Metal Concentrations In Grain Research Articles

Foliage application of selenium and silicon nanoparticles alleviates Cd and Pb toxicity in rice (Oryza sativa L.)

Direct discharge of untreated industrial waste water in water bodies and then irrigation from these sources has increased trace metals contamination in paddy fields of southern China. Among trace metals, cadmium (Cd) and lead (Pb) are classified as most harmful contaminants in farmland to many organisms including plants, animals and humans. Rice is a staple food which is consumed by half population of the world; due to longer growth period it can easily absorb and accumulate the trace metals from soil. The objective of study was to check the efficacy of Se and Si NPs (nanoparticles) alone or in combination on metals accumulation and Se-fortified rice (Oryzasativa L.) production as their efficiency remained untested. Alone as well as combined application of Se- and Si-NPs (5, 10 and 20 mg L−1) was achieved along with CK. All the treatments significantly reduced the Cd and Pb contents in brown rice, except CK, Se3, Si1 and Se1Si3. Combined application of Se and Si (Se3Si2) was more effective in reducing the Cd and Pb contents by 62 and 52%, respectively. In addition, foliar application of both NPs improved the rice growth and quality by increasing the grain yield, rice biomass, and Se contents in brown rice. Highest concentration of Se (1.35 mg kg−1) in brown rice was observed with combined application of Se- and Si-Nps (Se3Si2). Selenium speciation revealed the presence of organic species (74%) in brown rice. The combinations of different doses of Se- and Si-Nps are the main determining factor for total concentration of metals in grains. These results demonstrate that foliage supplementation of Se and Si-Nps alleviate the Cd and Pb toxicity by reducing the metals' concentration in brown rice. Additionally foliage supplementation improved the nutritional quality by reducing the phytic acid contents in rice grains.

Influence of Soil Amendments on Uptake and Accumulation of Cd and Pb in Maize (Zea maysL.)

China has a large population in comparison with its arable land area, as well as environmental problems caused by metal pollution, leading to significant food supply pressure. Therefore, safe agricultural production in metal-contaminated soil is of great significance. To explore the effectiveness of techniques designed to inhibit metal uptake and accumulation in maize cultivated in calcareous metal-contaminated soil, a pot experiment was performed. Effects of KH2PO4 (P), Na2SiO3 (S), chicken manure (M), bentonite (B), P+M, S+M, P+M+B, and S+M+B on Cd and Pb concentrations in maize grain were assessed. Amendments of P, P+M, and P+M+B fortified into the soil reduced soil Cd and Pb availability significantly and decreased the soil pH, but other amendments did not cause such changes. Results also showed that all tested soil amendments improved maize yield and decreased grain Cd and Pb concentrations. Among the amendments, P + M was most effective. A high dose increased maize yield by 48.2% and 38.9% for low-Cd-accumulating cultivar Tiantai 60 (maize A) and high-Cd-accumulating cultivar Longping 206 (maize B) and decreased Cd content in grain from maize A and maize B by 64% and 41.9% and decreased Pb content by 61.0% and 52.3%. Experimental results demonstrated that addition of P + M into the calcareous soil could reduce soil metal bioavailability and ultimately reduce metal concentrations in grain to levels deemed safe for human consumption.

Sewage sludge as an initial fertility driver for rapid improvement of mudflat salt-soils

Sewage sludge is by-product in the process of centralized wastewater treatment. Land application of sewage sludge is one of the important disposal alternatives. Mudflats in the interaction zone between land and sea can be important alternative sources for arable lands if amended by large amount of organic fertilizers. Rich in organic matter and other nutrients, sewage sludge has been considered as the economic choice for an initial fertility driver. However, sewage sludge amendment has been greatly hampered due to availability of potential toxic metals. Using sewage sludge in compliance with the national standards for agricultural usage could avoid the accumulation of heavy metals. Nevertheless, it is not clear whether massive input of sewage sludge would increase heavy metals concentration in crops. The objective of this study was to investigate impact of sewage sludge amendment (SSA) as an initial fertility driver by one-time input, with the rates of 0, 30, 75, 150, and 300tha−1, on biomass of green manures, soil chemical properties, and growth and heavy metals uptake of maize (Zea mays L.) grown in mudflat soil. Results showed that one-time sewage sludge amendment promoted an initial fertility for infertile mudflat soil, supported growth of ryegrass as the first season green manure. By tilled ryegrass, it modified the chemical properties of mudflat soil by increasing soil organic carbon, total and available N and P, and decreasing soil salinity and pH, which promoted subsequent growth of two green manures for sesbania and ryegrass. The sewage sludge as an initial fertility driver combined with planting and tilling green manures, increased dry matter of the aerial part and grain yield of maize grown in mudflat soil. Cd and Ni concentrations in grain of maize were positively correlated with sewage sludge amendment rates. Importantly, heavy metal concentrations in grain of maize at all SSA rates did not exceed the safety standard for food in China (GB 2762-2012). The study suggests that sewage sludge can be applied as an initial fertility driver for mudflat soil amendment, which provides an innovative solution for arable land resources and solid waste disposal.

