Influence of Perfluoroalkyl Substances on Occurrence of Coronavirus Disease 2019

Epidemiologic evidence indicates exposure to polyfluoroalkyl substances (PFAS) influences immunosuppression, with diminished vaccination response. The relationship between PFAS blood levels and coronavirus disease 2019 (COVID-19) occurrence by age warrants further examination. This assessment identified blood PFAS exposure levels in discrete populations. Recent PFAS population studies summarizing age and gender results were identified and included. Geographically corresponding COVID-19 incidence data were determined for selected counties in North Carolina (NC) and Ohio (OH), and the state of New Jersey (NJ). Centers for Disease Control and Prevention COVID-19 databases were accessed for national incidence data by age groupings. We assessed associations between blood PFAS concentrations, COVID-19 incidence rates, and key demographic characteristics, within subpopulations. COVID-19 incidence counts and blood PFAS concentration were obtained for each age group, along with estimated U.S. Census total population. A general trend observed is higher PFAS levels in older age groups. Younger age groups contained fewer COVID-19 cases. Global COVID-19 mortality is highest in elderly populations with hospitalization and death greatly increasing from age 50. PFAS exposures occurring early in life may cause deleterious health effects later in life, including decreased antibody response and reduced disease resistance. Highest levels of both PFAS exposure and COVID-19 were found in the oldest populations. While this does not determine causality, such associations should help promote further study.

Cigar and Marijuana Blunt Use Among Pregnant and Nonpregnant Women of Reproductive Age in the United States, 2006-2016

OBJECTIVES

To assess trends in prevalence of cigar and blunt use in relation to cigarette use among pregnant and nonpregnant women of reproductive age.

METHODS

We used 2006 to 2016 data from the US National Survey on Drug Use and Health to assess past-month use of cigarettes, cigars, and blunts among a total of 8695 pregnant women and 162 451 nonpregnant women aged 18 to 44 years.

RESULTS

Cigarette use was more prevalent than cigar or blunt use in pregnant and nonpregnant women, with higher prevalence in nonpregnant women for each product. Among all women, cigarette use decreased and blunt use increased over time, whereas cigar use remained stable. Smoking prevalence was highest in the first trimester.

CONCLUSIONS

The health implications of the increase in blunt use are not well known in the scientific literature or by the general public. Given the rapid changes in state marijuana laws, this issue should be a public health priority.

Assessment of relative potential for Legionella species or surrogates inhalation exposure from common water uses

The Legionella species have been identified as important waterborne pathogens in terms of disease morbidity and mortality. Microbial exposure assessment is a tool that can be utilized to assess the potential of Legionella species inhalation exposure from common water uses. The screening-level exposure assessment presented in this paper developed emission factors to model aerosolization, quantitatively assessed inhalation exposures of aerosolized Legionella species or Legionella species surrogates while evaluating two generalized levels of assumed water concentrations, and developed a relative ranking of six common in-home uses of water for potential Legionella species inhalation exposure. Considerable variability in the calculated exposure dose was identified between the six identified exposure pathways, with the doses differing by over five orders of magnitude in each of the evaluated exposure scenarios. The assessment of exposure pathways that have been epidemiologically associated with legionellosis transmission (ultrasonic and cool mist humidifiers) produced higher estimated inhalation exposure doses than pathways where epidemiological evidence of transmission has been less strong (faucet and shower) or absent (toilets and therapy pool). With consideration of the large uncertainties inherent in the exposure assessment process used, a relative ranking of exposure pathways from highest to lowest exposure doses was produced using culture-based measurement data and the assumption of constant water concentration across exposure pathways. In this ranking, the ultrasonic and cool mist humidifier exposure pathways were estimated to produce the highest exposure doses, followed by the shower and faucet exposure pathways, and then the toilet and therapy pool exposure pathways.

