Bioavailability Of Ni In Soils Research Articles

Calcite in combination with olive pulp biochar reduces Ni mobility in soil and its distribution in chili plant

The presence of Ni above the permissible limit in agriculture soils poses negative effects on soil health, crop quality, and crop productivity. Surprisingly, the usage of various organic and inorganic amendments can reduce Ni mobility in the soil and its distribution in the crops. A pot experiment was conducted to elucidate the effects of olive pulp biochar (BR), calcite (CAL), and wheat straw (WS), as sole amendments and their mixtures of 50:50 ratio, added to Ni polluted soil on Ni mobility in the soil, Ni immobilization index (Ni − IMi), soil enzymatic activities, Ni distribution in parts of chili plant, Ni translocation factor and bioaccumulation factor in fruit, plant growth parameters and oxidative stress encountered by the plants. Outcomes of this pot experiment revealed that amendments raised soil pH, improved soil enzymatic activities, values of Ni − IMi, while significantly reduced bioavailable Ni fraction in the post-harvest soil. However, the highest activities of acid phosphatase, urease, catalase, and dehydrogenase by 50, 70, 239, and 111%, respectively, improvement in Ni − IMi up to 60% while 60% reduction in the bioavailable Ni fraction was observed in BR + CAL treatment, compared to control was noted. Among all amendments, the top most reduction in Ni concentrations in shoots, roots, fruit, Translocation Factor (TF), and Bioaccumulation Factor (BAF) values of fruit by 72%, 36%, 86%, 72%, and 86%, in BR + CAL treatment, compared to control. Moreover, the plants growing on BR + CAL amended Ni contaminated soil showed the topmost improvement in plant phonological parameters while encountered the least oxidative stress. Such findings refer to the prospective usage of BR + CAL at 50:50 ratio than BR, CAL, WS alone, and BR + WS as well as WS + CAL for reducing Ni mobility in the soil, improving Ni − IMi, soil enzymatic activities, plant phonological and oxidative stress while reducing Ni distribution in plant parts. Novelty statement In this experiment, it was hypothesized that amending Ni polluted soil with olive pulp biochar (BR), CAL, and WS as alone soil amendments and their combinations at 50:50 ratios can reduce Ni bioavailability in soil, Ni distribution in chili plant and oxidative stress encountered by the plants. Moreover, these amendments may improve, soil enzymatic activities, Ni immobilization index, plant phenological traits. Therefore, it was aimed to undertake useful scientific planning and research, to restore and rehabilitate the dwellings, biological resources and to minimize the sufferings of the peoples in nutrient-poor Ni contaminated soils, by improving soil health and chili productivity.

Gastric bioaccessibility is a conservative measure of nickel bioavailability after oral exposure: Evidence from Ni-contaminated soil, pure Ni substances and Ni alloys.

Oral bioaccessibility (BAc) is a surrogate for the bioavailability (BAv) of a broad range of substances, reflecting the value that the approach offers for assessing oral exposure and risk. BAc is generally considered to have been validated as a proxy for oral BAv for the important soil contaminants Pb, Cd, and As. Here, using literature data for Ni BAc and BAv, we confirmed that Ni BAc (gastric only, with HCl mimicking stomach conditions) is a conservative measure of BAv for the oral exposure pathway. Measured oral BAv of Ni in soil was shown to be 50-100 times less than the simplest oral BAc estimates (%BAv=0.012(%BAc) - 0.023 (r=0.701, 95%CI [0.456, 0.847], n=30)) in rats, demonstrating a significant conservatism for exposure assessment. The relationship between the oral BAv and BAc of nickel sulfate hexahydrate (NSHH) was comparable to that of soil, with measured oral BAv of NSHH (1.94%) being a small fraction of NSHH gastric BAc (91.1%). BAc and BAv reflect the underlying Ni speciation of the sample, with the bioaccessible leaching limits being represented by the highly soluble Ni salts and the poorly soluble Ni monoxide, and the environmental (e.g. soil properties) or gastric (e.g. food present) conditions. BAc has potential utility for chemical classification purposes because pure Ni substances can be grouped by %BAc values(using standardized methodologies for the relevant exposure routes), these groupings reflecting the underlying chemistry and speciation of the samples of substances tested here, with 0.008% %BAc for alloys (SS304, SS316, Inconel, Monel), <1% in green NiO and Ni metal massives, 0.9-23.6% for Ni powders, 9.8-22.7% for Ni sulfides, 26.3-29.6% for black oxidic Ni, and 82-91% for the soluble Ni salts. Oral BAc provides realistic yet conservative estimates of BAv for the hazard classification and risk assessment of Ni substances.

