Occupational exposure of petroleum depot workers to BTEX compounds

Benzene, toluene, ethylbenzene and xylene [BTEX] are the most important toxic volatile compounds in the air and could be easily absorbed through the respiratory tract. In recent years, the risk of exposure to BTEX compounds, especially benzene as a carcinogen, has been considered in petroleum depot stations. To assess the occupational exposure of petroleum depot workers in Iran to BETX compounds. After completing a questionnaire and assessing occupational exposure to BETX compounds, 78 [46 exposed and 32 non-exposed] depot workers were randomly selected to participate in this study. Air sampling and analysis of BTEX was conducted according to the NIOSH method No. 1501. Analysis of urinary hippuric acid, as an indicator of toluene exposure, was carried out according to NIOSH method no. 8300. Personal monitoring of the high exposure group to BTEX compounds was repeated to verify the results obtained in the first phase of the monitoring. Among the 9 operating groups studied, occupational exposure to benzene and toluene was higher in quality control and gasoline loading operators - the median exposure ranged from 0.16 to 1.63 ppm for benzene and 0.2 to 2.72 ppm for toluene. Median exposure of other group members to BTEX compounds was below the detection limit of analytical method [0.07, 0.06, 0.05, and 0.05 ppm, respectively]. The level of toluene exposure measured showed correlation with neither post-shift urinary hippuric acid [Spearman's rho = 0.128, p=0.982] nor with the difference between post- and pr-shift urinary hippuric acid [Spearman's rho=0.089, p=0.847] in depot operational workers. Gasoline loading operators are exposed to a relatively high level of benzene

Urinary Hippuric Acid and trans,trans-Muconic Acid Levels According to Commuting Mode and Duration, Residential Environment, and Intake of Preservative-Added Foods and Beverages in University Students / 대한산업의학회지

OBJECTIVES: Automobile exhaust gases contain benzene and toluene, which are excreted in human urine as trans,trans-muconic acid and hippuric acid, respectively. Sorbic acid and benzoic acid, used as food preservatives, are also metabolized into trans,trans-muconic acid and hippuric acid in the human body. The purpose of this study is to estimate the level of benzene and toluene exposure according to the commuting mode and duration, residential environment, and preservative-added foods intake in university students who are not occupationally exposed to benzene or toluene. METHODS: Spot urine samples were collected from 211 university students who had no occupational exposure to volatile organic compounds. Information about their smoking history, residence type, traffic environments, commuting mode and duration, and their intake of bottled or canned food or beverages was gathered through a self-administered questionnaire. Urinary concentrations of trans,trans-muconic acid and hippuric acid were measured and statistically correlated to the individual's life style factors. RESULTS: There was no significant difference in the urinary concentrations of trans,trans-muconic acid or hippuric acid according to the smoking history. Mean urinary concentration of hippuric acid in females was higher than that found in males. Subjects living in districts with a population density of 1,000~4,999 people/km2 showed the highest urinary hippuric acid level; individuals living in cities of 5,000~9,999 people/km2 population density were next. The mean urinary trans,trans-muconic acid concentration was higher in students who were living where traffic jams are common compared to those who did not, and in subjects whose residence were within 149 m from a 4-lane road compared to those whose residence was not. However, neither mode nor duration of the commute showed any effect on the urinary trans,trans-muconic acid or hippuric acid concentrations of the students. Urinary hippuric acid levels increased when consuming canned fruit or canned coffee, and urinary trans,trans-muconic acid levels increased when consuming fruit juices or pickled radishes. CONCLUSIONS: The inhalation of vehicle exhaust and the ingestion of canned or pickled food may increase urinary hippuric acid and trans,trans-muconic acid levels in individuals who are not occupationally exposed to benzene or toluene.

