The Conundrum of the PFOA human half-life, an international collaboration.

The Steering Committee of the Alliance for Risk Assessment (ARA) opened a call for scientists interested in resolving what appeared to be a conundrum in estimating of the half-life of perfluorooctanoate (PFOA) in humans. An Advisory Committee was formed from nominations received and a subsequent invitation led to the development of three small independent working groups to review appropriate information and attempt a resolution. Initial findings were shared among these groups and a conclusion developed from the ensuing discussions. Many human observational studies have estimated the PFOA half-life. Most of these studies note the likely occurrence of unmonitored PFOA exposures, which could inflate values of the estimated PFOA half-life. Also, few of these studies estimated the half-life of PFOA isomers, the branched chains of which likely have shorter half-lives. This could deflate values of the estimated linear PFOA half-life. Fortunately, several studies informed both of these potential problems. The majority opinion of this international collaboration is that the studies striking the best balance in addressing some of these uncertainties indicate the likely central tendency of the human PFOA half-life is less than 2 years. The single best value appears to be the geometric mean (GM) of 1.3 years (Zhang et al., 2013, Table 3), based on a GM = 1.7 years in young females (n = 20) and GM = 1.2 years in males of all ages and older females (n = 66). However, a combined median value from Zhang et al. (2013) of 1.8 years also adds value to this range of central tendency. While the Collaboration found this study to be the least encumbered with unmonitored PFOA exposures and branched isomers, more studies of similar design would be valuable. Also valuable would be clarification around background exposures in other existing studies in case adjustments to half-life estimates are attempted.

Estudo microscópico dos materiais utilizados para confecção de máscaras para proteção contra a COVID-19 / Microscopic study of materials used to make masks to protect against COVID-19

Objetivo: analisar, por meio de um estudo microscópico, os materiais utilizados para confecção das máscaras de uso da população em geral para a proteção contra a COVID-19, em relação à superfície, o tamanho, a forma e a distribuição dos poros dos mesmos. Método: estudo analítico. Foram realizadas análises de amostras de tecidos e outros materiais utilizados para confecções de máscaras para proteção da comunidade em geral contra a COVID-19 em um Laboratório de Microscopia Eletrônica e Microanálise. Resultados: a análise do tecido de algodão 100% e da sarja evidenciou esses dois tipos de tecidos como efetiva barreira microbiana. Em contrapartida, o tricoline e os demais tecidos e materiais analisados, não se apresentam como barreiras eficazes na proteção a COVID-19. Conclusão: entre os tecidos analisados, o algodão 100%, fornece uma trama mais densa, com fios mais grossos e pouca porosidade, sendo uma barreira eficaz na proteção contra infecções.

Objective: to analyze the materials used to make masks to protect against COVID-19 for use by the general population in relation to the surface, size, shape and distribution of pores by means of a microscopic study. Method: analytical study. Analyzes of fabric samples and other materials used to make masks to protect the community in general against COVID-19 were performed in an Electron Microscopy and Microanalysis Laboratory. Results: the analysis of 100% cotton and twill samples showed these two types of fabrics are an effective microbial barrier. On the other hand, tricoline and the other fabrics and materials analyzed do not offer effective barriers to protect against COVID-19. Conclusion: among the analyzed fabrics, 100% cotton has a denser weft with thicker threads and little porosity, thereby being an effective barrier to protect against infections.

Silver serum levels in burned patients treated with silver sulfadiazine and its toxicity on inflammatory cells.

BACKGROUND: Silver sulfadiazine (SSD) has been widely used in burned patients for the prevention of local infections. To be biologically active and exert antimicrobial properties, silver needs to be present in the form of silver ions (Ag1+) that bind to negatively charged proteins, namely, the RNA and DNA in microorganisms. However, previous published studies conducted with SSD in the 1990s reported a high level of silver absorption through damaged skin and noted the potential cytotoxicity of Ag1+ to human cells. SSD toxicity, however, had been described in cell cultures using arbitrary silver concentrations. In the present study, we determined the serum silver levels in burned patients treated with SSD and, taking into account the molar Ag1+ concentrations found in these patients, we evaluated the Ag1+ toxicity effects on inflammatory cells (ROS and cytokine production) in vitro. METHODS: Twenty patients with an average burned body surface area of 27.68% were included in this study. RESULTS: Patients' Ag1+ serum levels reached up to 558 times those of the unexposed controls. Ag1+ was then added to inflammatory cells in vitro at levels up to 2000 times the level of the control, and there was no effect on the viability of the cells nor on the rate of apoptosis. We observed a decrease in reactive oxygen species production by mononuclear (MN) and polymorphonuclear (PMN) cells, as well as a substantial decrease in cytokines IL-1ß, IL-6, IL-8, IL-10, and TNF-α production by leukocytes (MN and PNM). CONCLUSION: These findings suggest that Ag1+ may contribute to negative outcomes after burns, decreasing the primary defense mechanism (respiratory burst) and altering cytokine production.

