Pb In Wheat Research Articles

Variations in Cadmium and Lead Bioaccessibility in Wheat Cultivars and Their Correlations with Nutrient Components.

To reduce the health risks of exposure to Cd and Pb in wheat, a field experiment was conducted to investigate the differences in Cd and Pb bioaccessibility among the grains of 11 wheat cultivars and their relationships with the nutrient compositions of grains. The grain concentrations (Cd: 0.14-0.56 mg kg-1, Pb: 0.08-0.39 mg kg-1) and bioaccessibility (5.28-57.43% and 0.72-7.72% for Cd and Pb in the intestinal phase, respectively) of Cd and Pb differed significantly among the 11 cultivars. A safe wheat cultivar (Shannong16) with a relatively low health risk and the lowest grain Cd and Pb concentrations was selected. Ca, Mg, phytate, and methionine played key roles in affecting Cd and Pb bioaccessibility in wheat, with Ca and phytate significantly negatively correlated with Cd and Pb bioaccessibility. These findings can be used to optimize the selection strategy for safe wheat cultivars for healthy grain production in Cd-polluted farmland.

Interaction and Transport Characteristics of Lead and Cadmium in Different Soil-wheat Systems

In this study, four groups of lead(Pb) and cadmium(Cd) combined treatments with different concentration ratios were set up in Hailun black soil, Xianning brown-red soil, and Changwu Heilu soil, and wheat(Zhengmai 9023) was planted for a five-month pot experiment to analyze the Pb-Cd interaction behavior on heavy metal bioaccumulation in wheat under three soil-wheat systems. The low pH brown-red soil had the highest water-soluble Cd and Pb contents with significant Pb-Cd interactions in the soil, whereas the black soil with high organic matter and Heilu soil with high calcium carbonate content exhibited lower Cd and Pb activities. Among the three soils, wheat height and dry weight showed the poorest growth performance in the Heilu soil, but the wheat height increased by 2.68-8.49 cm compared with that in the control under the Pb-Cd combined treatment, whereas Pb-Cd interaction had the least effect on wheat height and dry weight in black soil and inhibited the growth of wheat in the brown-red soil. In the transport process of Cd or Pb in wheat, Pb-Cd interaction showed quite different effects in the three soil-wheat systems. Under the 125 mg·kg-1 and 250 mg·kg-1 Pb treatments, the Pb content in wheat grain planted in brown-red soil significantly increased by 73.2% and 19.1% with the addition of Cd, respectively, and therefore there was a synergistic effect between Pb and Cd. Under the 0.3 mg·kg-1 and 0.6 mg·kg-1 Cd treatments, the Cd content in wheat grains planted in black soil decreased by 51% and 33% with the addition of Pb, respectively; therefore, there was an antagonist effect between Pb and Cd. In the Heilu soil, a synergistic effect of Cd on Pb transport in wheat leaves was only observed under high Pb treatment. Therefore, pH and organic matter content were the key factors that determined the interaction behavior of Pb and Cd. The wheat food security risk of Pb and Cd combined pollution was higher than that of single metal pollution in acidic brown-red soil and lower in high organic matter black soil, whereas the interaction of Pb and Cd had little impact on the wheat food security risk of alkaline Heilu soil.

Effects of biosolid biochar on crop production and metal accumulation through a rice-wheat rotation system in fields

ABSTRACT Biosolid-borne heavy metals are the main concern in soils. Therefore, the effects of biosolid biochar application in soils were evaluated in our study through a rice-wheat rotation in fields. The results showed that after the application of biosolid biochar, soil organic matter (SOM), soil pH, and soil total heavy metal concentrations (Cd, Zn, Cu, and Pb) were significantly increased. But the CaCl2 extracted metals concentrations were decreased, and no significant differences in metal concentrations of soil deeper layers (20–100 cm) were found among different treatments. The Cd, Zn, Cu, and Pb concentrations in rice decreased by 13.2%, 37.0%, 9.92%, and 63.0%, respectively, and the concentrations of Cd, Zn, Cu, and Pb in wheat decreased by 20.85%, 19.7%, 48.6%, and 23.6%, respectively, compared with the control treatment. Biosolid biochar can decrease metal availability in soils and increase crop production in fields, thus is suggested to use in fields.

