Detection of Arsenic, Chromium, Cadmium, Lead, and Mercury in Fish: Effects on the Sustainable and Healthy Development of Aquatic Life and Human Consumers

Heavy metals are among the most important pollutants that threaten the aquatic environment when their concentrations exceed certain limits. Some of these metals and metalloids are beneficial and necessary for fish, but others, such as arsenic (As), chromium (Cr), cadmium (Cd), lead (Pb) and mercury (Hg), are non-essential and toxic. In reviewing the recent relevant literature, 4 different continents, 13 different countries, and more than 50 different fish species were analyzed in terms of As, Cr, Cd, Pb and Hg concentrations. According to the comparative results, it was found that in Tercan Dam Lake, Turkey, the highest concentration of Cr was detected in Capoeta umbla (2.455 mg/kg), and of As in Ctenopharyngodon idella (0.774 mg/kg) species. Greater values than the permissible limits of FAO/WHO in terms of As were also found in Andalusia, Southern Spain, in Mullus surmuletus (0.427 mg/kg), and Sardina pilchardus (0.561 mg/kg) and in Sprattus sprattus (0.636 mg/kg) in the Baltic Sea, but a remarkably high content of As (8.48 mg/kg) was determined in Penaeus notialis, found in Guinea, Africa. Moreover, Cd concentration was low to nil in almost all cases, with the exception of Amblyceps mangois species collected from the Dhaleshwari River in Bangladesh, which showed the highest value (0.063 mg/kg). Finally, extremely high levels of Pb were found in Plectropomus pessuliferus (5.05 mg/kg) and Epinephelus summana (2.80 mg/kg) in Jeddah, Saudi Arabia. The Hg content in fish was under the permissible limit in almost all cases, with megrim and red mullet from the Andalusian Sea exhibiting a relatively higher content (0.091 and 0.067 mg/kg). In general, the sequence of accumulation of toxic elements in fish was As > Cr > Pb > Cd > Hg.