Estimation of individual rodent water consumption from group consumption data for gestation, lactation, and postweaning life stages using linear regression models

In rodent bioassays where chemicals are administered in the drinking water, water consumption data for individual animals are needed to estimate chemical exposures accurately. If multiple animals share a common water source, as occurs in some studies, only the total amount of drinking water consumed by all animals utilizing the common source is directly measurable, and water consumption rates for individual animals are not available. In the Four Lab Study of the US Environmental Protection Agency, which included a multigenerational rodent bioassay, a complex mixture of drinking water disinfection by-products was delivered to multiple Sprague-Dawley rats from a common drinking water container. To estimate disinfection by-product mixture exposure for each animal, authors developed four log-linear regression models to allocate water consumption among rats sharing a common water container. The four models represented three animal lifestages: Gestation, Lactation, and Postweaning, with separate Postweaning models for male and female. Authors used data from six Sprague-Dawley rat bioassays to develop these models from available individual cage data for the Postweaning models, and available individual animal data for the Gestation and Lactation models. The r(2) values for the model fits were good, ranging from 0.67 to 0.92. The Gestation and Lactation models were generally quite accurate in predicting average daily water consumption whereas the Postweaning models were less robust. These models can be generalized for use in other reproductive and developmental bioassays where common water sources are used and data on the explanatory variables are available.

Comparing and evaluating alternative (in vitro) tests on their ability to predict the Draize maximum average score

The Cosmetic, Toiletry, and Fragrance Association (CTFA) Evaluation of Alternatives Program comprised a multi-phased study of the relationship between Draize eye irritation test data and comparable data from a selection of promising alternative (in vitro) tests. The CTFA Program was designed to determine the effectiveness and limitations of several in vitro tests over a range of different cosmetic and personal-care product types. Test materials constituted experimental formulations representative of three distinct product types. Each material was tested in vivo (according to a modified Draize eye irritation test protocol) and in vitro (according to one of up to forty different protocols). A statistical ranking and selection procedure ("concordance analysis") was used to identify those in vitro tests where the relationships between in vitro and in vivo score was sufficiently well defined to warrant further statistical analysis. In vitro test performance was then evaluated by regression modelling of these relationships. Maximum average Draize score (MAS) was utilized as the primary quantitative measure of eye irritation potential in vivo. The goodness-of-fit of the observed data to the regression model and comparison of the magnitude of upper and lower prediction-bounds on the range of probable MAS values associated with the regression model fit (prediction intervals) provide a means by which the performance of each in vitro test may be measured relative to Draize test outcome. The narrower the prediction interval (i.e. the more precise the fit), the more predictive of in vivo score (MAS) is the in vitro test result. The prediction interval thus represents uncertainty associated with Draize test prediction. Such uncertainty depends heavily on the degree of irritancy. In Phases I and II, the widths of the prediction intervals were narrowest in the region corresponding to low irritation potential; increasing widths were observed as irritation potential increased. In Phase III, relatively narrow prediction interval widths were observed at both the low and high end of the observed range of irritation potential; wider intervals were observed in the middle of the observed range. In general, the selected endpoints in each phase had similar average prediction interval widths and thereby differed only slightly in their ability to predict MAS to a given level of precision; any differences between endpoints tended to occur at the low and/or high ends of the observed range of irritation potential. The primary contributor to total variability associated with prediction of MAS is the deviation between the Draize score as observed in the laboratory and what is predicted by the model for a given formulation. Consistently, this component is responsible for 70% to 95% of the total variability. The other components (i.e. variability among replicate MAS and in vitro scores) could be reduced simply by increasing the number of replicate tests performed on each test formulation. However, this would have relatively little impact on the overall precision of prediction.

