Recent Trends in Sustainable Remediation of Pb-Contaminated Shooting Range Soils: Rethinking Waste Management within a Circular Economy

Abstract

Soil metal contamination in recreational shooting ranges represents a widespread environmental problem. Lead (Pb) is the primary component of traditional ammunition, followed by metalloids such as antimony (Sb) and arsenic (As). Lead-based bullets and pellets deposited on the soil surface are subject to steady weathering; hence, metal(loid)s are released and accumulated in the underlying soil, with potential adverse consequences for ecosystem function and human health. Amongst the currently available environmentally-safe technologies for the remediation of metal-contaminated soils, chemical immobilization is recognized as the most practical and cost-effective one. This technology often uses inorganic and organic amendments to reduce metal mobility, bioavailability and toxicity (environmental benefits). Likewise, amendments may also promote and speed up the re-establishment of vegetation on metal-affected soils, thus facilitating the conversion of abandoned shooting ranges into public green spaces (social benefit). In line with this, the circular economy paradigm calls for a more sustainable waste management, for instance, by recycling and reusing by-products and wastes in an attempt to reduce the demand for raw materials (economic benefit). The objective of this manuscript is to present a state-of-the-art review of the different industrial and agro-food by-products and wastes used for the remediation of metal-contaminated shooting range soils.

Soil Washing Methods for Effective Removal of Heavy Metal Contaminants

“…Based on the equipment, there is a limiting factor in the amount of fine particles. The content of the soil with sand in 50 to 70 percent excess is more cost effective and primarily appropriate with physical separation [11]. A method that incorporates attrition scrubbing and wet screening or hydrocyclones can be used to remediate sediments in fine-grained matrices [12].…”

“…Compared to other classification machinery, hydrocyclones have low capital and operating costs. In the context of soil remediation, screw classifiers and elutriation-based hydroclassifiers can also be introduced [11]. In addition, more effective technologies have recently been developed for the mineral processing industry, such as the CrossFlow classifier and the HydroFloat separator [14].…”

Green Chemistry: From Wastes to Value-Added Products

“…The circular economy approach, in this case, lies in the use of industrial and agro-food by-products and wastes as valuable immobilizing agents for the remediation of metal-contaminated range soils. This topic is addressed in paper 4 of this Special Issue [8], which is a state-of-the art review.…”