Arthur Greenberg

The Total Human Environmental Exposure Study (THEES) to Benzo(a)pyrene: Comparison of the Inhalation and Food Pathways

The assessment of human exposure to an environmental contaminant requires the measurement of levels present in each pathway of possible contact. In this paper, the design considerations and Phase I results of a human exposure study focused on Benzo(a)pyrene (BaP) are discussed. This study site, located in Phillipsburg, New Jersey, is a city that contains a metal pipe foundry, which is a suspected major source of BaP. Three outdoor PM-10 samplers (used to collect BaP-containing particles with an aerodynamic size of less than or equal to 10 micron) were located in residential areas surrounding the foundry. Ten homes were sampled indoors for PM-10. Some homes have indoor combustion sources, e.g., cigarette smoke or a coal burning stove. The indoor and outdoor samples were 24 hr in duration. The mean outdoor concentration of BaP was 0.9 ng/m3, and the indoor concentrations ranged from 0.1-8.1 ng/m3. Food samples were acquired from family meals each day. They represented a one-third portion of each meal eaten at home. The range of BaP per gram of wet weight of food was between 0.004 and 1.2 ng/g. Of the 20 wk of exposure (10 x 2 wk), 10 had higher food exposures and the other 10 had higher inhalation exposures. Of the two groups, the higher food exposures usually had a greater number of ng of BaP/wk. The dominance of one or the other pathway appeared to depend upon personal eating habits and indoor combustion source use. In some instances, outdoor air pollution led to a major portion of indoor air BaP exposures. Water appears to be a minor source of BaP exposures in the study area.

Assessment of carcinogenic risk from personal exposure to benzo(a)pyrene in the Total Human Environmental Exposure Study (THEES)

The Total Human Environmental Exposure Study (THEES) was an investigation of multimedia exposure to the ubiquitous environmental carcinogen, benzo(a)pyrene (BaP). The three-phase study was conducted in Phillipsburg, New Jersey and involved the participation of 14-15 individuals (8-10 homes) during each 14-day monitoring period. Microenvironmental sampling of air, food, water and soil indicated that environmental exposure to BaP was primarily through air and food. Exposure and risk estimates were, therefore, based on the results of personal monitoring of breathing zone air and prepared food samples. Based on a comparison of the range and magnitude of inhalation and dietary BaP exposures, food ingestion was clearly the predominant exposure to pathway. The relative contributions of other potential sources of community exposure to BaP (e.g., soil and drinking water ingestion) were also assessed. The excess cancer risk estimates for food ingestion were consistently greater than those for personal air, reflecting both the predominantly higher BaP exposures through the diet and the higher carcinogenic potency value for oral exposure. Overall, the total lifetime risk from personal exposure to BaP for nonsmokers in the community was estimated at 10(-5). In identifying risk reduction options, it is important to account for the observation that personal activities, lifestyle, and diet strongly influenced individual exposures to BaP.

Polycyclic aromatic hydrocarbons in New Jersey: A comparison of winter and summer concentrations over a two-year period

Abstract Polycyclic aromatic hydrocarbons (PAH) have been analysed from inhalable airborne particulate matter collected at four New Jersey locations during four 6-week periods (Summer 1981, Winter 1982, Summer 1982 and Winter 1983). The sites included three urban locations (Newark, Elizabeth and Camden) and one rural site (Ringwood). The analytical methodology involved soxhlet extraction of preheated glassfiber filters with cyclohexane, thin-layer chromatography and ultimate analysis using reverse-phase highperformance liquid chromatography and ultraviolet and fluorescence detection. The quality assurance/quality control procedure is described. Discussions of differences in PAH levels between urban and rural sites as well as the summer/winter differences in concentrations rely upon consideration of sources as well as differences in PAH reactivities. Comparisons of PAH levels are also made between pollution episode and non-episode periods. In addition intra- and intersite correlations between PAHs as well as other pollutants are discussed. Profiles of PAH do not appear to differ significantly between the few sites during a given season.

