Food Safety Heavy metals and food safety in Sri Lanka: A review

Abstract

Entry of heavy metals to the food chain leads to food safety hazards. The origins of possible food safety hazards in Sri Lanka due to metalloid arsenic and the heavy metals cadmium, lead, and mercury are reviewed. Of them, arsenic and cadmium draw attention as contaminants in rice. Of the four heavy metals, cadmium in agricultural soils is of anthropogenic origin. Arsenic is of lithogenic origin. In some locations lead appears to be of anthropogenic origin, especially in commercial leafy vegetable cultivating soils. Marine fish, particularly swordfish and yellow fin tuna, occasionally carry cadmium and mercury concentrations above the tolerance limits established by the Codex and European Food Safety Authority. Heavy metals in well water are far below tolerance limits and are safe. Patterns of annual cancer incidences in Sri Lanka do not provide evidence to consider arsenic as a food safety hazard. Food safety hazards may occur with arsenic in the long term if attention is not paid to the quality of fertilizers or the current daily rice consumption level is not reduced. Arsenic being of lithogenic origin, unhealthy exposures cannot be prevented without affecting the food security of the country. High consumption of cadmium containing rice exposes Sri Lankans to health problems. Signs of hotspots of lead are visible. Food safety hazards are predicted by assessing exposure of humans based on their body weight and daily intake of hazardous constituents. Provincial Tolerable Weekly Intakes (PTWI) are calculated for Sri Lanka using information on heavy metals in foods from research publications. International food regulatory limits on heavy metals in foods are summarized. Horizontal standards for heavy metals in foods are developed to minimize food safety hazards in Sri Lanka.