An enzyme-linked immunosorbent assay for the determination of dioxins in contaminated sediment and soil samples

A 96-microwell enzyme-linked immunosorbent assay (ELISA) method was evaluated to determine PCDDs/PCDFs in sediment and soil samples from an EPA Superfund site. Samples were prepared and analyzed by both the ELISA and a gas chromatography/high resolution mass spectrometry (GC/HRMS) method. Comparable method precision, accuracy, and detection level (8 ng kg(-1)) were achieved by the ELISA method with respect to GC/HRMS. However, the extraction and cleanup method developed for the ELISA requires refinement for the soil type that yielded a waxy residue after sample processing. Four types of statistical analyses (Pearson correlation coefficient, paired t-test, nonparametric tests, and McNemar's test of association) were performed to determine whether the two methods produced statistically different results. The log-transformed ELISA-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin values and log-transformed GC/HRMS-derived TEQ values were significantly correlated (r=0.79) at the 0.05 level. The median difference in values between ELISA and GC/HRMS was not significant at the 0.05 level. Low false negative and false positive rates (<10%) were observed for the ELISA when compared to the GC/HRMS at 1,000 ng TEQ kg(-1). The findings suggest that immunochemical technology could be a complementary monitoring tool for determining concentrations at the 1,000 ng TEQ kg(-1) action level for contaminated sediment and soil. The ELISA could also be used in an analytical triage approach to screen and rank samples prior to instrumental analysis.

An observational study of the potential exposures of preschool children to pentachlorophenol, bisphenol-A, and nonylphenol at home and daycare

The Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study investigated the potential exposures of 257 preschool children, ages 1 1/2-5 yr, and their primary adult caregivers to more than 50 anthropogenic chemicals. Field sampling took place in selected counties in North Carolina (NC) and Ohio (OH) in 2000-2001. Over a 48-h period in each child's daycare center and/or home, food, beverages, indoor air, outdoor air, house dust, soil, participants' hand surfaces and urine were sampled. Additional samples-transferable residues, food preparation surface wipes, and hard floor surface wipes-were collected in the approximately 13% of the homes that had pesticide applications within the 7 days prior to field sampling. Three phenols were among the measured chemicals: pentachlorophenol (PCP), bisphenol-A [2,2-bis(4-hydroxyphenyl)propane], and nonylphenol (4-n-nonylphenol). Nonylphenol (NP) was detected in less than 11% of the samples in any medium. Among samples that were collected at all participants' homes and daycare centers, PCP was detected in >50% of indoor air, outdoor air, house dust, and urine samples; bisphenol-A (BPA) was detected in >50% of indoor air, hand wipe, solid food, and liquid food samples. The concentrations of the phenols in the sampled media were measured, and the children's potential exposures and potential absorbed doses resulting from intake through the inhalation, dietary ingestion, and indirect ingestion routes of exposure were estimated. The children's potential exposures to PCP were predominantly through inhalation: 78% in NC and 90% in OH. In contrast, their potential exposures to BPA were predominantly through dietary ingestion: 99%, for children in both states. The children's estimated exposures to PCP, calculated from the amounts excreted in their urine, exceeded their estimated maximum potential intake, calculated from the multimedia PCP concentrations, by a factor greater than 10. This inconsistency for PCP highlights the need for further research on the environmental pathways and routes of PCP exposure, investigation of possible exposures to other compounds that could be metabolized to PCP, and on the human absorption, metabolism, and excretion of this phenol over time periods longer than 48 h.

Development and application of immunoaffinity column chromatography for atrazine in complex sample media

