Assessing the possibility of airborne bismuth accumulation and spatial distribution in an urban area by tree bark: A case study in Duzce, Turkiye

Heavy metal accumulation has been a hot topic of many studies in recent years, as they are toxic elements that can be highly harmful to human health and the environment. The metal concentrations of some trees used for monitoring air quality give information about the pollutant sources in the ambient atmosphere. In this study, P. pinaster, C. arizonica, P. orientalis, C. atlantica, and P. menziesii were determined to investigate their use as biomonitors for air quality. Metallic bismuth and bismuth compounds, which have been widely used in several industries, have low toxicity to humans, although bismuth toxicity can show over-dosage depending on its application. The variability of bismuth levels in the organs of the species was investigated to explain atmospheric deposition over the years. The bismuth accumulation of C. arizonica and P. pinaster increases depending on time interval. The ascending-descending trend in other species could not be obtained clearly via dry and wet deposition of atmospheric metals. Our analysis reveals that the total deposit (barks and wood) of P. pinaster, C. arizonica, P. orientalis, C. atlantica, and P. menziesii were 134, 115, 94, 131, and 148 mg/kg, respectively, and they have been quite clearly reflected atmospheric bismuth deposition. The bismuth concentration has significantly increased since the 1983 sampling; P. menziesii can be valuable bioindicators for highlighting polluted areas. Compared with the traditional air samplers, the proposed P. menziesii bioindicator is proven to be more effective, low cost, and sustainable and thus has broad application prospects in bismuth concentration.