Exposure to p-dichlorobenzene and prevalent endocrine-related reproductive cancers among US women.

P-dichlorobenzene (p-DCB) is a pest repellent and air deodorant that is commonly found in the household and public buildings. Exposure to p-DCB has been suggested to have potential metabolic and endocrine effects. Little is known about its association with endocrine-related female cancers. In this cross-sectional study, a nationally representative subsample of 4459 women, aged 20 years or older, in the 2003-2016 National Health and Nutrition Examination Survey was analyzed for the association between p-DCB exposure, measured as urinary concentrations of 2,5-dichlorophenol (2,5-DCP), the primary metabolite of p-DCB, and prevalent endocrine-related female cancers (defined as breast, ovarian, and uterine cancers) using multivariate logistic regression models, adjusting for potential confounders. Of the study participants, 202 women (weighted prevalence, 4.20%) reported being diagnosed with any of these endocrine-related reproductive cancers. Women with reproductive cancers showed a statistically significant increase in urinary 2,5-DCP concentrations (weighted geometric mean, 7.97 vs. 5.84 µg/g creatinine; p < 0.0001), compared to women without these cancers. After adjusting for potential confounders, we found that women in the moderate (1.94- < 28.10 µg/g creatinine) and high level (≥ 28.10 µg/g creatinine) of 2,5-DCP had significantly increased odds of endocrine-related reproductive cancers (odds ratio of 1.66 (95% CI: 1.02, 2.71) and 1.89 (1.08, 3.29), respectively), as compared with those in the low exposure group (< 1.94 µg/g creatinine). This study demonstrates a potential relation between p-DCB exposure and prevalent endocrine-related reproductive cancers in US women. Prospective and mechanistic studies would further explore these interactions and elucidate the pathogenesis of endocrine-related female cancers potentially associated with p-DCB exposure.

Exposure to p-dichlorobenzene and serum α-Klotho levels among US participants in their middle and late adulthood.

P-dichlorobenzene (p-DCB) is a volatile compound commonly used as pest repellent and air deodorant in the home and public buildings, leading to a widespread exposure in indoor environments. There has been an increasing concern about its metabolic and endocrine effects. In this study, we explored the relation between p-DCB exposure and serum levels of soluble α-Klotho, an anti-aging hormone, in US adults. A nationally representative subsample of 1485 adults 40-79 ages in the 2013-2016 National Health and Nutrition Examination Survey was analyzed for the association between p-DCB exposure, measured as urinary concentrations of 2,5-dichlorophenol (2,5-DCP), the major metabolite of p-DCB, and serum α-Klotho levels using multiple general linear models, adjusting for potential confounders. Age- and sex-specific analyses were further conducted. The weighted geometric mean of urinary 2,5-DCP was 2.43 µg/L and the weighted mean of serum α-Klotho was 831.97 pg/mL in the study participants during 2013-2016. After adjusting for potential confounders and urinary creatinine, urinary 2,5-DCP was significantly associated with decreased serum levels of α-Klotho (regression coefficient ß = -9.88; p = 0.0133) in the total study population. When age- and sex-specific analyses being conducted, a significantly inverse association was found in older adults aged 60-79 years (ß = -20.40; p = 0.0001) and in males (ß = -13.81; p = 0.0097), but not in the middle ages (40-59 years) and in females. The strongest association was observed in older (60-79 years) male participants, with a 25.43 pg/mL reduction of α-Klotho levels per 1-unit increase of 2,5-DCP concentrations (p = 0.0008). This is the first study demonstrating a relation between p-DCB exposure, measured as 2,5-DCP, and decreased α-Klotho levels in older males. Additional studies would further explore these interactions and elucidate the pathogenesis of the potential effects of p-DCB exposure on aging.

Enhancing life cycle chemical exposure assessment through ontology modeling.

In its 2014 report, A Framework Guide for the Selection of Chemical Alternatives, the National Academy of Sciences placed increased emphasis on comparative exposure assessment throughout the life cycle (i.e., from manufacturing to end-of-life) of a chemical. The inclusion of the full life cycle greatly increases the data demands for exposure assessments, including both the quantity and type of data. High throughput tools for exposure estimation add to this challenge by requiring rapid accessibility to data. In this work, ontology modeling was used to bridge the domains of exposure modeling and life cycle inventory modeling to facilitate data sharing and integration. The exposure ontology, ExO, is extended to describe human exposure to consumer products, while an inventory modeling ontology, LciO, is formulated to support automated data mining. The core ontology pieces are connected using a bridging ontology and discussed through a theoretical example to demonstrate how data from LCA can be leveraged to support rapid exposure modeling within a life cycle context.