Working conditions and sleepiness while driving among truck drivers.

Objective: The objective of this study is to identify the role of working conditions as predictors of sleepiness while driving among truck drivers. Methods: This was a cross-sectional study carried out among truck drivers who transported grains to Paranaguá Port, Paraná, Brazil. The truck drivers were interviewed and completed a self-administered questionnaire to collect data on sociodemographic and behavioral variables, working conditions, consumption of illicit psychoactive substances, and sleep patterns. Drivers were considered to be sleepy while driving if they reported a medium or high probability of napping while driving at night, during the daytime, or while stopped in traffic. The statistical analysis used logistic regression models progressively adjusted for age, behavioral variables, sleep duration, and other working conditions. Results: In total, 670 male drivers, with a mean age of 41.9 (±11.1) years, were enrolled. The prevalence of sleepiness while driving was 31.5%. After model adjustments, the following working conditions were associated with sleepiness while driving: Distance from the last shipment of more than 1,000 km (odds ratio [OR] = 1.54; 95% confidence interval [CI], 1.07-2.23) and a formal labor contract with a productivity-based salary (OR = 2.65; 95% CI, 1.86-3.78). Consumption of illicit psychoactive substances (OR = 1.99; 95% CI, 1.14-3.47) was also associated with sleepiness while driving. Conclusions: Distance traveled and a formal labor contract with productivity-based earnings were the working conditions associated with sleepiness while driving, regardless of other working or behavioral characteristics, age, consumption of illicit psychoactive substances, and sleep duration.

Trace Elements Associated with Systemic Lupus Erythematosus and Insulin Resistance.

Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease of multifactorial origin. Studies have shown that trace elements such as zinc and copper may help maintain optimum function of the immune system and metabolism, while toxic metals such as lead may increase systemic autoimmunity. The current study aimed to assess the relationship between serum concentration of lithium (Li), vanadium (V), copper (Cu), zinc (Zn), molybdenum (Mo), cadmium (Cd), and lead (Pb) and SLE diagnosis, disease activity measured by SLE disease activity index (SLEDAI) and insulin resistance (IR). This case-control, cross-sectional study included 225 patients, 120 healthy controls, and 105 SLE patients. Serum concentration of Li, V, Cu, Zn, Mo, Cd, and Pb was measured. Serum concentrations of V (p < 0.001), Zn (p < 0.001), and Pb (p < 0.001) were lower and Mo (p < 0.001) and Li (p < 0.001) were higher in patients with SLE compared to healthy controls. SLE diagnosis was associated with higher serum Li (p < 0.001) concentration and lower V (p < 0.001), Zn (p = 0.003), and Pb (p = 0.020). Toxic metals and trace elements were not associated with disease activity. Levels of Cd were higher in patients with IR (p = 0.042). There was no significant association between IR and the other metals. The results indicate that SLE patients have different profiles of trace elements and toxic metals compared to healthy controls. While some toxic metals and trace elements were found to be associated with SLE diagnosis, they had no effect on disease activity and IR.

Blood manganese levels and associated factors in a population-based study in Southern Brazil.

