Asbestos-containing materials in abandoned residential dwellings in Detroit.

OBJECTIVE: The efforts of many municipalities to demolish abandoned residential dwellings (ARDs) are hampered by the presence of asbestos-containing materials (ACMs) in these structures. However, the extent of such materials is unknown. Our study sought to characterize ACMs present in ARDs demolished in Detroit. METHODS: Working with the City of Detroit, we obtained information on all ARDs demolished from 2014 to 2017. We randomly sampled 605 ARDs and analyzed the presence, type, and amount of ACM present, and the associated abatement and demolition costs. RESULTS: Asbestos was present in about 95% of the sampled ARDs. The most common types of ACMs were flooring, roofing, siding, and duct insulation. The material containing the greatest fraction of asbestos was duct insulation. The type of asbestos generally present was chrysotile. Only eight (1%) ARDs contained commercial amphibole asbestos; another 36 contained vermiculite. The total cost of demolition averaged $13,645 per home, of which 20.1% was asbestos abatement. CONCLUSIONS: The majority of the ACM in the ARDs was nonfriable and consisted of chrysotile. This study contributes information about the nature and extent of ACM in ARDs, which can provide part of the foundation for making an assessment of possible asbestos-containing air emissions during the demolitions of ARDs, and the nature or extent of pre-demolition abatement that may be needed (if any) to protect the public's health.

Human exposure from dioxins in soil.

Dioxins are a family of chemical compounds that has received considerable attention, both historically and currently. This article reviews scientific field studies that examine the relationship between living on soil contaminated with dioxins and the level of dioxins in people's serum, with an emphasis on the University of Michigan Dioxin Exposure Study (UMDES), the largest and most comprehensive study of its kind. These studies conclude that the levels of dioxins in serum are most strongly correlated with age, gender, body mass index, weight loss, breast feeding, and smoking. Levels of dioxins in soil are not significant predictors for dioxin concentrations in serum. The increase in serum dioxin levels that is seen with age results from historic exposure and does not represent ongoing exposure. Based on the scientific field studies conducted to date, it appears that, in the absence of the consumption of contaminated animal products, there is little evidence of ongoing exposure from contaminated soil.

Statistical comparison of residential soil concentrations of PCDDs, PCDFs, and PCBs from two communities in Michigan.

The University of Michigan dioxin exposure study was undertaken to address concerns that the industrial discharge of dioxin-like compounds in the Midland, MI area had resulted in contamination of soils in the Tittabawassee River floodplain and downwind of the incinerator. The study was designed in a rigorously statistical manner comprising soil measurements of 29 polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) from 766 residential properties, selected probabilistically, in the Midland area and in Jackson and Calhoun Counties (Michigan) as a background comparison. A statistical comparison determined that the geometric mean toxic equivalent (TEQ) levels in samples from the target populations were statistically significantly above background. In addition, the probabilities of being above the 75th and 95th percentiles of background were also greater. Congener contributions to the TEQ were dominated by 2,3,4,7,8-PeCDF and 2,3,7,8-TCDF in the floodplain and by 2,3,7,8-TCDD in the incinerator plume. However, PCB 126 was the top congener contributing to the background TEQ. On the basis of statistical inference to the total population, it was estimated that about 36% of the properties in the floodplain and incinerator plume have at least one soil sample over the Michigan Department of Environmental Quality's soil direct contact criterion of 90 pg/g TEQ.

Comparison of capillary pressure relationships of organic liquid-water systems containing an organic acid or base.

The presence of surface-active solutes such as organic acids and bases may have a profound influence on the transport of organic liquid contaminants through their impact on the constitutive relationship of capillary pressure vs. saturation. This relationship is a function of the interfacial tension and wettability of the system, which, in turn, depend on the pH and the concentration of organic acids and bases that are present. This study examines the impact of pH and the concentration on the interfacial tension, contact angle, and capillary pressure of systems consisting of tetrachloroethylene, water, and quartz containing either octanoic acid or dodecylamine. In general, the ionic form of the solute tended to remain in the aqueous phase and reduced the capillary pressure through its impact on the interfacial tension and contact angle; on the other hand, the neutral form of the solute partitioned into the organic liquid phase and had a lesser impact on the capillary pressure for the same total mass of solute. A comparison of these data with data generated in previous research in similar systems where o-xylene was the organic liquid showed that the trends are analogous. Thus, the behavior of these two solvent systems seems to be driven primarily by the aqueous phase speciation of the solute, and the differences between the capillary pressure relationships for the two systems could be attributed to the pure system interfacial tension.