A rabbit antibody immunoaffinity (IA) column procedure was evaluated as a cleanup method for the determination of atrazine in soil, sediment, and food. Four IA columns were prepared by immobilizing a polyclonal rabbit anti-atrazine antibody solution to HiTrap Sepharose columns. Atrazine was bound to the IA columns when the loading solvents were either 100% water, 2% acetonitrile in water, or 10% methanol in phosphate buffered saline (PBS). Quantitative removal of atrazine from the IA columns was achieved with elution solvents of either 70% ethanol in water, 70% methanol in water, or 100% methanol. One control column was prepared using nonspecific rabbit IgG antibody. This control column did not retain any applied atrazine indicating atrazine did not bind indiscriminately to protein or the Sepharose support. The four IA columns showed reproducible coupling efficiency for the immobilization of the atrazine antibody and consistent binding and releasing of atrazine. The coupling efficiency (4.25 mg of antibody in 1 mL of resin bed) for the four IA columns ranged from 93 to 97% with an average of 96+/-2% (2.1%). Recoveries of the 500, 50, and 5 ng mL(-1) atrazine standard solutions from the four IA columns were 107+/-7% (6.5%), 122+/-14% (12%), and 114+/-9% (8.0%) respectively, based on enzyme-linked immunosorbent assay (ELISA) data. The maximum loading was approximately 700 ng of atrazine for each IA column (approximately 0.16 microg of atrazine per mg of antibody). The IA columns could withstand 100% methanol as the elution solvent and could be reused more than 50 times with no change in performance. The IA columns were challenged with soil, sediment, and duplicate-diet food samples and effectively removed interferences from these various matrices for subsequent gas chromatography/mass spectrometry (GC/MS) or ELISA analysis. The log-transformed ELISA and GC/MS data were significantly correlated for soil, sediment and food samples although the ELISA values were slightly higher than those obtained by GC/MS. The IA column cleanup procedure coupled with ELISA analysis could be used as an alternative effective analytical method for the determination of atrazine in complex sample media such as soil, sediment, and food samples.

An assessment of neurotoxicity of aroclors 1016, 1242, 1254, and 1260 administered in diet to Sprague-Dawley rats for one year

As part of a comparative chronic toxicity/oncogenicity study of different Aroclors (1016, 1242, 1254, and 1260), neurotoxicity was assessed in male and female Sprague-Dawley rats using functional observational battery (FOB) and motor activity tests, and histopathologic evaluation of selected nervous system tissues. Doses varied by Aroclor and ranged from 25 to 200 ppm in the diet. Animals were evaluated prior to initiation of dosing and at 13, 26, 39, and 52 weeks of exposure. Clinical signs, body weights, and feed consumption were evaluated weekly. Data analysis of FOB and motor activity results revealed several instances where Aroclor-treated groups were different from control. However, these were considered incidental, as they lacked any consistent dose- or time-related pattern that would suggest Aroclor-induced neurotoxicity. The nonremarkable findings during each of the four assessments were supported by the absence of any treatment-related clinical signs or mortality. Decreased body weight gain was evident in the male 100 ppm Aroclor 1254 dose group and in all female Aroclor 1254 dose groups late in the study (when a linear relationship was assumed between body weight and time), correlating with decreased feed consumption. Although a variety of incidental, spontaneous, degenerative changes were found in nervous tissue evaluated histopathologically, these changes were seen with similar incidence and severity in treated and control groups. No lesions were found that could be attributed to Aroclor-related neurotoxicity. In summary, 52 weeks of exposure to Aroclors 1016, 1242, 1254, or 1260 mixed in the diet did not yield any functional or morphologic changes indicative of PCB-induced neurotoxicity.

A simple comparison of mass spectral search results and implications for environmental screening analyses

A simple assessment of the ability of environmental laboratories to perform automated library searching procedures on mass spectra of unknown pollutants was conducted. In this assessment, 10 laboratories analyzed a hexane solution containing eight organic chemicals using gas chromatography/mass spectrometry and searched their acquired mass spectral data against mass spectral reference libraries. The search results were used to evaluate the similarity of the lists of tentative identifications (TIDs) among the laboratories and to compare the observed searching success to the searching success reported in the literature using high-quality mass spectral data. A high degree of similarity was observed among the lists of TIDs reported by the laboratories for each chemical. The searching success observed in this study was slightly lower than that reported in the literature based on higher-quality mass spectral data. This simple comparison suggests that laboratories performing routine environmental analyses can successfully perform automated searching procedures for unknown sample components, and that the mass spectral searching component of analytical methods designed to screen for unknown organic pollutants should be successful, i.e., obtain similar and reproducible results among laboratories.

