Extending Regulatory Biokinetic Lead Models towards Food Safety: Evaluation of Consumer Baby Food Contribution to Infant Blood Lead Levels and Variability.

The U.S. Food and Drug Administration released proposed lead (Pb) action levels for foods intended for babies and young children in January 2023 based on the agency's interim reference value of 2.2 µg/day for dietary Pb. Since the 1980s, biokinetic models have estimated blood lead levels (BLLs) associated with environmental contamination, but their use in food safety assessment has been limited. We compared three recent biokinetic models (IEUBK Model, ICRP Model Version 5, and AALM) to develop insights on contributors to variability in potential exposures to Pb in consumer baby food products. While modest variation was observed for babies, the predictions trended to convergence for children aged 3 and older, approaching the U.S. FDA dietary conversion factor of 0.16 µg Pb/dL blood per µg Pb intake/day. We applied the IEUBK model in a probabilistic exposure assessment framework characterizing the distribution of Pb in soil, dust, water, and food intake in the United States. Soil and dust were the primary contributors to variance in infant BLLs, while food and water contributed <15% combined. Thus, reductions in upper-bound soil and dust concentrations will be necessary before achieving appreciable reductions in the frequency of BLLs greater than the BLRV of 3.5 µg/dL.

Combined analysis of job and task benzene air exposures among workers at four US refinery operations.

Workplace air samples analyzed for benzene at four US refineries from 1976 to 2007 were pooled into a single dataset to characterize similarities and differences between job titles, tasks and refineries, and to provide a robust dataset for exposure reconstruction. Approximately 12,000 non-task (>180 min) personal samples associated with 50 job titles and 4000 task (<180 min) samples characterizing 24 tasks were evaluated. Personal air sample data from four individual refineries were pooled based on a number of factors including (1) the consistent sampling approach used by refinery industrial hygienists over time, (2) the use of similar exposure controls, (3) the comparability of benzene content of process streams and end products, (4) the ability to assign uniform job titles and task codes across all four refineries, and (5) our analysis of variance (ANOVA) of the distribution of benzene air concentrations for select jobs/tasks across all four refineries. The jobs and tasks most frequently sampled included those with highest potential contact with refinery product streams containing benzene, which reflected the targeted sampling approach utilized by the facility industrial hygienists. Task and non-task data were analyzed to identify and account for significant differences within job-area, task-job, and task-area categories. This analysis demonstrated that in general, areas with benzene containing process streams were associated with greater benzene air concentrations compared to areas with process streams containing little to no benzene. For several job titles and tasks analyzed, there was a statistically significant decrease in benzene air concentration after 1990. This study provides a job and task-focused analysis of occupational exposure to benzene during refinery operations, and it should be useful for reconstructing refinery workers' exposures to benzene over the past 30 years.

Comparison of tire and road wear particle concentrations in sediment for watersheds in France, Japan, and the United States by quantitative pyrolysis GC/MS analysis.

Impacts of surface runoff to aquatic species are an ongoing area of concern. Tire and road wear particles (TRWP) are a constituent of runoff, and determining accurate TRWP concentrations in sediment is necessary in order to evaluate the likelihood that these particles present a risk to the aquatic environment. TRWP consist of approximately equal mass fractions of tire tread rubber and road surface mineral encrustations. Sampling was completed in the Seine (France), Chesapeake (U.S.), and Yodo-Lake Biwa (Japan) watersheds to quantify TRWP in the surficial sediment of watersheds characterized by a wide diversity of population densities and land uses. By using a novel quantitative pyrolysis-GC/MS analysis for rubber polymer, we detected TRWP in 97% of the 149 sediment samples collected. The mean concentrations of TRWP were 4500 (n = 49; range = 62-11 600), 910 (n = 50; range = 50-4400) and 770 (n = 50; range = 26-4600) µg/g d.w. for the characterized portions of the Seine, Chesapeake and Yodo-Lake Biwa watersheds, respectively. A subset of samples from the watersheds (n = 45) was pooled to evaluate TRWP metals, grain size and organic carbon correlations by principal components analysis (PCA), which indicated that four components explain 90% of the variance. The PCA components appeared to correspond to (1) metal alloys possibly from brake wear (primarily Cu, Pb, Zn), (2) crustal minerals (primarily Al, V, Fe), (3) metals mediated by microbial immobilization (primarily Co, Mn, Fe with TOC), and (4) TRWP and other particulate deposition (primarily TRWP with grain size and TOC). This study should provide useful information for assessing potential aquatic effects related to tire service life.

