Soil Pb Levels Research Articles

Application of PS2M Aptamer as Receptor Layer for Electrochemical Detection of Lead Ions.

Since lead can cause severe effects on living organisms' health and life, the regular monitoring of Pb levels in water and soil is of particular significance. Recently, it was shown that lead ions can also be detected using affinity-based biosensors, namely, using aptamers as recognition elements. In most cases, thrombin binding aptamer (TBA) was utilized; however, there are more examples of DNA aptamers which could also serve that purpose. Herein, we present studies on the electrochemical detection of lead ions using PS2M aptamer, which contains several guanine nucleotides, as the receptor element. Firstly, the method of aptamer-based layer fabrication was optimized along with the choice of a redox active indicator, which was a source of current signal. The experiments revealed the possibility of lead ion detection from 50 to 600 nM, which covers the range below and above the maximum accepted limit stated by US EPA (72 nM). Moreover, the sensing layer exhibited high selectivity towards lead ions and was successfully applied both for the analysis of tap water spiked with Pb2+ ions and as a miniaturized sensor. Finally, stability and regeneration studies on the aptamer-based receptor layer were executed to confirm the utility of the elaborated tool.

Surface soil-dust contamination of Phalaris arundinacea grown on former lead mine sites: Implications for biomass use, phytoremediation and phytomanagement.

This study evaluated the contribution of soil dust deposited on the surface of reed canary grass (Phalaris arundinacea) grown on historic lead (Pb) mine sites to the overall contamination of the biomass, with implications for phytoremediation, valorization and utilization. By applying a novel combination of imaging of plant material using X-ray computed tomography (XCT) and scanning electron microscopy (SEM), with washing experiments and bulk analysis, the research aimed to distinguish between (a) Pb uptake through biological processes (phyto-extraction), and (b) surficial dust and physical entrapment of Pb-rich dust on plants cultivated in contaminated soils (surface-contamination). The study established the presence and distribution of Pb-rich particles, which were difficult to remove even by means of sequential washing in 1M hydrochloric acid and surfactant. Analysis confirmed that the majority of Pb contamination was due to dust, but with significant levels remaining even after intense washing. This questions the effectiveness of phytoremediation in reducing bioavailable soil Pb levels through phyto-extraction, compared to achieving mechanical stabilization or reducing dispersion during phyto-management, and may represent a challenge to the viability of subsequent processing and use of the biomass product. Site-specific variations in contamination levels were observed, underscoring the influence of both local environmental conditions and plant morphology on dust accumulation. These observations highlight the necessity for standardized washing protocols to be adopted and for better reporting of the actual washing methods used in phytoremediation research, so as to correctly assess levels of contaminant uptake and actual remediation. The conclusion is that residual surficial dust contamination of biomass may have been overlooked in many previous phytoremediation studies and as a consequence the reported phyto-extraction potential has been over-estimated.

Contamination and health risk assessment of potentially toxic elements in rice (Oryza sativa) and soil from Ashanti Region.

Anthropogenic activities release potentially toxic elements into the environment, which contaminate the food chain. The main objective of this research was to analyze the concentrations of As, Cd, Cr, Hg, and Pb in rice grains and soils, establish their correlation and transfer factors between soil and rice grains as well as evaluate their human health risk from consumption of rice cultivated in the Asante Akim area. The levels of As, Cd, Cr, Hg, and Pb in soil and rice samples were assayed using an Agilent 7700 Series inductively coupled plasma-mass spectrophotometer. The mean heavy metal content in soil was 7.5, 0.52, 0.47, 1.30, and 8.69mg/kg for As, Cd, Cr, Hg, and Pb, respectively. Mean levels of the potentially toxic elements in rice were 0.082, 0.27, 0.48, 0.028, and 0.14mg/kg for As, Cd, Cr, Hg, and Pb, respectively. Soil pollution indices showed that the soils were unpolluted with the potentially toxic elements studied. The concentrations of the potentially toxic elements in rice were below the maximum allowable concentration (MAC) recommended by the Codex Alimentary Commission except Cd which was marginally higher than the MAC. Dietary exposure to the elements to consumers was assessed by comparing the estimated daily intake (EDI) to the provisional tolerable daily intake (PTDI). The estimated daily intake values for As, Cd, Cr, Hg, and Pb were 1.45 × 10-4, 4.8 × 10-4, 8.5 × 10-4, 4.95 × 10-5, and 2.4 × 10-4, respectively. The HQ for all the potentially toxic elements was less than the permissible value of 1, suggesting that the consumption of rice from the study area constitutes no potential non-carcinogenic health risk to the population. This study is unique because the risk is evaluated from rice that is directly consumed, and this gives a clearer picture of the risk to humans. Regular monitoring studies should be conducted to ascertain the levels of heavy metals in rice cultivated in the area since heavy metals can accumulate and the concentrations could increase to toxic levels with time.

