Adult Urine Research Articles

Tracking Declines in Mercury Exposure in the New York City Adult Population, 2004\u20132014

Mercury is a toxic metal that can be measured in human blood and urine. Population-based biomonitoring from 2004 guided New York City (NYC) Department of Health and Mental Hygiene (DOHMH) efforts to reduce exposures by educating the public about risks and benefits of fish consumption—a predominant source of exposure in the general population—and removing mercury-containing skin-lightening creams and other consumer products from the marketplace. We describe changes in exposures over the past decade in relation to these local public health actions and in the context of national changes by comparing mercury concentrations measured in blood (1201 specimens) and urine (1408 specimens) from the NYC Health and Nutrition Examination Survey (NYC HANES) 2013–2014 with measurements from NYC HANES 2004 and National Health and Nutrition Examination Surveys (NHANES) 2003–2004 and 2013–2014. We found that NYC adult blood and urine geometric mean mercury concentrations decreased 46% and 45%, respectively. Adult New Yorkers with blood mercury concentration ≥ 5 μg/L (the New York State reportable level) declined from 24.8% (95% CL = 22.2%, 27.7%) to 12.0% (95% CL = 10.1%, 14.3%). The decline in blood mercury in NYC was greater than the national decline, while the decline in urine mercury was similar. As in 2004, Asian New Yorkers had higher blood mercury concentrations than other racial/ethnic groups. Foreign-born adults of East or Southeast Asian origin had the highest prevalence of reportable levels (29.7%; 95% CL = 21.0%, 40.1%) across sociodemographic groups, and Asians generally were the most frequent fish consumers, eating on average 11 fish meals in the past month compared with 7 among other groups (p < 0.001). Fish consumption patterns were similar over time, and fish continues to be consumed more frequently in NYC than nationwide (24.7% of NYC adults ate fish ten or more times in the past 30 days vs. 14.7% nationally, p < 0.001). The findings are consistent with the hypothesis that blood mercury levels have declined in part because of local and national efforts to promote consumption of lower mercury fish. Local NYC efforts may have accelerated the reduction in exposure. Having “silver-colored fillings” on five or more teeth was associated with the highest 95th percentile for urine mercury (4.06 μg/L; 95% CL = 3.1, 5.9). An estimated 5.5% of the adult population (95% CL = 4.3%, 7.0%) reported using a skin-lightening cream in the past 30 days, but there was little evidence that use was associated with elevated urine mercury in 2013–14.

Recent biomonitoring reports on phosphate ester flame retardants: a short review.

Organophosphate triesters (PEFRs) are used increasingly as flame retardants and plasticizers in a variety of applications, such as building materials, textiles, and electric and electronic equipment. They have been proposed as alternatives to brominated flame retardants. This updated review shows that biomonitoring has gained incrementally greater importance in evaluating human exposure to PEFRs, and it holds the advantage of taking into account the multiple potential sources and various intake pathways of PEFRs. Simultaneous and extensive internal exposure to a broad range of PEFRs have been reported worldwide. Their metabolites, mainly dialkyl or diaryl diesters, have been used as biomarkers of exposure and have been ubiquitously detected in the urine of adults and children in the general population. Concentrations and profiles of PEFR urinary metabolites are seen to be variable and are highly dependent on individual and environmental factors, including age, country regulation of flame retardants, and types and quantities of emissions in microenvironments, as well as analytical procedures. Additional large biomonitoring studies, using a broad range of urinary diesters and hydroxylated metabolites, would be useful to improve the validity of the biomarkers and to refine assessments of human exposure to PEFRs.

Cadmium exposure and early renal effects in the children and adults living in a tungsten-molybdenum mining areas of South China