Triclosan occurrence in freshwater systems in the United States (1999-2012): a meta-analysis.

Recently, concern has grown regarding the presence of triclosan (TCS) in waters because of its potential for causing ecological and human health effects. The authors present a statistical analysis of TCS concentrations reported between 1999 and 2012 in freshwater environments in the United States and provide a comparison with available health-based and aquatic guidance values. Data from 46 peer-reviewed and unpublished investigations from 45 states and 1 US territory were included in the meta-analysis, encompassing the following coded water types: untreated (raw wastewater), effluent (wastewater treatment plant effluent), effluent-impacted environmental, environmental, and finished drinking water (total n = 2305). Triclosan was most frequently detected in untreated waters (92% detection frequency; mean ± standard error, 11 270 ± 2925 ng/L; n = 237), but concentrations were significantly reduced in effluent waters (83% detection frequency 775 ± 311 ng/L; n = 192, α = 0.05). Triclosan concentration in effluent-impacted environmental waters (62% detection frequency; 130 ± 17 ng/L; n = 228) was not significantly reduced from effluent waters but was significantly greater than TCS in environmental waters not classified as effluent impacted (11% detection frequency; 13 ± 3 ng/L; n = 1195). In finished drinking water, TCS was largely undetected (1% detection frequency; 4 ± 2 ng/L n = 453), suggesting that for the United States, drinking water is not an appreciable source of TCS exposure. In posttreatment waters, average TCS concentrations were below part-per-billion levels. Although no US regulatory standard exists for TCS in aquatic systems, comparison of averages reported in the present study with a predicted-no-effect concentration (PNEC) of 500 ng/L showed that 5.3% of effluent-impacted environmental waters were above the PNEC for changes in algal biomass, while only 0.25% of environmental waters surpassed this value.

Airborne concentrations of metals and total dust during solid catalyst loading and unloading operations at a petroleum refinery.

Workers handle catalysts extensively at petroleum refineries throughout the world each year; however, little information is available regarding the airborne concentrations and plausible exposures during this type of work. In this paper, we evaluated the airborne concentrations of 15 metals and total dust generated during solid catalyst loading and unloading operations at one of the largest petroleum refineries in the world using historical industrial hygiene samples collected between 1989 and 2006. The total dust and metals, which included aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, platinum, silicon, silver, vanadium, and zinc, were evaluated in relation to the handling of four different types of solid catalysts associated with three major types of catalytic processes. Consideration was given to the known components of the solid catalysts and any metals that were likely deposited onto them during use. A total of 180 analytical results were included in this analysis, representing 13 personal and 54 area samples. Of the long-term personal samples, airborne concentrations of metals ranged from <0.001 to 2.9mg/m(3), and, in all but one case, resulted in concentrations below the current U.S. Occupational Safety and Health Administration's Permissible Exposure Limits and the American Conference of Governmental Industrial Hygienists' Threshold Limit Values. The arithmetic mean total dust concentration resulting from long-term personal samples was 0.31mg/m(3). The data presented here are the most complete set of its kind in the open literature, and are useful for understanding the potential exposures during solid catalyst handling activities at this petroleum refinery and perhaps other modern refineries during the timeframe examined.

Analysis and modeling of airborne BTEX concentrations from the Deepwater Horizon oil spill.

Concerns have been raised about whether the Deepwater Horizon oil spill cleanup workers experienced adverse health effects from exposure to airborne benzene, toluene, ethylbenzene, and xylene (BTEX) which volatilized from surfaced oil. Thus, we analyzed the nearly 20 000 BTEX measurements of breathing zone air samples of offshore cleanup workers taken during the six months following the incident (made publicly available by British Petroleum). The measurements indicate that 99% of the measurements taken prior to capping the well were 32-, 510-, 360-, and 77-fold lower than the U.S. Occupational Safety and Health Administration's Permissible Exposure Limits (PELs) for BTEX, respectively. BTEX measurements did not decrease appreciably during the three months after the well was capped. Moreover, the magnitudes of these data were similar to measurements from ships not involved in oil slick remediation, suggesting that the BTEX measurements were primarily due to engine exhaust rather than the oil slick. To supplement the data analysis, two modeling approaches were employed to estimate airborne BTEX concentrations under a variety of conditions (e.g., oil slick thickness, wind velocity). The modeling results corroborated that BTEX concentrations from the oil were well below PELs and that the oil was not the primary contributor to the measured BTEX.

Occupational exposure to benzene at the ExxonMobil refinery in Baytown, TX (1978-2006).

