Spatial and vertical distributions of heavy metals and their potential toxicity levels in various beach sediments from high-background-radiation area, Kerala, India.

The spatial and vertical distribution of heavy metals and the sediment characteristics of beaches in Kerala, India (the upper surface sediments and the first, second and third one-foot-thick strata) were assessed in this study. The concentrations of most of the studied metals were highest at sampling site S1 (Cochin). The measured concentrations were compared with background and toxicological reference values. The results show that definite adverse biological effects are possible at most of the sampling sites due to the high Pb levels. Three different indexes were calculated to investigate the potential toxicity level. Most of the studied metals and all calculated indexes were highest in the third foot of sediment. Multivariate statistical analyses were performed and suggested that particular heavy metals, e.g., Pb, Cd, Cr and Ni, may represent contamination from a common source. The Cd and Pb concentrations and all the calculated index values show a relationship with the content of organic matter. The results of the present study suggest the recommendation that a systematic analysis is needed to monitor heavy metal levels in the studied area.