Metals In Maize Research Articles

Heavy metal contamination in soil and food crops and associated human health risks in the vicinity of Iringa Municipal dumpsite, Tanzania

Heavy metal contamination and potential risks to human health related to consuming major food crops near Iringa Municipal dumpsite are presented. Soil samples, maize (Zea mays L.) and common beans (Phaseolus vulgaris L.) were collected downslope around the dumpsite during wet season. Soil samples were analyzed using Energy-Dispersive X-Ray Fluorescence (EDXRF) while crop (maize and beans) samples were analyzed using Flame Atomic Absorption Spectrophotometer (FAAS). The potential health risks associated with human exposure to heavy metals in maize and common beans was evaluated according to the method prescribed by the United States Environmental Protection Agency. The concentrations Cd (3.25–10.78 mg/kg), As (1.84–10.98 mg/kg) and Ni (71.74–55.10 mg/kg) in soil samples exceed the maximum allowable limits set by Tanzania Bureau of Standards (TBS). The average heavy metal concentration in food crops followed the trend Cd, As < Cr, Pb < Ni < Cu < Mn < Zn with Pb in maize (0.96 mg/kg) and common beans (0.81 mg/kg) above FAO/WHO regulatory standards of 0.3 mg/kg. This implied health concerns to consuming food crops grown in the vicinity of the dumpsite. Further, lifetime–incremental cancer risk (ILCR) assessment suggest that consuming maize and common beans from the study area could increase the risk of both cancer and non-cancerous diseases in both adults and children. However, the degree of ILCR in children was noticeably higher (1.0 × 10–2) than in adults (5.10. × 10–6) for Pb in common beans. Therefore sustainable waste management should be stressed and continuous monitoring of environments around dumpsites is crucial to mitigate the negative impacts on public and environments.

Seasonal variation and uptake pattern of heavy metals in maize

The detrimental impact of heavy metals on human health necessitates a focus on their contamination in the food chain. Heavy metals possess carcinogenic, mutagenic, teratogenic, and endocrine-disrupting properties. The objective of the study was to ascertain how Zn, Pb, Cd, Ni, Co, Cu, Cr, and Hg are accumulated in the roots and grains of maize samples cultivated under the Kano River Irrigation Project during both wet and dry seasons production and subsequently compare the levels of these heavy metals with the recommended permissible limits established by FAO/WHO. Additionally, the research sought to employ Translocation Factors to examine the uptake pattern of heavy metals in maize during the two growing seasons. Maize samples were procured from 10 different locations within the irrigation scheme during 2022 wet season and 2023 dry season harvests. The samples were prepared using standard laboratory protocols and heavy metals were determined using atomic absorption spectrophotometer. The heavy metals accumulation in maize grains was found in the order Zn&gt;Cu&gt;Pb&gt;Ni&gt;Co during wet season production. Cd, Cr, and Hg were not detected in samples collected during the wet season. It is only the concentration of Zn that exceeded the permissible limit in the samples collected during wet season production. The accumulation order during the dry season was Zn&gt;Cu&gt;Cr&gt;Pb&gt;Ni&gt;Co&gt;Cd. Hg was not detected in all the maize grain samples. The concentrations of Zn, Pb, Cd and Cr exceeded permissible limits in maize grains samples collected during dry season production.

A Comparative Assessment of Concentrations of Heavy Metals in Un-soaked and Soaked Maize (Zea mays) and Guinea Corn (Sorghum bicolor) sold in Port Harcourt, Rivers State, Nigeria

