Environmental and Food Safety Risks from Heavy Metals in Mud Crabs (Scylla serrata) Cultured in Northern Samar, Philippines

Abstract

The study assessed heavy metal accumulation (As, Cd, Cr, Pb, Hg) in mud crabs (Scylla serrata) and soils from four municipalities in Northern Samar, Philippines. Although environmental conditions like pH, salinity, and temperature were suitable for crab farming, both crab meat and soil showed heavy metal levels exceeding FAO/WHO safety limits. Several factors may have contributed to the alarming issue of heavy metal levels in mud crab meat exceeding FAO/WHO standards, despite favorable environmental conditions. One of the major concerns is poor water quality particularly in farms located near polluted water bodies. These water sources are often plagued by industrial and agricultural runoff, which can seep into the farms and introduce heavy metals into the environment where the crabs live. Another concern is the use of low-quality feed, such as trash fish, which may contain high levels of heavy metals. Farmers who use this type of feed have reported foul odors, a clear indication of potential contamination. Additionally, natural environmental factors like saltwater intrusion and rising water temperatures may also contribute to the heavy metal contamination. The findings suggest that while the water conditions in the fish ponds are suitable for mud crab cultivation, the presence of heavy metals poses significant health risks to consumers and environmental concerns. The study highlights the need for further investigation and mitigation strategies to address the issue of heavy metal contamination in mud crab cultivation in Northern Samar.