Manganese (Mn) is an essential dietary nutrient for human health serving as a cofactor for many enzymes; however, exposure to excessive quantities of Mn may lead to toxicity with symptoms analogous to Parkinson's disease (PD). Population-based biomonitoring is an effective tool for characterizing the body burden of environmental or occupational pollutants, including Mn. The objective of this cross-sectional study was to (1) estimate reference values (RV) for blood Mn in an adult population and (2) assess the variables that were associated with higher blood metal levels. A total of 947 adults, aged 40 years or older, were randomly selected in a city in Southern Brazil. Information on socioeconomic, dietary, lifestyle, and occupational background was collected by trained interviewers. Blood Mn levels (µg/L) were analyzed by inductively coupled plasma-mass spectrometer (ICP-MS). The RV for blood Mn concentrations were obtained from the upper limits of the 95% confidence intervals (CI) of the 95th percentile distributions. Cluster analysis was performed to identify variables associated with high or low blood Mn concentrations. The RV for blood Mn levels in this study were 18.54 and 20.15 µg/L for men and women, respectively. Mn blood concentrations decreased with age and were higher in females compared to males. No marked association was noted between blood Mn and smoking or drinking habits, education levels and socioeconomic status. Diastolic blood pressure was higher in a group of women approximately 54 years of age associated with elevated blood Mn levels. Important reference data stratified by demographic and lifestyle factors that may prove useful for future surveillance of environmental exposure to Mn and health risks associated with this metal are presented.

Association of lead, cadmium and mercury with paraoxonase 1 activity and malondialdehyde in a general population in Southern Brazil.

Metal exposure is associated with increased oxidative stress (OS), which is considered an underlying mechanism of metal-induced toxicity. Malondialdehyde (MDA) is a final product of lipid peroxidation, and it has been extensively used to evaluate metal-induced OS. Pro-oxidant effects produced by metals can be mitigated by paraoxonase 1 (PON1), an antioxidant enzyme known to prevent cardiovascular disease and atherosclerosis. Among other factors, the Q192R polymorphism and the exposure to heavy metals have been known to alter PON1 activity. Here, we evaluated the association of blood lead (Pb), cadmium (Cd) and mercury (Hg) levels with PON1 activity, and with MDA concentrations in a randomly selected sample of Brazilian adults aged 40 years or older, living in an urban area in Southern Brazil. A total of 889 subjects were evaluated for blood Pb and Cd levels, and 832 were tested for Hg. Geometric mean of blood Pb, Cd and Hg was 1.93µg/dL, 0.06µg/L and 1.40µg/L, respectively. PON1 activity was significantly different among various genotypes: QQ (PON1=121.4U/mL), QR (PON1=87.5U/mL), and RR (PON1=55.2U/mL), p<0.001. PON1 genotypes were associated only with Cd blood levels. Those with QR genotype had Cd concentrations higher (0.07µg/L) than those with the RR genotype (0.04µg/L) with p=0.034. However, PON1 activity was not significantly associated with metal concentrations. Cluster analysis showed that men who reported to be current smokers and drinkers with higher blood Pb and Cd levels, had significantly lower PON1 activity than non-smokers or -drinkers, and women with lower Pb and Cd levels. RR genotype carriers had lower PON1 activity than those with the QR genotype, and had higher levels of Pb and Cd compared with other genotype carriers. For blood Hg, no association with PON1 activity or genotype was noted. We found low levels of Pb, Cd and Hg in environmentally exposed Brazilian adults. Cd concentrations were increased in subjects with QR genotype. Those with RR genotype had lower PON1 activity and higher levels of Pb and Cd than other genotype carriers. The results of cluster analysis suggested that smoking status exerts a significant influence on PON1 activity. Other studies with environmentally exposed populations are required to further clarify whether low blood levels of metals influence OS biomarkers.

Use of illicit drugs by truck drivers arriving at Paranaguá port terminal, Brazil.

OBJECTIVE: The purpose of this study was to estimate the prevalence of recent use of illicit drugs among truck drivers who had parked their vehicles at the terminal port in Paranaguá City at Paraná State, southern Brazil. METHODS: This cross-sectional study was part of a larger research project conducted among drivers at a regional Brazilian port. Data on professional characteristics, involvement in road traffic injuries, sleep, and use of alcohol and illicit drugs were collected using a questionnaire. Urine samples were collected and analyzed for amphetamines, cocaine, and cannabis using gas chromatography with mass spectrometric detection. RESULTS: Sixty-two drivers were included in the study. Toxicological analyses showed that 8.1 percent (95% confidence interval [CI], 2.7-17.8%) of the urine samples were positive for drugs (4.8% for cocaine, 1.6% for amphetamine, and 1.6% for both); 8.1 percent reported drug use during the preceding 30 days in the questionnaire and only one tested positive for the drug in the urine sample. No sample was positive for cannabinoids. In total, at least 14.5 percent (95% CI, 6.9-25.8%) had used illicit drugs during the preceding 30 days based on self-reports and urine testing. Drivers who reported involvement in traffic injuries the year before more often tested positive for drugs in biological samples (P <.05). CONCLUSIONS: This research provides preliminary evidence that the use of illicit stimulants was common among professional truck drivers transporting grain loads. Thus, actions are needed to reduce drug use among truck drivers in order to prevent drug-related road traffic injuries.