External Quality Assessment Scheme for Biological Monitoring of Occupational Exposure to Toxic Chemicals

OBJECTIVES: In this study, we summarized the External Quality Assessment Scheme (EQAS) for the biological monitoring of occupational exposure to toxic chemicals which started in 1995 and continued until a 31st round robin in the spring of 2010. The program was performed twice per year until 2009, and this was changed to once a year since 2010. The objective of the program is to ensure the reliability of the data related to biological monitoring from analytical laboratories. METHODS: One hundred and eighteen laboratories participated in the 31st round robin. The program offers 5 items for inorganic analysis: lead in blood, cadmium in blood, manganese in blood, cadmium in urine, and mercury in urine. It also offers 10 items for organic analysis, including hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid, N-methylformamide, N-methylacetamide, trichloroacetic acid, total trichloro-compounds, trans,trans-muconic acid, and 2,5-hexanedione in urine. Target values were determined by statistical analysis using consensus values. All the data, such as chromatograms and calibration curves, were reviewed by the committee. RESULTS: The proficiency rate was below 70% prior to the first round robin and improved to over 90% for common items, such as PbB and HA, while those for other items still remained in the range of 60-90% and need to be improved up to 90%. CONCLUSION: The EQAS has taken a primary role in improving the reliability of analytical data. A total quality assurance scheme is suggested, including the validation of technical documentation for the whole analytical procedure.

Estudo retrospectivo dos níveis de ácido hipúrico urinário em exames de toxicologia ocupacional / A retrospective study analysis of urinary hippuric acid levels in occupational toxicology exams

O ácido hipúrico é o principal metabólito do tolueno, solvente amplamente utilizado em processos industriais e com importantes efeitos tóxicos, fato que justifica a preocupação em monitorar regularmente sujeitos com risco de exposição ocupacional a este solvente. O objetivo deste trabalho foi avaliar os níveis de ácido hipúrico encontrados em trabalhadores submetidos à monitorização biológica. Foi realizado um estudo retrospectivo com dados dos anos de 2002 a 2005, no qual foram analisados os resultados e a situação do empregado na oportunidade do exame (periódico, demissional e admissional). Os resultados indicam uma redução significativa nos níveis de ácido hipúrico em 2005. Exames periódicos obtiveram resultados superiores aos exames admissionais e demissionais, e não foi verificada diferença significativa nas proporções dos sujeitos agrupados de acordo com a situação funcional em cada um dos intervalos estabelecidos segundo o valor de referência e o índice biológico máximo permitido. Os níveis de ácido hipúrico detectados indicam um baixo de risco de exposição ao tolueno na população avaliada, provavelmente em decorrência da preocupação crescente com a implantação de medidas de higiene ocupacional.

Hippuric acid is the primary metabolite of toluene, a solvent widely used in industrial processes with considerable toxic effects, a fact which justifies regularly monitoring individuals with occupational exposure to this solvent. This work aims at evaluating urinary hippuric acid levels found in workers subject to biological monitoring. A retrospective study was carried out with data referring from 2002 to 2005, in which exams results and employment status were analyzed (periodic, post-employment, and pre-employment exams). Results indicate a significant reduction in hippuric acid levels for 2005. Periodic exams presented higher results than pre-employment and post-employment exams. No significant difference was found in individuals grouped according to their status in each of the established intervals, their reference numbers, and maximum biological levels allowed. Hippuric acid levels detected indicate low risk of toluene exposure for the population under evaluation, probably due to a growing concern with the deployment of measures regarding occupational hygiene.

Health Effect Assessment on Volunteers Involved in the Cleanup Operation Following the Hebei Spirit Oil Spill Along the Taean Coast, Korea / 대한산업의학회지

OBJECTIVE: The objetive of this study is to assess the level of oxidative stress by the exposure to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) in volunteers who cleaned up the crude oil spilled from the Hebei Spirit on the Coast of Taean County, Korea. METHODS: The study subjects were 46 volunteers and 37 controls from the National Institute of Environmental Research. A self-administered questionnaire was used for volunteers to examine their working environment and health effects. Urinary concentrations of hippuric acid, 1-hydroxypyrene, and 2-naphthol were measured as exposure markers for VOCs and PAHs, and urinary thiobarbituric acid reactive substances (TBARS) and 8-hydroxydeoxyguanosine (8-OHdG) levels were measured as oxidative stress markers. RESULTS: Sixty-four percent of the respondents presented a variety of symptoms, including sore eyes and throat, nausea, dizziness, headache, low back pain, and leg pain after participating in the cleanup operation. Urinary 2-naphthol and TBARS concentrations appeared higher in the volunteers. Univariate and multivariate analyses showed that urinary TBARS and 8-OHdG levels were positively correlated with urinary 2-naphthol and 1-hydroxypyrene concentrations respectively, especially among the volunteers. CONCLUSIONS: The result implies that participating in cleanup work of oil spills may have a possibility to induce oxidative damage by exposure to PAHs in crude oil.

