Zeolite-Assisted Immobilization and Health Risks of Potentially Toxic Elements in Wastewater-Irrigated Soil under Brinjal (Solanum melongena) Cultivation

Abstract

Application of wastewater to agricultural soils not only enhances economic benefits but is also considered as a safe disposal option by the administrators. Worldwide, peri-urban horticulture is a common practice for growing vegetables. When agricultural soils are irrigated with wastewater, numerous potentially toxic elements (PTEs) contained therein are bioaccumulated and pose health risks. The presented study aimed to reveal the PTEs, i.e., copper (Cu), cadmium (Cd), nickel (Ni) and lead (Pb) concentration in the agricultural soils irrigated with wastewater for longer times. Zeolite, a natural mineral was used to immobilize these in contaminated soils to reduce its availability to brinjal (Solanum melongena L.). During a pot study, zeolite was applied at four different levels, i.e., 0.25, 0.50, 1.00 and 2.00% in contaminated soil, keeping one control. The results revealed that growth as well as biochemical and physiological characters were found best with treatment receiving zeolite at 2.00%. In edible parts (fruit), PTE contents were found lowest in the same treatment. Relative to the control, ~121, 87, 120 and 140% less DTPA-extracted Cu, Cd, Ni and Pb in soil was found with this treatment. Based on the results, it was revealed that zeolite effectively immobilized Cu, Cd, Ni and Pb in the soil. Although all the applied levels of zeolite had positive potential to immobilize PTEs in wastewater-contaminated soil, zeolite applied at 2.00% proved most effective.

Synergistic Effects of Urea, Poultry Manure, and Zeolite on Wheat Growth and Yield

“…This study provides evidence of the significant improvements in wheat yield and yield components through the application of urea, PM, and zeolites. The probable reason for the higher yield of wheat might be the role of nitrogen in plant metabolism that increases grain yield and the role of zeolite in nutrient retention and slow release in the root zone [49]. The maximum number of grains spike −1 of wheat recorded in our case for UN 120 treatment is in accordance with the findings of Ali et al [50], where they reported a significantly higher number of grains spike −1 from the treatment receiving a full application of chemical fertilizer.…”

“…The combination of PM with zeolites further increased K uptake, indicating the synergistic effects of organic matter and zeolites in improving K availability for wheat plants. The application of zeolites alone or with organic amendments improved crop quality by enhancing the retention of nutrients in the root zone for plant use [49]. Zeolite regulates the supply of nutrients from both organic and inorganic fertilizers, thereby increasing the efficiency of applied amendments [59].…”

Evaluation of Phytoremediation Potential of an Aquatic Macrophyte (Eichhornia crassipes) in Wastewater Treatment

“…Anthropogenic activities have boosted the rate of urbanization, industrialization, and agriculture [2], creating a huge pressure on freshwater availability across the globe that may cause water insecurity in the future [3]. Industries generate millions of tons of wastewater with solvents, toxic materials, and heavy metals and discharge them into water bodies untreated [4]. Wastewater constituents, especially heavy metals, and metalloids are of great concern and have destructive effects on the environment and human health [4,5].…”

“…Industries generate millions of tons of wastewater with solvents, toxic materials, and heavy metals and discharge them into water bodies untreated [4]. Wastewater constituents, especially heavy metals, and metalloids are of great concern and have destructive effects on the environment and human health [4,5]. Small quantities of certain heavy metals, i.e., copper, iron, zinc, and manganese are essential for normal growth and body functions, but higher concentrations of them are highly toxic [6].…”

“…Various physical (membrane filtration, physical adsorption), chemical (precipitation, ion exchange, coagulation, and flocculation), and biological (biosorption) approaches are being introduced to detoxify heavy metals' impact from wastewater and promote the reuse of water to mitigate water shortages [3,4,7]. Nevertheless, these approaches are not only economically non-sustainable and non-eco-friendly [8], but their efficiency (50%) is still questionable [9].…”