Adverse health effects related to accumulative cadmium (Cd) exposure have aroused widespread attention from the public in China. Knowledge on the relationships between Cd exposure and early renal effects is particularly limited for children, who are more susceptible to absorbing metals than adults. A typical Cd-polluted area of South China was selected to determine the Cd exposure and related early renal effects of the general population, including children. In total, 211 children and 806 adults were enrolled in the study. The urinary levels of Cd (U-Cd), β2-microglobulin (U-BMG), retinol binding protein (U-RBP), and N-acetyl-β-D-glucosaminidase (U-NAG) were measured. The relationship between U-Cd and ranked indicators of early renal effects was examined by multiple regression analysis. The average U-Cd ranged from 7.01μg/g creatinine (boys) to 13.55μg/g creatinine (women) in the Cd-polluted areas. These values are much higher than those of the control group and those that have been reported by other countries. In agreement with previous studies, environmental Cd pollution resulted in elevated Cd accumulation in the bodies of children, and it increased the concentration of NAG in their urine. Similarly, environmental Cd pollution increased NAG and BMG in the urine of adults. Multivariate models showed that the urinary excretion of BMG, RBP, and NAG was positively associated with Cd levels in the urine of both children and adults. The reference thresholds of U-Cd in relation to elevated U-BMG, U-RBP, and U-NAG were higher in children than adults after standardization for other covariates. These results reinforce the need to control and regulate the sources of environmental Cd contamination and to promote more effective risk management measures, especially for vulnerable groups.

Distribution, variability, and predictors of urinary bisphenol A levels in 50 North Carolina adults over a six-week monitoring period

Bisphenol A (BPA) is commonly manufactured to make polycarbonate plastics and epoxy resins for use in consumer products and packaged goods. BPA has been found in several different types of environmental media (e.g., food, dust, and air). Many cross-sectional studies have frequently detected BPA concentrations in adult urine samples. However, limited data are available on the temporal variability and important predictors of urinary BPA concentrations in adults. In this work, the major objectives were to: 1) quantify BPA levels in duplicate-diet solid food, drinking water, hard floor surface wipe, and urine samples (first-morning void [FMV], bedtime, and 24-h) collected from adults over a six-week monitoring period; 2) determine the temporal variability of urinary BPA levels using concentration, specific gravity (SG) adjusted, creatinine (CR) adjusted, and excretion rate values, and; 3) examine associations between available study factors and urinary BPA concentrations. In 2009–2011, a convenience sample of 50 adults was recruited from residential settings in North Carolina. The participants completed diaries and collected samples during weeks 1, 2, and/or 6 of a six-week monitoring period. BPA was detected in 38%, 4%, and 99% of the solid food (n=775), drinking water (n=50), and surface wipe samples (n=138), respectively. Total BPA (free plus conjugated) was detected in 98% of the 2477 urine samples. Median urinary BPA levels were 2.07ng/mL, 2.20ng/mL-SG, 2.29ng/mg, and 2.31ng/min for concentration, SG-adjusted, CR-adjusted, and excretion rate values, respectively. The intraclass correlation coefficient (ICC) estimates for BPA showed poor reproducibility (≤0.35) for all urine sample types and methods over a day, week, and six weeks. CR-adjusted bedtime voids collected over six-weeks required the fewest, realistic number of samples (n=11) to obtain a reliable biomarker estimate (ICC=0.80). Results of linear mixed-effects models showed that sex, race, season, and CR-level were all significant predictors (p<0.05) of the adults' urinary BPA concentrations. BPA levels in the solid food and surface wipe samples did not contribute significantly to the participants' urinary BPA concentrations. However, a significant positive relationship was observed between solid food intake and urine-based estimates of BPA dose, when aggregated over 24-h periods. Ingestion of BPA via solid food explained only about 20% of the total dose (at the median of the dose distribution), suggesting that these adults were likely exposed to other major unknown (non-dietary) sources of BPA in their everyday environments.

Quantification of Malondialdehyde in Human Urine by HPLC‐DAD and Derivatization with 2,4‐Dinitrophenylhydrazine

This study demonstrated that human urine can be derivatized in a simple manner and the proposed method can be suitable for the routine and noninvasive evaluation of oxidative stress. A rapid and sensitive method for the determination of malondialdehyde (MDA) concentrations in human urine has been developed using high‐performance liquid chromatography. The MDA concentration in pooled human urine samples was determined after its conversion with 2,4‐dinitrophenylhydrazine (DNPH) to a hydrazone (MDA‐DNPH). The MDA‐DNPH was separated on C18 column and quantified by diode array detection at 310 nm. The method was validated by the use of spiked human urine. The calibration curves of analyte showed good linearity (r 2 &gt; 0.999) in the ranges. The limit of detection was estimated as 0.16 µg/mL. In addition, accuracy was from 104.0 to 112.7% and the precision was less than 3.2%. In this study, the developed method was applied to the analysis of real human urine samples. The level of MDA in urine of adults was 1.3 ± 0.6 µg/mg creatinine.