Occupational exposure profile of Pb, Mn, and Cd in nonferrous Brazilian sanitary alloy foundries.

In addition to the primary components of alloys, approximately 5% of the formulation may contain other metals, including lead (Pb), cadmium (Cd), arsenic, manganese (Mn), iron, phosphorus, and nickel. Workers in the foundries are exposed to several compounds; therefore, it is important to assess the levels of injury that may reflect an additive, synergistic, or antagonistic effect caused by these compounds. The mean values of the environmental evaluation of the facilities range from 16.65 to 40.31 µg m(-3) for Pb, 0.99 to 1.73 µg m(-3) for Cd, and 0.91 to 1.70 µg m(-3) for Mn. The mean values of the metal concentrations for furnace, mold, melting, and automatic melting activities range from 15.37 to 19.26 µg m(-3) for Pb, 7.07 to 9.14 µg m(-3) for Cd, and 8.83 to 16.00 µg m(-3) for Mn. Biological samples were divided into two groups: control (n = 38) and exposed (n = 45). The obtained data are3.41 ± 3.40 and 14.89 ± 7.82 µg dL(-1) for Pb, 0.90 ± 0.80 and 1.91 ± 1.90 µg g(-1) creatinine for Cd, and 0.51 ± 0.40 and 3.17 ± 1.93 µg g(-1) creatinine for Mn. Statistical analysis showed significant differences (p < 0.05). Positive linear correlations were established between metal concentrations in the air and the biological matrixes: Pb (r = 0.68; p < 0.001), Cd (r = 0.81; p = 0.17), and Mn (r = 0.12; p < 0.03). Regression analysis showed that professional activities can interfere with element exposure profiles in occupational settings. The analysis in the event of exposure to metals in these companies allowed investigating whether the simultaneous exposure leads to biological damage even if the levels of the compounds are within the exposure limits that are considered to be safe.

Avaliação das concentrações de exposição aos metais Pb, Cd, Mn e Ni em fundições de metais não ferrosos e correlações com marcadores de dano oxidativo / Assessment of exposure to concentrations of Pb, Cd, Mn and Ni in non-ferrous metal foundries and correlations with markers of oxidative damage

De acordo com a ABIFA (Associação Brasileira de Indústrias de Fundição), a produção de metais não-ferrosos em março de 2006 no País foi de 279.353 toneladas, sendo que deste montante, a região de São Paulo responde por 77.011t, com 26.593 trabalhadores relacionados com a manufatura destes metais. Escumar, mexer, vazar, agitar, encher e outras operações associadas às fundições podem provocar a liberação de grandes quantidades de emanações. Assim podem ser liberadas no ambiente onde são usados metais derretidos, poeiras metálicas, que são pequenas partículas sólidas no ar, e fumos, partículas sólidas ainda menores. As inalações de fumos metálicos são mais perigosas que as das poeiras metálicas porque os fumos metálicos podem ser absorvidos mais facilmente pelos pulmões. As fundições de metais não ferrosos utilizam basicamente lingotes de latão (Cobre (Cu) Zinco (Zn)), nas quais os níveis de Cu variam de 68 a 98 %, e os de Zn de 2 -32 %, dependendo das características do latão. Além dos componentes primários da liga, aproximadamente 5 % da formulação contém outros metais, dentre eles: chumbo, cádmio, arsênio, estanho, ferro, fósforo, manganês e níquel. Uma vez que os trabalhadores nas fundições estão expostos a diversos compostos, é importante avaliar os níveis de lesões que possam refletir um efeito aditivo, sinérgico ou antagônico acarretado por esses compostos. No presente trabalho foram avaliados os níveis dos metais Pb, Cd, Mn e Ni no ar dos ambientes de trabalho, procurando correlacioná-los aos níveis destes metais no sangue e urina dos trabalhadores expostos em fundições de metais não ferrosos. Além disso, dois marcadores de dano oxidativo, o primeiro ao nível periférico MDA (malondialdeído) e o segundo ao intracelular DNA (8-oxo-7,8-dihidro-2'-desoxiguanosina) foram eleitos como indicadores de efeito à exposição ocupacional. Os métodos analíticos propostos apresentaram-se sensíveis, precisos e exatos para as análises dos elementos no ar do ambiente...

