Effects of Natural Zeolites on Bioavailability and Leachability of Heavy Metals in the Composting Process of Biodegradable Wastes

Abstract

The bioavailability and leachability of heavy metals play an important role in the toxicity of heavy metals in the final compost followed by land application. This chapter examines the effects of natural zeolite on bioavailability of heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd, and Cr) in the form of water soluble and diethylenetriaminepentaacetic acid (DTPA) extractable. The toxicity characteristic leaching procedure (TCLP) test was performed to examine the leachability of heavy metals. Water solubility, DTPA extractability, leachability, and most bioavailable fractions were reduced during agitated pile composting (APC) and rotary drum composting (RDC) of water hyacinth with zeolite addition. The addition of the natural zeolite (clinoptilolite) during the composting process led to an increase in Na, Ca, and K concentrations and significantly reduced the water solubility and DTPA and TCLP extractability of heavy metals. The addition of an appropriate amount of natural zeolite during the composting process enhanced the organic matter degradation, thereby increasing the conversion into the most stabilized organic matter and reducing the bioavailability and leachability of heavy metals.

Mineral Composition of Potted Cabbage (Brassica Oleracea Var. Capitata L.) Grown in Zeolite Amended Sandy Soil

“…zinc assimilation by plants depends on the content and form of zn, it further depends on the genetic characterises of plants and soil chemical characteristics (Murtic et al 2017). the accumulation of the micromineral in cabbage in relation to soil pH proved that heavy metals generally have low solubility at higher pH as they are normally present in their hydroxide forms (Singh et al 2016). in this study, zeolite application did not enhance micromineral accumulation in the cabbage heads.…”