Heavy metal contamination in eggs on poultry farms and ecological risk assessment around a gold mine area in northern Thailand

The aim of this study was to analyze and compare the Hg, Pb, Cd, and Mn levels in egg feed, soil, and water among laying hens, laying ducks, and free-grazing duck farms in contaminated and uncontaminated areas. This study revealed that the Hg concentration in the eggs of free-grazing ducks was significantly greater than that in the eggs of laying hens and ducks in both contaminated and uncontaminated areas. However, the Pb and Mn levels in the eggs of laying ducks and free-grazing ducks were significantly greater than those in the eggs of laying hens in the contaminated area. Unfortunately, the Hg, Pb, Cd, and Mn concentrations in the feed, soil, and water from these three farms in both areas were not significantly different (P > 0.05). Hg and Cd were confirmed to be enriched in the egg albumin fraction, while Pb and Mn were found mainly in the egg yolk. However, egg consumption from free-grazing duck farms was the riskiest to Hg, Pb, and Mn contamination in the contaminated area. Additionally, the ecological risk factor (ER) in the soil revealed that all the farms were at considerable to high environmental risk for Cd except for Hg and Pb. Although the potential ecological risk index (RI) indicated a moderate risk for all farms in both contaminated and uncontaminated areas, these results were not consistent with our hypothesis. Therefore, the information gained in this study could be useful for setting up mitigation strategies and making decisions about public health concerns related to health hazards, especially for ecological risk assessments of heavy metal contamination.

Microbial strategies for lead remediation in agricultural soils and wastewater: mechanisms, applications, and future directions.

High lead (Pb) levels in agricultural soil and wastewater threaten ecosystems and organism health. Microbial remediation is a cost-effective, efficient, and eco-friendly alternative to traditional physical or chemical methods for Pb remediation. Previous research indicates that micro-organisms employ various strategies to combat Pb pollution, including biosorption, bioprecipitation, biomineralization, and bioaccumulation. This study delves into recent advancements in Pb-remediation techniques utilizing bacteria, fungi, and microalgae, elucidating their detoxification pathways and the factors that influence Pb removal through specific case studies. It investigates how bacteria immobilize Pb by generating nanoparticles that convert dissolved lead (Pb-II) into less harmful forms to mitigate its adverse impacts. Furthermore, the current review explores the molecular-level mechanisms and genetic engineering techniques through which microbes develop resistance to Pb. We outline the challenges and potential avenues for research in microbial remediation of Pb-polluted habitats, exploring the interplay between Pb and micro-organisms and their potential in Pb removal.

Hazards of toxic metal(loid)s: Exploring the ecological and health risk in soil–crops systems with long-term sewage sludge application

Sewage sludge (SS) is commonly used as agricultural fertilizer worldwide. However, the toxic metal(loid)s in SS raises concerns about soil contamination and the potential risks to human health. This study, conducted since 2007 on the North China Plain, examines the impact of SS use on crops. An experiment was designed with five treatments: conventional fertilization (CK) and four levels of SS application (W1, W2, W3, and W4: 4.5, 9.0, 18.0, and 36.0 t ha−1, respectively). Soil concentrations of eight toxic metal(loid)s (Zn, Cu, Cr, Cd, Ni, Pb, As, and Hg) were analyzed to assess pollution risk using various indices. Health risks associated with maize and wheat grains were also evaluated. Additionally, the impact of long-term SS application on crop yield, soil quality, and human health within a wheat-maize rotation system was examined. SS application increased wheat and maize yields by 5.37 to 19.08 % and 6.97 to 17.94 %, respectively, across treatments W2 to W4. Despite the toxic metal(loid)s in the grains remaining within safe limits, their concentrations showed an upward trend, especially under the W4 treatment. Moreover, SS application significantly increased the soil Zn, Cu, Cr, Cd, Pb, and Hg levels (P < 0.05) without exceeding the national standards. The geo-accumulation index values revealed rising pollution levels for Zn, Cu, Cd, and Hg, which shifted from no contamination to moderate contamination and then to moderate-to-high contamination, yet the overall pollution level remained safe. Soil ecological risks increased from moderate to serious, with Hg posing the greatest risk, particularly under the W4 treatment. Long-term crop intake from the area significantly exposed children and adults to As, contributing 42.12 % and 34.62 % to hazard index (HI), respectively. The HI values for toxic metal(loid)s in these grains surpassed one in both age groups, suggesting health risks from long-term SS cultivated crops.

