Soil Pb Concentrations Research Articles

In Situ Bioremediation and Crop Growth Promotion Using Trichoderma Microbial Inoculant (TMI) Ameliorate the Effects of Cu Contamination in Lowland Rice Paddies

Soil contamination from mine tailings has impoverished the farming community of Mogpog, Marinduque, Philippines. Crop productivity has dwindled due to heavy metal (HM) contamination so the farmers’ incomes have consequently diminished. To help alleviate the constraints to crop productivity, a rice paddy experiment was conducted during the 2020 wet season in Mogpog, Marinduque to test the efficacy of using rice straw compost (RSC) and Trichoderma microbial inoculant (TMI) in increasing the yield and reducing the levels of soil copper and lead. The initial soil Cu content in the area was 379–512 mg kg−1, whereas the mean Pb concentration was 42 mg kg−1. Three treatments with three replicates each in a randomized complete block design were made: T0 (control), T1 (with RSC), and T2 (RSC + TMI). RSC was applied at 0.18 kg m−2. Mineral fertilizers were applied to all treatments at mean rates of 27.3 g m−2 for N and 16.17 g m−2 each for P and K fertilizers. After harvest, Cu, Pb, pH, organic matter (OM), and yield were measured. Data analysis showed that soil Cu levels had a significant, moderately negative correlation with yield. The combination of RSC and TMI in T2 significantly increased yield compared to the other treatments. Mean soil Cu and Pb concentrations in T2 were significantly lower than those in T1 and T0, respectively. Thus, using TMI together with RSC had a significant impact on yield accompanied by a reduction of total soil Cu and Pb concentrations. Possibly, TMI + RSC bioremediation and growth-promotion effects synergistically combined to produce large yield responses and remediation of HM in the soil, as discussed in the paper. Furthermore, rice grains harvested from these paddies have Cu content within the allowable limit for the element, whereas Pb was undetected in the rice grains.

Unraveling the source(s) and fate of Pb in urban soils and sediments of Ibadan metropolis using lead isotopes.

In this study an attempt was made to determine the source(s) and nature of Pb in environmental media of Ibadan, one of the largest cities in west Nigeria. Seventy-three samples comprising forty stream sediments, twenty-five soils and eight rocks samples were used for the study. Mineralogical compositions of the samples were determined by X-ray diffraction. The elemental constituents were determined using ICP-MS; while the Pb isotopes were determined using Sector-field ICP-MS. Sequential analysis of selected samples was carried out using a modified Tessier's five-step method. The dominant minerals identified were quartz, kaolinite, k-feldspar, and plagioclase. The concentrations (mg/kg) of Pb in soils, sediments, and rocks ranged from 13.00-470.00; 89.00-3288.00 and 2.90-20.30, respectively. The 204Pb, 206Pb, 207Pb, 208Pb ranged from 1.72-47.41; 30.69-779.68; 27.00-664.46 and 65.67-1642.27 in the soils and sediments, respectively, while they ranged from 0.02-0.07; 0.56-2.33; 0.38-1.56 and 1.19-4.13 in the rocks. Further evaluation of Pb concentration in the soils and sediments revealed high to extreme Pb pollution status, while the calculated Pb isotopic ratios (IRs) in the soil and sediments varied from that of the underlying bedrocks. The IRS in soils and sediments were characterized by low (1.161-1.172 and 1.127-1.200, and 2.281-2.444 and 2.276-2.474) 206/207 Pb and 208/207 Pb, while those of the rocks were high (1.456-1.753 and 2.647-3.149), indicating additional anthropogenic sourcing of Pb in the soils and sediments. The analyzed Pb revealed fractions more partitioned in the reactive geochemical phases with the Pb partitioned in the exchangeable (0.11-0.23%), carbonate (9.00-43.58%), reducible (8.32-13.53%) and organic/sulfides (42.78-82.45%) phases. This implies that there may be enhanced mobility of Pb in the environmental samples and ultimately bio-adsorption into living tissues in the environment.