Food is the most vital component of human existence. Maize and guinea corn purchased from open market in Port Harcourt, Rivers State, Nigeria were divided each into two group. One group was soaked in distilled water for four days and the other group remain unsoaked. After four days, they were both even dried to constant weight and digested using nitric acid and hydrogen peroxide. The digest were analyzed for heavy metals using atomic absorption spectrophotometer model model SN – SG 10960. The result obtained showed higher value of metals in the unsoaked grains as against the soaked grains. The percentage removal of metals in maize was 22.999, 19.867, 100, 1.252, 9.953, 10.198, 7.007 and 4.412% for Pb, Cr, As, Fe, Zn, Ni, Cu and Mn respectively. For guinea corn, the percentage removal of the metal after soaking were; 51.592, 25.491, 100, 1.139, -8.365, 23.292, 7.585 and 22.661% for Pb, Cr, As, Fe, Zn, Ni, Cu and Mn. However, Cd was not detected in any of the samples and Zn content in guinea corn slightly increased in value. The result implied that soaking of cereals before preparation for human consumption could be an important source of removal of toxic metals from food.

Heavy metal contamination assessment and probabilistic health risks in soil and maize near coal mines.

ObjectiveCoal mining activities have continuously introduced heavy metals into the soil–crop system, causing increasing damage to crops. This study integrated the analysis of the heavy metal contamination status and human health risk in soil and maize near coal mines to help formulate control strategies for soil quality, maize production, and safe consumption.MethodThis study was carried out on maize agricultural land near a coal mining plant. Heavy metal contamination was assessed by the geo-accumulation index (Igeo), enrichment factor (EF), and bioaccumulation factor (BCF). The Monte Carlo simulation was used to estimate the probabilistic health risk of heavy metals exposure in soil and maize. The relationship between the concentration of heavy metal in the soil and that in maize was further visualized by correlation analysis and random forest analysis.ResultsThe results revealed that the mean concentrations of soil Ni, Cu, As, Cd, Sn, Zn, Pb, and Hg were all above the local background level. Ni was the most severely polluted heavy metal in maize and had a concentration higher than the risk control standard for corn in China (NY 861-2004). The Igeo values of all heavy metals were low, and EF values showed enrichment in V, Cr, Ti, Ni, and As. The assessment of probabilistic health risk exposed by heavy metals in soil and maize indicated that 1.16 and 1.46% of residents exceeded the carcinogenic risk level due to heavy metal exposure from soil and maize, respectively. Children were the most sensitive to maize and soil heavy metal exposure in the contaminated area. Ingestion of heavy metals was associated with the highest health risk to residents, followed by dermal contact and inhalation. As and Cr in soil and Cr and Ni in maize had the greatest impact on human health risk. Furthermore, maize heavy metals were affected the most by soil Cr, Cd, and V.ConclusionThese results may provide useful information for human carcinogenic risk associated with soil and maize heavy metal exposure due to coal mining activities.

Role of Different Material Amendments in Shaping the Content of Heavy Metals in Maize (Zea mays L.) on Soil Polluted with Petrol.

Petroleum substances are among the xenobiotics that most often contaminate the natural environment. They have a strong effect on soil, water, and other components of the environment. The aim of this pot experiment has been to determine the effect of different soil material amendments (compost, 3%; bentonite, 2% relative to the soil mass or calcium oxide, in amounts corresponding to one full hydrolytic acidity) on the content of heavy metals in aerial parts of maize (Zea mays L.) grown on soil polluted with petrol (0, 2.5, 5, and 10 cm3 kg−1 of soil). The content of all heavy metals, except copper, in the aerial biomass of maize was positively correlated, but biomass yield negatively correlated, with the increasing doses of petrol. The highest increase in the content of heavy metals was noted for chromium and manganese. Materials used for phytostabilisation (compost, bentonite, and calcium oxide) had a significant effect on the content of heavy metals and biomass yield of maize. They contributed to the modified accumulation of elements, especially chromium, copper, and cobalt in the aerial biomass of maize. In comparison with the control series (without material amendments), the application of calcium oxide proved to be most effective. It had the most evident influence on the chemical composition of maize, limiting the accumulation of lead, zinc, manganese, and iron and increasing biomass yield.

