Distribution, source apportionment, bioavailability and ecological risks of metals in reef sediments and corals of the Persian Gulf (Iran): Khark Island, Chirouyeh, and Hendorabi Island

摘要

The concentrations of some trace metals in the Acropora downingi coral skeleton and sediment samples of Khark Island, Chirouyeh and Hendorabi Island in the northern part of the Persian Gulf were evaluated to determine the ecological risks of trace metal contamination in the sediment. Risk assessment indices revealed that Cd in all of the studied areas as well as Ni and Pb in Chirouyeh site would be expected to cause ecological risk occasionally. Moreover, Chirouyeh site showed a high tendency for trace metal adsorption. Khark and Chirouyeh sites showed higher risk values than the unpopulated Hendorabi, indicating that the anthropogenic activities had a significant impact on the trace metal contamination. Multivariate clustering dendrogram and Pearson's correlation coefficient indicated that Pb originated mainly from anthropogenic sources, Cu originated from both anthropogenic and natural sources, while other metals mainly originated from natural sources. The adsorption rate of trace metals in sediment samples was significantly correlated with the physico-chemical properties of the environment, whereas the uptake of trace metals by the Acropora downingi corals seemed to be dependent on their metabolic factors. Overall, the results showed that coral (Acropora downingi) reef ecosystems of the Persian Gulf are at the low to moderate risk of trace metal contamination of the bottom sediment. Overall, this study provides a 'snapshot' of the status of trace metals pollution in the coral reef ecosystems of the Persian Gulf, and also highlights the need for long-term studies in order to understand, monitor and mitigate further trace metal pollution in the region.