Impact of chitosan on nickel bioavailability in soil, the accumulation and tolerance of nickel in Calendula tripterocarpa

Excessive heavy metals in medicinal plants cause critical health issues to humans. Therefore, in the present study, the effect of soil amendment with chitosan (0, 0.125, 0.25, 0.5, and 1%) on bioavailability and tolerance of nickel in Calendula tripterocarpa grown in a soil spiked with Ni (100 and 150 mg/kg soil) was investigated. The results showed that Ni toxicity significantly reduced plant growth and content of chlorophyll a, b but increased carotenoid levels, lipid peroxidation, and catalase (CAT) and superoxide dismutase (SOD) activities in roots and shoots. The Ni bioaccumulation was significantly higher in shoots than roots. The soil amendment with chitosan reduced Ni bioavailability in soil, as well as lowered the biological accumulation of Ni in roots and shoots, and Ni transfer to leaves. The chitosan application also increased growth parameters and levels of chlorophyll a, b and carotenoids under both normal and Ni stress conditions. Furthermore, chitosan reduced the level of malondialdehyde and the activities of SOD and CAT in roots and shoots under Ni stress. In conclusion, results indicated that chitosan through lowering bioavailability of Ni in soils can remarkably relieve adverse effects of Ni toxicity in C. tripterocarpa.

Influence of Soil Bioamendments on the Availabilty of Nickel and Phytoextraction Capability of Marigold from the Contaminated Soil

Phytoremediation is an emerging technology involved in heavy metal remediation processes. It is evident from the several researches that the bioamendments greatly influences various biochemical processes and thus enhance the bioavailability of metals in the contaminated soil. It should favour greater absorption (removal) of metals by plants. Therefore, a pot experiments was conducted to examine the bioavailability and subsequent uptake of Ni by marigold during the application of different biomendments such as Farmyard manure (FYM), Composted poultry manure, Pressmud compost and Prosopis wood biochar. The result of pot experiment has shown the potential of bioamendments in enhancing the bioavailability of Ni in soil. The bioamendment application also enhanced the Ni content in plants. A significant positive correlations were obtained between Ni uptake by plants and water soluble and exchangeable Ni in soil. This explains the role of bioavailability in plant uptake of Ni. The bioconcentration factor (BCF) and enrichment factor (EF) were less than one but the translocation factor (TF) was greater than one in plants grown on soil amended with bioamendments. Marigold showed greater potential in tolerating and accumulating higher concentration Ni and therefore it could be integrated along with bioamendments for phytoextraction of Ni from contaminated soil.

Confident performance of chitosan and pistachio shell biochar on reducing Ni bioavailability in soil and plant plus improved the soil enzymatic activities, antioxidant defense system and nutritional quality of lettuce

Nickel being a toxic heavy metal is considered as a hazardous pollutant in the soil environment. The cultivation of edible vegetables on Ni contaminated soil can deteriorate plant quality which causes critical health issues to humans and animals. Therefore, the remediation for such Ni polluted soils has currently become a great challenge for the researchers. Contrastingly, lowering bioavailability of Ni in those soils based on applying appropriate immobilizing amendments demonstrating a target to relieve virulence to plants can remarkably diminish the environmental hazard. In this experiment, biochar (BR) along diverse clays like bentonite (BE), cationic-zeolite (C-ZE), chitosan (CN) and attapulgite (AP) as individual doses at 2% each in a soil synthetically spiked with Ni (at 50 ppm) magnificently immobilize Ni and curtailed its bioavailability to lettuce (Lactuca sativa L.). In addition, the related influences of planned treatments on translocation of Ni to shoots and leaves, antioxidant preventive system over oxidative injury, biochemistry and nutritional ability of lettuce were monitored. Results suggested that the CN2% treatment performed excellently in terms of reducing Ni concentrations in leaves and roots of lettuce plants along bioavailable Ni in the soil after plant harvest. Surprisingly, the BR2% treatment efficiently promoted enzymatic activities in the soil and developed moisture content, photosynthesis, biomass, biochemistry, and nutrition (both micronutrients and macronutrients) and antioxidant preventive system while diminished Ni oxidative injury in lettuce plants over rest of the treatments. Finally, our results confirmed that individually applying CN at 2% in a Ni contaminated soil could significantly control Ni bioavailability, whereas, application of BR at 2% could remarkably develop aforementioned parameters in lettuce plants.

