Remediation of Arsenic Toxicity in the Soil-Plant System by Using Zinc Fertilizers

Abstract

Availability of soil arsenic (As) and plant As at various levels of zinc (Zn) and As applications were examined. A pot-culture experiment with a leafy vegetable, Kalmi (Ipomoea aquatica), on an Inceptisols, was conducted where As was applied with irrigation water at the rates of 0 mg/L (As control), 0.5 mg/L, 1 mg/L and 2 mg/L and Zn was added to the soil as ZnCl 2 solution at the rate of 0 mg/L (Zn control), 1 mg/L, 2 mg/L and 3 mg/L during pot preparation. The experiment was conducted in triplicates for 45 days till the plants were grown to maturity. At the end of the experiment the remedial effect of Zn on As toxicity was examined and as such, yield parameters, As and Zn accumulation in Kalmi plants, residual concentrations of As and Zn in soils and plants were measured. It appeared from the present study that there exists an antagonistic relationship between Zn and As i.e., Zn in soils was found to reduce As availability in soils as well as its accumulation in plants, particularly at an elevated application rate of 3 mg/L Zn. The findings could be used as a strategy to mitigate arsenic toxicity in As contaminated soils.

Pronounced Antagonism of Zinc and Arsenate on Toxicity to Barley Root Elongation in Soil

“…The reduction of the soil solution As concentrations upon the Zn addition has been previously reported and is commonly attributed to the co-sorption or precipitation process involving Zn and As [15,16,19,20]. The Zn concentrations in the solution of single spiked soils reach >1mM and the same is true for AsO 4 −3 concentrations.…”

“…In well aerated soils, As is present as As(V), that is, different anions of AsO 4 (e.g., H 2 AsO 4 − ) with a strong sorption on Fe-Al oxyhydroxides, and with phosphate (PO 4 ) anions or organic matter as competing compounds [14]. Increasing the soil Zn decreases the As solubility in soil [15,16], whereas increasing the AsO 4 decreases the Zn solubility, and has also been shown in studies using Fe-oxides as adsorbents [17,18]. This may occur because of the precipitation of zinc arsenate or because of the formation of ternary Zn-As-(hydro)oxides complexes.…”

Arsenic-phosphorus interactions in the soil-plant-microbe system: Dynamics of uptake, suppression and toxicity to plants

“…Although Pi supply suppressed the As uptake by plants in the hydroponics, high S addition increased As uptake and decreased Pi content influencing the As-Pi interaction in plants. Application of As and Zn to soils shows an antagonistic relationship such as Zn in soils (at application rate of 3 mg/L) reduced As availability in soils and uptake in plants (Sanchary and Huq, 2017). Arsenic accumulation by plants is controlled by the oxidation state, As and P forms and plant species.…”

Interactions of arsenic, copper, and zinc in soil-plant system: Partition, uptake and phytotoxicity

“…The difference between interaction patterns may result from the selected model species and dose metrics. To date, not many phytotoxicity studies on metal(loid) mixtures are available in soil systems, and most of them are analyzed on the basis of total soil concentrations (Das et al, 2016;Kader et al, 2017;Sanchary and Huq, 2017). For example, the study of Cao et al (2007) observed antagonistic interactions between As and Cd on root elongation of wheat (Triticum aestivum L.) based on total metal concentrations in soil.…”