Fahim A. Shaltout

In spite of the fishes are recognized benefits, the fishes can bio accumulate nonessential toxic heavy metals, which may be a potential public health hazard to the consumers at high concentrations. The heavy metals are natural nonessential trace elements of the aquatic environment, which have no known beneficial functions; but their levels have increased to toxic concentrations due to the contamination from agricultural, industrial, and mining activities. Most of the fishes can easily be contaminated by a wide variety of toxic metals such as cadmium, lead, arsenic and mercury. The heavy metals contamination may originate from different sources, including the discharge from agriculture, industrial and the sewage effluent, the waste from accidental chemical spills, and the gasoline from the fishing boats. The heavy metals reach fish flesh via their feeding on benthic species as benthic worms and crustaceans, which in turn feed on the surrounding sediment having a high amount of heavy metals. In particular, because the toxic heavy metal elements cannot deteriorate, they can be persisted and accumulated in the environmental media, including the water and the sediments, and bio accumulate in the aquatic biota including the fish to levels that are hazardous to the consumers. The bioaccumulation of the heavy metals in the fish depends on several factors, such as, the area and the time of fishing, the feeding habits of the fish, the fish species, the gender, the age, the size, their levels in the water, and the duration of exposure, in addition to other factors including the water pH, the salinity, and the water temperature.

Keywords: public health, fish, heavy metals, contamination, cadmium, lead, arsenic, mercury

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