ENIVRONMENT ASIA

Volume 13, No. 02, Month MAY, Year 2020, Pages 88 - 100

Levels of heavy metals in fish and sediments from different salinity gradients of lower agusan river to butuan bay, caraga, philippines

Cresencio C. Cabuga, Jr., Rey Y. Capangpangan, and Joycelyn C. Jumawan

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While numerous studies have evaluated levels of metals across diff erent fi sh species, very few were actually done based on salinity gradients and trophic levels. Levels of Cd, Cr, Cu, Pb, Ni and Hg in muscles of fi shes and sediments from diff erent salinity gradients of Lower Agusan River to Butuan Bay, Philippines were determined. Freshwater fi shes (Oreochromis niloticus, Cyprinus carpio, Channa striata), brackish (Johnius borneensis, Pseudocoranx dentex, Scatophagus argus) and marine fi shes (Lutjanus malabaricus, Nemipterus japonicus, Selar crumenopthalmus) were collected from Brgy Buhangin, Butuan City, Brgy Pagatpatan and Brgy Dahekan, Magallanes, Agusan del Norte respectively. Highest Cd concentrations (17.5 ± 4.25 ppm) were detected from L. malabaricus, Cr (26.5 ± 12.87 ppm) from J. borneensis, and Cu (414.17 ± 255.89 ppm) from N. japonicus. Highest Pb (18.67 ± 3.77 ppm) was detected from S. argus and Ni (200.17 ± 131.98 ppm) from L. malabaricus. These concentrations were found to be above the standard values set by FAO, FEPA and WHO (Cd = = 0.05 ppm, Cr = = 0.01 ppm, Cu = = 0.15-1.0 ppm, Pb = = 0.5 ppm, Ni = = 2.0 ppm). The total mercury (tHg) concentrations were below detection in all tested fi shes. In sediments, highest Cr concentrations were found in the order: marine (98.33 ± 1.16ppm)> freshwater (77.56 ± 0.40 ppm) > brackish (76.67 ± 0.69 ppm) respectively. These concentrations were found to be above the standard values recommended by US-EPA and WHO (= 25 ppm) for soils. The results show no direct relationship regarding the accumulation of heavy metals in fi sh muscles and the three salinity gradients except for the higher Ni and Cu concentrations in fi sh from the brackish and marine stations. Comparison of heavy metal concentrations between trophic status show overall higher metal concentrations (except for Pb) in piscivores than non-piscivores and may pose health problems with frequent consumption of contaminated fi sh from the areas studied.

Keywords

Butuan Bay; Heavy metals; Salinity gradients; Bioaccumulation

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