Regulation of lead in seafood: FSANZ set maximum levels for lead in foods during its review of the Code in 1999. Proposal P157 – Contaminants in Food – Metals assessed which foods contributed significantly to dietary exposure to lead and set levels accordingly (Table 4.21).
Table 4.21: Maximum levels for lead in seafood in the Code
Commodity
ML (mg/kg)
Fish
0.5
Molluscs
2
Hazard identification and characterisation: Studies have shown excessive exposure to lead can affect many different organ systems, and biochemical and physiological processes in both animals and humans, the most sensitive being the nervous system. Lead exposure is cumulative in nature with long half-lives (up to 27 years in various bone compartments).
The available data suggests that the developing brain is more at risk from lead exposure compared to the mature brain. This has been supported by cross-sectional epidemiological studies. Differences between children and adults in several aspects contribute to the greater susceptibility of children to lead toxicity. These include the higher metabolic rates and rapid growth rates compared to adults; immaturity of organ systems (namely the nervous and immune systems); the higher energy requirements for children reflected in their dietary intakes (and hence the intake of contaminants per unit body weight); and the unique behavioural characteristics (for example, heightened hand-to-mouth activity), which may result in significant exposure to lead from non-food sources.
JECFA established a Provisional Tolerable Weekly Intake of 25 µg/kg bw (equivalent to a PTDI of 3.5 µg/kg bw/day) for all age groups (WHO 1987). In 1999, JECFA maintained this PTWI at its 53rd meeting and concluded that the results of a recent risk assessment suggest that concentrations of lead in food would have negligible effects on neurobehavioral development of infants and children (WHO 2000).
