Exposure to lead and cadmium of the general population of Malta

Lead and other metals in gestational hypertension

OBJECTIVES

To identify any effects that lead, calcium, magnesium, and zinc may have on the development of gestational hypertension.

METHODS

Third-trimester 110 normotensive and 33 gestational hypertension cases were assayed for various metal levels, using standard techniques, including atomic absorption spectrometry.

RESULTS

Gestational hypertension cases showed significantly higher blood lead levels than normotensives. No differences were noticed regarding calcium (ionized and total), magnesium, and zinc levels. Blood lead was significantly related with blood pressure, even after correcting for the body mass indices and age. Blood pressure levels showed no relation to the other analyzed metals. However, the lead:ionized calcium ratio showed a stronger association with blood pressure, than lead alone. Blood lead showed a significant negative relationship with ionized calcium, but none with the other metals.

CONCLUSIONS

Blood lead evidently influenced blood pressure increments and gestational hypertension development. This implies that all efforts should be made to reduce the population's exposure.

Validity and interpretation of blood lead levels: a study of Danish school children

Blood lead concentrations were measured in a group of children from a group of 9- to 10-year-old school children in Aarhus, Denmark. The study group was selected as a high-level and a low-level lead group, as identified by the lead concentration in the circumpulpal dentine in deciduous teeth shed 2-3 years previously. The validity of the blood sampling technique was investigated in adult volunteers, and lead was determined by electrothermal atomic absorption. Capillary blood sampling by a finger-stick method was preferred, as the slight contamination caused by this technique was deemed acceptable. The children with the highest dentine lead levels (n = 70), had blood lead concentrations of 0.08-0.63 mumol/l and a geometric mean of 0.28 mumol/l. The children with lowest dentine levels (n = 76) had blood lead concentrations of 0.08-0.70 mumol/l and a geometric mean of 0.18 mumol/l. The blood lead concentrations were compared with interview data on behaviour, family habits, diet, parents' tobacco smoking and occupation, water lead measurements, and traffic counts. A total of 20% of the variation in blood lead was explained by parents' tobacco smoking, the child's number in the sibship, gender, and consumption of canned food at home.

Assessment and comparison of human exposure to lead between Belgium, Malta, Mexico and Sweden

This is a follow-up study of UNEP/WHO Pilot Project on Assessment of Human Exposure to Lead and Cadmium through Biological Monitoring, carried out in 1983/1984. The main objectives of the follow-up study were: to study whether differences in blood-lead levels found between countries in the Biological Monitoring Project were confirmed and were primarily due to exposure via ingested lead (oral intake) or via inhaled lead; to make a preliminary survey, in selected areas, of the possible sources of high exposure (Malta, Belgium). Four countries participated: Belgium, Malta, Mexico, Sweden. To insure comparability between the populations, certain categories were monitored: teachers for socio-economic status, non smoking males, aged between 25 and 50 years old. The blood-lead concentration (PbB) was measured to determine the current exposure and the feces-lead excretion (PbF) was determined to find out the part of the exposure due to ingestion. Blood-lead levels and feces-lead excretion were very different between the four countries. Median values for PbB, in micrograms Pb/1, were, in decreasing values 247 in Malta, 188 in Mexico, 135 in Belgium and 53 in Sweden. Median values for PbF, in micrograms Pb/day, were 361 in Malta, 159 in Mexico, 82 in Belgium and 22 in Sweden. Oral intake seems to be the major exposure route in the four countries. The relationship between PbB and PbF is curvilinear. To investigate the possible source of high exposure, a preliminary survey was made in Malta and Belgium; lead in air suspended and sedimenting particles was monitored as well as the lead concentration in some food and street dust samples. Concerning the comparison of lead concentrations in these environmental samples between Belgium and Malta, no major differences were detected. The high internal exposure to lead in Maltese people, as measured by PbB, is probably due to a combination of several factors.