Ecological Risk Evaluation and Source Identification of Heavy Metal Pollution in Urban Village Soil Based on XRF Technique

The rapid urbanization in China has resulted in significant differences between urban and rural areas. The emergence of urban villages is inevitable in this context, for which complex problems regarding land use, industrial management and ecological environment have arisen. This study performed a case study on a typical urban village, by assessing heavy metal pollution and ecological risk in soil. It detected a total of 80 basic units through portable X-ray fluorescence (XRF) instrument. A total of 25 high-risk contaminated points were selected, sampled and analyzed in laboratory as confirmation. The results showed the mean concentrations of Pb, Cu, Zn and Ni in soil were significantly higher than background values. Pb, Zn and Ni showed obvious pairwise correlation, and the high-value zones could be attributed to automobile traffic and industrial activities. In addition, the pollution problem is complicated by a combination of agricultural activities, the absence of clear division between different functional zones, as well as a general lack of environmental awareness. All of these lead to increased ecological risk and are a serios threaten to public health.

Cadmium and lead transfer factors to kale plants (Brassica oleracea var. acephala) grown in mountain agroecosystem and its risk to human health.

The aim of the present study is to assess soil Cd and Pb contamination in kale (Brassica oleracea var. acephala) production sites in mountain agroecosystem, as well as its potential risk to human health. The study was carried out within 24 kale-production sites located in mountainous region of Rio de Janeiro (Brazil). Soil, plant, and fertilizer samples were collected in all assessed properties. Pseudo-total and bioavailable soil Cd and Pb content and their concentration and amount accumulated in plants were analyzed. The recorded results were used to calculate the pollution index. Risks to human health associated with kale consumption were assessed by comparing the limits set by the Brazilian regulating agency and by calculating estimated daily intake (EDI), noncarcinogenic target hazard quotient (THQ), and carcinogenic risk factor (CRF). Soil Cd and Pb enrichment was observed. Inappropriate management adopted in the assessed sites and terrain slope and the intensive use of mineral (phosphate and potassium) and organic (poultry litter) fertilizers were the main factors contributing to increase soil Cd and Pb pseudo-total and bioavailability contents. Most Cd and Pb contents in leaves, in natura, exceed the maximum values set by the Brazilian regulating agency. The present EDI, THQ, and CRF results recorded for these metals were within the tolerable ranges.

Approaches to the development of environmental regional standards for the content of lead in the soils of the Black Sea coast of the Caucasus on the basis of an integral indicator of the biological state of the soil

Introduction. The Black Sea coast of the Caucasus is an actively developing region with a progressively growing tourism and recreation infrastructure. However, there are rare and unique soils, such as southern chernozems (chestnut), brown soils of dry subtropics, yellow soils. Lead (Pb) is a priority group of toxicant metals. However, the use of uniform, common standards of Pb content in all types of soils is impractical, since local regional ecological and geochemical features of soils are not taken into account when calculating them. Materials and methods. Soil contamination of 100, 1000, 10,000 mg Pb per 1 kg of soil was modelling, corresponding to 1, 10 and 100 MPC of this element in Germany and several other countries. After 30 days, changes in biological parameters (the number of bacteria, the activity of soil enzymes and length of roots of radish) were evaluated. To combine the values of the studied biological indicators with different units of measurement into one common indicator, an integral indicator of the biological state (IIBS) of the soil was used. Results. In most cases, there was an inhibition of the biological properties of the studied soils. According to the resistance to Pb pollution, the soils of the Black Sea coast of the Caucasus form the series including southern chernozems (Haplic Chernozems Pachic) (85) > cinnamonics typical (Haplicisols Eutric) (79) ≥ soddy-carbonate typical (Rendzic Leptosols Eutric) (77) ≥ cinnamonics leached (Haplic Cambisols Eutric) (76) ≥ cinnamonics carbonate (Haplic Cambisols Eutric) (74) = sod-calcareouses leached (Rendzic Leptosols Eutric) (74) = yellow soils (Albic Luvisols Abruptic ) (74) > brown forest weakly-unsaturated (Haplic Cambisols Eutric) (67) ≥ brown forest acid (Haplic Cambisols Eutric) (65) > brown forest acid podzolized (Haplic Cambisols Dystric) (59). On the base of the analysis of the degree of failure of environmental functions of soils, regional values of maximum permissible concentrations (rMPC) of Pb in soils of the Black Sea coast of the Caucasus are established. Regional values of maximum permissible concentrations of Pb for southern chernozem is 120 mg/kg, for cinnamonics typical, cinnamonics leached, cinnamonics carbonate, sod-calcareouses leached, sod-calcareouses typical soils and yellow soil - 100 mg/kg, for brown forest acid, brown forest weakly-unsaturated - 70 mg/kg, 65 mg/kg for brown forest acid podzolized. Limitations. The proposed maximum permissible concentrations of Pb in soils are applicable primarily to the territory of the Black Sea coast of the Caucasus. Conclusion. The proposed maximum permissible concentrations of Pb in the soils of the Black Sea coast of the Caucasus can be used by environmental, agricultural and scientific institutions.

