Heavy Metal and Microbial Analyses of Janitor Fish (Pterygoplichthys spp.) in Laguna de Bay, Philippines

Hannibal M Chavez, Elvira A Casao, Eunice P Villanueva, Madeleine P Paras, Marites C Guinto, Marilou B Mosqueda
Vol 9 No 2 (2006), pp. 31-40




Janitor fish (Pterygoplichthys spp.) and water samples were obtained from the three sampling stations in Laguna de Bay (central, east and west bay) for heavy metal and microbial analyses during the dry and wet season. Results revealed that cadmium and chromium were not detected in the water samples. Copper concentration of water samples during the dry season in Taguig for west Bay (0.0767 mg/L) and Jala-jala for central Bay (0.097 mg/L) exceeded the limit of 0.05 mg/L for Class C waters. The fish flesh obtained from the three sampling stations had lead concentration ranging from 0.0573mg/kg to 0.1900 mg/kg (wet weight). Arsenic, cadmium, chromium and mercury in fish flesh were not detected during the dry season, but present at low concentrations during the wet season.

The total bacterial and coliform count of water samples differed in the three sampling stations. The total bacterial count in fish flesh in the three sampling stations were 800 to 5,650,000 cfu/g during the wet season and from 200,000 to 2,230,000 cfu/g during the dry season. Coliform were present in all sampling stations (22 to >1,600MPN/g).


Keywords: Pterygoplichthys spp. introduced species, janitor fish, heavy metal concentrations, Laguna de Bay, microbial analyses

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