Environmental exposure to xylenes in drivers and petrol station workers by urinary methylhippuric acid

The aims of this study were evaluation of exposed to xylenes in low concentration and compare urinary level of methyl hippuric acid in taxi drivers and petrol stations workers in West of Iran. This observation study was carried out on samples of the exposed men to xylenes in two occupational groups in Hamadan City [west of Iran] from March 2003 to March 2004. Subjects included 45 taxi drivers and 25 petrol station workers. The study group was selected from 54 workers at petrol stations and 300 drivers by simple random sampling. Xylenes was analyzed using gas chromatography equipped with a Flame Ionization Detector [FID]. The urinary methyl hippuric acid [MHA] was analyzed with High performance Liquid Chromatography [HPLC] equipped with an ultraviolet [UV] detector. Total xylene exposure was 1.05 +/- 0.55 ppm [mean +/- SD] with a range of 0.20-2.55 ppm that was about 4 times more than taxi drivers' exposure. The poor correlation coefficient was seen between xylenes concentration and urinary MHA for drivers [r2 = 0.09 to 0.42] but significant associations were noted between urinary MHA and xylene in the breathing zone of petrol station workers [r2 = 0.69 to 0.77; P < 0.05]. High xylenes levels are emitted in petrol stations at Iran. Urinary MHA level has a poor correlation with exposure to xylenes in drivers but has good correlation in petrol station workers

[Correlation between toluene environmental monitoring and biological index of urinary hippuric acid of workers in the coke industry]

Toluene is an organic solvent that it is one of the byproducts in the coke industry. Exposure to toluene causes central nervous system dysfunction and others disorders. Many workers are exposed to toluene due to leakage from tracks. Therefore the aim of this study was to determine the levels of exposure through environmental and biological monitoring of toluene Air toluene sampling of air inhaled by 36 coke oven workers was done by using activated charcoal tubes and personal sampling pumps. At the e[1id of the shift, urine samples of workers and control group were collected by urine samplers. Air toluene was determined by GC, urinary hippuric acid by FIPLC and urine creatinine level was determined by auto analyzer. The mean of air toluene and urinary hippuric acid levels in exposed and control samples were 14.34 ppm, 0.33 and 0.28 g/g creatinine. Air toluene and urinary hippuric acid showed a correlation of r = 0.8. Toluene TWA was lower than the TLV-TWA [p=0.000]. Urinary hippuric acid concentration was also lower than the BEI [p=0.008]. Difference between exposed and unexposed group was not significant. This study showed that hippuric acid because of its interaction with background factors can not be used as a sensitive biomarker for biomonitoring

Criterios para la vigilancia biológica en la exposición laboral al tolueno / Criteria for surveillance of work-related exposure to toluene

Se detectaron en los exámenes periódicos del personal con riesgo de exposición a tolueno, valores alterados en su estudio específico de control biológico (ácido hipúrico en orina), sin correlato clínico. El objetivo de este estudio fue revisar los datos disponibles relacionados con la seguridad y eficacia del rastreo de ácido hipúrico en orina como control y determinar el estado actual de la población en estudio, respecto de si se encuentra o no expuesta al tolueno, mediante rastreos que testifiquen datos más confiables. Se partió de la hipótesis de que el ácido hipúrico en orina es un examen de baja especificidad e influenciado por múltiples factores confundidores, lo cual implica una tasa de falsos positivos alta. Para aumentar la especificidad, se agregó otro test de control de exposición al tolueno consistente en la determinación de ortocresol en orina. Posteriormente se compararon los niveles de ácido hipúrico y ortocresol en 35 trabajadores expuestos y 5 no expuestos. En los primeros, 12 (12/35) presentaron ácido hipúrico sobre la norma, en tanto los segundos mostraron uno (1/5) alterado. El ortocresol resultó normal en todos los sujetos estudiados. Los niveles de exposición estuvieron bajo la norma en todos ellos. El estudio confirmaría la baja especificidad del ácido hipúrico como control de exposición, lo que implica una tasa alta de falsos positivos. El análisis de ortocresol es, en principio, más preciso y exacto. Aunque desconocemos la especificidad del mismo medida en poblaciones de tamaño suficiente, sería más sensible para detectar expuestos. La suma de ambos aumentaría la especificidad total y disminuiría la tasa de falsos positivos. Se propone, en consecuencia, un nuevo programa de vigilancia biológica.