Growth and Phytochemistry of Cymbopogon citratus Stapf Inoculated with Plant Growth-Promoting Bacteria under Different Lead Levels.

This study aimed to investigate the phytochemistry of lemongrass (Cymbopogon citratus) inoculated with Azospirillum brasilense and grown in lead (Pb)-contaminated soil to assess its responses to inoculation under different Pb levels. The experimental design was completely randomized in a 2 × 5 factorial scheme: two levels of A. brasilense (absence or presence) and five Pb levels. After four months of treatment, the following were analyzed: total and reducing sugars, total phenolic content, flavonoids, antioxidant activity, antioxidant enzymes, proline, and essential oil (EO) content and composition. Soil Pb levels and A. brasilense inoculation affected phytochemicals in lemongrass plants. Azospirillum inoculation reduced total sugars in the roots at all soil Pb levels, while increasing Pb levels favored a rise in sugar contents. There was an increase in flavonoid content in treatments associated with Pb and inoculated with A. brasilense. Antioxidant capacity was lower at lower Pb levels, regardless of bacterial inoculation. Enzymatic response was mainly affected by Pb concentrations between 50 and 100 mg kg-1 soil. EO content was influenced by soil Pb levels, with higher EO production at 500 mg Pb kg-1 soil and without A. brasilense inoculation. Overall, lemongrass cultivation in Pb-contaminated areas can be an alternative to phytoremediation and EO production for the industry.

Lead exposure and its relationship with fecal cortisol levels in black howler monkeys (Alouatta pigra).

Efficiently detecting early environmental threats to wildlife is vital for conservation. Beyond obvious dangers like habitat loss or deforestation, our study focuses on one of the most hazardous toxic metals for wildlife: lead (Pb). Pb is a widespread, cumulative, and insidious environmental pollutant that can trigger a wide range of physiological, biochemical, and behavioral disorders. In fact, Pb can cause permanent dysfunction of the major stress system, the hypothalamic pituitary adrenal (HPA) axis. We analyzed Pb and cortisol concentrations in fecal samples from Alouatta pigra in southern Mexico. Fecal samples were collected across six sites categorized as free-ranging (n = 65; conserved and disturbed) and from captive animals (n = 58). Additionally, we collected soil samples (n = 35). We found that Pb was present in 28% of fecal samples and 83% of soil samples. There was a positive relation between fecal and soil Pb levels, and fecal Pb concentration was negatively associated with cortisol levels. However, the claim of Pb being a direct interference with HPA axis requires further investigation. Given our findings, assessing wildlife exposure can be a valuable tool for understanding potential Pb exposure levels in the environment and its possible implications for human health. It can also serve as an early warning system of these consequences.

Characterization of soil trace metal pollution, source identification, and health risk assessment in the middle reaches of the Guihe River Basin.

The natural environment, as well as human production and survival, is intrinsically dependent on soil. This study comprehensively assessed the pollution status, health risks, and sources of trace metals in the middle reaches of the River Gui Basin (MRGB) utilizing the geoaccumulation index, potential ecological risk index (PERI), and human health risk evaluation method. The findings of this study provide the following key insights: (1) only Cu and Pb levels in the MRGB soils did not exceed the background values established for soils in Weifang City (WFC). (2) The geoaccumulation status in most areas of the MRGB ranged from non-polluted to mildly polluted, with the overall ecological risk classification ranging from mild to moderate. (3) The cumulative non-carcinogenic risk for humans in the MRGB remained within acceptable limits, whereas the carcinogenic risk indices fell within tolerable levels. Oral ingestion emerged as the primary exposure pathway for both non-carcinogenic and carcinogenic health risks. (4) Cu, Zn, Ni, and Cr concentrations in MRGB soils primarily stemmed from natural sources associated with parent rocks, with Zn exhibiting additional influence from anthropogenic factors. In contrast, Pb, Cd, Hg, and As concentrations were predominantly driven by anthropogenic sources. Although the soils in the MRGB typically exhibited mild-to-moderate contamination levels, the contamination levels of Hg and Cd were notably more severe. As and Cr were significant health hazards. Most soil contamination sources are attributed to anthropogenic factors, warranting heightened attention from the relevant authorities.