A comparison of low volume, Draize and in vitro eye irritation test data. III. Surfactant-based formulations

The third phase in a series of investigations of the relationship between low volume eye test (LVET) data, Draize eye irritation test data, and comparable data from in vitro assay protocols is presented. These investigations utilize Draize eye test and in vitro endpoint data generated previously as part of the CTFA Evaluation of Alternatives Program. LVET data were generated de novo using the same 25 representative surfactant-based personal-care formulations. In general, these formulations were minimally to moderately irritating. The linear correlation between maximum average score as determined by the Draize test (MAS) and the LVET (LVET-MAS) was 0.87; LVET-MAS values were typically about 30% lower then corresponding MAS values. Comparison of in vitro assay performance with that of the LVET was determined by statistical analysis of the relationship between LVET-MAS and in vitro endpoint. Regression modelling was the primary means of enabling such a comparison, the objective being to predict LVET-MAS for a given test material (and to place upper and lower prediction bounds on the range in which the LVET-MAS is anticipated to fall with high probability) based on observation of an in vitro score for that material. The degree of 95% confidence in prediction is quantified in terms of the relative widths of prediction intervals constructed about the fitted regression curves. Twenty in vitro endpoints were shown to have the greatest agreement with the LVET (these endpoints included those with low discordance rates relative to the Draize test) and were therefore selected for regression modelling. Although prediction interval widths tended to be narrower when predicting LVET-MAS compared with predicting MAS, the confidence with which the selected in vitro endpoints predicted both LVET-MAS and MAS for surfactant-based formulations was greatest when values were close to the lower or upper limits of the observed irritation range (i.e. 95% prediction interval widths were most narrow in these areas). Overall precision of LVET-MAS prediction for surfactant-based formulations was similar to that previously reported for hydroalcoholic formulations and considerably better than was reported for oil/water emulsions.

A comparison of low volume, draize and in vitro eye irritation test data. II. Oil/water emulsions

The second phase in a series of investigations of the relationship between low volume eye test (LVET) data, Draize eye irritation test data, and comparable data from in vitro eye irritation test protocols is presented. These investigations utilize Draize eye test and in vitro endpoint data generated previously as part of the CTFA Evaluation of Alternatives Program. LVET data were generated de novo using the same 18 representative oil/water based personal-care formulations. In general, these formulations were minimally to mildly irritating; only three were classified as moderate eye irritants. The linear correlation between maximum average score as determined by the Draize test (MAS) and the LVET (LVET-MAS) was 0.85; LVET-MAS values were typically about half the corresponding MAS values. Comparison of in vitro assay performance with that of the LVET was determined by statistical analysis of the relationship between LVET-MAS and each in vitro endpoint. Regression modelling was the primary means of enabling such a comparison, the objective being to predict LVET-MAS for a given test material (and to place upper and lower 95% prediction bounds on the range in which the LVET-MAS is anticipated to fall with high probability) based on observation of an in vitro score for that material. The degree of confidence in prediction is quantified in terms of the relative widths of prediction intervals constructed about the fitted regression curves. Sixteen endpoints were shown to have the greatest agreement with the LVET (all but two were selected for modelling when compared with the Draize procedure). While the lower maximum average scores values (compared with the Draize test) in the LVET led to lower variability in LVET-MAS compared to MAS, the upper and lower bounds on predicted LVET-MAS values conditional on observed in vitro scores were still wide. Because there was overlap in the range of scores determined by the prediction bounds for many formulations, each of the selected endpoints was frequently unable to distinguish between test formulations in terms of statistically different predicted LVET-MAS values. In summary, none of the in vitro endpoints evaluated were able to reliably predict values of LVET-MAS among the set of oil/water emulsions considered here.

Semivolatile organic compounds in adipose tissue: estimated averages for the US population and selected subpopulations

OBJECTIVES

The fiscal year (FY) 1986 Environmental Protection Agency National Human Adipose Tissue Survey (NHATS) was conducted to estimate average concentrations of 111 semivolatiles in human adipose tissue within the US general population and selected subpopulations.

METHODS

Population and subpopulation estimates of average semivolatile concentrations were established from 671 adipose tissue specimens pooled across 50 analytical samples.