According to ABIFA (Brazilian Foundry Producers Association), the total amount of non ferrous production in March 2006 was 279.353 tons, the São Paulo region respond per 77.011 tons, with 26.593 workers in this manufacture process. Mould, leak, melt, tune, clean and other foundry assembly line steps can release amounts of metal dust or fine particulate matter in the occupational setting. The metallic fume inhalation depends on the size of the particulate material, and this relates the toxicology profile. The non ferrous foundries raw material basically use brass alloys, mainly composed by Cu (cupper) 68 to 98 % and Zn (zinc) 2 32 % in formulation. Furthermore, other metals can be added as Pb (lead), Ni (nickel), Cd (cadmium) and manganese (Mn) to grant specific characteristic such as hardness and resistance to heat. Since the workers in foundries are exposed to various compounds, it is important to evaluate the levels of injury that may reflect an additive effect, synergistic or antagonistic caused by these compounds. The present study aimed to evaluate the levels of two markers of oxidative damage, the first level peripheral MDA (malonaldehyde) and the second intracellular DNA (8-oxo-7 ,8-dihydro-2 '-deoxyguanosine), trying to correlate them to levels of the metals Pb, Cd, Ni and Mn found in the blood and urine of workers exposed to non-ferrous metal smelters. The methods proposed showed to be sensitive, precise and accurate for the analysis of elements in the air of the workplace, as indicators of internal dose and effect. The concentrations obtained in population studies are consistent with exposure to metals. Analysis of oxidative damage in case of exposure to the metals mentioned above these companies allowed to investigate whether the simultaneous exposure leads to biological damage even if the levels of the compounds are isolated within the exposure limits considered safe.

Análise de fenol em amostras de urina de trabalhadores e no ar de fundição de metais / Phenol analysis in urine and air of a sanitary metal foundry

Phenol is used as a disinfectant agent, in paint pigments and preparation of phenolic resins. When in solid state, it shows a light pink color, ochre odor and it is hygroscopic. Environmental and biological monitoring are important in the occupational exposure setting. The analytical parameters for air analysis were: linearity from 0.13 – 4.00 ppm; coefficient correlation was (r2): 0.997. The limits of detection and quantification were: 0.08 and 0.13 ppm, respectively; intra-assay and inter-assay precision coefficient range were, 4.4 – 4.7 percent and 3.5 – 4.4 percent, respectively. The analytical procedure for urinary determination showed linearity in the dynamic range of the assay from 5 - 200 μg/mL; coefficient correlation was 0.999; limits of detection and quantification were: 2.0 and 5.0 μg/mL, respectively. The intra-assay precision coefficient was in the range of 4.5 – 8.9 percent and the inter-assay precision coefficient was in the range of 5.7 – 14.2 percent; accuracy coefficient was between 6.2 – 11.9 percent; recovery was higher than 87 percent. Gas chromatography with flame ionization detector was applied to phenol quantification of air sampling in the workplace and urine taken from workers located in the sanitary foundry molding area. Regarding the evaluated exposure conditions, it was not observed phenol exposure above the Limit of Tolerance, established by the Ministry of Labor and Employment, in its regulamentar standard – NR-15. However, for the bioindicator, the values of 4 of 7 workers examined had urinary phenol levels above the reference exposure values, but below the maximum allowable biological indicator.