Furocoumarin Kinetics in Plasma and Urine of Healthy Adults Following Consumption of Grapefruit (Citrus paradisi Macf.) and Grapefruit Juice.

Furocoumarins are a class of organic compounds found in a variety of vegetables and fruits. Relatively little is known about the absorption and excretion of these compounds following ingestion. The objective of this study was to identify furocoumarins in grapefruit and grapefruit juice and observe their kinetics in blood and urine. The furocoumarins detected in grapefruit using UPLC-MS/MS were bergamottin, 6',7'-dihydroxybergamottin (6',7'-DHB), epoxybergamottin, and bergaptol. Bergamottin, 6',7'-DHB, bergaptol, and bergapten were detected in grapefruit juice. In this study of 6 males and 3 females, only bergamottin and 6',7'-DHB were detected in plasma, whereas in urine, four distinct furocoumarin metabolites as well as bergaptol, 6',7'-DHB, 8-methoxypsoralen (8-MOP), bergamottin, and psoralen were identified. Following grapefruit ingestion, furocoumarins were detectable in plasma as early as 15 min and in urine within 1 h. They remained in plasma for up to 3 or more hours and in urine as late as 24 h.

Predator odor induces genome instability in the mouse bone marrow cells

Background. Long coevolution of prey and predator species of mammals creates specific mechanisms of their interaction, e. g. preys innate behavior aversive to the predator odor. However, little is known about genetic responses in the prey organism. We assessed genome instability of the bone marrow cells in mice affected by the cats odor influence, and proposed pathway of such action.&#x0D; Materials and methods. CBA mouse males were exposed to volatiles from adult cat urine for 2 or 24 hours. To estimate the genetic effect, ana-telophase method of chromosome aberration analysis and comet assay were used. The level of corticosterone was also measured after the exposure for 30 or 60 minutes.&#x0D; Results. The exposure to cats urine volatiles for 2 hours induced damage of DNA in bone marrow cells of the mouse males as was shown by the DNA comet analysis. The exposure for 24 hours elevated the frequency of chromosome aberrations in mitotically dividing cells at ana-telophase stage. No significant changes were found in the level of corticosterone in the peripheral blood.&#x0D; Conclusion. We have shown that volatile chemosignals from predators urine induce genomic instability in bone marrow cells of a prey. The hormonal pathway of such influence is still unknown. Intraorganismic paths leading to genome damage are discussed as well as far consequences of discovered effects.

Urinary Uromodulin and Risk of Urinary Tract Infections: The Cardiovascular Health Study

Laboratory studies suggest that urinary uromodulin, the most common protein in the urine of healthy adults, may protect against urinary tract infection (UTI). Epidemiologic studies evaluating this relationship in humans are lacking. Prospective longitudinal cohort study. 953 participants enrolled in the Cardiovascular Health Study. Uromodulin assayed using enzyme-linked immunosorbent assay in spot urine samples. Composite of outpatient UTI events or UTI-related hospitalizations and each of them individually identified using International Classification of Diseases, Ninth Revision (ICD-9) codes using negative binomial regression with robust standard errors adjusted for age, race, sex, body mass index, diabetes, estimated glomerular filtration rate, and urinary albumin and urinary creatinine excretion. Median uromodulin level was 25.9 (IQR, 17.3-38.9) μg/mL, mean age of participants was 78 years, 61% were women, and 15% were black. There were 331 outpatient UTI events and 87 UTI-related hospitalizations among 186 participants during a median 9.9 years of follow-up. Persons in the highest quartile (>38.93μg/mL) of uromodulin concentration had a significantly lower risk for the composite outcome (incidence rate ratio [IRR], 0.47; 95% CI, 0.29-0.79) compared with those in the lowest quartile (≤17.26μg/mL). This association remained significant for outpatient UTI events (highest vs lowest quartile even after excluding those with prior UTI: IRR, 0.42; 95% CI, 0.23-0.77). The direction of association with UTI hospitalization was similar, but not statistically significant (IRR, 0.78; 95% CI, 0.39-1.58). Use of ICD-9 codes to identify outcomes and lack of generalizability to younger populations. High urinary uromodulin levels are associated with lower risk for UTI in older community-dwelling adults independent of traditional UTI risk factors. This finding supports prior laboratory data indicating a protective role of uromodulin against UTI. Further research is needed to understand if this may lead to new treatments to prevent or treat UTI.