An assessment of a urinary biomarker for total human environmental exposure to benzo[a]pyrene

Urinary banzo[a]pyrene (BaP) metabolite levels were compared to human environmental exposure to BaP through inhalation and dietary ingestion to assess the predictive validity of the exposure biomarker. These measurements were made for 14 adult volunteers over 14 consecutive days, once during summer/fall, again during winter periods. Based on personal air monitoring, median potential inhalation doses of 11.0 and 2.3 ng/day were estimated for the winter and summer/fall studies, respectively. A median potential ingested dose of 176 ng/day, estimated from “duplicate plate” sampling, exceeded inhalation by 6-and 122-fold for the winter and summer/fall studies, respectively. “Total” urinary BaP metabolites were measured using a published “reverse metabolism” (BaP) method of analysis. Median rates of urinary BaP metabolite elimination for the winter and summer/fall studies were 121 and 129 ng/day, respectively. The changes in inhaled and ingested potential doses were regressed on the change in urinary metabolite elimination from week 1 to week 2 to test the predictive validity of the biomarker measurement. The regression was statistically significant (r = 0.620, p = 0.015, n = 25) when body weight was included and two extreme values were removed. Consistent with the exposure measurements showing diet as the dominant route of exposure, most of the variation in urinary metabolite elimination was explained by the ingested dose. It is concluded that the measurement of urinary BaP by “reverse metabolism” is qualitative and of marginal predictive validity as an exposure biomarker due to the methods low recoveries and the large unexplained variance.

Benzo(a) pyrene in New Jersey. Results from a twenty-seven-site study

The study presented was designed to establish a baseline for benzo(a)pyrene (BaP) levels in New Jersey prior to any large scale fuel switching to coal and wood in residential, Industrial, and/or utility boilers in the state. In addition, this study was used to explore the variability of BaP levels at 27 sites in New Jersey and the possible relationships between BaP, total suspended particulates (TSP), cyclohexane- soluble organics (Cx), sulfur dioxide (SO2), carbon monoxide (CO), and coefficient of haze (COH) measurements. Samples were collected as part of the N.J. Department of Environmental Protections statewide high-volume air sampling network. Benzo(a)pyrene was determined by the standard U.S. EPA procedure Involving ultrasonic extraction with cyclohexane followed by TLCfluorescence. Both urban/rural and seasonal differences in BaP levels are discussed, as are the relationships between the other criteria pollutants measured. In addition, source resolution is attempted employing state fuel-use rates a...

The thermodynamic effect of fluorine as a substituent: Vinylic CF2 and CFH and allylic CF2C

Abstract I 2 -catalyzed isomerizations of 3-fluoropropene and 3,3 - difluoropropene, and a Cope rearrangement of 1,1 - difluoro - 1,5 - hexadiene provide thermodynamic data which allow the determination of a number of important group values for contributions to ΔH o f which when combined with those determined in the preceding paper allow the calculations of ΔH o f s of most simple F-substituted hydrocarbons: [C d ue5f8(F)(H)] = − 38.4, [C d ue5f8(F) 2 ] = − 88.0, [Cue5f8(F) 2 (C)(C d )] = − 103.9, [Cue5f8(F) 2 (C) 2 ] = − 104.9 kcal/mole. A kinetic study of the conversion of 1,1 - difluoro- to 3,3 - difluoro - 1,5 - hexadiene provided activation parameters for the process: Log A = 10.8, E a = 33.0 kcal/mole and ΔS ≠ = − 12.2 e.u. Incremental geminal stabilizations of F and other substituents are discussed and contrasted.

Toxicity of construction materials in the marine environment: a comparison of chromated-copper-arsenate-treated wood and recycled plastic.

