Zinc protoporphyrin levels in children in Haifa: a pilot study

Zinc protoporphyrin (ZPP) levels of greater than or equal to 40 micrograms dl-1 were found in blood samples of 32 (12.1%) out of 264 children living in Kiryat Yam, Haifa Bay (a sea-level neighborhood with much vehicular traffic, located 4.5 km from an industrial zone in the bay area), 22 (8.8%) out of 251 children living in Neve Shaanan (located on a mountainside, 3.5 km from an industrial zone and exposed to visible smoke pollution), and 14 (6.5%) out of 214 children from Mt Carmel (Ahuza), which is furthest from industry and where visible signs of pollution are seldom seen. Zinc protoporphyrin levels, low in non-anemic infants, were slightly higher in 1st graders from all three neighborhoods; higher levels were found in both 3rd and 6th graders from Kiryat Yam, but only in 6th graders from Neve Shaanan. The ZPP levels remained unchanged in older, Mt. Carmel children. Zinc protoporphyrin concentrations of greater than or equal to 40 micrograms dl-1 varied inversely with two indices of socio-economic status (parental ethnic origin and father's educational level). Blood lead levels of greater than or equal to 20 micrograms dl of blood were found in eight (13%) out of 62 children with ZPP levels greater than or equal to 40 micrograms dl-1, but in none (0%) of 14 children with ZPP levels greater than or equal to 40 micrograms dl-1. Three (60%) out of five children with ZPP levels greater than or equal to 50 micrograms dl-1 had Pb levels of greater than or equal to 20 micrograms dl-1. In Kiryat Yam, Pb(B) was higher in 31 children with ZPP greater than or equal to 40 micrograms dl-1 compared with 13 with ZPP less than 40 micrograms dl-1. The data on age-associated increases in ZPP in children suggest the possibility of an effect on red blood cell porphyrin metabolism, in some cases from cumulative low level lead exposures, and in others from iron deficiency, especially in poorer socio-economic groups. The findings call for further studies, both in the populations studied here, and elsewhere, to determine the role of lead toxicity and iron deficiency in children of all age groups, and the need for preventive action.