Diagnostic and prognostic significance of systemic alkyl quinolones for P. aeruginosa in cystic fibrosis: A longitudinal study

BackgroundPulmonary P. aeruginosa infection is associated with poor outcomes in cystic fibrosis (CF) and early diagnosis is challenging, particularly in those who are unable to expectorate sputum. Specific P. aeruginosa 2-alkyl-4-quinolones are detectable in the sputum, plasma and urine of adults with CF, suggesting that they have potential as biomarkers for P. aeruginosa infection. AimTo investigate systemic 2-alkyl-4-quinolones as potential biomarkers for pulmonary P. aeruginosa infection. MethodsA multicentre observational study of 176 adults and 68 children with CF. Cross-sectionally, comparisons were made between current P. aeruginosa infection using six 2-alkyl-4-quinolones detected in sputum, plasma and urine against hospital microbiological culture results. All participants without P. aeruginosa infection at baseline were followed up for one year to determine if 2-alkyl-4-quinolones were early biomarkers of pulmonary P. aeruginosa infection. ResultsCross-sectional analysis: the most promising biomarker with the greatest diagnostic accuracy was 2-heptyl-4-hydroxyquinoline (HHQ). In adults, areas under the ROC curves (95% confidence intervals) for HHQ analyses were 0.82 (0.75–0.89) in sputum, 0.76 (0.69–0.82) in plasma and 0.82 (0.77–0.88) in urine. In children, the corresponding values for HHQ analyses were 0.88 (0.77–0.99) in plasma and 0.83 (0.68–0.97) in urine.Longitudinal analysis: Ten adults and six children had a new positive respiratory culture for P. aeruginosa in follow-up. A positive plasma HHQ test at baseline was significantly associated with a new positive culture for P. aeruginosa in both adults and children in follow-up (odds ratio (OR)=6.67;-95% CI:-1.48–30.1;-p=0.01 and OR=70; 95% CI: 5–956;-p<0.001 respectively). ConclusionsAQs measured in sputum, plasma and urine may be used to diagnose current infection with P. aeruginosa in adults and children with CF. These preliminary data show that plasma HHQ may have potential as an early biomarker of pulmonary P. aeruginosa. Further studies are necessary to evaluate if HHQ could be used in clinical practice to aid early diagnosis of P. aeruginosa infection in the future.

Total and single species of uronic acid-bearing glycosaminoglycans in urine of newborns of 2–3 days of age for early diagnosis application

BackgroundUrine are easily accessible and relatively simple to process and uronic acid-bearing glycosaminoglycans (UA-GAGs) may serve as biomarkers for several diseases, like for mucopolysaccharidosis. MethodsWe report a study from a large cohort of healthy newborns of 2–3days to have a basic profile of total content of urinary UA-GAGs, their composition and structural signatures utilizing a rapid extractive method and sensitive separation of enzymatic released disaccharides by capillary electrophoresis-light induced fluorescence. Results were also compared with those obtained from normal adult subjects. ResultsA total of UA-GAGs content of ~35μg/mg creatinine was observed in 331 newborns versus 1.5μg/mg creatinine of adult urine composed of ~90% chondroitin sulfate (CS), ~7% heparan sulfate (HS) and ~3% hyaluronic acid (HA). No significant differences were observed with adults. Specific ratios between the main CS disaccharides were informative of a significant greater 4-sulfation and charge density for newborn compared to adults. The HS from newborn urine was mainly composed by the non-sulfated (~64%) and mono-sulfated (~28%) disaccharides. No significant differences were observed versus adult urine. ConclusionsThe present method is able to measure changes in UA-GAG composition and their structure independently of the age of subjects and rapidly applicable to the newborn diagnosis without necessity to have creatinine levels. Moreover, modifications in charge density values as well as the presence of sulfate groups in specific positions may be indicative of altered conditions.

Human biomonitoring of heavy metals in the vicinity of non-ferrous metal plants in Ath, Belgium.