Simultaneous determination of three chlorobenzene compounds in workplace air by portable gas chromatography-mass spectrometry / 中国职业医学

OBJECTIVE: To establish a method for simultaneous determination of chlorobenzene, p-dichlorobenzene and o-dichlorobenzene in workplace air by portable gas chromatography-mass spectrometry(GC-MS). METHODS: The portable GC-MS heat tracing sampling probe was used for sampling. Samples were separated with LTM DB-5 MS rapid chromatographic column. The qualitative analysis was based on retention times and characteristic ions, and the quantification was based on standard curves. RESULTS: The linear correlation coefficient of this method was higher than 0.999 6. The minimum detectable concentrations were 0.03, 0.03 and 0.06 mg/m~3, and the minimum quantification concentrations were 0.10, 0.10 and 0.20 mg/m~3. The recovery rates were 84.68%-92.61%, 86.27%-93.92% and 82.31%-92.36% respectively for three chlorobenzenes compounds. The within-run relative standard deviations(RSD) were 8.51%-9.34%, 7.93%-9.19%, 5.47%-7.48% respectively for three chlorobenzenes compounds, the between-run RSD were 7.29%-9.73%, 8.08%-10.04% and 5.19%-5.98% respectively for three chlorobenzenes compounds. CONCLUSION: The portable GC-MS could be used for qualitative and quantitative detection of three chlorobenzenes compounds in workplace air.

Biosurfactant-enhanced removal of o,p-dichlorobenzene from contaminated soil.

Surfactant-enhanced remediation is less applicable for the treatment of dichlorobenzene (DCB)-contaminated soil. In this study, water solubility enhancements of o-dichlorobenzene (o-DCB) and p-dichlorobenzene (p-DCB) by micellar solutions of biosurfactants (saponin, alkyl polyglycoside) and chemically synthetic surfactant (Tween 80) were measured and compared. Solubilities of o,p-DCB in water were greatly enhanced in a linear fashion by each of Tween 80, saponin, and alkyl polyglycoside. Solubility enhancement efficiencies of surfactants followed the order of Tween 80 > saponin > alkyl polyglycoside. However, the ex situ soil washing experiment demonstrated the opposite result. The removal efficiency of o,p-DCB by biosurfactant saponin and alkyl polyglycoside was higher than that of chemically synthetic surfactant Tween 80 in contaminated soil. This difference may be due to the different adsorption behaviors of the surfactants onto soil. In addition, elution kinetics for o,p-DCB were relatively fast, with apparent elution equilibrium reached within 360 min, and can be described by a pseudo first-order kinetic equation. The elution process of o,p-DCB in soil-aqueous systems obeyed four-parameter biphasic first-order kinetic model including rapid and slow phases. The results confirmed potential application of saponin and alkyl polyglycoside in elution solution for enhanced remediation of DCB-contaminated soil.

Surfactant flushing remediation of o-dichlorobenzene and p-dichlorobenzene contaminated soil.

Surfactant-enhanced remediation is used to treat dichlorobenzene (DCB) contaminated soil. In this study, soil column experiments were conducted to investigate the removal efficiencies of o-dichlorobenzene (o-DCB) and p-dichlorobenzene (p-DCB) from contaminated soil using micellar solutions of biosurfactants (saponin, alkyl polyglycoside) compare to a chemically synthetic surfactant (Tween 80). Leachate was collected and analyzed for o-DCB and p-DCB content. In addition, soil was analyzed to explore the effect of surfactants on soil enzyme activities. Results showed that the removal efficiency of o-DCB and p-DCB was highest for saponin followed by alkyl polyglycoside and Tween 80. The maximum o-DCB and p-DCB removal efficiencies of 76.34% and 80.43%, respectively, were achieved with 4 g L-1 saponin solution. However, an opposite result was observed in the cumulative mass of o-DCB and p-DCB in leachate. The cumulative extent of o-DCB and p-DCB removal by the biosurfactants saponin and alkyl polyglycoside was lower than that of the chemically synthetic surfactant Tween 80 in leachate. Soil was also analyzed to explore the effect of surfactants on soil enzyme activities. The results indicated that surfactants were potentially effective in facilitating soil enzyme activities. Thus, it was confirmed that the biosurfactants saponin and alkyl polyglycoside could be used for remediation of o-DCB and p-DCB contaminated soil.

