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Med. Pr. 2000;(14)

The current risk of health effects induced by environmental exposure to heavy metals

Aktualne ryzyko wystąpienia skutków zdrowotnych w wyniku środowiskowego narażenia na metale ciężkie

M. Jakubowski

Abstract

The aim of the study was to assess the risk of health effects of environmental exposure to lead and cadmium, based on the current data on daily intake of these metals and their concentrations in biological material. The analysis of the data on the air cadmium (Cd) concentrations, daily intake with food and concentrations of these metals in the human biological material indicates the downward tendency in environmental exposure.
Approximately 85ś90% of total airborne cadmium emissions arise from anthropogenic sources, mainly from smelting and refining of nonferrous metals, fossil fuel combustion and municipal waste incineration.
Food is the main source of Cd exposure in the general population, which is responsible for about 99% of the total intake in non-smokers. Cigarette smoking can double Cd daily intake. The present average urine Cd concentrations (Cd-U) in nonsmokers in Europe are 5ś13 times lower than 2.5 ľg/g creatinine considered as the critical level in the case of environmental exposure. However, the margin of safety between the present daily intake of cadmium in diet and the intake which may result in a slight increase in early signs of kidney dysfunction is, particularly for smokers, very narrow.
Therefore every effort should be made to further reduce cadmium emissions and the direct input of cadmium to the soil from fertilizers and municipal sludge.
In adults, the hematopoietic system and in children, the central nervous system are critical for lead exposure. The probability of health effects of lead exposure is defined on the basis of blood lead concentration (Pb-B). Nowadays, the mean geometric of Pb-B concentrations in the adult general population is much below the threshold level for the concentration of zinc protoporphyrin (ZnPP) in blood, one of the most sensitive critical effects.
Children are more sensitive to the effect of lead exposure, therefore, they are regarded as a risk group in the general population. It as assumed that in children Pb-B concentration should not exceed 100 ľg/l, however, it is not known whether this is the threshold limit for lead effect on the central nervous system. In Poland, the study of the present level of environmental exposure in areas free from heavy industry indicates that this value is exceeded in about 1ś2% of children, while in the zone of steel works of non-ferrous metals this proportion increases up to 10%.

Key words

heavy metals, health effects of environmental exposure