BackgroundA previous study revealed an environmental contamination by heavy metals in the vicinity of two non-ferrous metal plants in Ath, Belgium. The purpose of the current cross-sectional study was to estimate exposure of the population to heavy metals in the vicinity of the plants, in comparison with population living further away.MethodsWe did a random sampling in the general population of Ath in two areas: a central area, including the plants, and a peripheral area, presumably less exposed. We quantified cadmium, lead, nickel, chromium and cobalt in blood and/or urine of children and adults in three age groups: (i) children aged 2.5 to 6 years (n = 98), (ii) children aged 7 to 11 years (n = 74), and (iii) adults aged 40 to 60 years (n = 106). We also studied subclinical health effects by quantifying retinol-binding protein and microalbuminuria, and by means of a Strengths and Difficulties Questionnaire.ResultsWe obtained a participation rate of 24 %. Blood lead levels were significantly higher in young children living in the central area (18.2 μg/l ; 95 % CI: 15.9–20.9) compared to the peripheral area (14.8 μg/l ; 95 % CI: 12.6–17.4). We observed no other significant mean difference in metal concentrations between the two areas. In the whole population, blood lead levels were higher in men (31.7 μg/l ; 95 % CI: 27.9–36.1) than in women (21.4 μg/l ; 95 % CI: 18.1–25.3). Urine cadmium levels were 0.06 μg/g creatinine (95 % CI: 0.05–0.07), 0.21 μg/g creatinine (95 % CI: 0.17–0.27), and 0.25 μg/g creatinine (95 % CI: 0.20–0.30) for children, men, and women, respectively.ConclusionsDespite higher blood lead levels in young children living close to the plants, observed metal concentrations remain in the range found in other similar biomonitoring studies in the general population and are below the levels of concern for public health.

Particle-Associated Ambient Benzo[a]pyrene and Levels of Urinary 1-Hydroxypyrene in a Non-occupationally Exposed Population of Adults and Children in Lanzhou, China.

Concentrations of benzo[a]pyrene (B[a]P) in ambient air from different areas in Lanzhou city in northwest of China, and its metabolite 1-hydroxypyrene (1-OHP) in the urine of resident children and adults were determined by using gas chromatography/mass spectrometry and high performance liquid chromatography. Results showed that the atmospheric environmental concentration of B[a]P varied significantly from one part of the city to another with levels of 150ng/m(3) in the industrial area of Xigu and 73.8ng/m(3) in the agricultural area of Yuzhong. The geometric mean urinary 1-OHP concentration was 0.42µmol/mol-creatinine, with a range of means between 0.067 and 2.05 for the various population sub-groups. The non-occupationally exposed populations' age, gender and area of residence were the major factors that influenced urinary 1-OHP levels. The health risks of B[a]P for adults and children in Xigu and for children in Yuzhong exceeded the acceptable level (1×10(-4)) of the US Environmental Protection Agency.

Determination of Bisphenol A, Tetrabromobisphenol A and 4-Tert-Octylphenol in Children and Adults Urine Using High Performance Liquid Chromatography-Tandem Mass Spectrometry

Abstract A method of high performance liquid chromatography (HPLC) coupled with tandem mass spectrometry for quantitative determination of bisphenol A (BPA), tetrabromobisphenol A (TBBPA) and 4-Tert-Octylphenol (OP) in urine of children and adults was developed. The frozen urinary samples were unfrozen at room temperature, then extracted by liquid-liquid extraction, evaporated to dryness, and dissolved by methanol so as to be analyzed by LC-MS/MS. The calibration curves for the determination of the three target compounds were linear in the concentration range of 0.2–50 μg L −1 with the correlation coefficients ( R ) greater than 0.99. The quantitative limits (LOQ) for the three target compounds were 0.05–0.27 μg L −1 . The recoveries of different levels (5, 10 and 50 μg L −1 ) were in the range of 85.7%–118.6% and the relative standard deviations (RSD) are 4.1%–10.5% ( n = 3). This method was successfully applied to the determination of BPA, TBBPA and OP in urine samples from 20 groups of children and adults. The results showed that exposure concentrations of TBBPA and OP in urines sample of children and adults were basically same, but exposure levels of BPA had significant difference (children > adults).