Occurrence of Campylobacter species in poultry forms in Lagos area of Nigeria.

Samples of poultry droppings were collected from fifty poultry farms in Lagos area of Nigeria. Campylobacter species were isolated from serially diluted samples using Bolton selective enrichment medium under microaerophilic condition at 42 degrees C. Samples of water, both treated and untreated used in the farms were also analysed in the same manner. Fifteen Campylobacter strains were isolated from the droppings. All the strains were identified using biochemical characteristics differentiating Campylobacter species. They were identified as hippurate positive (C. jejuni) and negative species (C. coli). They were biotype' using the extended scheme described by Lior (1984). Campylobacter coli biotype 'I was the most prevalent (66.66%) followed by C. jejuni biotype 1 (20.00%). The biotype ii of the two species accounted for 6.67% each. The C. jejuni biotype III and IV were not isolated during the study. The preponderance of C. coli indicates that poultry can be a major reservoir for the spread of human campylobacteriosis. Poultry farmers, therefore, must ensure prompt and adequate means of disposal of waste materials as well as maintaining good sanitary conditions.

Valores de referência de bioindicadores: avaliação estatística no caso do ácido hipúrico urinário / Reference values of bioindicators: statistical evaluation in the case of the urinary hippuric acid

Um procedimento eficiente para controlar o risco da exposição ocupacional a toxicantes é a biomonitorização dos trabalhadores. Para isso são imprescindíveis os valores de referência (VR) de bioindicadores na população não exposta ocupacionalmente ao xenobiótico. Fatores que diversificam acentuadamente o metabolismo do toxicante (gênero, idade, hábitos de vida, etc. ) devem ser considerados na composição da amostra de referência de modo a permitir a análise de cada subgrupo (estrato). O tratamento estatístico dos dados deve definir a distribuição que melhor descreve os dados amostrais e identificar os subgrupos distintos com base nos valores determinados para o ácido hipúrico (AH) em urina, indicador da exposição ao tolueno, objetivo deste trabalho. Os VR foram obtidos de 181 voluntários e os resultados analisados estatisticamente. A distribuição exponencial foi a que melhor se ajustou aos dados ( cerca de 91% de ajuste) e estes tiveram um valor médio de 0,246g AH/g de creatinina (0,21 - 0,29 g/g de creatinina de intervalo de referência). Não foram detectadas diferenças significativas nos níveis urinários de AH devidas a gênero, faixa etária, uso de tabaco ou de bebida alcoólica pelo teste de Wilcoxon-Mann-Whitney e pelo teste qui-quadrado (p≤0,05).

Diagnóstico laboratorial do consumo de inalantes a base de tolueno: um estudo entre adolescentes de rua de Porto Alegre, RS / Analytical method for toluene inhalant abuse diagnosis: a study among street youngsters in Porto Alegre, RS