In vitro estimates of bioaccessible nickel in field-contaminated soils, and comparison with in vivo measurement of bioavailability and identification of mineralogy

This study determined nickel (Ni) bioaccessibility in weathered smelter-contaminated soils, separately for particle-sized fractions using two in vitro methods: simulated gastrointestinal digestion (PBET) and PBET followed by absorption by Caco-2 cells. Relative bioavailability of Ni in soils was determined in vivo using rats, validating in vitro estimates; a mineralogical basis of variation in bioavailability/bioaccessibility among soils was explored. In vitro assays identified the same difference in bioaccessibility for Ni among particle size fractions. PBET estimates were more precise, thus likely to be more useful in discerning differences among soils. In vivo bioavailability for Ni was below limit of detection for the small soil particles, and 31% and 56% for the larger particles. The relative bioavailability calculated from this work suggests that risk from ingesting Ni-contaminated soils could be overestimated by between 2- and 50-fold if the estimates of exposure are not adjusted for the lower bioavailability of weathered Ni originating from smelter emissions. The overestimation that would occur by using total Ni is greatest for the particle size that is most likely to adhere to the hands of children, demonstrating the importance of particle-size separation of soils for bioavailability determination and risk assessment.

Phytoextraction of Nickel Contaminated Soil Using Castor Phytoextractor

ABSTRACT A field experiments was conducted to assess the performance of Ricinus communis and Tagetes erecta in nickel (Ni) contaminated soils at Nanjundapuram village of Coimbatore district (Tamil Nadu, India). The organic sources viz, farmyard manure (FYM) and poultry manure (PM) was added as amendments to increase the Ni bioavailability in soil. The results revealed that Ricinus communis accumulated more Ni than Tagetes erecta and it was enhanced with farmyard manure application over control and poultry manure application. Roots of both crops contained higher Ni concentration than aerial parts. The Ni accumulation ratio was higher in Ricinus communis than Tagetes erecta but both recorded the Ni accumulation ratio of more than one (4.40 and 1.64 respectively). Even though Ricinus communis was found to be effective in removing Ni from the soil, it would take much longer period (about 125 years) to remediate the soil contaminated with 165 mg Ni kg1 soil. The time requirement was reduced when farmyard manure was added as soil amendment.

Nickel transformation in two calcareous soil textural classes as affected by applied nickel sulfate

Sequential extraction has been used as a suitable method for identification of chemical forms of trace elements and their plant availability. However, in calcareous soils of Iran little attention has been paid to studying the capacity of soil components for nickel (Ni) retention and the change in its chemical forms as affected by time. The objective of this study was, therefore, to determine the effect of incubation time, soil texture, and application of different rates of Ni on chemical forms of Ni. The textural class of a clay loam calcareous soil [Fine, mixed (calcareous), mesic Typic Calcixerepts] was converted to sandy loam by adding acid-washed pure quartz sand and both the original clay loam and the produced sandy loam were treated with 0–60 mg kg − 1 Ni as nickel sulfate. The treated soils were placed in plastic containers and incubated at 25 ± 2 °C near field capacity moisture. After 0, 1, 2, 4, 8, and 16 weeks, a sequential extraction scheme was used to fractionate Ni of incubated samples into soluble + exchangeable (Sol+Ex), carbonate-bound (Car), organically-bound (ONi), Mn-oxide-bound (MnOx), amorphous Fe-oxide-bound (AFeOx), crystalline Fe-oxide-bound (CFeOx), and residual (Res) forms. Results showed that, although soils under study were calcareous in nature, the amounts of Car were negligible in both native and treated soils. This can be attributed to the lack of sufficient dissolution capacity of 1 M NaOAc (pH = 5), relatively low affinity of Ni for carbonate and the role of metal nature in distribution of its chemical forms. The conversion of applied Ni to Sol+Ex and Car in the sandy loam was higher than in the clay loam, whereas the reverse was true for other Ni forms. Increasing the Ni rate increased all forms of Ni. Iron oxides showed the highest capacity for Ni retention. Incubation time had a significant effect on Ni forms. At start of the experiment, added soluble Ni appeared in the more bioavailable fractions like Sol+Ex, Car, and ONi, but as the incubation proceeded, Sol+Ex, and Car fractions transformed into oxides and, to a lesser extent, into Res with relatively lower bioavailability. The fact that a major part of native soil Ni was extracted by the more aggressive reagents, and the conversion of added soluble Ni into forms such as oxides and Res, suggest that the bioavailability of Ni in soils under study might be low.