Comparison of the Levels of Five Heavy Metals in Human Urine and Sweat after Strenuous Exercise by ICP-MS

Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the levels of trace heavy metals in human urine and sweat, to compare the performance of ICP-MS using three sample processing methods, namely direct dilution, wet digestion, and microwave digestion. The results showed that the wet digestion ICP-MS method has the highest accuracy (relative standard deviation ≤10%) and is more useful for measuring the levels of trace heavy metals in urine and sweat. Hence, we used this method to compare the levels of the five trace heavy metals, namely chromium, copper, zinc, cadmium, and lead, in the urine and sweat of adults after strenuous exercise. The results showed that the levels of these five trace heavy metals in sweat were significantly higher than those in urine after strenuous exercise (The differences between the measurements in urine and those in sweat were significant P ≤ 0.01). The results suggested that exercise-induced sweating can effectively remove the harmful heavy metals from the human body.

Bisphenol A in Urine of Chinese Young Adults: Concentrations and Sources of Exposure.

Bisphenol A (BPA) is an endocrine disrupting environmental chemical. Urinary concentrations of BPA were measured in samples collected nationwide from Chinese young adults. The geometric mean urinary concentration of BPA in Chinese young adults was 2.23 ng/mL. The estimated daily exposure dose for BPA was 64.8 ng/kg bw/day. Contributions of various BPA sources to exposure in Chinese young adults were estimated. Dietary intake was the primary exposure pathway. The contribution of dietary intake, indoor dust, paper products and personal care products to BPA intake was 72.5 %, 0.74 %, 0.98 %, 0.22 % of the total exposure dose, respectively. This is the first study on the occurrence of BPA in young adults from most provinces and autonomous regions of China. The results can be used to establish a database for BPA exposure assessment for Chinese general population.

Levels of markers for smoking and oxidative stress in the urine of Korean adults

Levels of markers for smoking and oxidative stress in the urine of Korean adults

Levels of phenolic polycyclic aromatic hydrocarbons in Koreans' urine by LC-MS/MS

Medicinal plants are widely used throughout the world. About 80% of the world's population relies on plant-derived medicines for their primary healthcare [1]. Also some of them are willingly used for culinary purposes or as raw materials for pharmaceutical products, cosmetics and herbal medicinal products. However, the chemistry and efficacy of many of these plants are relatively unknown [2]. Levels of polycyclic aromatic hydrocarbons (PAHs) are generally low in fresh plants, but in grown in close proximity to urban pollution sources, levels of PAHs might be higher [2]. PAHs are products of the incomplete combustion of organic compounds, and man is exposed to PAHs by smoking, diet and environmental pollution. Several PAHs are classified as carcinogens. Because of their global occurrence in food and the environment, they are of toxicological and public concern. Urine samples for this study were collected from 1028 Korean adults. Urine samples were prepared by enzymatic hydrolysis and solid-phase extraction with Sep-pak cartridges. The analysis of PAHs was validated with blank urine by liquid chromatography tandem mass spectrometry; we used blank urine because all the urine samples some metabolites contains of PAHs. The linearity was very satisfying for 17 PAH compounds, with a coefficient of correlation (r2) higher than 0.99. The limit of detections was 0.01 to 0.08 ng/mL, the accuracy was 80% to 120%, and the precision was lower than 20%. Detected PAH metabolites from 1028 adult urine samples included (mean ± SD) 1-naphthol (8.56 ± 20.16 ng/mL), 2-naphthol (8.77 ± 17.46 ng/mL), 2-OH-fluorene (0.81 ± 1.39 ng/mL), 3-OH-fluorene (0.23 ± 0.45 ng/mL) and 1-OH-IP (0.23 ± 0.60 ng/mL), respectively.

Temporal variability of pyrethroid metabolite levels in bedtime, morning, and 24-h urine samples for 50 adults in North Carolina

