[Lead poisoning: Zinc protoporphyrin in blood of children from Santo Amaro da Purificação, Bahia, Brazil]. / Intoxicação pelo chumbo: Zinco protoporfirina no sangue de crianças de Santo Amaro da Purificação e de Salvador, BA.

A cross-sectional epidemiological study has investigated lead poisoning among all the 101 children aged 1 to 5 years, living at less then 500 m from a lead smelter which has been operating since 1960 in Santo Amaro da Purificação, State of Bahia, Brazil. Lead poisoning was evaluated by determining the concentrations of zinc protoporphyrin (ZPP) in whole blood. Results were compared with those obtained from 98 children of the same age range, in a nursery from Salvador, capital of the State of Bahia. In Santo Amaro, ZPP geometric mean was 65.5 mg/dl (geometric S.D. = 1.7), much higher, therefore, than the normal threshold of 30 microg/dl recommended by the CDC-USA. A child was excluded from statistical analyses because of very high ZPP level: 789 mg/dl. In Salvador, ZPP geometric mean was 31.0 mg/dl (geometric SD = 1.6). "Extremely elevated" ZPP levels (above 156 mg/dl) were observed in 8% of the children from Santo Amaro and in none (0%) of the children from Salvador, this statistical difference being highly significant. Anaemia was present among 35.0% of the children from Santo Amaro and among 25.5% of those from Salvador. One year-old children showed the highest levels of ZPP and anaemia. No marked statistical association was found between ZPP levels and anaemia. Lead contamination of this children population remained in a permanently high level during, at least, the period from 1980 to 1992. In December, 1993 the lead smelter has definitively ceased its industrial activities in Santo Amaro da Purificação.

Lead poisoning among children of Santo Amaro, Bahia, Brazil in 1980, 1985, and 1992.

A cross-sectional epidemiologic survey conducted at the beginning of 1992 evaluated the status of lead intoxication among children from 1 to 5 years of age living within 500 meters of a primary lead smelter in the Brazilian city of Santo Amaro, Bahia. A total of 103 children in this age group were initially enrolled in the study; however, 2 were later excluded because they could not be located, and 1 was excluded from the statistical analyses for reasons noted below. The results were compared with those from similar surveys made in 1980 and 1985 in the same area with children of the same age. A blood sample was obtained from each child, the child's hematocrit and zinc protoporphyrin (ZPP) level were determined, and an interview questionnaire was used to collect information of clinical or epidemiologic interest from the child's mother or guardian. The geometric average ZPP was 65.5 micrograms/100 mL (geometric standard deviation = 1.7), a level far exceeding the upper limit of normality established by the U.S. Centers for Disease Control and Prevention of 30 micrograms/100 mL. One child was excluded from the statistical analyses because it exhibited an extremely high ZPP level (789 micrograms/100 mL). Higher average ZPP levels were found for girls, children with darker-skinned racial backgrounds, children from homes where smelter slag was commonly used around the house, children presenting pica, and children of smelter workers. Of the symptoms of lead poisoning investigated, only nervousness and easy irritability exhibited high frequencies among the children studied. However, the prevalence of above-normal ZPP levels suggestive of lead poisoning was 92.2% in 1980, 98.4% in 1985, and 97.0% in 1992. Hence, the apparent prevalence of lead poisoning continued very high in 1992, indicating that the control measures adopted were ineffective or that other unidentified and uncontrolled risk factors were playing an important role. Overall, however, the proportion of children with very high ZPP levels fell sharply, and that of children with moderately high levels also declined notably, indicating that the severity of the problem had been reduced even though new cases of intoxication continued to occur. The Santo Amaro smelter closed its doors in December 1993.

Erythrocyte protoporphyrin versus blood lead: relationship with iron status among children exposed to gross environmental pollution.

The dose-response relationship between erythrocyte protoporphyrin (EP) and blood lead (PbB) was investigated among children with different subgroups of iron status. The data bank from Santo Amaro City, Brazil, was taken to study 490 children aged 1-9 years who lived at less than 900 m from a primary lead smelter. Mean PbB was 58.9 +/- 25.3 micrograms/dl and mean EP was 87.1 +/- 68.1 micrograms/dl. At PbB levels lower than 60 micrograms/dl, the dose-response curve for EP versus PbB followed the classical pattern; children with low iron status showing greater EP "response" than those with typical iron status and those with high iron status, after controlling for the effects of age and racial group. Among children with PbB > or = 60 micrograms/dl, EP response increased according to the following order: typical < low < high iron status.

Cadmium in hair of children living near a lead smelter in Brazil.

In a cross-sectional study, concentrations of cadmium in hair (CdH) were determined for 263 children aged 1-9 years, living less than 900 m from a lead smelter in Santo Amaro, Brazil. The mean CdH level was significantly higher when individuals with the following characteristics were considered: female, racial group "dark" or "medium", and children of lead workers. The mean CdH value did not vary significantly according to nutritional status or iron status or hair type. Hair Cd levels increased significantly in relation to an increase in cadmium concentration in soil. An increase of 0.024 ppm in mean CdH level was estimated for each 1 ppm increase in the cadmium concentration in soil. However, children with the habit of pica had only a slight increase in CdH levels, when compared with those without the habit. The marked variations observed in CdH levels suggest the possibility of using them as an epidemiological index in situations of intense environmental pollution.

