Influence of phosphate amendment and zinc foliar application on heavy metal accumulation in wheat and on soil extractability impacted by a lead smelter near Jiyuan, China

Selenium and Bacillus proteolyticus SES increased Cu-Cd-Cr uptake by ryegrass: highlighting the significance of key taxa and soil enzyme activity

Many studies have focused their attention on strategies to improve soil phytoremediation efficiency. In this study, a pot experiment was carried out to investigate whether Se and Bacillus proteolyticus SES promote Cu-Cd-Cr uptake by ryegrass. To explore the effect mechanism of Se and Bacillus proteolyticus SES, rhizosphere soil physiochemical properties and rhizosphere soil bacterial properties were determined further. The findings showed that Se and Bacillus proteolyticus SES reduced 23.04% Cu, 36.85% Cd, and 9.85% Cr from the rhizosphere soil of ryegrass. Further analysis revealed that soil pH, organic matter, soil enzyme activities, and soil microbial properties were changed with Se and Bacillus proteolyticus SES application. Notably, rhizosphere key taxa (Bacteroidetes, Actinobacteria, Firmicutes, Patescibacteria, Verrucomicrobia, Chloroflexi, etc.) were significantly enriched in rhizosphere soil of ryegrass, and those taxa abundance were positively correlated with soil heavy metal contents (P < 0.01). Our study also demonstrated that in terms of explaining variations of soil Cu-Cd-Cr content under Se and Bacillus proteolyticus SES treatment, soil enzyme activities (catalase and acid phosphatase) and soil microbe properties showed 42.5% and 12.2% contributions value, respectively. Overall, our study provided solid evidence again that Se and Bacillus proteolyticus SES facilitated phytoextraction of soil Cu-Cd-Cr, and elucidated the effect of soil key microorganism and chemical factor.

Heavy metals pollution from smelting activities: A threat to soil and groundwater

Throughout the literature, the word "heavy metal" (HM) has been utilized to describe soil contamination; in this context, we characterize it as those elements with a density greater than 5 g per cubic centimeter. Contamination is one of the major global health concerns, especially in China. China's rapid urbanization over the past decades has caused widespread urban water, air, and soil degradation. This study provides a complete assessment of the soil contamination caused by heavy metals in China's mining and smelting regions. The study of heavy metals (HMs) includes an examination of their potential adverse impacts, their origins, and strategies for the remediation of soil contaminated by heavy metals. The presence of heavy metals in soil can be linked to both natural and anthropogenic processes. Studies have demonstrated that soils contaminated with heavy metals present potential health risks to individuals. Children are more vulnerable to the effects of heavy metal pollution than adults. The results highlight the significance of heavy metal pollution caused by mining and smelting operations in China. Soil contaminated with heavy metals poses significant health concerns, both carcinogenic and non-carcinogenic, particularly to children and individuals living in heavily polluted mining and smelting areas. Implementing physical, chemical, and biological remediation techniques is the most productive approach for addressing heavy metal-contaminated soil. Among these methods, phytoremediation has emerged as a particularly advantageous option due to its cost-effectiveness and environmentally favorable characteristics. Monitoring heavy metals in soils is of utmost importance to facilitate the implementation of improved management and remediation techniques for contaminated soils.

Interactive effect of silicon and zinc on cadmium toxicity alleviation in wheat plants