Effect of inorganic and organic amendments on maize biomass, heavy metals uptake and their availability in calcareous and acidic washed soil

Abstract Soil washing with chelators followed by addition of amendments has been used for remediating heavy metals contaminated soil. This study investigated the effects of amendments (Ca(OH)2, biochar and chicken manure) on maize (Zea mays L.) biomass, heavy metals uptake and heavy metals availability in mixed chelator (MC)-washed soils. The results showed that the stem–leaf and root biomass of maize increased by 102.94% and 52.34% in the acidic MC-washed soil with Ca(OH)2 and chicken manure, respectively, compared with the acidic MC-washed soil without amendments. Compared with the calcareous MC-washed soil, the addition of amendments in acidic MC-washed soil that had a significant effect on reducing metal concentration in stem–leaf of maize. Among the amendments, Ca(OH)2+Chicken manure most effectively decreased the uptakes of Cd, Pb, Cu, and Zn in stem–leaf of maize planted in the acidic MC-washed soil by 89.7%, 52.8%, 57.7%, and 60.2%, respectively, compared with the acidic MC-washed soil without amendments. The reason for this finding is that the amendments significantly decreased the transfer factor of heavy metals in maize. Therefore, the combination of Ca(OH)2 and chicken manure has the potential feasibility for the restoration of MC-washed soil, especially for the acidic MC-washed soil.

Effect of Organic Manure and Mineral Fertilizers on Bioaccumulation and Translocation of Trace Metals in Maize.

Mineral fertilizers and organic manure are used as soil amender to enhance the mineral status of the soil. These fertilizers contain trace metals besides providing macro and micronutrients. The present study was performed to observe the effect of mineral fertilizers, poultry manure and cow manure on trace metal content of soil and various parts (root, shoot, and grains) of maize plant (Zea mays L.). The analysis of metals was performed by atomic absorption spectrophotometer (AA-6300 Shimadzu Japan). The highest level of Pb, Fe, Ni and Cu was observed in the root as 0.36-0.55, 70.41-83.03, 4.98-7.44 and 2.94-4.43 mg kg- 1, respectively. The highest level of Cd, Zn and Mn was determined in grains as 0.44-1.59, 28.05-46.39 and 26.24-46.57 mg kg- 1, respectively. The values of all metals were found within their permissible limit given by FAO/WHO except for the Cd. The interactive use of mineral and organic fertilizers enhanced the level of trace metals in maize as compared to their sole application. In the present findings, the health risk index for all metals was less than 1 in all treatments. So, it was concluded that the level of metals in poultry manure, cow manure and mineral fertilizer treated maize did not pose any potential threat to the consumers.

Prediction and risk assessment of five heavy metals in maize and peanut: A case study of Guangxi, China

To assess the contamination levels and health risk of cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), and zinc (Zn) to human beings, the concentrations of these heavy metals in soil were surveyed and the concentrations in maize and peanut grains were estimated by models. The geo-accumulation index (I geo) was calculated, and chronic daily intake (CDI), hazard quotient (HQ) and hazard index (HI) were estimated. Results indicated that the concentrations of Cd, Cu, Hg, Pb, and Zn in the soil samples exceeded the limit set by authorities in China. However, the concentrations in maize and peanut grains were rarely higher than the allowable concentrations suggested by the Ministry of Health of China (MHC). In accordance with geo-accumulation, these heavy metals in soil samples were polluted to different extents. Prediction models were developed to effectively assess the health risk of using TOC, Mn, pH, and CaO to human beings. Therefore, the concentrations of these heavy metals in the grains could be decreased by changing their levels in soil. The CDI, HQ, and HI were estimated by estimating concentrations of Cd, Cu, Pb, and Zn in maize grains, indicating that these metals exhibited a slight health risk to adult residents.