Ecological Risk Assessment of Potentially Toxic Metals in Arable Soils around Adudu Lead – Zinc Mine, North-Central Nigeria

Mining is a major source of toxic heavy metals into the soil when mine wastes are discharged into the nearby farmlands used for the cultivation of food crops. This study investigated the influence of Pb–Zn mining on the quality and ecological risk of arable soils around active mining sites in Adudu, Nasarawa State, Nigeria. Composite soil samples were collected at 0–20 cm depth, pulverized, and analyzed for heavy metal (Al, As, Cr, Cu, Fe, Mn, Pb, and Zn) concentration using X–ray fluorescence technique. Enrichment factor, geo–accumulation index, improved Nemerow index (IIN), contamination factor (CF), degree of contamination (Cd), pollution load index (PLI), and ecological risk assessment (ERA) were used to evaluate the effect of the mining activities on the environment. Results showed elevated levels of Pb, Zn, Cu, Fe, Mn, and Cr in arable soils around the mine and lower levels of these metals in the control soil. IIN, Cd, and PLI showed that the mine and the nearby arable soils were the most deteriorated, and soil quality improved away from the mining vicinity. ERA revealed that the mine and the closest arable soils (sites F1 and F4) have significant to high ecological risk index as a result of the dominant presence of Pb, Zn, and Cu at the sites. Thus, arable soils which are disposal channels for mine wastes are not good for growing food crops. This study clearly shows that Pb–Zn mining activities introduced heavy metals into the arable soils surrounding the mine.

Anthropogenic effect on the pedochemical variability of potentially toxic elements at the vicinity of an Antarctic research station.

Antarctica represents an isolated continent devoted to conservation and scientific research, although it accumulates records of increasing anthropic contamination. The historical continued use of fuel for power generation in Antarctic settlements is a potential source of toxic elements to the soil. We investigate Cd, Cr, Cu, Mn, Ni, Pb, V and Zn levels in surface soils in the vicinity of the Henryk Arctowski Antarctic Station, aiming to identify anthropic effects on their local pedochemical variability. Pollution indices were used and compared to evaluate possible cumulative anthropic impacts, whereas correlation analyzes were explored to identify potential sources of contamination. High concentrations of Pb and Zn were locally observed near fuel tanks and machinery facilities. Correlation and principal component analysis suggest that old fuel tanks, vehicle traffic and machinery disturbance are key, and contrasting, sources of contamination. Among the eight indices we compared, Enrichment Factor and Modified Degree of Contamination were chosen, showing very high enrichment for Pb and moderate for Zn. All other elements presented minimal or null enrichment. The evidence of potentially toxic elements enrichment on Antarctic soils associated with the long-term occupation of Antarctic research stations highlights the need for further monitoring and mitigation measures, especially in energy-generating systems.

Assessment of spatial distribution of lead in soils around an active military shooting range

Abstract In this study, the extent of Pb contamination around an active military shooting range is re-assessed to ascertain current contamination status comparatively to data’s reported 20 years ago. This is because lead bullet disintegration and mobility takes several years and extensively affects levels of soil-Pb contamination. A total of 120 topsoil samples were collected within the impact area (front) and non-impact area (back) for Pb determination. High concentrations of Pb were found at impact berm both front (28940±2996 μg/g) and back (775±128 μg/g). Spatial distribution of contamination reflects the distances from berm. Soil-Pb contamination around non-impact area was notable at back berm through to 100 m distance with significant difference in Pb, Cr, Ni and Zn levels. Concentration of Pb at berm was observed to have increase five-fold over a period of about twenty years from previous study with accumulation factor of about 1000. Principal component analysis PCA indicated 67 % of total metal load of range soil was majorly from impact areas of the berm. The correspondence analysis relay plot shows pollution order of Pb &gt; Ni &gt; Cd &gt; Cr &gt; Zn &gt; Cu. This confirms soil contamination especially around the impact area, i.e. impact berm and firing lines and non-impact area at 0 m, 10 m, 50 m and 100 m. Environmental consequence of high soil-Pb levels within the range especially non-impact areas utilized for farming activities will leave much to desire. Hence, extensive and continuous monitoring is needed. However, remediation through appropriate soil washing technique could reduce Pb levels and improve soil condition regardless of age.