Silicon (Si) and Zinc (Zn) have been frequently used to alleviate cadmium (Cd) toxicity, which are feasible strategies for crop safety production. However, the mechanisms underlying the interaction of Si and Zn on alleviating Cd toxicity are not well understood. A hydroponic system was adopted to evaluate morphological, physiological-biochemical responses, and related gene expression of wheat seedlings to Si (1 mM) and Zn (50 µM) addition under Cd stress (10 µM). Cd induced obvious inhibition of wheat growth by disturbing photosynthesis and chlorophyll synthesis, provoking generation of reactive oxygen species (ROS) and interfering ion homeostasis. Cd concentration was decreased by 68.3%, 43.1% and 73.3% in shoot, and 78.9%, 44.1% and 85.8% in root by Si, Zn, and combination of Si with Zn, relative to Cd only, respectively. Si and Zn effectively ameliorated Cd toxicity and enhanced wheat growth; but single Si or combination of Si with Zn had more efficient ability on alleviating Cd stress than only Zn, indicating Si and Zn have synergistic effect on Cd toxicity; Interaction of them alleviated oxidative stress by reducing ROS content, improving AsA-GSH cycle and antioxidant enzymes activities, and regulating Cd into vacuole through PC-Cd complexes transported by HMA3 transporter. Our results suggest that fertilizers including Si and Zn should be made to reduce Cd content, which will beneficial for food production and safety.

Research Progress on Heavy Metals Pollution in the Soil of Smelting Sites in China

Contamination by heavy metals is a significant issue worldwide. In recent decades, soil heavy metals pollutants in China had adverse impacts on soil quality and threatened food security and human health. Anthropogenic inputs mainly generate heavy metal contamination in China. In this review, the approaches were used in these investigations, focusing on geochemical strategies and metal isotope methods, particularly useful for determining the pathway of mining and smelting derived pollution in the soil. Our findings indicate that heavy metal distribution substantially impacts topsoils around mining and smelting sites, which release massive amounts of heavy metals into the environment. Furthermore, heavy metal contamination and related hazards posed by Pb, Cd, As, and Hg are more severe to plants, soil organisms, and humans. It's worth observing that kids are particularly vulnerable to Pb toxicity. And this review also provides novel approaches to control and reduce the impacts of heavy metal pollution. Hydrometallurgy offers a potential method for extracting metals and removing potentially harmful heavy metals from waste to reduce pollution. However, environmentally friendly remediation of contaminated sites is a significant challenge. This paper also evaluates current technological advancements in the remediation of polluted soil, such as stabilization/solidification, natural attenuation, electrokinetic remediation, soil washing, and phytoremediation. The ability of biological approaches, especially phytoremediation, is cost-effective and favorable to the environment.

Relative contribution of environmental medium and internal organs to lead accumulation of wheat grain

Lead (Pb) pollution in wheat has received considerable research attention globally due to its persistence and ease of accumulation, posing severe health risks to humans. This study explored the relative contribution of the environmental medium (atmospheric deposition and soil) and wheat internal organs to Pb accumulation in wheat grains, using field experiments by contrasting treatments. The concentration and bioavailability of Pb in the soil were significantly lower than those of atmospherically deposited Pb (P < 0.05). Pb accumulation rate in wheat grains was consistent with the grain filling rate, which first increased and then decreased, reaching the highest level at the middle filling stage. Pb isotope analysis showed that atmospheric deposition was the main source of Pb in the shoots of wheat plants, contributing more than 80.0% of Pb in grains. Although the roots had the highest Pb concentration, the spikes had the greatest relative contribution (58.4%) to Pb accumulation in the wheat grains, followed by that of the leaves (24.5%), whereas the contribution of roots was the lowest (17.1%) among all plant organs. In addition, among all leaves, the contribution of flag leaves to Pb accumulation in the grain was higher than the cumulative contribution of all other leaves, where flag leaves and other leaves contributed 13.8% and 10.7%, respectively. Collectively, the absorption of atmospherically deposited Pb by wheat spikes is the leading cause of Pb pollution in wheat grains. These results may aid in formulating strategies to reduce Pb concentration in grains and ensure food quality and safety.