Evaluation of Chelating Agents Used in Phytoextraction by Switchgrass of Lead Contaminated Soil.

Soil lead (Pb) contamination is a recognized environmental and global health problem. Phytoextraction of Pb using switchgrass (Panicum virgatum L.), a second-generation biofuel crop, is typically enhanced by soil chelation. The effectiveness of four different chelating agents, phytic acid (inositol hexaphosphate), citric acid, NTA (nitrilotriacetic acid), and EDTA (ethylenediaminetetraacetic acid) was examined in pot culture. Plants treated with EDTA (1 mM) showed significantly higher shoot Pb concentrations compared to control plants and plants treated with other chelates. Lead-solubility following phytoextraction was examined by soil washing using 0.01 and 0.05 M acetic acid as an extractant solution revealed no significant differences in Pb concentrations in soil among different chelate treatments and control. Furthermore, the effects of different concentrations (1, 2, 5 and 10 mM) of NTA on Pb phytoextraction of switchgrass were examined. Plants receiving 5 mM and 10 mM NTA had significantly higher foliage concentrations of Pb compared to plants treated with lower levels (1 and 2 mM) of NTA. Moreover, the effect of NTA application alone was significantly improved by a combined application of Triton X-100, an alkyl polyglucoside (APG); the Pb concentration in the foliage of switchgrass was more than doubled when treated with NTA combined with APG. The use of NTA combined with APG has great potential in improving phytoextraction efficiencies of switchgrass on Pb-contaminated soils.

Synergistic Repair Effect of Calcite-Based Passivator and Low-Accumulation Maize

In this study, a field experiment of soil passivation and low accumulation-crops was carried out for typical northern alkaline cadmium and lead compound-polluted farmland soil. Calcite was used as the main passivation material, and a small amount of slaked lime, zeolite powder, and biochar were combined to form a group passivation agent. The effects of passivators on soil physicochemical properties, bioavailability of the heavy metals Cd and Pb, and the yield and plant (stalk and seed) content of heavy metals Cd and Pb in low-accumulation maize were investigated under different grouping conditions of calcite+slaked lime (CL), calcite+zeolite (CZ), calcite+biochar (CB), and calcite+slaked lime+zeolite+biochar (CLZB). The results showed that:① all applications of passivating agent ensured the normal growth of maize and slightly increased the 1000 grain weight and maize yield. ② The effects of different calcite-based passivators on soil physical and chemical properties were different. The CL, CZ, CB, and CLZB treatments increased soil pH by 0.46, 0.25, 0.12, and 0.13 units, respectively, but had no significant correlation with soil fertility index (P>0.05). ③ DTPA leaching and ion exchange state contents of Cd and Pb in soil could be significantly reduced by different calcite-based combinations with passivators, and the reduction rates of Cd and Pb in DTPA leaching were 49.36% and 72.55%, respectively. The reduction rates of ion exchange Cd and Pb contents were 55.39% and 78.52%, respectively. ④ The contents of Cd and Pb in stems, leaves, and grains of low-accumulation maize were further reduced by different passivating agents. The contents of Cd and Pb in the stems and leaves of maize were reduced by 45.93% and 67.00% after CLZB treatment, and the contents of Cd and Pb in grains were decreased by 25.17% and 46.62%, respectively. Moreover, the contents of Cd and Pb in DTPA extraction and ion exchange states were significantly positively correlated with the contents of Cd and Pb in corn stems, leaves, and grains (P<0.01). The results showed that the combined use of combination passivators and low-accumulation crop varieties can obtain better restoration effects in the remediation of cadmium and lead combined-polluted farmland in the middle alkaline soil in northern China.