Although occupational benzene exposure of refinery workers has been studied for decades, no extensive analysis of historical industrial hygiene data has been performed focusing on airborne concentrations at specific refineries and tasks. This study characterizes benzene exposures at the ExxonMobil Baytown, TX, refinery from 1978 to 2006 to understand the variability in workers' exposures over time and during different job tasks. Exposures were grouped by operational status, job title, and tasks. More than 9000 industrial hygiene air samples were evaluated; approximately 4000 non-task (> 3 h) and 1000 task-related (< 3 h) personal samples were considered. Each sample was assigned to one of 27 job titles, 29 work areas, and 16 task bins (when applicable). Process technicians were sampled most frequently, resulting in the following mean benzene concentrations by area: hydrofiner (n=245, mean=1.3 p.p.m.), oil movements (n=286, mean=0.23 p.p.m.), reformer (n=575, mean=0.10 p.p.m.), tank farm (n=9, mean=0.65 p.p.m.), waste treatment (n=446, mean=0.13 p.p.m.), and other areas (n=460, mean=0.062 p.p.m.). The most frequently sampled task was sample collection (n=218, mean=0.40 p.p.m.). Job title and area did not significantly impact task-related exposures. Airborne concentrations were significantly lower after 1990 than before 1990. Results of this task-focused study may be useful when analyzing benzene exposures at other refineries.

Benzene exposure in refinery workers: ExxonMobil Joliet, Illinois, USA (1977-2006).

While petroleum industry studies have indicated low benzene exposure potential for refinery workers, most provide limited data for assessing job or task-related benzene exposures. This study characterizes job and task-specific airborne benzene concentrations and variability over time for the ExxonMobil refinery in Joliet, Illinois from 1977 to 2006. A database of 2289 industrial hygiene air samples, including 1145 non-task (≥180 min) personal samples and 480 task-related (<180 min) personal samples, were analyzed. Samples were grouped by operational status, job, and task. Benzene concentrations were determined for each job category and task bin, with additional analyses conducted to determine whether benzene concentrations changed over time. The results indicate that the benzene concentrations for non-task and task samples were relatively low. For all non-task samples, the arithmetic mean benzene concentration was 0.12 part per million (ppm). The most frequently sampled workers (process technicians during routine operations) had an arithmetic mean benzene concentration of 0.038 ppm. The most frequently sampled task bin (blinding and breaking) had an arithmetic mean benzene concentration of 1.0 ppm. This study provides benzene air concentration data that can be used in combination with job histories to reconstruct historical benzene exposures for workers at the Joliet Refinery over the past 30 years.

Occupational exposure to benzene at the ExxonMobil refinery in Beaumont, TX (1976-2007).

Because crude oil and refined petroleum products can contain benzene and benzene is considered a known carcinogen by numerous independent and governmental agencies, including the International Agency for Cancer Research, the petroleum industry has implemented exposure control programs for decades. As part of the benzene control programs, significant exposure assessments have been performed; both qualitatively and through quantitative measurements. In this study, we evaluated the airborne concentrations of benzene and their variability over time at the ExxonMobil refinery in Beaumont, TX between 1976 and 2007. The results of 5854 personal air samples are included in this analysis; 3761 were considered non-task (> or =180 min) personal samples, and 2093 were considered task-related (<180 min) personal samples. Dock and loading rack samples were analyzed separately from the refinery samples because in addition to refinery products, employees at the dock and loading rack also handled chemical plant products. In general, the non-task personal refinery air samples indicated that exposures of the past 30 years were generally below the occupational exposure limit of 1 ppm (mean=0.30 ppm, SD=3.1), were higher during routine (mean=0.32 ppm, SD=3.3) than turnaround operations (mean=0.16 ppm, SD=0.87), and decreased slightly over time. The job sampled most frequently during routine operations was that of process technician, and, as broken down by area, resulted in the following mean benzene air concentrations: coker (n=146, mean=0.014 ppm, SD=0.036), lube extraction unit (n=31, mean<0.070 ppm), pipestills (n=136, mean=0.12, SD=0.47), waste treatment (n=107, mean=0.20, SD=0.28), and all other areas (n=1115, mean=0.059 ppm, SD=0.36). Task-based samples indicated that the highest exposures resulted from the tank cleaning tasks, although the overall task mean benzene air concentration was 1.4 ppm during routine operations. The most frequently sampled task during routine operations was blinding and breaking, and the mean benzene air concentrations associated with this task were statistically higher in the reformer area of the refinery (n=311, mean=3.2 ppm, SD=7.9) than in all other areas (n=200, mean=0.92 ppm, SD=3.1). However, task-related exposures were found to be statistically similar across job categories for a given task. This study thus provides a task-focused analysis for occupational exposure to benzene during refinery operations, and will be useful for understanding exposures at this refinery.