Effect of Bio-Organomineral Fertilizer on Soil Chemical Properties and PB Content of Industrial Waste Polluted Soil

Rancaekek Sub-district is one of the agricultural centers in Bandung Regency, Indonesia, which is currently experiencing land conversion into an industrial area. The industrial activities produce waste containing heavy metal lead (Pb), which if not treated can pollute the soil and surrounding waters. Efforts to overcome soil pollution are through fertilization. The purpose of this study was to determine the effect of the dose and incubation time of Bio-organomineral fertilizer with Bacillus subtilis biological agent on improving soil chemical properties and reducing soil Pb levels. This study used a two-factor Factorial Randomized Block Design, namely the dose and incubation time of Bio-organomineral fertilizer. The results showed that the combination of Bio-organomineral fertilizer dose of 225 kg.ha-1 and an incubation time of 30 days was able to increase soil K-potential. The independent factor of Bio-organomineral fertilizer dose had a significant effect on increasing soil pH. The independent factor of incubation time had a significant effect on reducing soil Pb levels. In particular, there was an interaction between the dose and incubation time of Bio-organomineral fertilizer on soil K-potential.

Calculating Health and Ecological Risks of Pm2.5, and Lead Pollutants Exposure Among Communities Due to Cement Plant Emission, Maros Indonesia 2023

Purpose: This study assessed the possible impacts of PM 2.5, and Lead exposures on populations and ecology as a result of breathing contaminated air and contaminated soil exposure near the Bosowa cement mill in Maros, Indonesia in 2023. Theoretical Framework: Anthropogenic and lithogenic activities can lead to an increase in the amount of heavy metals in ambient air and in soil as well as a decline in the quality of the environment. Methods: The magnitude of PM 2.5, and Lead were measured during the period of April-June 2023. The level of PM 2.5 on ambient air sampling was conducted using direct reading HAZ-Dust EPAM 5000, uses a laser analyzer in order to measure particulate level matter. The result or time-weighted average (TWA) value directly can be read after the measurement at the site. Then meteorological data was collected from Indonesia Agency for Meteorology, Climatology, and Geophysics online database. Then, lead concentrations on surface Soil were taken and analyzed using AAS. Potential ecological and human health risks. Results and Conclusion: Station 9 had the highest level of PM 2.5 concentration (98.23 g/m3), followed by station 11 (97.14 g/m3). In comparison, station 3 had the lowest amount at (31.24 g/m3) and station 5 had the highest level at 32.91 g/m3, respectively. Additionally, station 10 had the greatest amount of Pb air particulate concentration, followed by station 11 with 88.33 g/m3, while station 6 had the highest level of Pb in surface soil, at 196.90 and 166.91 mg/g, respectively. In comparison, station 15 had the lowest amount at (54.76 mg/g), and station 14 had the highest level at (88.87 mg/g), respectively. The findings implied that both PM2.5 and Pb have medium risks to exposed communities. It could be valuable for managing the air quality due to the industry activities and soil remediation in residential areas. Research Implications: Exposure to PM2.5 and Pb air particulates is more hazardous to the environment than it is to human health. PM2.5 and Pb levels in the soil and air had accumulated. More thought should be given, and remedial action should be set to lowering PM2.5 and Lead concentrations and their consequences on the environment in the research region. Originality/value: This study encompasses relevant study that have conducted between 1990 and 2022 and lucidly summarizes the magnitude of PM2.5 and Pb in the air and soil, in addition this research emphasize the risks of environmental and human due to the PM2.5 and Pb Contamination acutely and chronically.