Evaluation of Health Effect of Some Selected Heavy Metals in Maize Cultivated in Katsina State, North West Nigeria

This study was conducted to determine the heavy metals concentration in maize cultivated in Katsina state Nigeria. The objectives were mainly to detect the presence of heavy metals in the cultivated maize in the study area, compare the concentration of heavy metals in samples in relation to the permissible limits specified by WHO/FAO/USEPA Standards and asses the health risks to the local consumers. Samples of cultivated maize were collected in the year 2017 from the selected areas. Analysis for the concentration of these heavy metals; Cr, Cd, Fe, Ni, Mn, Pb and Zn was conducted by the use of AAS (by Atomic Absorption Spectrophotometry) method. The health risks to the local inhabitants from the consumption of the samples were evaluated based on the Target Hazard Quotient (THQ). The possibility of cancer risks in the samples through the intake of carcinogenic heavy metals was estimated using the Incremental Lifetime Cancer Risk (ILCR). Results from this study have shown that with the exception of the heavy metal Pb the concentration values of Cr, Cd, Fe, Mn and Zn in the samples were generally lower than the USEPA, WHO/FAO maximum permissive limits. The results have also indicated that the estimated daily intake of the heavy metals was lower than the tolerable daily intake limit set by the USEPA in all samples. The risk level of Target Hazard Quotient (THQ &lt; 1) was observed for all the evaluated heavy metals for both adults and children.. The THQ for the samples was in the decreasing order Zn&gt;Pb&gt;Fe&gt;Cr&gt;Cd, for all the samples respectively. All the studied samples showed the hazard index (HI &lt; 1) with highest in the sample from Dabai and lowest in the sample from Funtua. In adults the ILCR for Cd violated the threshold risk limit (&gt;10−4) in all the studied samples, while the ILCR for Pb reached the moderate risk limit (&gt;10−3) except for the sample from Kafur which is above the limit (&gt;10−2). In children ILCR for Cd in all samples and Pb for samples from Birchi, Katsina and Malunfashi has reached the moderate risk limit (&gt;10−3) while the ILCR for Pb in samples from Dabai, Funtua and Kafur is above the limit (&gt;10−2). The trend of risk for developing cancer as a result of consuming the studied maize samples showed: Kafur&gt; Dabai &gt; Funtua&gt; Malunfashi &gt; Katsina. Cumulative cancer risk (∑ILCR) in adults of all the studied maize samples reached the moderate risk limit (&gt;10−3) except for sample from Kafur which is above the moderate risk limit (&gt;10−2). While the cumulative cancer risk (∑ILCR) in children of all the studied maize samples is above the moderate risk limit (&gt;10−2) except for sample from Katsina which is within the moderate risk limit (&gt;10−3). Among all the studied samples maize sample from Kafur has the highest chances of cancer risks (ILCR 1.297980 × 10−2 in adults, 1.510018 × 10−2 in children) and sample from Katsina has the lowest chances of cancer risk (ILCR 1.68603093 × 10−3 in adults, 7.775840 × 10−3 in children). The study suggests that consumption of the studied maize samples in Katsina state is of public health concern as they may contribute to the population cancer burden.

Chemical composition and in vitro digestibility of whole-crop maize fertilized with synthetic fertilizer or digestate and harvested at two maturity stages in Boreal growing conditions

Maize cultivation for silage could be a sustainable option in Boreal conditions, especially when combined with nutrient recycling. Effects of digestate (sludge from biogas of domestic origin) application in comparison with synthetic fertilizer and two maturity stages on chemical composition and in vitro digestibility of whole-crop maize were investigated. Starch, neutral detergent fiber, water soluble carbohydrate (WSC) and digestible organic matter (DOM) contents of maize did not differ in response to the two fertilizer treatments. However, starch, DOM and metabolizable energy of maize increased, while ash, crude protein and WSC contents decreased with increasing maize maturity. Heavy metals in maize fertilized with digestate remained low. The results indicate that whole-crop maize fertilized with digestate and harvested at 150 days after sowing is a promising feed and has good nutritive value, even in Boreal conditions.