Introdução: O tolueno é a principal substância contida em diversos produtos empregados como inalantes e possui importantes efeitos tóxicos que atingem principalmente o sistema nervoso central. Estudos prévios indicaram a elevada prevalência de uso de inalantes a base de tolueno entre jovens em situação de rua de Porto Alegre. Considerando o intenso consumo deste solvente é importante definir parâmetro laboratorial para avaliar sua exposição aguda, uma vez que a clínica destas intoxicações muitas vezes se confunde com a exposição a outros depressores do sistema nervoso central. Objetivos: Definir níveis de ácido hipúrico urinário, relacionados à exposição intencional ao tolueno, correlacioná-los à concentração de tolueno no sangue e descrever alterações bioquímicas e hematológicas em adolescentes de rua usuários de inalantes à base de tolueno. Métodos: Foram aplicados questionários sobre consumo de drogas e realizadas análises toxicológicas para avaliar o consumo de tolueno, xilenos, benzeno, cocaína, maconha, anfetaminas e etanol em uma amostra de conveniência composta por 65 adolescentes de rua de Porto Alegre, Rio Grande do Sul. Foram investigadas alterações clínicas através da realização de análises bioquímicas e hematológicas. Resultados: Foi observado que 87,7 por cento da população investigada havia consumido tolueno recentemente, apresentando níveis de tolueno no sangue de até 83,7 Ng/mL. As concentrações de tolueno no sangue atingiram concentrações consideradas incompatíveis com estado de alerta, sugerindo o desenvolvimento de tolerância decorrente do uso crônico intenso. Houve boa correlação entre as concentrações de ácido hipúrico urinário e as concentrações de tolueno no sangue (r = 0,78). Com exceção da gama-glutamiltransferase, que estava mais elevada entre os usuários, não foram detectadas diferenças significativas nos resultados dos exames bioquímicos e hematológicos entre os indivíduos com resultados positivos e negativos para tolueno no sangue...

Effects of Air Pollutants on Childhood Asthma

Epidemiologic studies have suggested the association between environmental exposure to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) and the increased risk of incurring asthma. Yet there is little data regarding the relationship between personal exposure to air pollution and the incidence of asthma in children. This study was designed to evaluate the effect of exposure to air pollution on children with asthma by using exposure biomarkers. We assessed the exposure level to VOCs by measuring urinary concentrations of hippuric acid and muconic acid, and PAHs by 1-OH pyrene and 2-naphthol in 30 children with asthma and 30 children without asthma (control). The mean level of hippuric acid was 0.158+/-0.169micromol/mol creatinine in the asthma group and 0.148+/-0.249micromol/mol creatinine in the control group, with no statistical significance noted (p=0.30). The mean concentration of muconic acid was higher in the asthma group than in the control group (7.630+/-8.915micromol/mol creatinine vs. 3.390+/-4.526micromol/mol creatinine p=0.01). The mean level of urinary 1-OHP was higher in the asthma group (0.430+/-0.343micromol/mol creatinine) than the control group (0.239+/-0.175micromol/mol creatinine), which was statistically significant (p=0.03). There was no difference in the mean concentration of 2-NAP between the two groups (9.864+/-10.037micromol/mol in the asthma group vs. 9.157+/-9.640micromol/mol in the control group, p=0.96). In conclusion, this study suggests that VOCs and PAHs have some role in asthma.

Determination of the inhibitory activity of angiotensin-converting enzyme inhibitor captopril by high performance capillary electrophoresis / 药学学报

<p><b>AIM</b>To establish a method for determinate of the inhibitory activity of angiotensin-converting enzyme inhibitor captopril by high performance capillary electrophoresis.</p><p><b>METHODS</b>The characteristic absorptive wavelength of hippuric acid determined by ultraviolet spectrophotometer is 228 nm. The method employed a melted capillary column, 50 mmol.L-1 phosphoric acid (pH 8.3) buffer solution, inject pressure 4.8 kPa, inject time 3 s, separation voltage 20 kV and detection wavelength 228 nm.</p><p><b>RESULTS</b>The reactant and resultant was separated completed within 7 min. IC50 of captopril was 0.019 mumol.L-1. Captopril is a competitive inhibitor, which was proved by enzyme reaction dynamics.</p><p><b>CONCLUSION</b>The method was shown to be accurate, simple and rapid and can be used for determination of the inhibitory activity of captopril.</p>

Influência de fatores individuais sobre o valor de ácido hipúrico urinário em indivíduos não expostos ocupacionalmente ao tolueno, residentes na região metroplolitana de Belo Horizonte-Brasil / Individual factors and values of urinary hippuric acid in toluene non-exposed individuals: a study in Belo Horizonte, Brazil

O ácido hipúrico (AH) é o principal biomarcador de exposição ao tolueno. Este composto é produzido no organismo mesmo na ausência de exposição ao solvente apresentando desvantagem se influenciado por fatores individuais e ambientais. Estudos tem demonstrado a influência da idade, sexo e hábito de ingerir café sobre o metabolismo do tolueno. O efeito destes fatores sobre a excreção urinária do AH não está ainda bem estabelecido. o objetivo do presente trabalho foi avaliar so os fatores sexo, idade e ingestão de café teriam influência sobre o valor urinário do AH em indivíduos não expostos ao tolueno

High levels of hippuric acid in the urine of Thai press workers.