Lead and lead isotopes as tracers of soil contamination in southwestern Nigeria

The association of soil Pb levels has received considerable attention in recent times in developing countries like Nigeria due to its human health and environmental effect. Unfortunately, the sources of the pollutant has not been resolved for environmental health interest. Therefore, the aim of this study is to trace the sources of Pb contamination using the isotopic composition of Pb in the soil. Thirty (30) soil samples were collected at 0-20 cm depth in 3 different land-use zones, industrial area (IDA, n=10), municipal solid waste facility (MSW, n=10), and traffic section (TRS, n=10). In addition, 3 rock (gneisses) and 3 blacksmith dust samples were collected in the study area for comparison. Properties of the soil such as physico-chemical parameters (pH, organic content, and soil texture) and mineralogical composition were determined to understand the distribution of Pb in the soil of the study area. Similarly, the samples were analyzed for their Pb concentrations and Pb isotopic compositions using inductively coupled plasma mass spectrometry. The soil pH, organic matter, and texture were slightly acidic (4.9-6.9), average organic content (7.9-19.1%), and sandy clay loam in nature, respectively. Therefore, the Pb distribution was enhanced by the physico-chemical parameters. However, the mineral constituent of the soil in order of their abundance include quartz, feldspars, illite-muscovite, kaolinite, Biotite, goethite, and hematite. Consequently, there is no Pb-rich primary mineral in the soil. The environmental assessment of Pb in the study area showed that all the zones were contaminated on the basis of the average contamination factor and geoaccumulation index values. Similarly, the ecological risk factor estimation of Pb showed that the three zones had moderate potential ecological risk factors (41-54). The isotopic compositions of 208Pb/207Pb, and 206Pb/207Pb of the contaminated soil were lower than the corresponding component in gneisses, while the composition of 208Pb/206Pb was higher than the gneisses. Furthermore, the standard plot of (208Pb/207Pb) vs (206Pb/207Pb) showed clearly that the source of Pb in the contaminated soil was mainly from anthropogenic sources.Therefore, from the Pb concentration and isotopic composition acquired, the Pb contamination was mainly sourced from anthropogenic activities from the study area. These sources mainly include scrap metal recycling industry, vehicle emission and domestic and industrial waste. So, more effective remediation strategies need to be developed to reduce the contamination.

Perception and legacy of soil chromium and lead contamination in an operational small-scale coal mining community.

Operational small-scale coal mining (OSCM) is one of the most significant sources of chromium (Cr) and lead (Pb) pollution in Bangladesh. Attempts to minimize or lessen the use of Cr and Pb in OSCM have shown unsatisfactory results, mainly because they need to address the sociotechnical complexity of pollution concerns in OSCM. This research adopts a multidisciplinary, sociotechnical approach to addressing Cr and Pb problems, coupling soil sampling for Cr and Pb with questionnaires of miners' and inhabitants' perceptions of pollution and its distribution. The study was undertaken in the Barapukuria coal basin in northwest Bangladesh. Except for mining areas (average of 49.80 ± 27.25mg/kg), Cr levels in soils exceeded the world average in the periphery (73.34 ± 24.39mg/kg, ~ 1.2 times) and residential areas (88.85 ± 35.87mg/kg, 1.5 times the world standard of 59.5mg/kg). Pb levels in soils exceeded national and global averages in mining (53.56 ± 37.62mg/kg, ~ 1.9 times), periphery (35.05 ± 21.77mg/kg, ~ 1.3 times), and residential areas (32.14 ± 26.59mg/kg, ~ 1.2 times) when compared to Bangladesh and global standards of 20 and 27mg/kg. Pb levels were highest in mining areas, while Cr concentrations were highest in residential areas. The questionnaire findings indicated that miners and inhabitants did not correctly assume that the highest levels of Cr and Pb pollution would be found in these areas. Among all respondents, 54% are unaware of the health impacts of prolonged Cr and Pb exposure. They face respiratory problems (38.6%), skin diseases (32.7%), and other health issues. A large number of people (66.6%) agreed with the fact that Cr and Pb contamination has an impact on drinking water. Cr and Pb pollution has caused 40% crop loss and a 36% decrease in productivity in the agricultural sector. However, respondents underestimated the level of Cr pollution in mining areas, and most assumed that only individuals working directly with mines were impacted by the Cr and Pb content. Participants also rated the reduction of Cr and Pb contamination as of low importance. There is less awareness of Cr and Pb pollution among miners and inhabitants. Sincere efforts to reduce Cr and Pb pollution will likely be met with extra attention and hostility.

