Occurrence and seasonal variations of heavy metal (loid)s in lake case: effects of climate and water source perspectives

Heavy metals and metalloids (HMLs) are toxic, non-biodegradable pollutants that can accumulate in sediments and aquatic organisms, posing significant risks to ecosystems. Their persistence in the environment leads to long-term contamination, harming aquatic life, disrupting ecosystems, and threatening water quality. HMLs have not been extensively studied in Dukan Lake, Kurdistan region, northern Iraq; thus, their environmental fate remains largely unknown. To address this, we conducted a field monitoring study to examine the presence of HMLs in the lake, collecting samples from common carp, sediment, and water. HMLs were regularly measured during the sampling period, with median concentrations detected in common carp (Cyprinus carpio) tissues (0.01–2.9 × 102 µg/g), sediment (0.5–7.8 × 102 µg/g), and water (0.01−6.9 µg/L). Fe, Mg, and Zn were the dominant metals across all samples. Seasonal variations of the HMLs were observed, with higher concentrations found in summer and autumn seasons compared to winter and spring, indicating the impact of temperature and precipitation. Despite high concentrations in sediment and water, HMLs accumulation remained below the threshold. These results underscore the significance of lake monitoring in evaluating ecosystem health and surface water quality. The environmental impact and ecotoxicological significance of HMLs from places that are not monitored and still need further evaluation.