Analysis of metals and metalloids present in Sri Lankan dried seaweeds and assessing the possibility of health impact to general consumption patterns

Seaweeds are considered as a functional food across many regions of the world and has an increasing consumption trend due to its health benefits. However, there is a concern regarding the amount of heavy metals and metalloids present in seaweeds. Therefore, the study aimed to assess the levels of metals present in specific seaweeds and its potential impact on consumption. Considered metal ions were Arsenic (As), Copper (Cu) Chromium (Cr), Nickel (Ni), Cadmium (Cd), Lead (Pb) and Mercury (Hg). At the assessment done at four different sites in the coastal regions of Sri Lanka for chlorophytes, rhodophytes and phaeophytes. Concentration of metals were analyzed using the ICPOES. According to the arrived results, concentration of metals varies as Cr > Ni > Cd > Cu > As > Pb = Hg with having zero concentration for Hg and Pb for all varieties and all sites. It was also found that the least amounts of metals were present at Jaffna site in phaeophytes (Sargassum sp.) and chlorophytes (Ulva sp.) When considering the Hazardous Index of the varieties, least was found in Sargassum sp. in Jaffna site. Studies were repeated for 2 seasons and there are significant differences (p < 0.05) between the dry season and wet season in the concentration of heavy metals present. However, since the seaweeds are grown for commercial purposes only in Jaffna area, it is evident that the chlorophyte and phaeophyte varieties claim very low health risk for potential heavy metals and are suitable for consumption purposes.