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

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.

Ecological and Human Health Risks of Heavy Metals in Shooting Range Soils: A Meta Assessment from China

Contamination of shooting ranges by heavy metals in particular Pb represents a widespread environmental issue attracting concern worldwide. Contaminant accumulation in shooting range soils can pose potential ecological risks and health risks for shooters and workers. Based on the published data on metal contamination at five shooting ranges in China, potential ecological and human health risks of several metals, and in particular, Pb were assessed for the five surveyed shooting ranges. Data show the mean concentrations of Pb, Cu, Hg, Sb, Ni and Cr in various ranges were all higher than the local soil background values, implying their accumulation was induced by shooting activities. The degree of contamination varied with sites and metals, very high Pb contamination at Range 1, Range 2 and Range 5-1, while moderate Pb contamination at Range 3 and Range 5-2. Comparatively, As, Zn and Co showed no contamination. Among the surveyed metals, Pb, Cu, Hg and Sb in shooting range soils displayed relatively high potential ecological risks. The overall degree of potential ecological risk was very high at Range 1 and Range 2, considerable at Range 4 and Range 5-1, and low at Range 3 and Range 5-2. The mean HI (hazard index) of Pb at Range 2 and the maximum HI values at Range 1 and Range 4 were higher than 1, suggesting a possibility of non-carcinogenic risks of Pb contamination at these sites. However, Pb in other range soils and other metals, across the five ranges, all exhibited no non-carcinogenic risks. The cancer risks of the four carcinogenic contaminants (As, Co, Cr, and Ni) were acceptable or negligible at all ranges. In conclusion, contamination of Pb and other metals such as Cu, Hg and Sb can cause various potential ecological risks at all the surveyed ranges, but only Pb at three ranges shows possible health risks. Contamination of Pb in the surveyed shooting ranges should be managed to reduce its possible environmental and health risks.