Bioaccumulation in Nile Tilapia (Oreochromis niloticus) from Laguna de Bay, Philippines

Victorio B Molina, Ma. Victoria O Espaldon, Maxima E Flavier, Enrique P Pacardo, Carmelita M Rebancos
Vol 14 No 2 (2011), pp. 28-35




This study provides an assessment of the risks to human health associated with the exposure to heavy metals bioaccumulation in Nile tilapia (Oreochromis niloticus) from Laguna de Bay. Samples of the fish were collected in eight sampling stations in three major areas of the lake during the dry and wet seasons. Dry season samples were collected from May to June 2010 and wet season samples from September to November 2010. Coordinates of sampling site locations were recorded using Global Positioning System (GPS) and plotted in Geographic Information System (GIS) digital maps. Heavy metals analyses for cadmium (Cd), lead (Pb), mercury (Hg), arsenic (As), and chromium (Cr) were conducted using am Atomic Absorption Spectrophotometer (AAS) and a Mercury Analyzer (Mercur-Duo).

Estimates of health risks associated with fish consumption were summarized according to non-carcinogenic and carcinogenic health effects. Non-carcinogenic Health Quotient (NHQ) values of the five heavy metals showed that lead is the most urgent pollutant of concern in terms of adverse health effects from risks associated with fish consumption from all sampling locations in the lake. Among the five heavy metals only arsenic is a confirmed human carcinogen (Class A) through the oral route of exposure.

The highest life time cancer risk for arsenic was computed from sampling station 2B (west bay) during the dry season with risk value of 8.5x10-4 or an excess of 85 cancer cases per 100,000 population. From the point of view of human health protection and disease prevention, the Nile tilapia from Laguna de Bay is not fit for human consumption due to arsenic and lead contamination.


Keywords: Heavy Metals, Health Risk Assessment, Bioaccumulation

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