Previous studies have demonstrated leaching from chromated-copper-arsenate (CCA)-treated wood, which is used in pilings and bulkheads, and resulting toxicity to various estuarine organisms. The current study compared effects of leachates from CCA-treated wood with those of recycled plastic “lumber,” a possible alternative construction material. Limb regeneration in fiddler crabs, while depressed in leachates from CCA wood, was accelerated in three formulations of recycled plastics. The acceleration was reduced in subsequent trials with the same pieces of plastic. Using a sea urchin fertilization test, no effects were seen in 1- and 3-day leachates from the plastics. However, CCA wood reduced fertilization by 90%, and totally inhibited larval development of those that did fertilize. A smaller piece of wood, one-tenth the size (0.4 cm2), did not have a significant effect on fertilization or development. With 1–3 weeks of leaching, significant reductions in fertilization were seen in sea urchin gametes exposed to one plastic formulation and no fertilization was seen in leachates from the small piece of CCA wood. Two formulations enriched to 30% polystyrene (PS) had no significant effect on fertilization, but did reduce larval growth. When the same pieces of plastic and wood were used for a second set of experiments, all three formulations of plastic, as well as the small piece of wood, inhibited fertilization significantly, and one of the 30% PS formulations and the wood caused reduced larval growth.In another assay, snails and an alga were exposed to plastics for two months with no observed effect; the CCA leachates caused 100% snail mortality within one week and chlorosis of the alga. Chemical analysis by GC/MS revealed a large number of chemicals leached in various quantities from the plastic.

Summertime variations in polycyclic aromatic hydrocarbons at four sites in New Jersey.

Variations in the summertime concentrations of selected polycyclic aromatic hydrocarbons (PAH) collected by using inhalable particulate samplers (IPM-D/sub 50/ < 15 ..mu..m) at four sites in New Jersey are presented and examined. The levels of PAH found in this study are consistent with other urban values reported in the literature. While day-to-day trends in PAH concentrations at the four sites were influenced by regional meteorology, it appears that local sources had the greatest influence on ambient levels. Comparison of selected PAH with IPM, EOM (extractable organic matter), and SO/sub 4//sup 2 -/ values at each site showed weak correlations. However, intersite and intrasite Spearman rank correlations among PAH were significant and suggest a common type of source emitter at the urban locations during the summer. The intersite correlations also reflect the proximity of the four sites.

The New Jersey Project on Airborne Toxic Elements and Organic Substances (ATEOS): A Summary of the 1981 Summer and 1982 Winter Studies

An overview of the purpose, design, and results of the summer 1981 and winter 1982 ATEOS studies is presented. Daily sampling was conducted during 6-week periods at three urban sites and one rural site: Newark, Elizabeth, Camden, and Ringwood. Inhalable particulate matter was characterized with respect to organic and inorganic composition, the bacterial mutagenic activity of three organic fractions and fine particle mass. The study showed that the IPM fractions of the atmospheric aerosol was composed primarily of EOM (extractable organic matter) sulfate, and crustal material. There were seasonal shifts in the composition, however, with winter time space heating and local motor vehicle traffic appearing to be important factors. Each EOM fraction and the PAH associated with the nonpolar particulate matter increased by a large factor during the winter. The mutagenic activity of the EOM increased, but the types of mutagens present appear to be different in each season. The average SO/sub 4//sup -2/ levels were similar for the two seasons. There were few significant day to day excursions in concentration during the winter. The volatile organic substance measurements showed distinct local source relationships, although benzene levels were fairly constant in all urban locales. Winter time values of VOC (volatilemorexa0» organic compounds) were generally higher than those in the summer. 7 figures, 8 tables. (DP)«xa0less

Structural relationships in silatrane molecules

An updated compendium of silatrane structural data is presented. The relationships between nonplanarity at silicon (δSi) andd(N-Si), the length of the dative bond, and nonplanarity at nitrogen ΔN andd(N-Si) are examined. Excluding a platinum-substituted derivative: the ΔSi relationship is strong and predicts the limiting length of a strong N → Si bond, while the ΔN relationship is weak. A good relationship between ΣσI for the four (non-N) exo- and endocyclic substituents attached to Si holds for silatranes, methyl, keto, and diketo derivatives as well as for 2-carbasilatranes. The relationship fails for strong π-donor exocyclic substituents, implicating resonance, and for benzo- and tribenzosilatranes, where steric effects dominate.