Mechanisms of lead uptake and accumulation in wheat grains based on atmospheric deposition-soil sources

Lead (Pb) accumulation in wheat grains depends on two aspects: i) Pb uptake by the roots and shoots, and ii) the translocation of organ Pb into the grain. However, the underlying mechanism of the uptake and transport of Pb in wheat remains unclear. This study explored this mechanism by establishing field leaf-cutting comparison treatments. Interestingly, as the organ with the highest Pb concentration, only 20.40 % of the root's relative contribution to grain Pb. The relative contributions of the spike, flag leaf, second leaf, and third leaf to grain Pb were 33.13 %, 23.57 %, 13.21 %, and 9.69 %, respectively, which was opposite to their Pb concentration distribution trends. According to Pb isotope analysis, it was found leaf-cutting treatments reduced the proportion of atmospheric Pb in grain, and grain Pb predominantly comes from atmospheric deposition (79.60 %). Furthermore, from the bottom to the top, the concentration of Pb in internodes decreased gradually, and the proportions of Pb originating from soil in the nodes also decreased, revealing that wheat nodes hindered the translocation of Pb from roots and leaves to the grain. Therefore, the hindering effect of nodes on the migration of soil Pb in wheat resulted in atmospheric Pb having a more convenient pathway to the grain than soil Pb, and further leading grain Pb accumulation primarily depended on the contribution of the flag leaf and spike.

Influence mechanism of awns on wheat grain Pb absorption: Awns' significant contribution to grain Pb was mainly originated from their direct absorption of atmospheric Pb at the late grain-filling stage

The spike is the organ that contributes the most to lead (Pb) accumulation in wheat grains. However, as an important photosynthetic and transpiration tissue in spike, the role of awn in wheat grain Pb absorption remains unknown. A field experiment was conducted to investigate the influence mechanism of awn on grain Pb accumulation through two comparative treatments: with and without awns (de-awned treatment). The de-awned treatment decreased wheat yield by 4.1 %; however, it significantly lowered the grain Pb accumulation rate at the late filling stage (15 days after anthesis) and led to a 22.8 % decrease in grain Pb concentration from 0.57 to 0.44 mg·kg-1. Moreover, the relative contribution of awn-to-grain Pb accumulation gradually increased with the filling process, finally reaching 26.6 % at maturity. In addition, Pb isotope source analysis indicated that the Pb in the awn and grain mainly originated from atmospheric deposition, and the de-awned treatment decreased the proportion of grain Pb from atmospheric deposition by 8.9 %. Microstructural observations further confirmed that the contribution of awns to grain Pb accumulation mainly originated from their direct absorption of atmospheric Pb. In conclusion, awns play an important role in wheat grain Pb absorption at the late grain-filling stage; planting awnless or short-awn wheat varieties may be the simplest and effective environmental management measure to reduce the health risks of Pb in wheat in regions with serious atmospheric Pb contamination.

Pb Content, Risk Level and Primary-Source Apportionment in Wheat and Rice Grains in the Lihe River Watershed, Taihu Region, Eastern China.

This study detailed a complete research from Lead (Pb) content level to ecological and health risk to direct- and primary-sources apportionment arising from wheat and rice grains, in the Lihe River Watershed of the Taihu region, East China. Ecological and health risk assessment were based on the pollution index and US Environmental Protection Agency (EPA) health risk assessment model. A three-stage quantitative analysis program based on Pb isotope analysis to determine the relative contributions of primary sources involving (1) direct-source apportionment in grains with a two-end-member model, (2) apportionment of soil and dustfall sources using the IsoSource model, and (3) the integration of results of (1) and (2) was notedly first proposed. The results indicated that mean contents of Pb in wheat and rice grains were 0.54 and 0.45 mg/kg and both the bio-concentration factors (BCF) were <<1; the ecological risk pollution indices were 1.35 for wheat grains and 1.11 for rice grains; hazard quotient (HQ) values for adult and child indicating health risks through ingestion of grains were all <1; Coal-fired industrial sources account for up to 60% of Pb in the grains. This study provides insights into the management of grain Pb pollution and a new method for its source apportionment.

Ecological risk assessment of Cd, As, Cr, and Pb metals in farmed wheat in the vicinity of an industrial park

ABSTRACT Heavy metals are one of the most concerning pollutants in the environment that can enter the food chain. This study aimed to evaluate metals pollution and their bioaccumulation in the farmed wheat around an Industrial Park and to assess the health risk of these metals. Sampling of soil and farmed wheat irrigated by both groundwater and treated wastewater was performed. The heavy metal concentration in the soil and framed wheat samples were measured by atomic absorption spectrometry. The mean concentrations of Cd, As, Cr, and Pb in wheat were 0.171, 0.003, 6.437 (mg/kg), and 1.052 (mg/kg) and this metals for soil were 1.884, 8.924, 36.848, 16.283 (mg/kg) for irrigated farms with groundwater and 0.149, 0.315, 4.638 (mg/kg), and 2.066 (mg/kg) for wheat farms irrigated farms with treated wastewater, and 0.939, 4.643, 24, 692, 14.135 for soil with treated wastewater respectively. The Cd, Cr and Pb content of wheat were higher than the standards limit set by the U.S. EPA. Non-carcinogenic risk was not observed through all 4 exposure routes for the studied population. However, the carcinogenic risk of Cd, As and Pb through oral route for wheat and ingestion of soil was considerable in the studied population.

