To Örebro University

Pine needles have been studied worldwide, particularly in areas affected by heavy metal pollution from traffic and industrial activities. These studies aim to assess the extent to which pine needles can serve as bio-monitors of environmental contamination, especially with heavy toxic metals and due to them being present all year round. Another type of contamination from heavy metals can arise, for example, from shooting ranges [1].

Shooting ranges play a crucial role in providing a controlled environment for firearm enthusiasts and professionals to practice their skills. However, the environmental consequences of shooting range activities often go unnoticed. The discharge of lead and other heavy metals poses a serious threat to ecosystems and public health. An old closed Shooting Range named Munkatorp Shooting Range, located in Sweden Örebro, has been looked at closely for causing heavy pollution specifically heavy metals. There are plans to decontaminate the area, but so far, it seems that no action has been taken. One of the most significant pollutants associated with shooting ranges is lead. The primary source of lead contamination is ammunition, as bullets are typically made of lead or contain lead components. When fired, these bullets release lead particles into the environment, contaminating the soil and water. Over time, the accumulation of lead in the ecosystem can have detrimental effects on plants, animals, and even human health [2].

Four sampling points were identified within the Munkatorp shooting range, and pine needle samples were collected for analysis. Before initiating the analysis, the needle samples underwent a thorough preparation procedure. Initially, the pine needle samples were washed with nitric acid solution, followed by drying in an oven until reaching a constant weight. The needles were then homogenized into a powder using a mortar and pestle. Triplicate preparations were made for each of the four distinct needle samples, and these preparations underwent a digestion method. The digestion method is an open digestion technique, wherein the samples were heated using a water bath. The solution used in this process consisted of nitric acid, MilliQ water, and hydrogen peroxide. Hydrogen peroxide was added every hour to compensate for its consumption during the process. The samples were considered complete when all the pine needles had completely dissolved in the solution. The digestion solutions were then diluted with MilliQ water and finally filtered using a syringe with a 0.2 μm filter. The samples will then be analyzed using Microwave Plasma Atomic Emission Spectroscopy (MPAES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). This research investigates the efficiency of two elemental analysis techniques, Microwave Plasma Atomic Emission Spectroscopy (MPAES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), for determining elemental composition in polluted pine plant material. This study focuses on optimizing analytical parameters for both methods and evaluating their respective capabilities in terms of sensitivity, precision, and accuracy. The results obtained from MPAES and ICP-MS are compared to assess the reliability of each technique in identifying and quantifying elements present in the samples.

[1] M. Zeiner et al., Molecules 26 (2021) 3318.[2] J. Bai, X. Zhao, Toxics 8 (2020) 32.