Occupational exposure to benzene at the ExxonMobil refinery at Baton Rouge, Louisiana (1977-2005).

Because crude oil contains up to 3% benzene and there is an association between high chronic exposure to appreciable concentrations of benzene and acute myelogenous leukemia, exposure of refinery workers has been studied for many years. To date, no extensive industrial hygiene exposure analyses for historical benzene exposure have been performed, and none have focused on the airborne concentrations in the workplace at specific refineries or for specific tasks. In this study, the authors evaluated the airborne concentrations of benzene and their variability over time at the ExxonMobil refinery in Baton Rouge between 1977 and 2005. Refinery workers were categorized into 117 worker groups using company job descriptions. These 117 groups were further collapsed into 25 job categories based on similarity of measured exposure results. Results of 5289 personal air samples are included in this analysis; 3403 were considered nontask (>or= 180 min) personal samples, and 830 were considered task-related (< 180 min) personal samples; the remainder did not fit in either category. In general, nontask personal air samples indicated that exposures of the past 30 years were generally below the occupational exposure limit of 1 ppm, but there was only a small, decreasing temporal trend in the concentrations. The job sampled most frequently during routine operations was process technician and, as broken down by area, resulted in the following mean benzene concentrations: analyzers (mean = 0.12 ppm), coker (mean = 0.013 ppm), hydrofiner (mean = 0.0054 ppm), lube blending and storage (mean = 0.010 ppm), waste treatment (mean = 0.092 ppm), and all other areas (mean = 0.055 ppm). Task-based samples indicated that the highest exposures resulted from the sampling tasks, specifically from those performed on process materials; in general, though, even these tasks had concentrations well below the STEL of 5 ppm. The most frequently sampled task was gauging (mean = 0.12 ppm). Task-related exposures were also similar across job categories for a given task, with a few exceptions. This study thus provides a task-focused analysis for occupational exposure to benzene during refinery operations, which can be insightful for understanding exposures at this refinery and perhaps others operated since about 1975.

Airborne concentrations of asbestos onboard maritime shipping vessels (1978-1992).

The exposure of shipyard workers to asbestos has been frequently investigated during the installation, repair or removal of asbestos insulation. The same level of attention, however, has not been directed to asbestos exposure of maritime seamen or sailors. In this paper, we assemble and analyze historical industrial hygiene (IH) data quantifying airborne asbestos concentrations onboard maritime shipping vessels between 1978 and 1992. Air monitoring and bulk sampling data were compiled from 52 IH surveys conducted on 84 different vessels, including oil tankers and cargo vessels, that were docked and/or at sea, but these were not collected during times when there was interaction with asbestos-containing materials (ACMs). One thousand and eighteen area air samples, 20 personal air samples and 24 air samples of unknown origin were analyzed by phase contrast microscopy (PCM); 19 area samples and six samples of unknown origin were analyzed by transmission electron microscopy (TEM) and 13 area air samples were analyzed by scanning electron microscopy (SEM). In addition, 482 bulk samples were collected from suspected ACMs, including insulation, ceiling panels, floor tiles, valve packing and gaskets. Fifty-three percent of all PCM and 4% of all TEM samples were above their respective detection limits. The average airborne concentration for the PCM area samples (n = 1018) was 0.008 fibers per cubic centimeter (f cc(-1)) (95th percentile of 0.040 f cc(-1)). Air concentrations in the living and recreational areas of the vessels (e.g. crew quarters, common rooms) averaged 0.004 f cc(-1) (95th percentile of 0.014 f cc(-1)), while air concentrations in the engine rooms and machine shops averaged 0.010 f cc(-1) (95th percentile of 0.068 f cc(-1)). Airborne asbestos concentrations were also classified by vessel type (cargo, tanker or Great Lakes), transport status (docked or underway on active voyage) and confirmed presence of ACM. Approximately 1.3 and 0% of the 1018 area samples analyzed by PCM exceeded 0.1 and 1 f cc(-1), respectively. This data set indicates that historic airborne asbestos concentrations on these maritime shipping vessels, when insulation-handling activities were not actively being performed, were consistently below contemporaneous US occupational standards from 1978 until 1992, and nearly always below the current permissible exposure limit of 0.1 f cc(-1).