138
R.T. Vinarao et al.
The Gulf serves as a natural catchment receiving both organic and inorganic loads
from farmlands, rural communities and commercial establishments. Two rivers,
the Agno and Bued, drain into the Gulf. Although mining is not prevalent along
Lingayen Gulf, mineral loads in the sediment are high enough to support a number
of small-scale gold panning miners along the coast.
Past management efforts and environmental studies in Lingayen Gulf have
concentrated on assessing water quality and productivity status of fisheries (Mines
1986; Calud et al. 1989; Silvestre et al. 1989; McManus and Chua 1990; Hilomen
and Jimenez 2001; Hilomen et al. 2002; McGlone et al. 2004; Silvestre and
Hilomen 2004); however, no attempts have been made to investigate heavy metal
contamination, despite the existence of Philippine laws establishing acceptable
limits for exposure and human consumption (DENR 1990; BFAR 2001b, c). Heavy
metal contamination in the aquatic environment is of critical concern due to the
toxicity and accumulation of metals in aquatic habitats (Ahmad et al. 2010). Once
heavy metals are accumulated by aquatic organisms they can be transferred up
the food chain (McGlone et al. 2004; Erdogrul and Ates 2006) and increase in
concentration through bio-magnifications (Mance 1987; Langston 1990). Even at
low levels, long term exposure of humans to Cd is known to cause renal dysfunction
(McCluggage 1991; INECAR 2000; EU 2002; Young 2005). Ricklefts (2007) also
reported that low concentrations of Hg, As and Pb are toxic to most forms of
life. According to Lanphear et al. (2005), low levels of Pb have been reported
as an anthropogenic neurotoxicant and are known to mostly affect children. An
inverse relationship between blood lead concentrations and intelligent quotient (IQ)
score was established; associating Pb with intellectual deficits. In a clinical study
conducted by Riddell et al. (2007) in the Philippines, 21 % of 2,861 children living
in rural areas had cases of elevated blood-lead levels. Metals in its ionic form such as
Cd
2C , Pb
2C , Hg
2C and As
3C form very stable compounds within the body making
them difficult to remove during medical detoxification therapy hence resulting in
human poisoning over time (Duruibe et al. 2007).
The threats and hazards on food safety involving heavy metal contamination in
the Gulf will always remain unnoticed unless a baseline information and responsive
monitoring system is established.
Objective
The objective of the study was to determine the seasonal and temporal concentration
of heavy metals Cadmium (Cd), Lead (Pb), Arsenic (As) and Mercury (Hg) in
oyster tissues, as they relate to concentrations in the water column and sediments
in Lingayen Gulf to establish baseline information for monitoring and designing
responsive food safety and environmental management plans.
R.T. Vinarao et al.
The Gulf serves as a natural catchment receiving both organic and inorganic loads
from farmlands, rural communities and commercial establishments. Two rivers,
the Agno and Bued, drain into the Gulf. Although mining is not prevalent along
Lingayen Gulf, mineral loads in the sediment are high enough to support a number
of small-scale gold panning miners along the coast.
Past management efforts and environmental studies in Lingayen Gulf have
concentrated on assessing water quality and productivity status of fisheries (Mines
1986; Calud et al. 1989; Silvestre et al. 1989; McManus and Chua 1990; Hilomen
and Jimenez 2001; Hilomen et al. 2002; McGlone et al. 2004; Silvestre and
Hilomen 2004); however, no attempts have been made to investigate heavy metal
contamination, despite the existence of Philippine laws establishing acceptable
limits for exposure and human consumption (DENR 1990; BFAR 2001b, c). Heavy
metal contamination in the aquatic environment is of critical concern due to the
toxicity and accumulation of metals in aquatic habitats (Ahmad et al. 2010). Once
heavy metals are accumulated by aquatic organisms they can be transferred up
the food chain (McGlone et al. 2004; Erdogrul and Ates 2006) and increase in
concentration through bio-magnifications (Mance 1987; Langston 1990). Even at
low levels, long term exposure of humans to Cd is known to cause renal dysfunction
(McCluggage 1991; INECAR 2000; EU 2002; Young 2005). Ricklefts (2007) also
reported that low concentrations of Hg, As and Pb are toxic to most forms of
life. According to Lanphear et al. (2005), low levels of Pb have been reported
as an anthropogenic neurotoxicant and are known to mostly affect children. An
inverse relationship between blood lead concentrations and intelligent quotient (IQ)
score was established; associating Pb with intellectual deficits. In a clinical study
conducted by Riddell et al. (2007) in the Philippines, 21 % of 2,861 children living
in rural areas had cases of elevated blood-lead levels. Metals in its ionic form such as
Cd
2C , Pb
2C , Hg
2C and As
3C form very stable compounds within the body making
them difficult to remove during medical detoxification therapy hence resulting in
human poisoning over time (Duruibe et al. 2007).
The threats and hazards on food safety involving heavy metal contamination in
the Gulf will always remain unnoticed unless a baseline information and responsive
monitoring system is established.
Objective
The objective of the study was to determine the seasonal and temporal concentration
of heavy metals Cadmium (Cd), Lead (Pb), Arsenic (As) and Mercury (Hg) in
oyster tissues, as they relate to concentrations in the water column and sediments
in Lingayen Gulf to establish baseline information for monitoring and designing
responsive food safety and environmental management plans.