Investigation of Farmland Soil and Wheat Heavy Metal Contamination Character in Jinding of Lanping

The contents of Cd and Pb in soil and wheat in Jinding of Lanping in Yunnan were investigated and sampled. And single pollution index method, comprehensive pollution index method and correlation analysis were used to evaluate heavy metal contamination in wheat and soil. Zone A is in the upper reaches of the Pijiang River, and the zone does not contain large mines, where soil in the farmland is not polluted by the heavy metals Cd and Pb. The soil in zone B is slightly polluted by Cd and Pb, and the over-standard rate of the Cd of the samples measured is 75%, and the over-standard rate of the Pb of the soil is 25%. The condition of soil polluted by two heavy metals is Cd > Pb, and the heavy metal pollution of the soil in this Zone is mainly affected by mining activities. Zone C is in the lower reaches of the Pijiang River, and the soil in Zone C is not polluted by Cd and Pb. The content of Cd and Pb in the wheat in Zone A reached the standard and was not polluted. The wheat in Zone B was not polluted by Cd and Pb. Although Cd and Pb in the soil in this Zone was over-standard, it could be concluded that Cd and Pb in the soil did not migrate to wheat. The wheat in Zone C was not contaminated by Cd and Pb.

Interaction of ZnO nanoparticle and AM fungi mitigates Pb toxicity in wheat by upregulating antioxidants and restricted uptake of Pb

The study aims at investigating the efficacy of individual as well as combined application of AM fungi (Glomus macrocarpum) and ZnO nanoparticles on the uptake of lead and its toxicity in wheat (Triticum aestivum L.). The plants were grown in pots with different treatments of AM Fungi, ZnO NP, and Pb. The individual applications of AM fungi (Glomus macrocarpum) and ZnO NPs increased the growth and biochemical attributes of wheat and decreased the Pb uptake under Pb stress. The combined application of AM fungi (Glomus macrocarpum) and ZnO nanoparticles synergistically enhanced the overall growth performance of the plant and significantly reduced the uptake of Pb in wheat grown in Pb spiked soils. The combined application was effective, with 30.66 % increase in plant height, 30.62 % increase in plant fresh weight, 54.26 % increase in plant dry weight, 45.45 % increase in total chlorophyll content, 19.59 % increase in proline content, 26.65 % higher activity of SOD, 15.12 % higher activity of catalase (CAT), 17.69 % increase in H2O2 content, 17.69 % increase in lipid peroxidation content, 52.09 % and 58.19 % decrease in Pb concentration in root and shoot of wheat, respectively, grown in Pb spiked soil (100 mg kg−1 soil). The results indicate that combined application of AM fungi and ZnO nanoparticles can be a promising technique for the utilization of Pb-contaminated soils.

Effect of industrial wastewater on wheat germination, growth, yield, nutrients and bioaccumulation of lead

Due to fresh water scarcity, farmers are using polluted water for irrigation. This research was conducted to study the bioaccumulation of Pb in wheat (Cv. Shafaq-2006). The experiment was comprised of seven treatments of lead i.e. 0–1,000 mg Pb/kg. The results revealed that lead severely reduces germination (− 30%), seedling fresh weight (− 74%), seedling dry weight (− 77%), vigor index (− 89%), tolerance index (− 84%), plant height (− 33%), number of leaves (− 41%), root fresh weight (− 50%), shoot fresh weight (− 62%), root dry weight (− 63%), shoot dry weight (− 71%), and root length (− 45%). The physiological parameters also respond negatively like stomatal conductance (− 82%), transpiration rate (− 72%) and photosynthetic rate (− 74%). Similarly, biochemical parameters also showed negative impacts, like carotenoids (− 41), total chlorophyll (− 43), chlorophyll a (− 42) and chlorophyll b (− 53). Yield parameters like the number of seed/plant, seed weight/plant, 1,000 seed weight and harvest index were reduced by 90%, 88%, 44% and 61%, respectively in T6. In addition, protein contents (− 81%), phosphorous (− 60%) and potassium (− 55%) were highly effected in the highest lead concentration (T6). Lead accumulation was extremely higher in seeds (119%) as compared to control plants. Lead bio-accumulation above threshold concentrations in crop parts is a serious human health concern.

