Document Type : Research Paper
Authors
1
Department of Aquatic animal, Veterinary medicine college, Ka.C., Islamic Azad University, Karaj, Iran
2
Department of Animal Health, Karaj branch, Islamic Azad University, Karaj, Iran
3
Institute of Agricultural Education and Extension, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran
10.22124/janb.2026.33853.1309
Abstract
The proliferation of various pollutants, including heavy metals, has negatively affected numerous marine and freshwater ecosystems and their inhabitants. Heavy metals are non-degradable pollutants, and their measurement in water, sediments, and fish serves as an indicator of environmental contamination and its impact on human communities. The bioaccumulation of heavy metals across the food chain poses significant threat to human society. Considering the crucial role of fish muscle tissue in human nutrition, ensuring its safety is of particular importance.In this study, 24 wild common carp (Cyprinus carpio) weighing 1450±161g were randomly collected in April 2022 from fish markets in the cities of Astara, Hashtpar, Anzali, Rasht, Kelachai, and Kiashahr in Guilan Province. They were examined for the levels of four heavy metals: lead, zinc, cadmium, and mercury. Measurements were performed using an atomic absorption spectrophotometer.
Following biometric measurements and coding, 100 g of muscle tissue was stored at −20 °C until digestion. The results showed no significant differences in the accumulation of heavy metals between male and female fish, nor between the heavy metal levels and the measured biometric traits of the experimental samples. The mean concentrations of zinc (24.73±14.24 µg/g dry weight), cadmium (0.003±0.00020 µg/g), lead (0.0252±0.001 µg/g) and mercury (0.0842±0.0659 µg/g) were found to be well within the permissible limits of international standards (FAO/WHO) and the Iran national standard (Iran Veterinary Organization).
Since common carp larger than 18 mm are predominantly benthic feeders, sediment contamination can lead to pollution of small benthic organisms and subsequently transfer contamination to benthic and bottom-feeding fish. The lower levels of zinc, cadmium, lead, and mercury contamination observed in this study may indicate low contamination in sediments and small benthic organisms in the region.
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