Toxic elements in Sardina pilchardus and food toxicological significance

Elements in cultured fishes in Chittagong, Bangladesh and risk assessment

The concentrations of manganese, iron, copper, lead, nickel, cadmium, arsenic, copper and mercury were determined in 10 cultured fish species, which were collected from local markets of Chittagong, Bangladesh, in June 2021. Measurements were performed by atomic absorption spectrophotometry, after acid digestion of the samples. In some cases, the concentration of the investigated elements was more than the maximum limit set by the WHO. Although the concentration of toxic elements in fishes was relatively high in some species, no health risk has been identified in comparison to the estimated daily intake and the maximum limit. Calculated hazard indices were below 1, which indicates the investigated fish would not cause human health risks. Carcinogenic risk indices for Cr, As, and Cu in all species were considered to be significant.

Trophic transfer and biomagnification potential of environmental contaminants (heavy metals) in aquatic ecosystems

Physical, chemical weathering and volcanic eruptions release heavy metals into soils and surface waters naturally. Contaminants from anthropogenic sources originated from industrial and municipality waste substantially modify and increase their contributions. They are then absorbed by fish gills, amphipod cuticles, and other sensitive organs of aquatic creatures. This article discusses the essences on the determination, potential and plausible factors of trophic transfer and biomagnification of environmental contaminants particularly heavy metals across aquatic ecosystem. In general, arsenic is found to be bio-diminished across food webs in freshwater ecosystem while it biomagnified in marine ecosystem of higher trophic level (tertiary consumer of predatory fish) and dilute its concentration from lower trophic level (from producer to bottom level of consumer, secondary and lastly to tertiary consumer (forage fish)). Early study for Cadmium shown that it has no potential for biomagnification while later studies prove that cadmium does magnify for gastropod and epiphyte-based food webs. Mercury shown obvious biomagnification potential where it can bio-magnify from trophic level as low as particulate organic matter (POM) to higher trophic of fish. These findings proved that aquatic ecosystems must be preserved from contamination not just for human benefit, but also to prevent environmental degradation and biodiversity loss.