Change in the content of Pb and Cd mobile compounds in sod-podzolic soil at application increasing doses of mineral fertilizers

Results are presented of study of seasonal dynamics of lead and cadmium mobile compounds content in arable sod-podzolic soils of long stationary trial on application of increasing doses of mineral fertilizers. The studies revealed that the concentrations of mobile compounds of elements in the soil are insignificant and do not exceed MAC and background concentrations; this fact indicates the absence of anthropogenic contamination of the studied arable soils. During the growing seasons of two years of observation, the content of mobile Pb changed from 0.08 to 1.03 mg/kg in the first year and from 1.34 to 3.10 mg/kg in the second. The content of mobile Cd was from 0.04 to 0.10 mg/kg in the first and from 0.02 to 0.05 mg/kg in the second year of observation, respectively. During the growing season, the content of mobile forms of elements was very dynamic. The maximum content of mobile lead was characteristic of the initial phase of the growing season (end of May - June) at the most favorable combination of hydrothermal factors. Clear reliable patterns in changing the content of mobile forms of cadmium during the season were not revealed. The application of increasing doses of fertilizers leads to an increase in the acidity (decrease in pH) of the arable layer of soils. However, the influence of this factor on the dynamics and content of lead and cadmium was ambiguous, which indicates a complex influence of other unaccounted soil factors.

Distribution of heavy metals in surface soil near a coal power production unit: potential risk to ecology and human health.

Coal thermal power plants are the dominant factor in producing various hazardous elements in surrounding surface soil, resulting in a significant human health hazard. In the current study, the seasonal (pre- and post-monsoon) concentration of As, Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Ni, Pb, and Zn in surface soil around coal power production unit was analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). The possible health risks throughout multiple exposure routes, i.e., ingestion, dermal, and inhalation were estimated for adult and children. Furthermore, geo-accumulation index (Igeo), enrichment factor (EF), pollution factor (CF), ecological risk index, and pollution load index (PLI) were applied to interpret the environmental pollution in the study area. The geospatial distribution pattern was computed to understand the trace and hazardous element distribution in the surface soil. As a result, the concentration of Fe (mg/kg) in pre-monsoon (15,620) and post-monsoon (27,180), Ni (mg/kg) in pre-monsoon (19.8), and post-monsoon (81.7) was found above the standard limits of soil prescribed by the WHO and FAO. Enrichment factor was observed between 0.95-6948 (pre-monsoon) and 0.53-116.09 (post-monsoon). The ecological risk index was found moderate to considerable for As and Cd metals during both seasons. In addition, the average PLI value was observed high for both seasons indicating the contamination of the study area with heavy metals. Moreover, Igeo values for Fe, Mg, and As were found relatively high. Conversely, health risks to the human population were found within the USEPA acceptable limits.

Traffic emission dominates the spatial variations of metal contamination and ecological-health risks in urban park soil

Metals in urban park soil are closely related to traffic emissions, which adversely affect soil quality and human health. However, little is known about the quantitative impacts of traffic on the spatial variations of metals in park soil after the banning of leaded gasoline. Herein, concentrations of Cu, Pb and Zn in surface soil of four recreational parks of Sydney (Ashfield, Robson, Lamberts and Leichhardt) were measured to evaluate their spatial characteristics in contamination, ecological and health risks and relationships with traffic emissions. Contamination of metals are assessed by contamination factor (CF). Normalized metal concentrations (<63 μm) in the park soil were 24–614, 23–3520 and 99–3060 mg kg−1 for Cu, Pb and Zn, respectively, and CFs ranged from 1.4 to 207, whose variations inter- and intra-parks were related to traffic volumes. Traffic emission accounted for 72–84% of metals contamination in soil of Ashfield, Robson and Lamberts by sites, whereas the values were 25–70% for Leichhardt due to the absence of a surrounding arterial road. In Ashfield and Robson Parks, metal concentrations from traffic decreased exponentially with distance from arterial roads. Metals in Lamberts Park and in areas near arterial roads in Ashfield and Robson Parks may raise ecological risk, and traffic sources contributed to 61–81% of the risk. The ranges of ecological risk zones away from arterial roads and average daily traffic volumes showed an exponential relationship. Copper and Zn in soil of the four parks have no non-carcinogenic health risk for children and adults, and Pb has negligible health risk for adults. Lead in Lamberts Park and in sites near arterial roads of Ashfield and Robson Parks may raise non-carcinogenic risk for children (HI > 1) due to traffic emissions. These results emphasize the remarkable influence of traffic emissions on urban soil metal, which can be predicated quantitatively by traffic volume.