Heavy Metal, Waste, COVID-19, and Rapid Industrialization in This Modern Era—Fit for Sustainable Future

Heavy metal contamination, waste, and COVID-19 are hazardous to all living things in the environment. This review examined the effects of heavy metals, waste, and COVID-19 on the ecosystem. Scientists and researchers are currently working on ways to extract valuable metals from waste and wastewater. We prefer Tessier sequential extraction for future use for heavy metal pollution in soil. Results indicated that population growth is another source of pollution in the environment. Heavy metal pollution wreaks havoc on soil and groundwater, especially in China. COVID-19 has pros and cons. The COVID-19 epidemic has reduced air pollution in China and caused a significant reduction in CO2 releases globally due to the lockdown but has a harmful effect on human health and the economy. Moreover, COVID-19 brings a huge amount of biomedical waste. COVID-19’s biomedical waste appears to be causing different health issues. On the other hand, it was discovered that recycling has become a new source of pollution in south China. Furthermore, heavy metal contamination is the most severe ecological effect. Likewise, every problem has a remedy to create new waste management and pollution monitoring policy. The construction of a modern recycling refinery is an important aspect of national waste disposal.

Hormetic effects of zinc on growth and antioxidant defense system of wheat plants

Although hormesis induced by heavy metals is a well-known phenomenon, the involved biological mechanisms are not fully understood. Zinc (Zn) is an essential micronutrient for wheat, an important crop contributing to food security as a main staple food; however, excessive Zn is detrimental to the growth of wheat. The aim of this study was to evaluate morphological and physiological responses of two wheat varieties exposed to a broad range of Zn concentrations (0-1000 μM) for 14 days. Hormesis was induced by Zn in both wheat varieties. Treatment with 10-100 μM Zn promoted biomass accumulation by enhancing the photosynthetic ability, the chlorophyll content and the activities of antioxidant enzymes. Increased root/shoot ratio suggested that shoot growth was severely inhibited when Zn concentration exceeded 300 μM by reducing photosynthetic ability and the content of photosynthetic pigments. Excessive Zn accumulation (Zn treatment of 300-1000 μM) in leaf and root induced membrane injuries through lipid peroxidation as malondialdehyde (MDA) content increased with increasing Zn concentration. The results show that MDA content was higher than other treatments by 16.1-151.1% and 15.0-88.3% (XN979) and 36.8-235.7% and 20.6-83.8% (BN207) in the leaves and roots under 1000 μM Zn treatment. To defend against Zn toxicity, ascorbate (AsA), glutathione (GSH), non-protein thiols (NPT) and phytochelatin (PC) content of both wheat varieties (except leaf GSH content of BN207) was increased, while, the activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, and the content of soluble protein decreased by 300-1000 μM Zn. The results showed that AsA-GSH cycle and NPT and PC content of wheat seedlings play important roles in defending against Zn toxicity. This study contributes new insights into the physiological mechanisms underlying the hormetic response of wheat to Zn, which could be beneficial for optimizing plant health in changing environments and improving risk assessments.

Contribution of the flag leaf to lead absorption in wheat grain at the grain-filling stage

Wheat flag leaf (FL) is one of the primary sources of carbohydrates in grains; however, its role in grain lead (Pb) absorption remains unclear. A field experiment was conducted to assess the relative contribution of the FL to Pb accumulation in wheat grain by two contrasting treatments: without (CK) and with FL removal (FLR) at the grain-filling stage. The Pb concentration in leaves was closely related to leaf strata and decreased from FL to the third leaf. FLR treatment significantly reduced the yield and grain Pb concentration by 2.79% and 11.47%, respectively. The contribution of FL to grain Pb accumulation decreased gradually with the filling process, from 35.08% (at early stage) to 13.94% (at maturity stage). After FLR, the contribution proportion of atmospheric fallout to grain Pb decreased from 69.01% (CK) to 62.43% (FLR). Combined isotope analysis with scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS) revealed that the main contribution of FLs to grain Pb originated from Pb fallout in fine atmospheric particles. Therefore, taking measures to reduce the influence of fine atmospheric particles on wheat may be an effective way to control wheat grain Pb contamination.