Distribution of heavy metals in maize and mudflat saline soil amended by sewage sludge

Sewage sludge has been considered as the economic choice for soil amendment. However, whether sewage sludge can effectively amend mudflat saline soil remains unclear. This paper was one of first studies to fill this knowledge gap by assessing the persistent effects of one-time application of sewage sludge on distribution of heavy metals in maize (Zea mays L.) grown in mudflat saline soil. On the premise of total amount of heavy metals from sewage sludge being in compliance with agricultural standard in China (GB/T 24600-2009), sewage sludge was used through one-time application, with the rates of 0, 30, 75, 150, and 300 t ha−1, to amend infertile mudflat soils. Ryegrass, Sesbania, and ryegrass were chosen as green manures for three consecutive seasons, successively planted and tilled. Maize was chosen as a test crop and sowed in 10th July 2013 and harvested 72 days after sowing. The results indicated that the sewage sludge amendment (SSA) increased uptake of cadmium (Cd), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) in maize tissues, whereas it did not inhibit maize growth, and dry matter of maize plant tissues increased with increasing SSA rates. Total Cd, Cu, Pb, and Zn concentrations in mudflat soil increased with increasing SSA rates, but there were no significant changes in total Mn and Ni concentration in response to SSA. The highest Cd, Cu, Mn, Ni, and Pb concentrations were observed in roots of maize, and the root system acted as a barrier for metals, so metal uptake and translocation were lower in aerial parts of maize plant. The labile fraction of Cd, Cu, Mn, Ni, Zn, and immobile fraction of Pb in the sludge-amended soils increased with increasing SSA rates. The metal levels in grains were negligible in all the treatments and below the maximum permitted concentrations as specified in the national control standard in China (GB2715-2005). Sewage sludge can be applied with green manure for mudflat saline soil amendment, which provides an innovative solution for arable land resources and solid waste disposal.

The Impact of the Type of Soil Contaminated with Heavy Metals on the Risk of their Translocation to the Consumption Parts of Maize

Abstract The purpose of the research was to examine the extent to which the type of soil co-contaminated with Cd, Pb and Zn affected the accumulation and distribution of these metals in maize; a crop that plays a significant role in feeding of animals and humans. Two 1-year microplot experiments were conducted using four types of soils. The soils were as follows: sandy soil with a low content of organic matter (S1), sandy soil of analogical granu-lometric composition, but with a higher content of organic mat-ter (S2), loess poor in organic matter (L1) and the same loess with its higher content (L2). The differences between the soils in terms of the availability of individual metals for maize and their transport from the roots to the aerial parts were evaluated on the basis of bioaccumulation factors (BF) and translocation indexes (TL). It was found that maize cultivation on the soil poorly pol-luted with Cd, Pb and Zn, regardless of its type, poses the dan-ger of translocation of these metals to the grains in the amounts exceeding the maximum limit in foods. However, the amount of metals accumulated in the grain, as well as in the cobs, do not exclude the use of these plant parts for feed.

Quantitative trait loci mapping of metal concentrations in leaves of the maize IBM population.

Characterizing concentrations of several beneficiary and toxic metals in maize leaves is of importance for ionomic studies and for silage production. The intermated B73 × Mo17 maize population (IBM) was evaluated for concentrations of eight metals (cadmium - Cd, copper - Cu, iron - Fe, potassium - K, magnesium - Mg, manganese - Mn, strontium - Sr and zinc - Zn) in ear-leaf to map quantitative trait loci (QTL) with 2161 molecular markers across the genome. QTL analysis revealed nine significant QTLs for concentrations of Cd, Cu, Fe, K, Mg and Sr combined over two environments. Median resolution for the QTL interval was less than 1 cM on a regular F2 map, which is a big improvement compared with the prior mapping (8 cM). The highest LOD scores of 15.52 and 15.31 were detected for K and Cd concentrations, respectively, explaining more than 20 percent of the phenotypic variance. No QTLs were found to be colocalized. QTL mapping in the IBM population did not confirm our earlier QTL results demonstrating considerable QTL ×genetic background interaction. The only exception is confirmation of the major QTL for Cd accumulation on chromosome 2. Our results could facilitate further genetic and physical mapping of genes for metal accumulation in maize.