RESULTS

Among polychlorinated biphenyls (PCBs), average concentrations for the group aged 45 and older were from 188% to 706% higher than for the 0- through 14-year-old age group. Similar increases with age were observed for pesticides. Geographic effects on average concentration were mixed, and no significant race or sex effects were observed. Statistically significant increases from FY 1982 NHATS results were observed for PCBs and hexachlorobenzene, whereas a decrease from FY 1982 was significant for beta-BHC (benzene hexachloride). Increases from FY 1984 NHATS results were significant for p,p-DDT (dichlordiphenylethylene), p,p-DDE (dichlordiphenyldichlor), hexachlorobenzene, and PCBs.

CONCLUSIONS

The survey establishes baseline average levels of semivolatile compounds in the adipose tissue of US residents.

Comparison of low-volume, Draize and in vitro eye irritation test data. I. Hydroalcoholic formulations

The first phase in a series of investigations of the relationship between low-volume eye test (LVET) data, Draize eye irritation test data, and comparable data from 25 in vitro assay protocols is presented. These investigations utilize Draize eye test and in vitro assay data generated previously as part of the Cosmetic, Toiletry and Fragrance Association (CTFA) Evaluation of Alternatives Program. LVET data were generated de novo using the same 10 representative hydroalcoholic personal-care formulations. The linear correlation between maximum average score (MAS) as determined by the Draize test and the LVET (LVET-MAS) was 0.93. Comparison of in vitro assay performance with that of the LVET was determined by statistical analysis of the relationship between LVET-MAS and in vitro endpoint. As in the CTFA program, regression modelling is the primary means of enabling such a comparison. The objective is to predict LVET-MAS for a given test material (and to place upper and lower prediction interval bounds in the range in which the LVET-MAS is anticipated to fall with high probability) conditional on observing an in vitro assay score for that material. The degree of confidence in prediction is quantified in terms of the relative widths of prediction intervals constructed about the fitted regression curves. Four assays [EYTEX MPA (membrane partition assay), HET-CAM (hen's egg test-chorioallantoic membrane HET-CAM) I, neutral red release and HET-CAM II] were shown to have the greatest agreement with the LVET. These assays were also among those with low discordance rates relative to the Draize test. Prediction of LVET-MAS values from experimentally determined in vitro scores was more accurate for hydroalcoholic formulations with lower rather than higher irritancy potential.

The CTFA Evaluation of Alternatives Program: an evaluation of in vitro alternatives to the Draize primary eye irritation test. (Phase III) surfactant-based formulations

The CTFA Evaluation of Alternatives Program is an evaluation of the relationship between data from the Draize primary eye irritation test and comparable data from a selection of promising in vitro eye irritation tests. In Phase III, data from the Draize test and 41 in vitro endpoints on 25 representative surfactant-based personal care formulations were compared. As in Phase I and Phase II, regression modelling of the relationship between maximum average Draize score (MAS) and in vitro endpoint was the primary approach adopted for evaluating in vitro assay performance. The degree of confidence in prediction of MAS for a given in vitro endpoint is quantified in terms of the relative widths of prediction intervals constructed about the fitted regression curve. Prediction intervals reflect not only the error attributed to the model but also the material-specific components of variation in both the Draize and the in vitro assays. Among the in vitro assays selected for regression modeling in Phase III, the relationship between MAS and in vitro score was relatively well defined. The prediction bounds on MAS were most narrow for materials at the lower or upper end of the effective irritation range (MAS = 0-45), where variability in MAS was smallest. This, the confidence with which the MAS of surfactant-based formulations is predicted is greatest when MAS approaches zero or when MAS approaches 45 (no comment is made on prediction of MAS > 45 since extrapolation beyond the range of observed data is not possible). No single in vitro endpoint was found to exhibit relative superiority with regard to prediction of MAS. Variability associated with Draize test outcome (e.g. in MAS values) must be considered in any future comparisons of in vivo and in vitro test results if the purpose is to predict in vivo response using in vitro data.