O fenol é utilizado como agente desinfetante, em pigmentos de tintas e no preparo de resinas fenólicas. Apresenta-se no estado sólido em temperatura ambiente, com coloração fracamente rósea, odor acre e é higroscópico emcontato com o ar. O monitoramento ambiental e biológico é importante em situações de exposição ocupacional. Em relação ao método para determinação de fenol no ar do ambiente de trabalho obtiveram-se as seguintes figuras demérito analítico: linearidade de 0,13 a 4,00 ppm; coeficiente de regressão linear (r2) de 0,997; os limites de detecção e quantificação 0,08 e 0,13 ppm, respectivamente; precisão intra-ensaio entre 4,4 e 4,7 por cento e interensaios entre 3,5 e 4,4 por cento. Para a análise de fenol em urina, o ensaio mostrou-se linear entre 5 e 200 μg/mL; coeficiente de regressão linear (r2) de 0,999; os limites de detecção e quantificação 2,0 e 5,0 μg/mL, respectivamente; precisão intra-ensaio entre 4,5 e 8,9 por cento e interensaios entre 5,7 e 14,2 por cento; exatidão entre 6,2 e 11,9 por cento e recuperação superior a 87 por cento. Aplicando-se a técnica de cromatografia gasosa com detecção de ionização por chama, foram analisadas amostras de ar do ambiente de trabalho e de urina de trabalhadores provenientes do setor de macharia em uma fundição de metais sanitários. Nas situações de exposição avaliadas não foi observada exposição ao fenol superior ao Limite de Tolerância, de acordo com a Norma Regulamentar NR-15, do Ministério do Trabalho e Emprego. Porém, em relação ao bioindicador, os valores de 4 dos 7 trabalhadores analisados apresentaram níveis de fenol urinário superior ao Valor de Referência, porém inferior ao Índice Biológico Máximo Permitido.

Determinação de fenol urinário por cromatografia em fase gasosa em trabalhadores que utilizam resinas fenólicas em fundições / Determination of urinary phenol by gas chromatography in workers using phenolic resins in foundries

O fenol é utilizado na indústria como agente desinfetante no preparo de resinas fenólicas e pigmentos de tintas. Apresenta-se no estado sólido à temperatura ambiente, com coloração fracamente rósea, odor acre e higroscópico. Na exposição ocupacional aguda o composto pode levar a lesões eritematosas e, cronicamente, afetar a maturação celular no compartimento medular ósseo devido à formação de quinonas livres e 1,4-benzoquinona, proveniente do metabolismo hepático da hidroquinona via CYP2E1. A monitorização biológica possui relevância nas situações de exposições ocupacionais. Para tal, utiliza-se o fenol urinário, considerado bioindicador de exposição a este composto. O objetivo do presente trabalho foi validar uma técnica de extração líquido-líquido para quantificar o fenol urinário, por meio da cromatografia em fase gasosa com detetor de ionização por chama (CG/DIC) em urina de trabalhadores expostos ao fenol em fundições. O método mostrou-se linear de 5 a 200 µg/mL; coeficiente de regressão linear ('r POT. 2') de 0,999; limites de detecção e quantificação 2,0 e 5,0 µg/mL, respectivamente; precisão intra-ensaio entre 4,5 e 8,9% e inter-ensaio entre 5,7 e 14,2%; exatidão entre 6,2 e 11,9% e recuperação superior a 87%. O método demonstrou ser simples e rápido. Amostras provenientes de trabalhadores expostos ao fenol foram analisadas comprovando a aplicação da técnica na monitorização biológica

Phenol is used as an industrial chemical, disinfectant agent, in the preparation of phenolic resins and paint pigments. When in solid state, it shows a light pink color, ocre odor, and is hygroscopic. In acute occupational exposure, the compound can produce erythemic injuries and burn sensation and, chronically, affect the cellular maturation of bone marrow due the free quinones and 1,4-benzoquinone, deriving from hepatic metabolism of the hydroquinone by P450 isozyme (CYP2E1). The biological monitoring is important in occupational exposure situations. So, urinary phenol, considered the biological indicator of phenol exposure has to be determined. The aim of this work was to validate a method for urinary phenol quantification, using liquid-liquid extraction. Gas chromatography with flame ionization detector (GC/FID) was used in this method. The analytical procedure showed linearity in the dynamic range of the assay from 5 - 200 µg/mL. The limits of detection (LOD) and quantification (LOQ) were: 2.0 and 5.0 µg/mL, respectively. Intra-assay precision coefficient was between 4.5 - 8.9% and the inter-assay precision coefficient was between 5.7 - 14.2%. The accuracy coefficient was between 6.2 - 11.9%. Recovery values were higher than 87%. The coefficient of correlation was 0.999. The method is simple, rapid and efficient. Urine samples from workers exposed to phenolic resins were analyzed to show the method application in biological monitoring