Metal(loid)s Spatial Distribution, Accumulation, and Potential Health Risk Assessment in Soil-Wheat Systems near a Pb/Zn Smelter in Henan Province, Central China.

To understand the influence of Pb/Zn smelter on surrounding environment, 110 soil and 62 wheat grain samples (62 paired samples) were collected nearby a Pb/Zn smelter in Jiaozuo City, Henan Province, China. The content and spatial distribution of metal(loid)s in the soil-wheat system, and the potential health risk via consumption of wheat grains were determined. Results showed that the average content of Pb, Cd, As, Cu, Zn, and Ni in soil were 129.16, 4.28, 17.95, 20.43, 79.36, and 9.42 mg/kg, respectively. The content of Cd in almost all soil samples (99.1%) exceeded the national limitation of China (0.6 mg/kg). Spatial distribution analysis indicated that atmospheric deposition might be the main pollution source of Pb, Cd, As, and Zn in soil. In addition, the average content of Pb, Cd, As, Cu, Zn, and Ni in wheat grain were 0.62, 0.35, 0.10, 3.7, 35.77, and 0.15 mg/kg, respectively, with the average Pb and Cd content exceeding the national limitation of China. The average bioaccumulation factor of these metal(loid)s followed the following order: Zn (0.507) > Cu (0.239) > Cd (0.134) > Ni (0.024) > Pb (0.007) > As (0.006). Health risk assessment indicated that the average noncarcinogenic risk of children (6.78) was much higher than that of adults (2.83), and the carcinogenic risk of almost all wheat grain is higher than the acceptable range, with an average value of 2.43 × 10−2. These results indicated that humans who regularly consume these wheat grains might have a serious risk of noncarcinogenic and carcinogenic diseases.

Oyster shell amendment reduces cadmium and lead availability and uptake by rice in contaminated paddy soil.

Contamination with cadmium (Cd) and lead (Pb) in rice and paddy soil threatens food safety and human health. This study determined the effects of oyster shell amendment (0, 6, and 12gkg-1) on the mobility and uptake of Cd and Pb by two rice plants (ZY18, japonica and DL5, indica) in contaminated paddy soil. Oyster shell amendment significantly increased the pH of soil and pore water, and decreased the DTPA-extractable Cd concentration in soil, but not the Cd concentration in pore water. Furthermore, the DTPA-extractable Pb concentration in rhizosphere soil was not significantly influenced by oyster shell addition. Application of oyster shell reduced the Pb concentration in pore water and Pb uptake by both cultivars, but excessive application (12gkg-1) resulted in Cd accumulation in tissues for ZY18. Furthermore, oyster shell addition significantly increased the dissolved organic carbon, calcium, and magnesium concentrations in soil pore water, and decreased glutathione and phytochelatin levels in roots, all of which alleviated heavy metal toxicity and improved rice growth. These results demonstrate that amendment with the appropriate amount of oyster shell, combined with rice cultivar type, could simultaneously reduce Cd and Pb accumulation in rice grown in heavy metal-contaminated soil.

Health Risks Due to Metal Concentrations in Soil and Vegetables from the Six Municipalities of the Island Province in the Philippines.