Toluene is an important toxic volatile agent found in many modern industrial processes. Toluene exposure is of particular concern because of the ongoing exposure of thousands of workers in industrial plants and recent research has indicated that toluene/exposure can result in chronic toxicity. The monitoring and control of toluene exposure among at-risk workers is necessary. Urine hippuric acid determination is a helpful test monitoring groups of at-risk workers. In this study, urine samples were obtained from 20 control subjects and 48 press workers from a factory in Bangkok. Each subject gave a specimen of urine; each specimen was analyzed for hippuric acid level by the Ohmori method. The average urine hippuric acid level in the control group was 0.23 +/- 0.15 mg/gCr (range = 0.05 - 0.58 mg/gCr) while that of the experimental group was 0.37 +/- 0.37 mg/gCr (range = 0.06 - 0.18 mg/gCr). A significant higher urine hippuric acid level among the press workers was found (p = 0.03). Based on this study, the prevention of exposure to toluene among high-risk workers is recommended.

The effect of cigarette smoking on urinary hippuric acid concentration in Thai workers with occupational exposure to toluene.

Urine hippuric acid determination is helpful for monitoring of group of workers at risk for exposure to toluene. However, some problems about the external source of variation are mentioned. Some studies have indicated that smoking is an important external source of variation for determination of urine hippuric acid level while the others stated the opposite findings. This study was conducted in an attempt to study the difference of urine hippuric acid between smoking and non smoking subjects in a press workers group. Urine samples were obtained from 46 workers (all male) who worked as press workers in the same press factory in Bangkok. The individuals were classified as control (non smoking, N = 26) and experimental (smoking, N = 20) according to their smoking. All samples were analyzed for hippuric acid level. The average urine hippuric acid level for the control were (0.35 +/- 0.31 mg/gCr) and experimental group (0.40 + 0.45 mg/gCr) were respectively. No significant difference was found between urine hippuric acid level between both groups. The data from the current study indicates that smoking does not influence the urinary hippuric acid levels in this study group.

Occupational exposure to toluene inhalant among young car-paint-workers

Forty young car-paint-workers from Mahalla El Kobra, Gharbia Governorate were selected from those who recently joined work [less than one week] at car workshops and were subjected to the following: a] complete personal, family, and medical history taking, b] Complete medical examination, c] Psychological assessment battery of 24 items, d] Complete blood picture, liver function tests, blood urea, serum calcium, potassium, magnesium, and acid phosphatase, and hippuric acid level in urine. Results showed disturbed general behavior. Of the studied cases 89.7% suffered from irritability, 68.9% from talk slow, 34.5% from depressed mood, 65.5% had illusionary misinterpretations, 72.4% had visual hallucinations, 24.2% had distorted body form perception, and 55.2% showed impaired recent memory. Serum magnesium and Hippuric acid level in urine showed significant increase after three-month period of exposure. Attention is drawn to the necessity for educational programs in this area

Valores de referência do ácido hipúrico urinário na regiäo metropolitana de Belo Horizonte / Urinary hippuric acid reference values in Belo Horizonte metropolitan area, Brazil

Objetivando estabelecer a faixa de valor referência para o ácido hipúrico na regiäo metropolitana de Belo Horizonte, urinas de indivíduos näo expostos ocupacionalmente ao tolueno foram analisadas por cromatografia em fase gasosa, utilizando-se detector de ionizaçäo de chama. Os valores encontrados experimentalmente (n=281) variaram de <0,1 a 2,79 g/L, mas a aplicaçäo de estudo estatístico delimita como faixa de referência,a nível de significância de 95 porcento, os valores de 0,361 a 0,481 g/L. Säo descritas, também, as condiçöes analíticas padronizadas para a determinaçäo cromatográfica do ácido hipúrico urinário