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.

Compound health risk assessment of cumulative heavy metal exposure: a case study of a village near a battery factory in Henan Province, China.

The concentrations of the heavy metals Hg, As, Ni, Pb, Cd, Cr, Cu and Zn in soil, groundwater, air, and locally produced grain (wheat and corn) and vegetables were determined in a village near a battery factory in Xinxiang, Henan Province, China. A multimedia, multipathway health risk assessment of heavy metal exposure was carried out using the health risk model recommended by the United States Environmental Protection Agency (US EPA). The results showed that the concentrations of Cd in soil, Cd and Pb in wheat, Hg in corn, Cd, Hg, and Pb in vegetables, and Cd and As in PM2.5, PM10, and TSP were all higher than the corresponding limits for heavy metals in China. The non-carcinogenic risks (HIs) for all environmental media were higher in children than in adults, and the carcinogenic risks (TCRs) of heavy metal exposure in other media except for soil were higher in adults than in children. The total HI and TCR in adults and children were higher than the standard limit values because of heavy metal exposure through soil, groundwater, PM10, grain and vegetables. Cd was the most significant heavy metal in terms of HI and TCR factors; among the evaluated pathways, the contribution of diet was the largest. The HI and TCR caused by dietary crops account for 96.7% and 98.9% of the total in adults and 90.2% and 96.2% of the total in children, respectively. To maintain the health of the residents in the study area, it is strongly recommended to stop planting edible agricultural products immediately, start buying grain and vegetables from outside the study area, and strictly strengthen the control of heavy metal pollution in the study area. The source apportionment results show that Cd, Ni and As were mainly from industrial sources, which was related to sewage irrigation and battery plant deposition, and Pb and Cr were mainly from agricultural activities.

Effects of Atmospheric Fallout on Lead Contamination of Wheat Tissues Based on Stable Isotope Ratios.

In order to trace the source of Pb pollution in wheat, the contribution ratio of soil and atmospheric fallout source was quantified based on stable isotope ratios. Results showed that the average Pb content of soil was significantly lower than that of fallout, and Pb in the fallout had a higher weak acid fraction than soil. Pb in wheat had a distinct distribution in its tissues and the content of Pb in wheat roots was significantly higher than it in shoots. The 206Pb/207Pb ratio of soil was significantly higher than that in atmospheric fallout (p< 0.05). According to a binary mixing model, the 206Pb/207Pb ratio in wheat roots, leaves, and grains reflect 67%, 65%, and 90% of Pb content contributions from fallout, respectively. This results suggest that fallout Pb was absorbed by wheat leaves and transferred to other organs, and it is important to develop effective strategies to control fallout Pb risks.

Chemical speciation and bioavailability of cadmium and lead in the gray calcium soil

ABSTRACTA pot experiment was conducted to study chemical speciations and bioavailability of cadmium (Cd) and lead (Pb) in the gray calcium soil from northwestern China, and accumulation and translocation of Cd and Pb in wheat (Triticum aestivum L.) grown on the soil was also studied. The results showed that significant changes of Cd and Pb fractions in the soil and Cd and Pb concentrations in the wheat were observed with increasing soil Cd and Pb concentrations, and both Cd and Pb in exchangebale fraction in the soil made the greatest contribution to the accumulation of Cd and Pb in the wheat. Higher bio-concentration factors (BCFs) and translocation factors (TFs) for Cd and lower BCFs and TFs for Pb were observed in the wheat, respectively, and Cd had much higher accumulation than Pb in the edible parts of the wheat. Therefore, Cd has higher risk than Pb when people eat the wheat.

Accumulation of As, Cd, and Pb in Sixteen Wheat Cultivars Grown in Contaminated Soils and Associated Health Risk Assessment.