Genome-wide gene expression analysis of mouse embryonic stem cells exposed to p-dichlorobenzene.

Because of the limitations of whole animal testing approaches for toxicological assessment, new cell-based assay systems have been widely studied. In this study, we focused on two biological products for toxicological assessment: mouse embryonic stem cells (mESCs) and long noncoding RNAs (lncRNAs). mESCs possess the abilities of self-renewal and differentiation into multiple cell types. LlncRNAs are an important class of pervasive non-protein-coding transcripts involved in the molecular mechanisms associated with responses to chemicals. We exposed mESCs to p-dichlorobenzene (p-DCB) for 1 or 28 days (daily dose), extracted total RNA, and performed deep sequencing analyses. The genome-wide gene expression analysis indicated that mechanisms modulating proteins occurred following acute and chronic exposures, and mechanisms modulating genomic DNA occurred following chronic exposure. Moreover, our results indicate that three novel lncRNAs (Snora41, Gm19947, and Scarna3a) in mESCs respond to p-DCB exposure. We propose that these lncRNAs have the potential to be surrogate indicators of p-DCB responses in mESCs.

Associations between urinary concentrations of 2,5-dichlorophenol and metabolic syndrome among non-diabetic adults.

We investigated in this study the relationship between exposure to para-dichlorobenzene (p-DCB), measured as urinary concentrations of 2,5-dichlorophenol (2,5-DCP), and metabolic syndrome in non-diabetic adult participants. A nationally representative subsample of 1706 non-diabetic adult participants aged 20-79 years randomly selected for measurement of urinary concentrations of 2,5-DCP in the 2007-2010 US National Health and Nutrition Examination Survey was analyzed. A dose-dependent increase in the prevalence of metabolic syndrome was observed in the study participants across quartiles of urinary 2,5-DCP (p-trend = 0.0025). After adjusting for potential confounders, individuals in the third and fourth quartile of urinary 2,5-DCP had 1.47 (95% CI 1.02, 2.14) and 1.56 (95% CI 1.10, 2.23) increased odds of metabolic syndrome, respectively, compared with individuals with the lowest quartile. Of the five components of metabolic syndrome, waist circumference and HDL-cholesterol showed a significant and monotonic association with urinary 2,5-DCP. Participants with the highest quartile of 2,5-DCP had 3.18 cm (95% CI 1.34, 5.02) higher mean waist circumference and 2.83 mg/dL (95% CI -4.68, -0.98) lower mean HDL-cholesterol than the participants in the lowest quartile. This study suggests a potential relationship between p-DCB exposure and metabolic syndrome in non-diabetic adults. Prospective epidemiological and mechanistic studies are needed to further explore these interactions.

Cancer risk disparities between hispanic and non-hispanic white populations: the role of exposure to indoor air pollution.

BACKGROUND: Hispanics are the fastest growing minority group in the United States; however, minimal information is available on their cancer risks from exposures to hazardous air pollutants (HAPs) and how these risks compare to risks to non-Hispanic whites. METHODS: We estimated the personal exposure and cancer risk of Hispanic and white adults who participated in the Relationships of Indoor, Outdoor, and Personal Air (RIOPA) study. We evaluated 12 of the sampled volatile organic compounds and carbonyls and identified the HAPs of most concern and their possible sources. Furthermore, we examined sociodemographic factors and building characteristics. RESULTS: Cumulative cancer risks (CCRs) estimated for Hispanics (median = 519 x 10(-6), 90th percentile = 3,968 x 10(-6)) and for whites (median = 443 x 10(-6), 90th percentile = 751 x 10(-6)) were much greater than the U.S. Environmental Protection Agency (EPA) benchmark of 10(-6). Cumulative risks were dominated by formaldehyde and p-dichlorobenzene (p-DCB) and, to a lesser extent, by acetaldehyde, chloroform, and benzene. Exposure to all of these compounds except benzene was primarily due to indoor residential sources. Hispanics had statistically higher CCRs than did whites (p