This paper investigated the health risks due to metal concentrations in soil and vegetables from the island province in the Philippines and the potential ecological risks. The concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in vegetables and soil in six municipalities of the province were analyzed using the Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) Perkin Elmer Optima 8000. It was recorded that all metal concentrations in the soil, except for Cd, exceeded the soil quality standard (SQS). The concentration of Fe and Mn was highest among other metals. The Nemerow synthetical pollution index (Pn) in all soil samples was under Class V which means severe pollution level. Likewise, the risk index (RI) of soil ranged from high to very high pollution risk. Most of the metal concentrations in the vegetables analyzed also exceeded the maximum permissible limit (MPL). All health hazard indices (HHIs) were less than 1, which means potential low non-carcinogenic risk to human population by vegetable consumption. However, it was found that concentration of Cr and Ni in vegetables is a potential health hazard having concentrations exceeding the maximum threshold limit. A 75% temporary consumption reduction of bitter melon, eggplant, sweet potato tops, and string beans produced from two municipalities may be helpful in reducing exposure to target metals. Additional studies are needed to confirm this recommendation. Spatial correlation analysis showed that six out of target metals had datasets that were more spatially clustered than would be expected. The recorded data are useful for creation of research direction, and aid in developing strategies for remediation, tools, and programs for improving environmental and vegetable quality monitoring.

Heavy Metal Concentrations of Soil, Rock, and Coal Gangue in the Geological Profile of a Large Open-Pit Coal Mine in China

Risk assessment related to heavy metals in mining areas is crucial to ensuring the sustainable development of regional ecosystems and protecting human health. However, almost all research on the impact of mining activities on environmental quality entails field monitoring of surface soils or soil profiles. Here, to compare the variety of heavy metal concentrations in the geological profile, 39 samples (including soil, rock, and coal gangue) were collected and analyzed from hundreds of meters underground in the Pingshuo coal mine (Anjialing coal mine, Antaibao coal mine, and Donglutian coal mine), which is the largest open-pit coal mine in China. The mean heavy metal concentrations of Cd, Hg, As, Pb, Cr, Cu, Zn, and Ni in soils were 0.15 mg/kg, 0.02 mg/kg, 13.70 mg/kg, 27.12 mg/kg, 70.89 mg/kg, 26.10 mg/kg, 79.88 mg/kg, and 37.68 mg/kg, respectively; most of these metals were more concentrated in the soil samples than in the rock and coal gangue samples. A potential ecological risk assessment indicated that As, Pb, Cr, Cu, Zn, and Ni in all samples showed low risk, while the ecological risk degrees of Cd and Hg were higher and contributed most to the total risk index (RI). The highest E_r^i value (92.94) for Cd was found in rock samples, contributing to approximately 55.18% of the to tal RI. For Hg, four rock sampling sites had the highest E_r^i values (427.70, 270.78, 198.96, and 188.70), contributing approximately 68.36–88.07% of the total RI. Ranked after soil (0.15 mg/kg), limestone and shale showed high mean Cd concentrations (both 0.13 mg/kg). The highest mean concentration was found in coal gangue samples (0.1 mg/kg). Compared with the other types of samples, the mean concentrations of Cr, Cu, and Ni in soils, limestone, and mudstone were relatively higher. At different sites, heavy metal concentrations varied greatly at different depths, owing to diverse sample types and rock types. Correlations between heavy metals and soil nutrients indicated that N and P were closely correlated with heavy metals. Comparing the proportions of different heavy metals in various types of samples showed that heavy metals in soils were extremely similar to those in limestone, mudstone, and shale, implying that soils might indirectly inherit their features from their parent material.

Risk assessment of trace elements accumulation in soil-herbage systems at varied elevation in subalpine grassland of northern Tibet Plateau.

