Study the concentrations of lead and cadmium in farmed rainbow trout (Oncorhynchus mykiss) in Talesh of Guilan

Trout (Oncorhynchus mykiss) is one of the most popular fish in the world. It is considered to as a best fish, and its pollution is important in terms of health and food hygiene. Trout is of the cold water fish and is in the subgroup of free fish. Animal protein, especially fish, has an important role in tissue retention, health and human happiness, and in general, the growth of the body due to the necessary amino acids and growth promoters, and the deficiency of this protein causes an imbalance in the nervous system, mental retardation, neuroticism, physical weakness in humans. and reduces the resistance of the body to infectious diseases. But, despite having a nutritional value and the body's need for aquatic animals, if the accumulation of heavy metals exceeds the limit, it can be a cause of disease and problem for humans, and therefore research in health matters is of particular importance. The presence of these compounds is harmful to human health and is not permitted. Heavy metals are environmental pollutants. The contamination of fish to heavy metals can lead to the accumulation of these elements in the body of consumers and the appearance of some diseases. Non-degradable pollutants such as heavy metal salts accumulate in the environment. The accumulation of toxic substances in the food chain may increase their concentration in animals at higher levels in the food chain. The accumulation and biological role of heavy metals in marine organisms can lead to the risk of human health from these metals. Exposure of fish to contaminants and its transmission to humans, can cause several diseases. The present research was aimed at determining concentrations of Lead and Cadmium, in muscles of farmed rainbow trout (Oncorhynchus mykiss) in Guilan’s Talesh, Iran, comparing levels of the metals in the flesh of both female and male rainbow trout, and comparing them with standards of Food and Agriculture Organization, Food and Drug Administration and Iran Veterinary Organization. Material and This research had 6 groups, consisting of trout which were 700-900 g and <300 g in weight. They were obtained in December, 2014. The homogenized flesh (15 numbers) was examined using an atomic absorption spectrometer. Trout fish was biometric. The trout were 478.56 g in weight and 318.93 cm in length. Despite pH and temperature, water hardness of studied pools showed significant differences (P<0.05). PH of water ponds was neutral. The water temperature was 15-16 ºC. The water temperature of the pool was not proper for heavy metals absorption to fish. Lead and Cadmium varied between 0.01> and 0.03. In this study, the amount of lead compared to Cadmium was not showed significant reduction(P<0.05). Hardness were 85.50 mg/l in A and B pols and 153.90 mg/l in pole C. Was not observed significant differences in water hardness factor between pools A and B compared with C pool. Water pools A and B were medium hardness and C pool was hard. Water of pools A and C were medium hardness, but water pool B was hard. Water hardness on cadmium in comparison to Lead had more effect. Correlation Lead and cadmium with age, length and weight in some of the pools were positive and in the others were negative. Between age groups similar were not observed significant differences in studied pools of Talesh (P>0.05). No significant differences in per farmed ponds between lead and cadmium concentrations in the age groups below 300 g 700 -900g(P>0.05). Except of the age group 300g< of pond A from Talesh, the other ponds in the age groups including of 300g< and 700 -900g was showed significant differences compared with FDA, FAO, WHO and Iran Veterinary organization in Lead and cadmium concentrations(P<0.05). There was no correlation between the accumulation of cadmium and lead compared with sex. According to achieved results and decreasing accumulation of heavy metals in farmed Trout Talesh compared with international standards, in terms of cadmium and lead contamination and food sanitary, farmed Trout of these regions are no side effects for human consumption in the autumn. According to the achieved results on farmed rainbow trout 700-900 g and <300 g in Talesh in fall, it must be declared that they cause no adverse effects and are fit for human consumption in terms of food hygiene and concentrations of lead and cadmium in them.