Evaluation of blood lead concentration in workers of the electrical storage battery recuperation sector and solder of radiator in the Great Cuiabá-MT, Brazil.

Paulo A. ROSSIGNOLI¹

Edinaldo CASTRO E SILVA²

Lázaro J. OLIVEIRA³

Stela M. SILVESTRIN⁴

¹Departamento de Ciências, Tecnologia de Alimentos e Nutrição Básica/FEN e Doutorando do Programa de Pós-graduação em Saúde e Ambiente/UFMT

²Departamento de Química/ICET e Orientador do Programa de Pós-graduação em Saúde e Ambiente/UFMT

³UNEMAT e Mestrando do Programa de Pós-graduação em Saúde e Ambiente/UFMT

⁴Departamento de Pediatria/FCM/UFMT

ABSTRACT

The xenobiotic called lead had its occurrence furthered in the environment since the industrial revolution and it has being characterized by its absence in known metabolic process. The objective of this study was to check the occurrence of this metal in workers of the electrical storage battery recuperation sector and solder of radiator shop in the city of Cuiabá and Várzea Grande, Mato Grosso, Brazil. The determination of the blood lead concentration (PbB) was done in workers at the industries mentioned above through the Atomic Absorption Spectrophotometric method after removing lead with TRITON X-100 in complexation with pirrolidinaditiocarbamato de ammonium. Of the 55 workers searched, 19 (34,5%) showed PbB above 25 mg/dl and according to recent data this level can provoke important metabolic changes that must be appropriately investigated. The Brazilian Laborite Legislation consider the level of 40 mg/dl as being the limit of biological tolerance but this level has been contested by countless research in the heavy metals area. At the same time the determination of PbB was perfomed in the control group which had correlate activity to that mentioned above, like car repair firm (car machine) and motor-car electric shop; the PbB concentrations of the group not exposed to lead, which was composed by government employees, students and workers from building, were also determinated. It was verified that 100% of people in this last two groups had PbB below 25 mg/dl. These data show (prove) the contamination of important fragment (parcel) of workers denoting the necessity of studies to establish the interation of climate/intoxication by lead.

Key words: lead, Occupational health, Ambiental chemistry

CORRESPONDÊNCIA/CORRESPONDENCE:

Paulo Afonso Rossignoli.

Depto de Ciências, Tecnologia de Alimentos e Nutrição Básica.

Universidade Federal de Mato Grosso.

Av. Fernando Correa da Costa s/n. Cuiabá – MT, Brasil – CEP: 78060-900

Fone: 0-XX-65-615-8813

E-mail: parossi@zaz.com.br

INTRODUCTION

The great Cuiabá comprises the municipal district of Cuiabá and Várzea Grande with a population around 900 thousand of people. In the region predominates the binominal agriculture/cattle raising and the transport of consumable things is done nearly always by highway. The great distance from the others production and consumption centers in the country promotes the growing of all substructure of possessions and services that are dependent on the highway transport.

The manufacture and reformation industry of electrical storage battery and automotive radiator soldering (heat exchanger) has 26 establishment in the region that was charted for this search. The electrical accumulator industry is the greatest lead consumer of the industrial sector and it has occured mainly in development countries where the control of using this metal is characterized by uncertainty which affects the man and the environment in a crescent scale. ROCHA and HORTA (1987) have demonstrated that 52% of workers from the sector of electrical accumulator production in Belo Horizonte (MG) showed intoxication caused by this heavy metal.

The metal lead has demonstrated no physiological action known in human being until this present moment. The human history records clinical manifestation of lead-poisoning or saturnism since remote periods and it has been believed as an important problem of public health. In humans, lead can result in a wide range of biological effects depending upon the level and duration of exposure. The lead-poisoning is able to cause since apprenticement perturbation and/or psychological disturb until cerebral damage and sudden death among intoxicated person according to GONZÃLEZ (1997) and SCHVARTSMAN (1971).

In 1995 the WORLD HEALTH ORGANIZATION divulged a publication about inorganic lead where was observed that the parameters named biological index can be influenced by others physiological factors other than lead and that these index have not the specificity and sensibility of blood lead (PbB) measurements as an indicator of either current exposures or body stores of lead.