This study investigated the accumulation of As, Cd, and Pb in 16 wheat cultivars and the associated health risks for the inhabitants of Jiyuan, China. The results indicated that the concentrations of As, Cd, and Pb decreased in the order of root > leaf > stem > grain. The concentrations of As, Cd, and Pb in wheat grains varied from 0.13 for Pingan8 to 0.34 mg kg−1 for Zhengmai7698, 0.10 for Luomai26 to 0.25 mg kg−1 for Zhengmai7698, and 0.12 for Zhoumai207 to 0.42 mg kg−1 for Zhengmai379, respectively. There were significant differences in the bioaccumulation factors of As, Cd, and Pb among the 16 wheat cultivars. Cd was more readily accumulated to higher levels than As and Pb in wheat. The Target Hazard Quotients (THQs) of Cd and Pb in the grains from 16 wheat cultivars were below 1, while As THQ exceeded 1. The lowest detrimental human health effects via wheat consumption were found in cultivar AY58 among the 16 wheat cultivars, with total THQs (TTHQs) of 1.82 for children and 1.60 for adults, suggesting that children absorb more heavy metals than adults and they are more vulnerable to the adverse effects of these metals.

Transport and Partitioning of Lead in Indian Mustard (Brassica juncea) and Wheat (Triticum aestivum)

ABSTRACTLead (Pb) contamination in soils is a serious concern because it can be taken up by crops and then transferred through the food chain, posing a potential risk to human health. Indian mustard (Brassica juncea) and wheat (Triticum aestivum) are important crop species known to accumulate heavy metals in their tissues. This study aimed at understanding the transport and accumulation of Pb in these two species and the risk associated with consumption of these foods, which would help us in mitigating accumulation of Pb in edible tissues. The plants were grown at different Pb concentrations for the entire life cycle, and the partitioning of the metal to different tissues was examined. The results showed that plant species differ widely in their ability to transport and accumulate Pb in different tissues. In B. juncea, there was significant accumulation of Pb in both siliques and seeds, whereas most of the Pb in wheat was concentrated in the vegetative tissues and less to the flag leaf and reproductive tissues. In both species, although seed Pb concentrations exceeded acceptable limits, dietary intake did not exceed acceptable limits in most treatments, indicating that more studies on Pb transport and redistribution in crop species is necessary.

Heavy metals in soil and crops of an intensively farmed area: a case study in Yucheng City, Shandong Province, China.

Yucheng City is located in northwestern Shandong Province, China, and is situated on the Huang-Huai-Hai Plain, the largest alluvial plain in China. In this study, 86 surface soil samples were collected in Yucheng City and analyzed for cation exchange capacity (CEC), soil organic matter (SOM), pH, available phosphorus (avail. P), phosphorus (P), aluminum (Al), and iron (Fe). These soils were also analyzed for ‘total’ chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), mercury (Hg), cadmium (Cd), and lead (Pb), together with 92 wheat samples and 37 corn samples. There was no obvious heavy metal contamination in the soil and irrigation water. But the long-term accumulation of heavy metals in soil has lead to an increase of Ni, As, Hg and Pb concentrations in some of wheat and corn samples and Cd in wheat samples. Because of the numerous sources of soil heavy metals and the lower level of heavy metal in irrigation water, there is no significant relation between soil heavy metal concentrations and irrigation water concentrations. Cr, Ni were mainly from the indigenous clay minerals according to multivariate analysis. Little contribution to soil heavy metal contents from agricultural fertilizer use was found and the local anomalies of As, Cd, Hg, Pb in wheat and corn grain are attributed to the interactive effects of irrigation and fertilizer used. Aerial Hg, however may also be the source of Hg for soil, wheat and corn.

Uncertainty and sensitivity analysis of spatial predictions of heavy metals in wheat.

Heavy metals seriously threaten the health of human beings when they enter the food chain. Therefore, policymakers require precise predictions of heavy metal concentrations in agricultural crops. In this paper we quantify the uncertainty of regression predictions of Cd and Pb in wheat (Triticum aestivum L.) and the contributions to the uncertainties in these predictions associated with inputs to the regression model. For each node of the 500- x 500-m grid covering the arable soils in The Netherlands, a latin hypercube sample size of 1000 is constructed from the uncertainty distributions of the explanatory variables (pH, soil organic matter [SOM], and heavy metal concentration in soil), the regression coefficients, and the random term of the regression model. This sample is used as input for the regression model to obtain 1000 values from the uncertainty distributions of the log(Cd) and log(Pb) concentration in wheat. There were no nodes where the recent EU quality standards for Cd and Pb (0.2 mg kg(-1) fresh wt.) in wheat were almost certain to be exceeded. For most nodes with clay soils, the quality standard for Cd in wheat almost certainly will not be exceeded; for Pb this is much less certain. The uncertainty in the Cd concentration in soil contributes most to the uncertainty in the predicted Cd concentrations in wheat (36% on the average), followed by the random term of the regression model (23%). For Pb the contribution of the random term is by far the largest (52%).