Steel Shot as a Risk Factor for Soils at the Area of Shooting Activity

Abstract

This study is follow-up of the steel shot transformation under the influence of environmental factors research (Lisin et al., 2022) and is the initial stage of investigating the iron behavior in soils during steel shot corrosion under a number of factors: the metallic lead in soils, atmospheric precipitation, excess organic matter. The results obtained show that corrosion of steel ammunition is a continuous process, including the formation of a poorly soluble rust crust on the surface of the steel and the mineralization of the metal until it is destroyed. As a result, the metal transformed into rust form, is a constant source of iron ions and dispersed rust particles migrating in soil waters and accumulating in soils. In addition, the aggregation of corrosion products of steel ammunition is the cause of a change in physical and mechanical properties of soils, which leads to a violation of the air and water migration regime of soils and an increase in surface runoff from the territories of shooting activity. The highest environmental risks are observed when steel ammunition is used on shooting areas where metallic lead intensifies steel shot corrosion rate, while the deposited steel shot activates the deterioration of previously encapsulated metal and — if steel and lead ammunition are used at the same time — slows down the encapsulation of newly deposited metallic lead, which catalyses the accumulation and migration of lead in environmental components.

Bioaccessibility of Metals of Lead and Steel Shot and Soils at the Area of Shooting Activity

“…The joint presence of lead and steel shot into the GI tract of mammals results in the limited Pb bioaccessibility, more pronounced if there is more steel shot in the mixture, due to the lead ion sorption from the solution on the corrosion layer surface of steel shot and coprecipitation with the formed Fe (hydr)oxides; (Lisin et al, 2022). Fe bioaccessibility in the GI tract is not influenced by the presence of lead shot; it remains stable regardless of the lead-and-steel-shot ratio in the soil.…”

“…When conducting the experiments to study Pb and Fe bioaccessibility in the case of the entering of soil dust into the GI tract of mammals, authors took into the account the conclusions of their earlier paper (Lisin et al, 2022) showed that the Pb in soil is forming specifically sorbed, carbonate, and sulphate species and is bound with iron hydroxides and organic matter, and iron forms part of the soil matrix and is assimilated in the form of corroded iron hydroxide particles.…”

“…The following testing samples were used: 1 -the soils of shooting areas where only lead shot was used; 2 -the soils of shooting areas (only lead ammunition was used), with the adding of steel shot; 3 -the joint entering of steel shot and lead shot into the soils of areas with no prior shooting activities. Shot was deposited into soils of the second and third types for four months under the conditions of moderate humidification (the methodology is described in the paper by Lisin et al (2022)). After the exposure, all soils were air dried and sieved (<1 mm) and pulverization (74 µm).…”

“…After being deposited into the soil, lead ammunition oxidizes under the influence of the environment and is encapsulated by the poorly soluble lead compounds (hydroxide, carbonate, sulphate) within two or three weeks. The transformation of the lead ammunition surface in the soil is accompanied with the fixation of lead in the upper part of the soil profile, as part of the soil adsorption complex (Lisin et al, 2020). The formation of soil dust containing lead compounds may result from the wind erosion of the surface soil which should also be considered a probabilistic process.…”

“…Like lead ammunition, steel ammunition accumulates on the soil surface and may serve as gastroliths for birds. According to authors earlier paper (Lisin et al, 2022), as a result of steel shot transformation in natural conditions, corrosive iron particles (rust) do not only become irreversibly assimilated by the soils and become part of the soil dust but also form dispersed dust on the soil surface. Moreover, unlike the cyclical process of lead shot corrosion, the corrosion of steel shot is a continuous process which results in its complete assimilation in the environment, leading to a longer presence of an iron dust source in shooting areas.…”