The Cancer Risk Associated with Residential Exposure to Soil Containing Radioactive Coal Combustion Residuals.

Coal combustion residuals (CCRs) are composed of various constituents, including radioactive materials. The objective of this study was to utilize methodology on radionuclide risk assessment from the Environmental Protection Agency (EPA) to estimate the potential cancer risks associated with residential exposure to CCR-containing soil. We evaluated potential radionuclide exposure via soil ingestion, inhalation of soil particulates, and external exposure to ionizing radiation using published CCR radioactivity values for 232 Th, 228 Ra, 238 U, and 226 Ra from the Appalachia, Illinois, and Powder River coal basins. Mean and upper-bound cancer risks were estimated individually for each radionuclide, exposure pathway, and coal basin. For each radionuclide at each coal basin, external exposure to ionizing radiation contributed the greatest to the overall risk estimate, followed by incidental ingestion of soil and inhalation of soil particulates. The mean cancer risks by route of exposure were 2.01 × 10-6 (ingestion), 6.80 × 10-9 (inhalation), and 3.66 × 10-5 (external), while the upper bound cancer risks were 3.70 × 10-6 (ingestion), 1.18 × 10-8 (inhalation), and 6.15 × 10-5 (external), using summed radionuclide-specific data from all locations. The upper bound cancer risk from all routes of exposure was 6.52 × 10-5 . These estimated cancer risks were within the EPA's acceptable cancer risk range of 1 × 10-6 to 1 × 10-4 . If the CCR radioactivity values used in this analysis are generally representative of CCR waste streams, then our findings suggest that CCRs would not be expected to pose a significant radiological risk to residents living in areas where contact with CCR-containing soils might occur.

The effect of clothing care activities on textile formaldehyde content.

Textiles are commonly treated with formaldehyde-based residues that may potentially induce allergic contact dermatitis in sensitive individuals. This study examined the initial formaldehyde content in clothing and resulting changes due to care activities. Twenty clothing articles were examined and 17 of them did not have detectable levels of formaldehyde. One shirt contained a formaldehyde concentration of 3172 ppm, and two pairs of pants had formaldehyde concentrations of 1391 ppm and 86 ppm. The two highest results represent formaldehyde levels that are up to 40-fold greater than international textile regulations. The two items with the greatest formaldehyde content were washed and dried in a manner similar to that used by consumers, including hand and machine washing in hot or cold water followed by air or machine drying. The washing and drying procedures reduced formaldehyde levels to between 26 and 72% of untreated controls. Differences in the temperature or type of washing and drying did not result in a clear trend in the subsequent formaldehyde content. In addition, samples were hot ironed, which did not affect the formaldehyde content as significantly. Understanding the formaldehyde content in clothing and its potential reduction through care activities may be useful for manufacturers and formaldehyde-sensitive individuals.

An analysis of historical exposures of pressmen to airborne benzene (1938-2006).

Benzene is an aromatic hydrocarbon that, with sufficient cumulative lifetime doses, can cause acute myelogenous leukemia. Because of its volatility and solvent properties, it was used in the printing industry in inks, ink solvents, and cleaning agents from the 1930s to the 1970s. This analysis represents the first known attempt to gather and synthesize the available data on historical airborne benzene concentrations in printing facilities and exposures to pressmen. The sources of fugitive benzene vapors from printing operations have been identified as evaporation from ink fountains, exposed sections of the printing cylinder, the paper web, the paper post exit, and spilled ink. In addition, specific activities that could lead to benzene exposure, such as filling the fountains, using solvents to clean the press, and using solvents as personal cleaning agents, potentially occurred multiple times per work period. Eighteen studies were identified that reported workplace airborne concentrations in printing facilities between 1938 and 2006. Typical benzene air concentrations, considering both personal and area samples of various durations, were as high as 200 p.p.m. in the 1930s through the 1950s, 3-35 p.p.m. in the 1960s, 1.3-16 p.p.m. in the 1970s, 0.013-1 in the 1980s, and far less than 1 p.p.m. in the 1990s and 2000s. The decrease in benzene air concentrations by the late 1970s was likely to be linked to the decreased benzene content of printing materials, increased engineering controls, and to more stringent occupational exposure limits.

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.

Deposition and spatial distribution of insecticides following fogger, perimeter sprays, spot sprays, and crack-and-crevice applications for treatment and control of indoor pests.