Assessment of Hazardous and Essential Elements in a Food Crop Irrigated with Municipal Sewage Water: Risk Appraisal for Public Health

ABSTRACTTo assess the impact of sewage water on metal accretion in selected diverse varieties of wheat (i.e., Lasani-2008, ARRI-10, Faisalabad-83, Punjab-85, Aas-2010, and Sehar-2006), their seeds were sown in pots containing soil. The results showed that the concentration of heavy metals in grains from the wheat plants supplied with sewage water was considerably higher than the plants supplied with canal irrigation water (control). In canal water irrigated wheat grains the metal concentrations (mg/kg) ranged from 2.20–3.5 for Cu, 12.50–32.4 for Zn, 22.45–35.22 for Mn, 0.05–0.15 for Pb, 0.012–0.029 for Cd, 2.5–5.3 for Ni, 18.16–29.63 for Fe, and 0.90–3.64 for Cr in different wheat varieties, whereas the wheat grains raised from sewage water, had metal concentrations (mg/kg): 3.8–5.30 for Cu, 29.60–40.50 for Zn, 32.9–50.40 for Mn, 1.14–7.50 for Pb, 0.26–0.42 for Cd, 3.90–7.55 for Ni, 32.21–40.35 for Fe, and 2.88–7.84 for Cr. Since these metals bioaccumulate in wheat grains with unremitting use of metal-enriched wastewater, care has to be taken for irrigating wheat plants with household wastewater for a longer time, particularly in those soils where this crop is grown regularly.

Atmospheric Deposition and Heavy Metal Contamination in an Organic Farming System in a Seasonally Dry Tropical Region of India

Increased consciousness about agricultural sustainability and health risks associated with agrochemicals has lead organic farming to be a globally emerging alternative farm practice. We report the effect of atmospheric deposition on soil quality and heavy metal contamination of agricultural produce under an organic farming system using wheat and corn as test crops. Data obtained in the open field (OFO) were compared with a plastic-covered glass-house-grown system (OFG). The results showed that depositions of Cd, Cu, Ni, Pb, and Zn increased with time. Soil porosity, water holding capacity, microbial biomass carbon (Cmic), substrate-induced respiration (SIR), alkaline phosphatase, and FDAase activity decreased, whereas the bulk density and contents of Cd, Cu, Ni, Pb, and Zn increased over time in open plots receiving atmospheric deposition. Concentrations of metals in grains in OFO crops exceeded the safe limits of Indian standards and were three to sixfold higher than those recorded in OFG plots. These results indicate that atmospheric deposition of heavy metals can have a destabilizing effect on soil fertility in organic farming and can greatly increase the dietary intake of toxic metals. This may have long–term implications for human health as well as for agricultural sustainability. The data presented here have particular concern for developing countries, where unprecedented urban–industrial growth and consequently increased input fluxes of heavy metals will continue for decades to come.

Genotypic and environmental variation in cadmium, chromium, arsenic, nickel, and lead concentrations in rice grains

Genotypic and environmental variation in Cd, Cr, As, Ni and Pb concentrations of grains, and the relationships between these heavy metals and Fe, Zn were investigated using 9 rice genotypes grown in 6 locations for two successive years. Significant genotypic variation was detected in the five heavy metal concentrations in grains, indicating the possibility to reduce the concentration of these heavy metals in grains through breeding approach. The environmental effect varied with metal, with Pb and Ni having greater variation than the other three metals. There was significant genotype-environment (location) interaction of the concentrations of all five heavy metals in grains, suggesting the importance of cultivar choice in producing rice with low heavy metal concentrations in grains for a given location. Correlation analysis showed that Cd and As, Cr and Ni, and As and Pb concentrations in rice grains were closely associated, and that Ni concentration in grains was negatively correlated with Zn concentration.

The effect of biosolids on cereals in central New South Wales, Australia. 2. Soil levels and plant uptake of heavy metals and pesticides

Two forms of biosolids, with and without lime, were applied to acid soils at 2 sites growing wheat and triticale in central New South Wales. The forms of biosolids used were dewatered sewage sludge cake, and N-Viro Soil which is a lime-amended sewage sludge. Dewatered sewage sludge cake was applied at rates of 0, 6, 12 and 24 dry Mg/ha, and N-Viro soil at 0, 1.5, 3.0 and 4.5 dry Mg/ha. The soil was sampled and analysed at 2 points in time to determine the effect of the biosolids on heavy metal concentrations. Vegetative plant material and grain were also analysed for heavy metal and organo-chlorine pesticide levels. Zinc and copper concentrations increased significantly with the addition of biosolids, especially with the highest rates of dewatered sewage sludge cake. However, all soil heavy metals were below the maximum allowable soil contaminant concentrations set by Environment Protection Authority, NSW. Cereal species, the addition of lime, and biosolids each affected heavy metal concentrations in plant material, but the responses differed between sites. Also, the changes in heavy metal concentrations in plant material were smaller and less consistent than the changes in soil heavy metal concentrations. The maximum heavy metal concentrations in grain were all below the maximum permitted concentrations of Food Standards Australia New Zealand. There were no detectable changes in the levels of organo-chlorine pesticides in the grain.

Contamination of wheat crops around a lead-zinc smelter

Wheat grown in contaminated soils adjacent to a lead-zinc smelter contained higher concentrations of lead, zinc and cadmium than wheat grown on uncontaminated soils. The distribution of crop contamination closely corresponded to the distribution of contaminated soils. Heavy metal concentrations in grain did not arise by surface contamination even at sites closest to the smelter. In grain grown on polluted soils, the heavy metal concentrations did not exceed prescribed health standards, and should not present any risk to human health.