A chemometrics-based approach for the chemical prediction of lead (Pb) levels in surface soil, Dammam, Saudi Arabia

High levels of trace metals in top soil may impose serious health problems to humans and the environment. Thus, there is a need to assess the geochemical conditions of surface soils where various human activities are intensified. This study aims to evaluate contaminations associated with trace metals within Dammam, Saudi Arabia. The study also aims to hyphenate the results into a chemometrics-based approach for predicting the concentration of lead (Pb) due to its toxicity. No previous work was found on Pb prediction in top soils using chemometrics-based approach. Surface soil samples were collected from the different zones and analyzed in the laboratory for their trace metals’ constituents. According to the study’s findings, all trace metals were below international allowable metals with the highest mean concentration of Ba (309.7 mg/kg), Zn (7.9 mg/kg), and Cr (10.2 mg/kg) in industrial, agriculture and residential areas, respectively. The prediction steps involve the application of two AI-based techniques; Gaussian process regression (GPR) and Least-square (L-Boost), as well as a linear Step-Wise-Linear Regression (SWLR). The modelling was featured in two scenarios, M1 and M2, based on the input–output relationship designated according to the correlational feature extraction approach. The performance results of the models indicate that the second scenario (M2) showed higher performance skills than the first scenario (M1) in all three approaches. Overall, the performance accuracy of the models showed that the non-linear GPR-M2 showed higher performance accuracy than all the model combinations applied in the current work with 99% accuracy and an MSE of 0.012.

Phytoremediation of Cadmium-, Lead-, and Nickel-Polluted Soils by Industrial Hemp

The restoration of polluted soils is crucial for ecosystem recovery services. Evidently, phytoremediation is a biological and sustainable technique that includes the use of plants to remediate heavy-metal-contaminated land; the plants should be tolerant to the contamination and capable of uptake or immobilization of the heavy metals in the soil. Moreover, defining an economically efficient approach to the remediation of a contaminated area, with the possibility of further utilization of phytoremediation biomass, renders energy crops a great option for this technique. Energy crops, in fact, are known for their ability to grow with low agricultural input, and later, the biomass product can be used to produce biofuels, bioenergy, and bioproducts in a sustainable and renewable way, creating economic potential, especially when these crops are cultivated in marginal lands. The aim of this work is to test two monoecious industrial hemp varieties in different levels of Cd, Pb, and Ni in soil. Both varieties were tolerant to levels of Cd and Pb contamination that were higher than the limit for commercial and industrial use, while Ni showed a significant effect at all the tested concentrations. The variety Futura 75 performed better than Kc Dora in terms of productivity and tolerance.

Fate and Exposure Assessment of Pb Leachate from Hypothetical Breakage Events of Perovskite Photovoltaic Modules.

Emerging lead halide perovskite (LHP) photovoltaics are undergoing intense research and development due to their outstanding efficiency and potential for low manufacturing costs that render them competitive with existing photovoltaic (PV) technologies. While today's efforts are focused on stability and scalability of LHPs, the toxicity of lead (Pb) remains a major challenge to their large-scale commercialization. Here, we present a screening-level, EPA-compliant model of fate and transport of Pb leachate in groundwater, soil, and air, following hypothetical catastrophic breakage of LHP PV modules in conceptual utility-scale sites. We estimated exposure point concentrations of Pb in each medium and found that most of the Pb is sequestered in soil. Exposure point concentrations of Pb from the perovskite film fell well below EPA maximum permissible limits in groundwater and air even upon catastrophic release from PV modules at large scales. Background Pb levels in soil can influence soil regulatory compliance, but the highest observed concentrations of perovskite-derived Pb would not exceed EPA limits under our assumptions. Nonetheless, regulatory limits are not definitive thresholds of safety, and the potential for increased bioavailability of perovskite-derived Pb may warrant additional toxicity assessment to further characterize public health risks.

Dose-dependent impact of compost on rhizosphere bacterial community in heavy metal-contaminated paddy soil

Different doses (1%, 5%, 10%, mass fraction) of animal manure compost were added into a multi-heavy metal contaminated paddy soil for 150 d, and the changes in microbial structure and composition were evaluated. Compost exhibited dose-dependent effects on the rhizosphere bacterial community. Low (1%) and middle (5%) additions of compost exerted more distinct influence on bacterial community structure in rhizosphere soil than in bulk soil. The bacterial diversity after addition of compost decreased in rhizosphere soils compared with that in bulk soil. Results of redundancy analysis (RDA) indicated that different responses of rhizosphere and non-rhizosphere bacterial community to the changed soil physicochemical properties (soil pH, Pb, Cd and Cu levels) might be one reason for the differences. Thus, in agricultural management practice, the influence of compost on rhizosphere microbes should be considered.