Quantifying source-specific intake risks of wheat cadmium by associating source contributions of soil cadmium with human health risk

Sources of cadmium (Cd) contamination of farmlands and the potential risk to human health via dietary intake of wheat Cd are of great concern to consumers. A source-specific risk assessment (SSRA) model, which combined a positive matrix factorization receptor model and spatial analysis with a health risk assessment model, was developed based on a wheat field investigation in northern China. It was used to estimate the daily intake risk from different sources of ingesting Cd from wheat. The mixed source of wastewater and residues from industrial activities and atmospheric deposition were identified as the dominant sources of Cd contamination. Wheat Cd uptake could be predicted reliably from the pH and total Cd concentration of field soil. Based on the predictive model of Cd transfer from soil to wheat, the SSRA model then linked sources to the Cd intake risk from wheat grain. Results showed that the mixed source and the atmospheric deposition source accounted for 52.8% and 29.3%, respectively, of the wheat Cd intake risk. In combination with the spatial analysis, the potential risk of Cd contamination in western and central eastern areas was mainly attributed to the mixed source of wastewater and industrial residues, whereas the risk in the northwestern area was associated mainly with atmospheric deposition. Regionalized risk management strategies, focusing on different sources, were proposed to minimize the Cd input to field cropping system and to mitigate health risk for local residents.

Water management of alternate wetting and drying combined with phosphate application reduced lead and arsenic accumulation in rice

Lead (Pb) and arsenic (As) exist in soil with different ionic forms, and it is difficult to immobilize simultaneously Pb and As in soil. The objective of this study is to determine the effects of water management including flooding (FL), alternate wetting and drying (AWD) and dry farming (DF) combined with addition of phosphate (P) on the accumulation of Pb and As in rice. Our results showed that Pb accumulated in root during vegetative stage, and most of As in root was transported to the above ground parts during the reproductive stage. Pb was evenly distributed in grains, and As was mostly accumulated in bran and aleurone layer. Water management had a reverse effect on the accumulation of Pb and As in rice. However, the effects of P on arid soil environment and Pb, As accumulation in rice were stronger than that in flooded soil. Application of P under AWD treatment could maintain a similar quantity of Fe plaque with flooding, decrease the availability of Pb in rhizosphere soil, reduce Pb and As accumulation in root, and result in the reduction of Pb and As accumulation in grains by 86% and 66% respectively. Besides, our study also found that flooding or AWD during vegetative stage facilitated the formation of iron plaque. In conclusion, AWD combined with P application could maintain a relatively lower concentrations of Pb and As in grains.

Lead smelting alters wheat flour heavy metal concentrations and health risks

Wheat (Triticum aestivum L.) flour consumption may be a major source of human metal intake, especially when wheat is cultivated in metal-contaminated soils. This work investigated Cd, Cu, Pb, and Zn distribution in whole wheat flour, wheat flour, and wheat bran when grown in an area polluted by Pb smelting. Wheat product heavy metal concentrations were analyzed, and the (non)carcinogenic risks were assessed. Mean Cd, Cu, Pb, and Zn concentrations in whole wheat flour were 0.38, 3.83, 0.48, and 29.3 mg kg^-1 , respectively; those in flour were only slightly reduced. The ratios between noncarcinogenic average daily dose of whole wheat flour and wheat flour consumption ranged from 1.06 to 3.76, with Pb having the greatest values compared with other metals. For children, the average hazard quotients (HQs) of whole wheat flour consumption of Cd, Cu, Pb, and Zn were 4.19, 1.06, 1.53, and 1.07; those for wheat flour consumption were 3.81, 0.68, 0.70, and 0.98, respectively. The HQs of adults were less than those of children. Overall results indicated that consumption of wheat products may lead to health concerns in the heavy metal contaminated area, yet when wheat flour rather than whole wheat flour is consumed, only the human health risk from Pb ingestion is reduced. Altering or removing human edible crops in the most contaminated areas should be considered.

