Heavy metal levels in two food fish species from Negombo estuary, Sri Lanka: Relationships with the body size

Abstract

The present study was carried out to assess the levels of eight metals viz. Pb, Cu, Cd, Ni, Cr, Mn, Hg and Zn in two species of food fish, Etroplus suratensis and Ambassis commersoni from Negombo estuary. The levels of Hg were analyzed by cold vapour atomic absorption spectrometry whereas the other metals were analyzed by flame/graphite furnace atomic absorption spectrometry. Total metal levels in muscle, gill and liver tissues of the fish showed a wide range. Accumulation of most metals in the tissues of the fish followed the increasing order, muscle < gills ≤ liver. Of the different metal levels detected in the fish, only the level of Cd in liver tissue of 6% of E. suratensis and 12% of A. commersoni exceeded the level specified for human consumption by European Union. Interspecies comparisons revealed that mean level of Zn in the muscle tissue of A. commersoni was two fold higher than that of E. suratensis. The levels of metals in the muscle tissue of both fish species were positively correlated with the body weight or body length of the fish. Based on the levels of Hg, Pb, and Cd in the fish, edible muscle of both fish species collected from the estuary was found to be safe for human consumption. However, heavy consumption of bigger size fish may pose a health risk to the consumers as there were strong positive correlations between body weight or body length and metal levels in muscle tissues of both species of fish. H.A.P. Indrajith et al./ Sri Lanka J. Aquat. Sci. 13 (2008): 63-81

Distribution of five toxic heavy metals in biotic and abiotic constituents of the Negombo Lagoon, Sri Lanka

“…Flushing and the re-suspension of metals through the disturbance of sediment or soil would temporarily cause elevation of metal loads in water at a particular site (Eisenreich et al, 1980). Heavy metal levels observed in the present study for sediment in the Negombo lagoon are similar for Pb and Cr, whilst Cd values are higher than previously recorded values (Indrajith et al, 2008). It is also noteworthy that although Hg has been previously recorded in sediment from the Negombo lagoon (Indrajith et al, 2008), the present study did not detect this metal in any of the soil or sediment samples.…”

“…The absence/low concentration of the heavy metals in the water reported here is in conflict with previously documented values for the Negombo lagoon. For instance, values reported by Indrajith & Pathiratne (2006) and Indrajith et al (2008) for Cd and Pb, and by Asanthi et al (2007) for arsenic, in water, were as high as 5.70, 2.10 and 2.16 µg/L, respectively. The seemingly contradictory results obtained in the present study could be viewed in the light of the conditions and processes that prevail in the lagoon.…”

Assessment of some heavy metals in the tissues (gills, liver and muscle) of Clarias gariepinus from Calabar River, Cross River State, South-eastern Nigeria

“…Indrajith et al [23] reported lower values of cadmium and manganese in muscle and gills, lower values of cadmium and higher values in liver of Etroplus suratensis and Ambassis commersoni compared to the present study. Nwabueze [24] reported a higher mean accumulation for cadmium.…”

Preliminary study on heavy metal concentrations of Anatolian Khramulya, Capoeta tinca (Heckel, 1843) from Çamlıgöze Dam Lake, Sivas, Turkey

“…Among the different metals analyzed, Pb and Cd are classified as toxic metals, which causes chemical hazards and therefore maximum residual levels have been prescribed for human consumption by various agencies of food standards [31-33]. Pb and Cd are biologically non essential metals which are acumulated in human tissues and harmful to human health [34]. …”