The effect of barium element that can be extremely harmful heavy metal to human and environmental health in urban centers. The barium can cause various environmental pollution due to its anthropogenic accumulation in the environment. Also, it has negative effects on plants, animals, and humans through atmospheric deposition. All Barium (Ba) compounds are harmful heavy metals and they show a poisonous effect on the environment. Thus, it is crucial to determine the Ba concentration in plants grown in areas with high pollution in the landscape, park, and roadside. Biomonitoring with the tree species can be determined which is the best passive biomonitoring method with the tree rings formed by the effect of seasonal differences. The barium has been accumulated in the tree rings for a long time that can provide critical knowledge about the atmospheric barium deposition. The temporal and spatial variations of Ba concentration were analyzed with organs of Ailanthus altissima (Mill.) as biomonitors. This study results show that the outer bark of Ailanthus altissima (Mill.) is a convenient biomonitor for Ba deposition.

This study investigates the spatial and temporal variations in chromium (Cr) concentrations in Picea orientalis L., across different directions (north, east, south, and west) and plant organs (outer bark, inner bark, and wood) in a forested region. The research, conducted over eight age periods spanning 1980 to 2020, aimed to assess the effectiveness of Picea orientalis L. as a biomonitor for Cr pollution. The highest Cr concentrations were observed in the east direction, particularly in the inner bark and wood, while the lowest levels were found in the west. The study was conducted in an urban area near the industrial zone and highway, as well as in forested regions. A total of 100 trees were selected for the study, with samples collected from three different organs: outer bark (OB), inner bark (IB), and wood. Samples were taken from each organ at breast height (approximately 1.3 meters above the ground) to ensure consistency. The sampling covered various age periods, specifically 1980–2020, to analyze temporal changes in Cr concentrations. Statistical analysis revealed significant variations in Cr concentrations across most directions and periods, with notable increases during certain periods, especially in the west direction. These variations can be attributed to several factors, including the proximity to industrial sources of pollution, which typically release higher levels of chromium into the environment. The eastern direction likely experiences greater exposure to these emissions due to prevailing wind patterns and urban runoff, leading to increased accumulation in Picea orientalis L. Additionally, seasonal changes, temperature fluctuations, and soil characteristics may influence the bioavailability of chromium, affecting its uptake by the tree. The results suggest that Picea orientalis L. can effectively reflect Cr pollution levels, with significant directional and temporal variations that highlight the influence of these environmental factors on Cr accumulation. This study underscores the potential of Picea orientalis L. as a valuable tool for monitoring and managing Cr pollution in forested environments.