Abstract
Simple SummaryRapid urbanization and industrialization has resulted in substantial contamination of various ecosystems, especially aquatic environments with heavy metals. Heavy metals are classified as either essential (iron, zinc, or copper) or non-essential (cadmium, lead, or mercury) for organisms. Cadmium is a toxic, cancerogenic, and mutagenic metal, occurring as anthropogenic contamination in aquatic environments. The level of cadmium uptake in animals depends on the rate at which they are accumulated and eliminated. Exceeding the permissible levels of cadmium in fish muscle may pose risks for human health in the case of contaminated fish consumption. The aim of the present study was to evaluate the influence of melatonin on cadmium accumulation and elimination in fish muscle. Prussian carps were exposed to two doses of cadmium in the presence or without the melatonin implants. This is the first study to report that melatonin co-administration can effectively protect fish from the accumulation of cadmium in muscle tissue, improve the accumulated cadmium depuration from muscle, and prevent disturbance of the concentration of essential metals in fish body.The aim of this study was to investigate the bioaccumulation of cadmium in the muscle tissue of Prussian carp during 7 and 13 weeks of exposure to different concentrations of this metal in water (0.4 and 4.0 mg/L), and the depuration of cadmium from muscle during the following 6-week depuration period in the presence of melatonin implants. Furthermore, the relationship between cadmium accumulation and the levels of essential bioelements (copper, zinc, iron) in muscle was evaluated, as well as the bioconcentration factor of cadmium. Heavy metal concentration was determined using atomic absorption spectrometry. Cadmium accumulation in fish muscle increased with the duration of exposure. Cd concentrations exceeded the permissible levels for human consumption in groups exposed to the higher concentration of this metal. Moreover, a significant increase of Zn and Fe levels in the muscle was observed. In the fish that received melatonin implants and were exposed to Cd, its level in the muscle was significantly lower. The depuration of accumulated cadmium depended mainly on the duration of the elimination period. This is the first study to report that melatonin co-administration can effectively protect the fish from the accumulation of cadmium in muscle tissue and changes in trace metal levels.
Highlights
Environmental pollution is one of the main challenges of today’s world
After 6 weeks of depuration, a significant increase in the body weight of fish in that group was observed (196.2 ± 16.2 g) and it was found that the body weight of these fish was statistically significantly higher compared with that of the fish that were exposed to Cd throughout the duration experiment (164.6 ± 19.6 g)
Cadmium is a priority substance, harmful to living organisms. This is confirmed by the results of the present study, which found a decrease in body weight and a higher mortality rate in the group of fish exposed to the higher concentration of cadmium (Table 2)
Summary
Environmental pollution is one of the main challenges of today’s world. Heavy metal contamination poses a threat to the environment and raises serious concerns. There are heavy metals that are toxic to living organisms They include, for instance, cadmium (Cd), lead (Pb), and mercury (Hg) [3]. All heavy metals can be potentially toxic to fauna and flora, depending on their dose and duration of exposure They are persistent in the environment, accumulate in living organisms, and are transferred from lower to higher trophic levels in the food chain, undergoing biomagnification. The World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) state that monitoring eight metals in fish, i.e., mercury, cadmium, lead, arsenic (As), copper, zinc, iron, and tin (Sn), is obligatory [7]. Cadmium can cross the blood–brain barrier and cause Alzheimer’s and Parkinson’s diseases [9]
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