Dynamic interactions between soil cadmium and zinc affect cadmium phytoavailability to rice and wheat: Regional investigation and risk modeling

Characterizing the interactions between Cd and Zn with respect to the soil soluble Cd and crop Cd uptake allows the development of risk-based approaches to the performance of grain crops. By means of a three-year survey of 358 rice fields and 206 wheat fields across China, this study investigated the effect of Cd-Zn interactions on the phytoavailability of Cd to rice and wheat. The interactive nature between the Cd:Zn ratio and pH of soil affected crop Cd uptake, and the resulting grain Cd intake risk, were examined by the Free-Ion Activity-based model and probability analysis. In highly acidic rice soils (pH < 5.9), soil Zn had no effect on rice Cd uptake, whereas, under near-neutral conditions (pH > 5.9), a site-specific influence of soil Zn on grain Cd concentration was found. Soil Zn could inhibit Cd uptake and translocation by the plant in soil-wheat system when the soil Cd:Zn ratio decreased to 0.0083 and lower. Rice grain poses a significant health risk to local consumers due to its high Cd accumulation and its low Zn accumulation. In order to reduce the health risks from dietary Cd to local consumers, approximately 63.9% of the rice fields and 30.5% of the wheat fields require strategies ameliorating soil acidity in rice soils and increasing Zn concentrations in wheat soils.

Combined application of Bacillus sp. MN-54 and phosphorus improved growth and reduced lead uptake by maize in the lead-contaminated soil

Lead (Pb) is considered an important environmental contaminant due to its considerable toxicity to living organisms. It can enter and accumulate in plant tissues and become part of the food chain. In the present study, individual and combined effects of Bacillus sp. MN-54 and phosphorus (P) on maize growth and physiology were evaluated in Pb-contaminated soil. A pristine soil was artificially contaminated with two levels of Pb (i.e., 250 and 500 mg kg^-1 dry soil) and was transferred to plastic pots. Bacillus sp. MN-54 treated and untreated maize (DK-6714) seeds were planted in pots. Recommended doses of nutrients (N and K) were applied in each pot while P was applied in selective pots. Results showed that Pb stress hampered the maize growth and physiological attributes in a concentration-dependent manner, and significant reductions in seedling emergence, shoot and root lengths, fresh and dry biomasses, leaf area, chlorophyll content, rate of photosynthesis, and stomatal conductance were recorded compared with control. Application of Bacillus sp. MN-54 or P particularly in combination significantly reduced the toxic effects of Pb on maize. At higher Pb level (500 mg kg^-1), the combined application effectively reduced Pb uptake up to 42.4% and 50% by shoots, 30.8% and 33.9% by roots, and 18.4% and 26.2% in available Pb content in soil after 45 days and 90 days, respectively compared with that of control. Moreover, the use of Bacillus sp. MN-54 significantly improved the P uptake by maize plants by 44.4% as compared with that of control. Our findings suggest that the combined use of Bacillus sp. MN-54 and P could be effective and helpful in improving plant growth and Pb immobilization in Pb-contaminated soil.

Cadmium, copper, lead and zinc accumulation in wild plant species near a lead smelter

Smelting activities have been shown to increase the likelihood of environmental heavy metal accumulation and bioaccumulation potential within relative proximity to smelter sites. This investigation focused specifically on cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) accumulation in 43 wild plant species and corresponding soils near a Pb smelting contaminated area. Soils in the study area had elevated Cd, Cu, Pb and Zn concentrations, with pollution indices ranked as Cd > Pb > Cu > Zn. Aboveground plant heavy metal concentrations ranked Pb > Zn > Cd > Cu, with plants having greater bioconcentration factor (BCF) values for Cd than for Pb, Cu and Zn. Plant Cd BCF averaged 1.42, while Pb, Cu and Zn averaged 0.128, 0.256 and 0.560, respectively. The greatest Cd BCF value was 5.40 for Dendranthema indicum; Cd accumulation for this species has not been reported previously. The greatest shoot Cd concentration (66.5 mg kg^-1) was found in Viola verecunda. Significant correlations existed between plant shoot Cd and Pb concentrations and soil total and DTPA-extractable Cd and Pb. Plant species with greater heavy metal accumulation could potentially be used for phytoextraction in the study area, while those having less accumulation potentially being used to reduce heavy metal flow into the food chain, reducing the health risks associated with elevated heavy metal soil contamination.