Evaluation of Heavy Metal Concentration in Maize Grown in Selected Industrial Areas of Ogun State and its Effects on Urban Food Security

This project was carried out to investigate the effect industrial pollution as it affects the heavy metal concentrations flared into the atmosphere, washed down by rain and absorb by maize cultivated in industrial areas of Ogun State. This was suspected to have effects on food safety .In addition to determine the effect of soil factor and the accumulation of metals in maize. This study also ascertained the basis for environmental protection and reduction of the negative implication of heavy metals in the human and livestock health. Maize and soil samples were collected from industrial areas in Ogun State and were analyzed for both chemical and metal concentrations. The metals Fe, Cu, Mg, Ni, Pb, Ca, and Co were determined using Atomic Absorption Spectrophotometer (AAS). The results of the chemical analysis of the maize collected from the industrial areas of Ogun State ranged between 6.35-9.45%, 8.31-12.68%, 1.49-8.294% 1.746-2.792%, and 71.32-78.896% for moisture, crude protein, ether extract, and carbohydrate respectively while the chemical analysis of the soil ranged between 0.65-1.90%, 6.63-7.89%, and 4.01-8.6% for moisture, pH, and nitrogen content respectively. The concentrations of the metals Fe, Cu, Mg, Ni, Pb, Ca, and Co in maize ranged between 28.5-59.5mg/kg, 2-10.7mg/kg, 248.3-321mg/kg, 1.8-4.775mg/kg, 62.5-150mg/kg, and 1.2-10.2mg/kg respectively while the concentrations of the soil samples were 28.9-59.6mg/kg, 4-12.2mg/kg, 297.3-350.5mg/kg, 4.55-9.28mg/kg, 83.3-177.5mg/kg, 7.6-21.8mg/kg, and 0.075-0.46mg/kg for Fe, Cu, Mg, Ni, Pb, Ca, and Co respectively. Some of the metals such as Ni in Ewekoro, Pb in Sango, exceeded the recommended limits proposed by WHO/FAO. The results showed that the high concentrations of certain heavy metals in maize revealed the level of food insecurity and this calls for public concern.

Further characterization of ferric--phytosiderophore transporters ZmYS1 and HvYS1 in maize and barley

Roots of some gramineous plants secrete phytosiderophores in response to iron deficiency and take up Fe as a ferric–phytosiderophore complex through the transporter YS1 (Yellow Stripe 1). Here, this transporter in maize (ZmYS1) and barley (HvYS1) was further characterized and compared in terms of expression pattern, diurnal change, and tissue-type specificity of localization. The expression of HvYS1 was specifically induced by Fe deficiency only in barley roots, and increased with the progress of Fe deficiency, whereas ZmYS1 was expressed in maize in the leaf blades and sheaths, crown, and seminal roots, but not in the hypocotyl. HvYS1 expression was not induced by any other metal deficiency. Furthermore, in maize leaf blades, the expression was higher in the young leaf blades showing severe chlorosis than in the old leaf blades showing no chlorosis. The expression of HvYS1 showed a distinct diurnal rhythm, reaching a maximum before the onset of phytosiderophore secretion. In contrast, ZmYS1 did not show such a rhythm in expression. Immunostaining showed that ZmYS1 was localized in the epidermal cells of both crown and lateral roots, with a polar localization at the distal side of the epidermal cells. In maize leaves, ZmYS1 was localized in mesophyll cells, but not epidermal cells. These differences in gene expression pattern and tissue-type specificity of localization suggest that HvYS1 is only involved in primary Fe acquisition by barley roots, whereas ZmYS1 is involved in both primary Fe acquisition and intracellular transport of iron and other metals in maize.