Cadmium Uptake and Relationship to Feeding Habits of Freshwater Fish from the Ayeyarwady River, Mandalay, Myanmar.

Background: Pollution of the aquatic ecosystem by heavy metals is increasing due to anthropogenic activities. Cadmium (Cd) can accumulate in soil, be taken up by plants, and passed on in the food chain to animals and humans.

Objectives: The present study was conducted to analyze the uptake of Cd in muscles of sampled fish with different feeding habits and to compare levels of Cd in fish from the Ayeyarwady River, Myanmar with international standards.

Methods: The acid digestion procedure was used for sample preparation. Cadmium concentrations in fish samples were determined by flame atomic absorption spectrophotometry (Perkin Elmer AAanalyst 800 and Winlab-32 software).

Results: In herbivorous fish species, Cd content ranged from 0.07 (Catla catla) to 0.086 mg/kg (Osteobrama belangeri). In carnivorous fish species, Cd ranged from 0.060 (Mystus leucophasis) to 0.083 mg/kg (Wallago attu). In omnivorous fish species, Cd ranged from 0.07 (Botia histrionica) to 0.084 mg/kg (Gudusia variegata). Cadmium content did not differ significantly across the three types of feeding habits (p>0.05).

Discussion: The accumulation of Cd in the muscle of studied fish was lower than the permissible limit set down by the European Union in 2001 (0.1 ppm), but above the limits set down by the Food and Agriculture Organization/World Health Organization, European Commission (0.05 ppm) and within the limit of United States Food and Drug Administration (0.01-0.21 ppm). The data obtained in the present study indicate that levels of Cd were not significantly different across fish species with different feeding habits.

Conclusions: The examined fish samples were not fully safe for human consumption due to high levels of Cd.

Competing interests: The authors declare no competing financial interests.