; Mn &gt; Zn &gt; Cd &gt; Ni &gt; Cr and Cd &gt; Cr &gt; Ni &gt; Mn &gt; Pb &gt; Zn respectively while the pollution load index (PLI) values for the three auto mechanic garages were all greater than 1, indicating a decline in the soil quality for the three studied sites following the order station 3 &gt; station 1 &gt; station 2. The Geo accumulation index (Igeo) revealed that the soils were extremely contaminated by Cd and were all contaminated with trace metals when compared with regulatory standards such as WHO and world average values in shale. Therefore, regular monitoring of the soil in the studied sites be carried out to mitigate dangers implicit in the continued presence of the metals determined. &nbsp;

Landscape variability of riparian buffers and its impact on soil and water chemistry of an urbanized watershed

Water and sediment transport and redistribution around drainage ways are major riparian zone processes that affect soil chemistry and water quality of watersheds. This is more so for urbanized watersheds that generate more runoff and sediments which end up in the drainage ways. This study was done to evaluate the pedogeomorphic variability of the Aldridge Creek Watershed in Alabama, and to assess its impact on the water quality and soil properties of the watershed. Sampling locations along the creek were subdivided into five stream sites and geo-referenced. Soil samples from the riparian buffers and water samples from the creek were collected from upstream, midstream, and downstream sites of the watershed and analyzed for trace metal concentration and distribution. The trace metal concentration in soils of the riparian buffers varied from 20 to 34 µg g−1 for lead (Pb), 50–85 µg g−1 for zinc (Zn), 6–17 µg g−1 for copper (Cu), 11–18 µg g−1 for nickel (Ni) and 5–21 µg g−1 for arsenic (As). At all sites, Pb, Zn, Ni, Cu and As concentrations in the riparian zone locations were 7–67% higher than the upper slopes indicating that the riparian zone is a potential source or sink of trace metals along the flow pathways between the upper slope soils and the stream. While there were significant differences in the distribution of trace metals in soils between the upslope and riparian zone locations at the upstream, midstream, and downstream sites, there was no significant difference in the stream water trace metals concentration between the sites of the watershed.