Pyrethroid insecticides are widely used to control insects in both agricultural and residential settings worldwide. Few data are available on the temporal variability of pyrethroid metabolites in the urine of non-occupationally exposed adults. In this work, we describe the study design and sampling methodology for the Pilot Study to Estimate Human Exposures to Pyrethroids using an Exposure Reconstruction Approach (Ex-R study). Two major objectives were to quantify the concentrations of several pyrethroid metabolites in bedtime, first morning void (FMV), and 24-h urine samples as concentration (wet weight), specific-gravity (SG) corrected, creatinine (CR) corrected, and excretion rate values for 50 Ex-R adults over a six-week monitoring period and to determine if these correction approaches for urine dilution reduced the variability of the biomarker levels. The Ex-R study was conducted at the United States Environmental Protection Agency’s Human Studies Facility in Chapel Hill, North Carolina USA and at participants’ homes within a 40-mile radius of this facility. Recruitment of participants and field activities occurred between October 2009 and May 2011. Participants, ages 19–50 years old, provided daily food, activity, and pesticide-use diaries and collected their own urine samples (bedtime, FMV, and 24-h) during weeks 1, 2, and 6 of a six-week monitoring period. A total of 2503 urine samples were collected from the study participants. These samples were analyzed for the pyrethroid metabolites 3-phenoxybenzoic acid (3-PBA), cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis/trans-DCCA), and 2-methyl-3-phenylbenzoic acid (MPA) using high performance liquid chromatography/tandem mass spectrometry. Only 3-PBA was frequently detected (>50%) in the adult urine samples. Median urinary 3-PBA levels were 0.88ng/mL, 0.96ng/mL-SG, 1.04ng/mg, and 1.04ng/min for concentration, SG-corrected, CR-corrected, and excretion rate values, respectively, across all urine samples. The results showed that median urinary 3-PBA concentrations were consistently the lowest in FMV samples (0.77ng/mL, 0.68ng/mL-SG, 0.68ng/mg, and 0.58ng/min) and the highest in 24-h samples (0.92ng/mL, 1.06ng/mL-SG, 1.18ng/mg, and 1.19ng/min) across all four methods. Intraclass correlation coefficient (ICC) estimates for 3-PBA indicated poor reproducibility (<0.22) for all urine sample types and methods over a day, week, and six weeks. Correcting for urine sample dilution, based on either SG, CR or urine output, introduced additional measurement variability both between- and within-individuals. These results indicate that a single measure of urinary 3-PBA was not sufficient to characterize average exposure regardless of sample type, correction method, and time frame of collection. In addition, the study results can be used to inform the design of exposure characterization strategies in relevant environmental epidemiology studies in the future.

Phthalate metabolites in urine of Chinese young adults: Concentration, profile, exposure and cumulative risk assessment

Phthalates are widely used in consumer products. People are frequently exposed to phthalates due to their applications in daily life. In this study, 14 phthalate metabolites were analyzed in 108 urine samples collected from Chinese young adults using high-performance liquid chromatography–tandem mass spectrometry. The total concentrations of 14 phthalate metabolites ranged from 71.3 to 2670ng/mL, with the geometric mean concentration of 306ng/mL. mBP and miBP were the two most abundant compounds, accounting for 48% of the total concentrations. Principal component analysis suggested two major sources of phthalates: one dominated by the DEHP metabolites and one by the group of mCPP, mBP and miBP metabolites. The estimated daily intakes of DMP, DEP, DBP, DiBP and DEHP were 1.68, 2.14, 4.12, 3.52 and 1.26–2.98μg/kg-bw/day, respectively. In a sensitivity analysis, urinary concentration and body weight were the most influential variables for human exposure estimation. Furthermore, cumulative risk for hazard quotient (HQ) and hazard index (HI) were evaluated. Nearly half of Chinese young adults had high HI values exceeding the safe threshold. This is the first study on the occurrence and human exposure to urinary phthalate metabolites with Chinese young adults.

A Study of 2-Mercaptobenzothiazole (2-MBT) and HBM values for 2-MBT in the urine of adults and children: Opinion of the "Human Biomonitoring" Commission of the German Federal Environment Agency

2-Mercaptobenzothiazole (2-MBT, CAS No. 149-30-4) is mainly used as a vulcanization accelerator in the production of rubber. Other applications are as a fungicide in paints and varnishs and for the external treatment of animals. Because of its manifold application in consumer products, for example in soothers, exposure of the general population to 2-MBT can't be excluded. For the purpose of a toxicological evaluation of a possible body burden, the German HBM-commission derived HBM-I values for 2-MBT in the urine of children and adults. The no observed adverse effect level of 94 mg/kg bw/d from a subchronic oral study with mice was used as the point of departure. After considering a total assessment factor of 350, a tolerable daily intake of 0.3 mg/kg bw/d was deduced for humans. Considering further the percentage of 2-MBT and its glucuronide excreted in urine together with the body weight proportional urine volume leads to an HBM-I value for 2-MBT of 4.5 mg/l urine for children and 7 mg/l urine for adults.