Long-term stabilization of Cd in agricultural soil using mercapto-functionalized nano-silica (MPTS/nano-silica): A three-year field study

Cadmium (Cd) contamination in agricultural soil is a worldwide environmental problem. In situ stabilization has been considered an effective approach for the remediation of Cd-contaminated agricultural soil. However, information about the long-term effects of amendment on soil properties and stabilization efficiency remains limited. In the present study, mercapto-functionalized nano-silica (MPTS/nano-silica) was used to stabilize Cd in contaminated agricultural soil under field conditions for three years (with application rates of 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1.0%). The application of MPTS/nano-silica reduced the soil aggregate stability (PDA_0.25) (14.8%) and available K (24.9%) and significantly increased the soil dehydrogenase (DHA) (43.4%), yield of wheat grains (33.5%) and Si content in wheat tissues (55.2% in leaf, 50.4% in stem, and 37.7% in husk) (p < 0.05). More importantly, MPTS/nano-silica decreased the leachability (36.0%) and bioavailability (54.3%) of Cd in the soil and transformed Cd into a more stable fraction. The content of Cd in wheat grains decreased by 53.9%, 61.9% and 54.1% in 2017, 2018 and 2019, respectively, in comparison with the control. These results indicated that MPTS/nano-silica has long-term stabilization effects on Cd in agricultural soil and is a potential amendment for the remediation of Cd-contaminated agricultural soils.

Cadmium foliar application affects wheat Cd, Cu, Pb and Zn accumulation

Cadmium is toxic to plants, easily reaching unsafe levels for animal and human consumption. A greenhouse experiment investigated the effect of foliar-applied Cd on the accumulation and distribution of Cd, Zn, Cu and Pb in wheat (Triticum aestivum) grown in heavy metal-contaminated soil. Cadmium solutions (0, 10, 20, 30 and 40 mg L^-1) were repeatedly sprayed on entire aboveground wheat plants during heading stage to medium milk development stage. Plant sample analyses after harvest indicated that both the biomass yield and grain yield were negatively affected by Cd application (p < 0.05); compared to controls, leaf and grain Cd concentrations increased 187-547% and 26.3-91.8%, respectively. However, grain Cd accumulation (concentration × yield) was not affected by Cd treatments (p > 0.05). Stem, leaf and glume Zn concentrations increased by less than 31%, while grain Zn concentrations were negatively affected by Cd treatments (3.4-34.4% lower than the control). Grain Cu concentrations were also negatively affected by Cd treatments, while grain Pb concentrations were similar between treatments. The antagonistic effect of Cd on grain Zn accumulation may mainly be due to competition for transporters and binding compounds in wheat leaves and stems. Preventing excess Cd from entering aboveground plant tissues should lessen negative plant and potentially animal/human health effects.

Heavy metal pollution and health risk assessment of agricultural soil near a smelter in an industrial city in China

To assess heavy metal pollution and human health risk, a total of 28 topsoil samples were collected during four seasons from seven agricultural soil sites near a famous smelter in Jiyuan, China. The maximum concentrations of Cd, Pb, Hg, As, Zn, Cu, Ni, and Cr were 26.00, 2601.00, 3.29, 65.00, 410.00, 156.30, 54.80, and 73.60 mg kg^-1, respectively. Compared with the sampling site nearest to the smelter, the concentrations of six metals at the farthest site were decreased significantly (P < 0.05). All sites were heavily contaminated, with Nemerow index (P) >3.0, and all sites had very high ecological risks related to Cd and Hg. The non-carcinogenic risk for children (based on combined exposure to the eight metals) was above the safety level. The carcinogenic risk of As for adults (8.98 × 10^-6) and children (1.49 × 10^-5) exceeded the acceptable level (1 × 10^-6). Results suggest a serious health risk in the polluted areas, particularly for children.Abbreviation Cd: Cadmium; Pb: Lead; Hg: Mercury; As: Arsenic; Zn: Zinc; Cu: Copper; Ni: Nickel; Cr: Chromium; P: Nemerow index; RI: Potential ecological risk index; E_i: Monomial potential ecological risk of a specific heavy metal; HI: non-carcinogenic hazard index; CR: Carcinogenic risk; TN: Total nitrogen; TP: Total phosphorus; OM: Organic matter; MC: Moisture content; ADD: Average daily dose.