The purpose of this search was to evaluate the real stage of contamination among workers at the manufacture and reformation sector of electrical storage battery and the repairing automobile radiator by solder of the great Cuiabá through determination of blood lead level. The industries were not only localizated by using the cadaster at the municipal board of trade but also and principally by the personal indication of these establishment. The PbB level was determinated in the control groups that were compound by workers occasionally exposed to lead and the another one by workers not exposed to it.

MATERIALS AND METHODS

The exposure to lead was evaluated among workers at the electrical storage battery manufacturing and radiator repair using solder of the great Cuiabá by determinating the blood lead level. The samples for blood were collected in tubes of glasses with heparin and stored in freezer at low temperature (-20⁰C) until the analysis be done. All the glasses used in the experiment were immersed into nitric acid 20% for 24 hours to prevent secondary contamination by lead.

The sample was compound by industries registered in the cadaster at the municipal board of trade or announcement in the telephone directory and principally by the personal indication of these establishment. The workers took part in the experiment voluntarily and with formal consent. Twenty six establishment were visited and only one refused in participating of the search.

The subjects were divided into three groups: A) occupationally exposed (represented by employees who work directly with lead automobile battery manufacture or repair automobile radiators using solder in which is used alloy of tin/lead in proportion of about 50% for each); B) workers occasionally exposed (person from mecanic shop or from “auto-elétrica”, it means person who occasionally handled electrical accumulators) and C) person without exposure to lead (workers from civil architecture, student of a university, technician from laboratory and public workers).

The PbB levels were determinated by Espectroscopy of Atomic Absorbance technic with flame after removing lead by TRITON X-100 in conjunction with ammonium pyrolidindytyicarbamate and solubilization of the complex formated in metyl isobutil ketone. A model of Atomic Absorption Spectrophotometer - VARIAN AA-200 was used.

The Merck standard was used ... for analytical control.

RESULTS AND DISCUSSION

The Brazilian legislation of work (1983) through governmental regulation establishes that the biological tolerance limit for blood lead is 60 mg/dl while the normal value is 40 mg/dl. These index have been questioned constantly cause of recent studies that observed symptoms even in so inferior levels. ARAÚJO et al. (1993) observed that person with PbB concentration above 25 mg/dl could be strongly contaminated. STAUDINGER and ROTH (1998) verified that the level equal to or lower than 9 mg/dl could be considered the normal value for lead.

Many searches put into practice by the 70th decade (ENVIRONMENTAL HEALTH CRITERIA, 1995) have mentioned lower levels with capacity for inhibiting the enzyme activity in blood. ROELS et al. (1976) have already observed that PbB levels greater than 5 mg/dl can provoke enzymatic inhibition and anothers crew of authors (GRANICK et al., 1973; HERNBERG & NIKKANEM, 1970) had already emphasized that PbB levels lower than 15 mg/dl appear scatterred.

The results of table 1 show 55 measurements of blood lead levels among workers exposed to this metal. In the group with PbB level lower than 25 mg/dl the arithmetic medium was 13,3 mg/dl while in the group occasionally exposed it was 4,1 mg/dl (table 2) and in the last group, those people without lead exposure, it was 1,2 mg/dl (table 3). The falling of these medium clearly outpoint that the office of the workers rolled up into this search signalized at the present moment the contamination degree by lead it means that those working in industries where lead is used or produced may be subject to additional exposure compared with the general population.. The tendency of high medium is strengthened by the measurement of 25 to 40 mg/dl where only the group exposed to lead has shown the medium of 30,8 mg/dl and for the rest there were not workers at this zona. The picture of contamination is still reinforced by evidences that 34,5% of workers occupacionally exposed show blood lead levels greater than 25 mg/dl.

TABELAS

TABLE 1 – PbB level among workers occupacionally exposed to lead (Pb) - Cuiabá - MT, 1999.

PbB level (mg/dl)	N	%	X (mg/dl)
< 25	36	65,45	13,3
25 – 40	18	32,73	29,9
> 40	1	1,8	44,9
TOTAL	55	100	100

TABLE 2 - PbB level among workers occasionally exposed to Pb - Cuiabá - MT, 1999.

PbB level (mg/dl)	N	%	X (mg/dl)
< 25	49	100	4,1
25 – 40	_	_	_
> 41	_	_	_
TOTAL	49	100

TABLE 3 - PbB level among workers not exposed to Pb - Cuiabá - MT, 1999.

PbB level (mg/dl)	N	%	X (mg/dl)
< 25	49	100	1,2
25 – 40	_	_	_
> 40	_	_	_
TOTAL	49	100

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