Leiliane Coelho Andre Amorim

Os biomarcadores e sua aplicação na avaliação da exposição aos agentes químicos ambientais

A Saude Ambiental tem como um de seus objetivos, a prevencao dos danos a saude causados por contaminantes quimicos presentes no meio ambiente, fazendo com que os niveis desta exposicao sejam mantidos em valores que nao constituam um risco inaceitavel. Para isso, tornam-se necessarias a identificacao e quantificacao deste risco atraves da avaliacao biologica da exposicao humana. Este e um artigo de revisao que busca apresentar conceitos e concepcoes que abrangem o uso dos parâmetros biologicos com a finalidade de avaliar a exposicao as substâncias quimicas e estimar o risco das populacoes expostas. Os biomarcadores podem ser usados para varios propositos, dependendo da finalidade do estudo e do tipo da exposicao e podem ser classificados em tres tipos: de exposicao, de efeito e de suscetibilidade, os quais sao instrumentos que possibilitam identificar a substância toxica ou uma condicao adversa antes que sejam evidenciados danos a saude. Novos parâmetros sao apresentados, como os biomarcadores de neurotoxicidade (ou marcadores substitutos), que tem como desafio detectar acoes precoces de agente quimicos que agem no sistema nervoso central atraves da identificacao de indicadores presentes no sistema periferico, que sao equivalentes aos parâmetros presentes no tecido nervoso.

Analysis of hydroxylated polycyclic aromatic hydrocarbons in urine using comprehensive two-dimensional gas chromatography with a flame ionization detector

The determination of polycyclic aromatic hydrocarbon (PAH) metabolites in human urine is the method of choice for assessing exposure to carcinogenic compounds. The objective of this study was the development of a comprehensive two-dimensional gas chromatography (GCxGC) method using a flame ionisation detector (FID) to simultaneously determine 10 hydroxylated PAH. The method was based on enzymatic deconjugation, liquid-liquid extraction, and trimethylsilyl (TMS) derivatization of the analytes by microwave heating. Satisfactory separation was achieved. The coefficient of variance was 3.8-12.8%. LOD was 0.03-0.18 microg/L, and LOQ was 0.1-0.5 microg/L. The mean recovery was 76%. The method was applied to the analysis of urine from smokers and non-smokers.

An optimized method for determination of benzene in exhaled air by gas chromatography-mass spectrometry using solid phase microextraction as a sampling technique

The determination of benzene in exhaled air has contributed for the increase in the use of breath analysis in biological monitoring. This paper describes SPME as a sampling technique for determining benzene in exhaled air by GC-MS. A system was developed to generate a gaseous benzene standard by a permeation method to accomplish the breath analyses. The method presented good resolution, repeatability (the mean of %RSD values for intra-day measurements was 6.3), sensitivity (2.4 and 3.1 ppb for LOD and LOQ, respectively), and linearity of response (R(2)=0.994). After optimizing the conditions, analyses of real samples were performed on two groups (exposed and not exposed to benzene). The results presented an average of 8.2 ppb for the control group and 25.3 ppb for the exposed group.

Determination of o-cresol by gas chromatography and comparison with hippuric acid levels in urine samples of individuals exposed to toluene

Hippuric acid is the most frequently used biomarker in the biological monitoring of occupational exposure to toluene. This product of solvent biotransformation may be also found in the urine of individuals who have not been exposed to the solvent. A smaller fraction of the absorbed toluene is oxidized to aromatic compounds including ortho-cresol, which is not found significantly in the urine of nonexposed individuals. An analytical methodology whereby gas chromatography with flame ionization detection is utilized for determination of o-cresol in urine of workers exposed to toluene is described. The levels obtained were subsequently compared to hippuric acid levels determined in the same urine samples. The analytical method has demonstrated an adequate precision (intra- and interassay coefficient of variation in the range of 2.4-5.4%) and average recovery of 98%. The samples for o-cresol determination were obtained from workers exposed to toluene in three different industrial activities. The concentration range found in exposed groups varied from < 0.21 to 2.8 micrograms/ml. The o-cresol values in the urine did not differ significantly among the exposed groups analyzed at the 5% level. The o-cresol and hippuric acid values found in the urine samples showed a significant correlation at the 1% level. These results may represent an additional contribution to studies for a definitive evaluation of the validity of o-cresol as a biomarker of exposure to toluene.

Sampling and Analytical Methods for Determining VOC in Air by Biomonitoring Human Exposure

Volatile organic compounds (VOC) are the total organic compounds that contribute to photochemical ozone formation. They have a vapor pressure greater than 0.013 kPa at 298 K (according to the American Society for Testing and Materials (1996)), 0.01 kPa at 293 K (according to the European Union (1999)), or 10 Pa at 298 K (according to the U.S. Environmental Protection Agency (1999)), with a lower boiling point limit of 50–100°C and an upper boiling point limit of 240–260°C. VOC include countless potentially hazardous substances released to the outdoor or indoor environment. The prevention or reduction of exposure to VOC in the air requires qualitative and quantitative analysis of these chemical agents. A correct assessment of human exposure to VOC requires appropriate and efficient methods of sampling and analysis. The authors present a survey of VOC definitions, an analytical discussion of the necessity and viability of exposure studies, the principal VOC studied, and a critical revision of methods of sampling and analyses.

Analytical Methods for Performing Pesticide Degradation Studies in Environmental Samples

Pesticides are groups of artificially synthesized substances, toxic and non-biodegradable in the environment, that persist after application and are subject to some chemical processes of degradation, hydrolysis, oxidation, and photolysis by the ecosystem (Ormad et al., 1997; Ariaz-Estevez et al., 2008). According to Law 7802 of 11 July 1989, pesticides and similar substances are defined as those products and agents of physical, chemical or biological processes intended for use in the production, storage and processing of agricultural products, in pastures, in the protection of native or implanted forests and other ecosystems, and also in urban, aqueous and industrial environments, whose purpose is to change the composition of the flora or fauna, to preserve them from the harmful action of living organisms considered to be harmful (Mahalashmi et al., 2007). This group of substances can be classified according to the purpose for which they are intended, the mode or period of action, or the chemical function such as: insecticide (insects), fungicide (fungi), rodenticide (rodents), moluscicide (snails), defoliant (leaf harvesting), dissecting (foliage). They are extensively used as insecticides, herbicides and nematicides, and they are included in the classes of organochlorides, organophosphates, and pyrethroids. More than 500 different formulations of pesticides have been used in the environment, largely in agricultural activities, for many decades. Pesticides are widely studied as environmental contaminants because of their extensive use in the control of pests affecting agricultural crops, homes, and gardens. Because of their chemical characteristics, they represent a type of pollutant that shows variable persistence and biochemical and photochemical degradation (Bandala et al., 2007). Some studies show that, less than 1% of the total quantity of pesticides used in agriculture reaches its target. The remainder contaminates soil and other environmental compartments, air, and surface and groundwater. The fact that they are not biodegradable, together with their continued use, makes them a significant problem and a critical issue, with potentially damaging and unforeseen consequences for the future (Kapustka et al., 1996; Bandala et al., 2002; Acero et al., 2008; Veiga et al., 2006). In 1995, US

Breath air analysis and its use as a biomarker in biological monitoring of occupational and environmental exposure to chemical agents

1.6 million in actual pesticides were sold in Brazil. That amount increased to

Sampling of benzene in environmental and exhaled air by solid-phase microextraction and analysis by gas chromatography-mass spectrometry

2.5 million in 2007 (Andreu & Pico, 2004). The use of pesticides in the world has increased five fold in the last 30 years (Nawab et al., 2003).