The indoor surface deposition and distribution of insecticides applied as foggers, baseboard or perimeter sprays, spot sprays and crack-and-crevice sprays represent distinct pathways of potential unintentional and unavoidable residential pesticide exposure of children and adults. Fogger, perimeter spray, crack-and-crevice, and spot sprays using registered commercial products were studied using three 5-part deposition plates positioned in unoccupied residences in Riverside, CA. Pesticide active ingredients included permethrin, chlorpyrifos, cyfluthrin, cypermethrin, and deltamethrin. Horizontal distribution factors of 100% (total release fogger in a small room), 50% (perimeter spray), 15% (crack-and-crevice), and 2% (spot spray) were assigned based upon application of selected commercial products by a licensed pest control operator and investigators who participated in these studies. This research reduces uncertainties associated with assessing human exposure following different application methods.

Lead testing wipes contain measurable background levels of lead.

Lead is registered under the California Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65) as both a carcinogen and a reproductive hazard. As part of the process to determine if consumer products satisfy Proposition 65 with respect to lead, various wipe sampling strategies have been utilized. Four commonly used wipe materials (cotton gauze, cotton balls, ashless filter paper, and Ghost Wipes) were tested for background lead levels. Ghost Wipe material was found to have 0.43 +/- 0.11 microg lead/sample (0.14 microg/wipe). Wipe testing for lead using Ghost Wipes may therefore result in measurable concentrations of lead, regardless of whether or not the consumer product actually contains leachable lead.

Potential exposure of children and adults to cypermethrin following use of indoor insecticide foggers.

The magnitude and distribution of cypermethrin from total release, over-the-counter foggers was studied in a test room and in residences to facilitate evaluation of regulatory exposure algorithms and new human exposure assessments based upon urine biomonitoring. Surface residue (SR) was evenly distributed in a small test room (3.6 mciro g cypermethrin/cm(2)) where thorough mixing of the aerosol occurred. In a residence SR was significantly affected by room size and distance from the fogger. Air levels in the residence were as high as 30 mciro g cypermethrin/cm(3) after 4.5 h. The availability of surface residues was measured with an automated surface cotton cloth wipe and ethyl acetate extraction. Only 5% of the SR was available from nylon carpet. Tile, wood and linoleum resulted in 30, 10, and 10% of SR being available, respectively. These data are used to estimate cypermethrin exposure of children and adults for comparison with existing regulatory reference dosages and exposure assessments based upon biomonitoring.

Screening-level human health risk assessment of toluene and dibutyl phthalate in nail lacquers.

Toluene and dibutyl phthalate (DBP) are found in many consumer products, including cosmetics, synthetic fragrances, and nail polish. In 2012, the California Environmental Protection Agency evaluated 25 nail products and found that 83% of the products that claimed to be toluene-free contained toluene at concentrations ranging up to 190,000 ppm, and 14% of the products that claimed to be DBP-free contained DBP at concentrations ranging up to 88,000 ppm. We conducted a preliminary, screening-level analysis of the potential toluene and DBP-related health risks to consumers and professionals based on the medium and maximum concentrations of toluene and DBP presented in the 2012 report and evaluated dermal and inhalation exposure to a salon patron, nail technician, and home user. We concluded that the maximum toluene concentration for the technician and home user scenarios exceeded the California MADL, but the estimated air concentrations did not exceed the Federal or Cal OSHA PEL. The MADL for DBP was exceeded for all user scenarios at both the median and maximum concentrations. Using these highly conservative assumptions, exposures above regulatory limits could possibly occur during routine use of nail products; further research is needed in order to evaluate potential human health risks.

Estimation of the safe use concentrations of the preservative 1,2-benzisothiazolin-3-one (BIT) in consumer cleaning products and sunscreens.

1,2-Benzisothiazolin-3-one (BIT; CAS # 2634-33-5) is a preservative used in consumer products. Dermal exposure to BIT at sufficient dose and duration can produce skin sensitization and allergic contact dermatitis in animals and susceptible humans.The purpose of this study is to derive a maximal concentration of BIT in various consumer products that would result in exposures below the No Expected Sensitization Induction Level (NESIL), a dose below which skin sensitization should not occur. A screening level exposure estimate was performed for several product use scenarios with sunscreen, laundry detergent, dish soap, and spray cleaner. We calculated that BIT concentrations below the following concentrations of 0.0075%, 0.035%, 0.035%, 0.021% in sunscreen, laundry detergent, dish soap, and spray cleaner, respectively, are unlikely to induce skin sensitization. We completed a pilot study consisting of bulk sample analysis of one representative product from each category labelled as containing BIT, and found BIT concentrations of 0.0009% and 0.0027% for sunscreen and dish soap, respectively. BIT was not detected in the laundry detergent and spray cleaner products above the limit of detection of 0.0006%. Based on publically available data for product formulations and our results, we were able to establish that cleaning products and sunscreens likely contain BIT at concentrations similar to or less than our calculated maximal safe concentrations and that exposures are unlikely to induce skin sensitization in most users.