Repeated surveillance of lead poisoning among children.

In 1980, a survey of lead poisoning was carried out among 592 children aged 1 to 9 years living within 900 m of a lead smelter in Santo Amaro, Brazil. From 1980 to 1985, the lead smelter carried out a number of major improvements aimed at reducing environmental pollution. In January, 1985, a second survey was carried out among a sample of 250 children living in this same geographical area. The geometric mean of zinc protoporphyrin (ZPP) concentration in whole blood was 1.17 (standard deviation = 1.5) mumol l-1. Blood lead concentrations (PbB) determined in a subsample of 53 children had an arithmetic mean and standard deviation of 1.77 +/- 1.00 mumol l-1, with 22 children showing PbB greater than or equal to 1.68 mumol l-1. Twenty-nine (11.6%) of the 250 children lived in houses where the lead content of the soil was greater than 10,000 ppm, and they presented higher ZPP levels than the rest of the population. Children with the habit of pica for soil had elevated ZPP levels. Comparing the results from the 1980 and 1985 surveys, slight improvements in ZPP and PbB levels were observed. However, new cases of lead poisoning are still occurring in the area. The soil is highly contaminated by lead and represents a long-lasting risk factor for child intoxication.

Cadmium concentrations in blood of children living near a lead smelter in Bahia, Brazil.

A prevalence study of cadmium absorption was carried out among 396 children aged 1 to 9 years living at less than 900 m from a primary lead smelter in Santo Amaro City, northeast Brazil. Geometric mean and geometric standard deviation of cadmium concentrations in blood (CdB) were 0.087 and 2.5 mumole/liter, respectively, ranging from 0.004 to 0.511 units. Ninety-six per cent of these children presented CdB higher than 0.0089 mumole/liter (or 1.0 microgram/liter) which is usually taken as a reference level. Higher CdB levels were significantly associated with shorter distance from child's home to smelter chimney, residence time in the area greater than 7 months, racial groups Light and Medium, and heavy infection by hookworm. The variation in CdB levels was not associated with child's age, nutritional status, iron status, family per capita income, blood lead level, being a child of a lead worker, the habit of pica, and contamination of child's peridomiciliar environment by smelter dross.

Multiple causes of anaemia amongst children living near a lead smelter in Brazil.

A prevalence study of anaemia was carried out amongst children, aged one to nine years, living near a lead smelter in Santo Amaro City, Northeast Brazil. It was found that the variation in haemoglobin levels was significantly associated with malnutrition and with the interaction between malnutrition and iron deficiency, but not with lead poisoning, iron deficiency, or hookworm infection, having allowed for the effects of age, area of residence, family per capita income and race. The effect of the interaction between malnutrition and iron deficiency on haemoglobin levels was most prominent amongst children aged one year and amongst those living in the most deprived area. The lack of demonstrable interaction between lead poisoning and iron deficiency in the causation of anaemia amongst these children is discussed.

Lead and cadmium concentrations in the hair of fishermen from the Subae River basin, Brazil.

Previous studies have shown heavy pollution by lead and cadmium in the Subae River basin, State of Bahia, Brazil, caused by a lead smelter. Concentrations of these metals were determined in scalp hair of fishermen from three riverside towns and from a reference town. Increased levels for both metals were associated with increasing proximity to the smelter. Mean concentrations of lead and cadmium were higher among fishermen with straight hair than among those with curly hair. The effects of hair washing, hair type, and color and age on metal concentrations in fishermen's hair were studied.

Absorcao e intoxicacao por chumbo e cadmio em pescadores da regiao do Rio Subae. / Absorption and poisoning by lead and cadmiun among fishermen from the Subae river region

Em 1960, uma fundicao primaria de chumbo, subsidiaria do grupo multinacional Penarroya, instalou-se em Santo Amaro da Purificacao, Bahia, e tem liberado metais pesados para o meio ambiente. Pescadores de Santo Amaro e de mais duas localidades ribeirinhas foram estudados quanto a absorcao e efeitos toxicos de chumbo e cadmio.As concentracoes destes metais, em cabelos de pescadores de cada localidade, estavam significativamente mais elevadas (P<0,05) que em cabelos de pescadores de uma area de referencia, nao poluida. Os niveis de acido delta-aminolevulinico na urina dos pescadores das duas localidades mais proximas da fundicao estavam significativamente mais elevados (P<0,05) que os niveis para a populacao de referencia. Os pescadores do Rio Subae apresentaram prevalencias de proteinuria tubular (metodo do acido sulfossalicilico) mais elevadas que pescadores da area de referencia. Contudo, estas diferencas nao foram estatisticamente significantes ao nivel de probabilidade de 5%