Ecological environment of remote grassland has become a problem in many countries due to mining, tourism, grazing, and other human activities. In this study, a total of 15 pairs of soil-herbage samples were collected in the northeast of the Tibet Plateau to study the relationship between physicochemical properties and content of trace elements in soils at different elevation, and to examine the accumulation and fractionation of heavy metals in soil-herbage systems. In addition, the ecological risk of the subalpine grassland was also assessed. The average concentrations of Hg, As, Cu, Zn, Pb, Cd, Cr, and Mn in soil were higher than their background values of Gansu soil, but the average concentrations of these heavy metals in herbage satisfied Hygienical Standard for Feeds. The speciation analysis of heavy metals in soil indicated that the exchangeable content of heavy metal was very low, except Pb, Cd, and Mn. There was a linear relationship between pH, CaCO3, total phosphorus (TP), organic matter (OM), concentrations of Hg, As, Zn, Pb, Cr, and Mn in soils, dry weight of herbage, and elevation, while there was a quadratic curve trend between Cu, Cd in soils, and elevation. The results of risk assessment showed that there was no obvious ecological risk in the study area.

Health Risks Assessment of Heavy Metal Pollution in the Soil-Crop System from an E-Waste Dismantling Area

Soil is an essential resource for agricultural production. In order to investigate the pollution situation of heavy metals in the soil-crop system in the e-waste dismantling area, the crop and soil samples (226 pairs, including leaf vegetables, solanaceous vegetables, root vegetables, and fruits) around the e-waste dismantling area in southeastern Zhejiang Province were collected. The concentrations of Cd, Cu, Pb, and Cr were determined. The average concentrations of Cd, Cu, Pb, and Cr in soils were 0.94, 107.79, 80.28, and 78.14 mg kg-1, respectively, and their corresponding concentrations in crops were 0.024, 0.7, 0.041, and 0.06 mg kg-1, respectively. The transfer capacity of leaf vegetables was significantly higher than that of non-leaf vegetables, and the accumulation of four heavy metals in crops tended to be Cd > Cu > Cr/Pb. The pollution index’s results revealed that the soil pollution degree under different land uses ranked as root vegetables soil > leaf vegetables soil > solanaceous vegetables soil > fruit soil. The carcinogenic and non-carcinogenic risks of heavy metal exposure were ranked as food intake > accidental ingestion > dermal contact > inhalation. The comprehensive non-carcinogenic risk was ranked as Cr > Cd > Pb/Cu. Our results could be used to provide useful information for further crop cultivation layout in the study area, which can guarantee the local residents’ health and food safety.

Monitoring the Concentrations of Cd, Cu, Pb, Ni, Cr, Zn, Mn and Fe in Cultivated Haplic Luvisol Soils Using Near-Infrared Reflectance Spectroscopy

Monitoring the Concentrations of Cd, Cu, Pb, Ni, Cr, Zn, Mn and Fe in Cultivated Haplic Luvisol Soils Using Near-Infrared Reflectance Spectroscopy

Effect of iron slag, zeolite, and Piriformospora indica fungus on mazut biodegradation in a heavy metal-polluted soil that was amended with cow manure under canola cultivation

Aims: Petroleum hydrocarbon pollution in the soil is one of the important problems in environmental studies. Thus, this research was conducted to evaluate the effect of iron slag, zeolite, and Piriformospora indica fungus on mazut biodegradation in a heavy metal-polluted soil that was amended with cow manure under canola cultivation. Materials and Methods: Treatments included application of zeolite (0% and 2% [W/W]) and iron slag enriched cow manure (0, 15, and 30 t/ha) in a mazut-polluted soil (0%, 4%, and 8% [W/W]) under canola cultivation in the presence of P. indica. After 70 days, plants were harvested and the mazut biodegradation in the soil was measured. In addition, the soil and plant Pb and Cd concentration was measured using atomic absorption spectroscopy. Findings: Soil application of zeolite (2% [W/W]) in the mazut-polluted soil (4% [W/W]) significantly increased the mazut biodegradation in the soil by 13.1%. In addition, plant inoculation with P. indica significantly increased the mazut biodegradation in the soil and decreased the plant Pb and Cd concentration. Soil application of cow manure at the rate of 15 and 30 t/ha has also increased the mazut biodegradation in the soil by 14.1% and 17.4%, respectively. Conclusion: Using iron slag enriched cow manure and zeolite had additive effects of increasing the mazut biodegradation in the soil and decreasing the soil and plant heavy metal concentration. However, these changes depend on the plant physiology and soil physic-chemical properties that should be considered in different studies.