Lead smelting effects heavy metal concentrations in soils, wheat, and potentially humans

Cadmium, Cu, Pb and Zn concentrations and distribution in soil, wheat, and the potential for human heavy metal accumulation near a Pb smelting affected area were investigated. Farm land soil, wheat grain and scalp hair samples were collected from three villages (named QD, GF and BS) with increasing distance from a large Pb smelter in China. Soil Cd and Pb concentrations exceeded national standards 46-100% of the time, depending on location. Soil and wheat grain Cd, Cu, Pb and Zn concentrations increased as distance to the smelter decreased. Similarly, greater Cd, Cu and Pb concentrations were present in human scalp hair for those residents living closest to the smelter. Decreasing trends existed for hair-to-wheat grain ratios for Cd and Pb as distance to the smelter increased. Results suggest that as distance to the smelter decreases, human heavy metal absorption via the consumption of metal-contaminated food products (e.g., wheat) increases.

Quantitative analysis of lead sources in wheat tissue and grain under different lead atmospheric deposition areas

Due to rapid growth of industrialization and human activities, such as mining and smelting, lead (Pb) has become a major environmental contaminant. As Pb can pose risks to human health, preventing Pb pollution in wheat is important for food safety, requiring accurate verification of pollution sources. Pb concentrations and isotope ratio levels in soil, in the atmosphere, and wheat tissue (root, stem, leaf, grain) in an area of high-Pb deposition (in the vicinity of a Pb smelter in Jiyuan city) and an area of low deposition (the northwest suburb of Zhengzhou city) were examined. The Pb isotope ratio and the binary mixed model were used to quantify the contribution of soil and atmospheric deposition to Pb content in wheat tissues. Results show that Pb content in soil, atmospheric deposition, and wheat in the high deposition area were significantly higher than those in the low deposition area. Pb content in soil, atmospheric deposition, wheat roots, stems, leaves, and grains in the high-deposition area were 355.32 ± 14.78, 5477.90 ± 187.85, 158.72 ± 9.56, 21.36 ± 1.72, 26.49 ± 1.96, and 0.94 ± 0.02 mg kg^-1, respectively. Pb content in the low-deposition area were 6.10 ± 0.75, 78.50 ± 4.35, 2.47 ± 0.23, 1.03 ± 0.07, 2.11 ± 0.13, and 0.08 ± 0.01 mg kg^-1, respectively. The Pb isotope ratio recorded obvious differences between soil and atmospheric deposition in the two areas. Combined with the significant correlation between Pb isotopes in various tissues of wheat and environmental media, and analysis of the isotopic composition characteristics of wheat and environmental media, in the high-deposition area, the contribution rate of atmospheric deposition in wheat roots, stems, leaves, and grains was 14%, 66%, 84%, and 77%, respectively. And the soil contribution rate was 86%, 34%, 16%, 23%, respectively. In the low-deposition area, the contribution rate of atmospheric deposition in wheat roots, stems, leaves, and grains was 49%, 73%, 93%, and 83%, respectively. And the soil contribution rates were 51%, 27%, 7%, and 17%, respectively. In the low-Pb deposition area, the contribution rate of atmospheric deposition in wheat was higher than that in the high-deposition area. Atmospheric deposition was the main source of Pb in grains, leaves, and stems of wheat in different depositional areas. Pb in wheat roots mainly derives from soil, and the Pb contribution rate of soil to wheat roots in the high-deposition area was significantly higher than that in the low-deposition area.