First assessment of trace metals in the intertidal zone of the world's longest continuous beach, Cox's Bazar, Bangladesh.

This study aimed to assess the concentrations of eight trace metals - Cr, As, Pb, Mn, Ni, Zn, Hg, and Co - in the intertidal zone of Cox's Bazar of Bangladesh, the world's longest continuous beach. Most metal concentrations were below sediment quality guidelines and other comparative studies. The mean metal concentrations (mg kg) were as follows: Mn (471.67) > Zn (256.35) > Cr (89.96) > Pb (39.66) > Ni (36.44) > As (18.79) > Co (11.08) > Hg (0.0036). Statistical analyses revealed that only samples collected from stations 5 and 7 presented any cause for concern. Risk assessment indices, i.e., Geo-accumulation Index (I), Contamination Factor (CF), Pollution Load Index (PLI), Potential Ecological Risk Index (PERI), and Toxic Risk Index (TRI), all indicated a low to moderate risk of pollution for all sites, suggesting that the study area is currently free from any significant negative impacts resulting from human activities. The calculated Hazard Index (HI) was <1, indicating no significant non-carcinogenic impact on adults or children. The Total Carcinogenic Risk was also well below the threshold value.