SEASONAL VARIATION IN TRACE METAL CONCENTRATIONS IN SOIL AND VEGETABLE SAMPLES FROM SELECTED MINING AREAS IN JOS SOUTH AND BARKIN LADI LGA, PLATEAU STATE

In this study, the seasonal variation in concentrations of the trace metals Cu, Zn, Pb, Cd, As Ni and Co in soil and vegetable samples from farms in some mining areas in Jos South and Barkin Ladi LGA, Plateau State were investigated in two major seasons (dry and wet). This was done to assess the pollution status of the farms and hence, the safety levels of the vegetable samples. The samples were treated and digested using 10 cm3 HNO3 and 30 cm3 HCl in the ratio of 1:3. Trace metal concentrations were determined using the PG-990 model atomic absorption spectrophotometer. Analytical results of soil samples from mining areas indicated higher concentration of Cu and As for both seasons than the values reported by the FAO/WHO (2007). Similarly, the metals Cu (15.12±1.50 mg/kg), Zn (76.45±2.40 mg/kg), Pb (23.75±1.35 mg/kg), Cd (3.69±0.15 mg/kg), Ni (17.80 ±0.15 mg/kg) and Co (28.14+1.35 mg/kg) showed high concentrations in dry season than wet season. Comparing the vegetable samples, spinach was found to accumulate high concentration of trace metals than tomato and Irish potato. In general, the levels of trace metals in soil and vegetable samples were higher in dry season than in wet season. The levels of Pb, Cd, As, Ni and Co were significantly above the critical toxic level in vegetables as reported by WHO/FAO (2007), while Zn and Cu occurred within the acceptable limit for both seasons.

Determination of Heavy Metals in Soil around Amasoma Community in Bayelsa State, Nigeria

Aims: Anthropogenic activities such as crude oil exploration and exploitation has led to the suspicion of heavy metals contamination in the study area. This study investigated the concentration of zinc, nickel, lead and cadmium in the soil extracted from the area where Scent Leaf (Ocimum gratissimum) and Pawpaw tree (Carica papaya) are grown in Amassoma community, Bayelsa State, Nigeria.&#x0D; Study Design: Scent leaf (Ocimum gratissimum) and Pawpaw tree (Carica papaya) soils from where these plants are grown were randomly collected for heavy metal analysis from within Amassoma community in Southern Ijaw Local Government Area of Bayelsa State, Nigeria&#x0D; Place and Duration of Study: This study was carried out in Biological Sciences, Faculty of Science, Niger Delta University, Wilberforce Island, Amassoma, Bayelsa State between March 2019 to September 2019&#x0D; Methodology: Scent leaf (Ocimum gratissimum) and Pawpaw tree (Carica papaya) soils were digested and analyzed for heavy metals using Atomic Absorption Spectrophotometer (AAS, model S471096). The method used was wet-ashing method for the analysis.&#x0D; Results: the concentrations of Lead (Pb), Nickel (Ni), Cadmium (Cd), and Zinc (Zn), in pawpaw soil and scent leaf soil. From the sample data analysis, the average lead (Pb) contents in pawpaw soil and scent leaf soil were 1.283 mg/kg and 1.44 mg/kg respectively. The average Cadmium (Cd) in pawpaw soil and scent leaf soil were 0.256 mg/kg and 0.256 mg/kg respectively. The average Nickel (Ni) compositions in pawpaw soil and scent leaf soil were 4.71 mg/kg and 5.09 mg/kg respectively. While the Average Zinc (Zn) in pawpaw soil and scent leaf soil is 2.280 mg/kg and 2.160 mg/kg respectively. The soil analyzed for heavy metals were below the threshold target values recommended by the WHO.&#x0D; Conclusion: The Scent leaf (Ocimum gratissimum) and Pawpaw tree (Carica papaya) soils analyzed for heavy metals were below the permissible limit recommended by WHO for soil safety. The result from the present study revealed that there may not be soil contamination as a result of the selected heavy metals, however, It is recommended that caution should be taken in regulating the anthropogenic activities that may tend to elevate the level of heavy metals in the surrounding to prevent contamination of soil over time which could be detrimental to the health of the populace.