Indoor and outdoor BTX levels in German cities.

On the basis of the ongoing study INGA (INdoor exposure and Genetics in Asthma), Germany's most detailed and standardized epidemiological study on indoor exposure to both allergens in house dust and volatile compounds in the air of the home environment has been performed. The purpose of this paper is to describe the spatial and seasonal variability of indoor and outdoor BTX (Benzene, toluene, ethyl benzene, ortho-xylene, meta- and para-xylene) concentrations for the study period from June 1995 to November 1996. Within this framework, air concentrations of volatile organic compounds (BTX) were measured in 204 households in Erfurt (Eastern Germany) and 201 households in Hamburg (Western Germany). BTX sampling was conducted over one week using OVM 3500 passive diffusion sampling devices in the indoor (living room and bedroom) and outdoor environment (outside the window of the living room). Indoor and outdoor median BTX concentrations in Erfurt were slightly, but significantly higher than those in Hamburg. This gap was most pronounced in the levels of indoor toluene (37.3 microg/m3 for Erfurt and 20.5 microg/m3 for Hamburg, P < 0.0001). In both cities, winter indoor and outdoor concentrations for the five compounds exceeded the summer values. Outdoor concentrations of ethyl benzene and ortho-xylene were very low (50% < L.D.). In general, the indoor BTX air concentrations were significantly higher than the outdoor concentra- tions, the lowest I/O ratios were found in the case of benzene. Living room and bedroom values for the five compounds were highly correlated (Spearman coefficient 0.5-0.9). Despite the better insulation of the homes in West Germany, no indication for the expected higher indoor concentrations of BTX in the West could be found. The strong and yet undiscovered indoor source for toluene in East Germany might lead to a further increase in the indoor air load in those homes in the East, which undergo renovations which will lead to improved insulation.

Pentachlorophenol in indoor environments. Correlation of PCP concentrations in air and settled dust from floors.

The investigation of settled dust is a proven and simple screening-method for considering indoor contamination for semivolatile compounds. Here we investigate the correlation of PCP concentrations in air and freshly settled dust from floors. Air and dust samples were taken from 75 rooms in 30 buildings with suspicion of an application of PCP-containing wood preservatives. Sampling was repeated four times within 18 months. PCP air concentrations were found in the range of <0.3-576 ng m-3 (mean value 25.3 ng m-3, median 2.5 ng m-3). PCP dust concentrations were found in the range of 0.083-79 microg g-1 (mean value 3.5 microg g-1, median 1.1 microg g-1. A weak highly significant correlation (P < 0.0001) with a correlation coefficient of R2 = 0.433, of the PCP concentration in dust with the PCP concentration in air, was observed. Measurement of PCP concentrations in dust, therefore, is a suitable screening method for the evaluation of indoor contamination with PCP. Due to the high dispersion of the data it is not possible to calculate PCP concentrations in air from concentrations in dust although a highly significant correlation of the PCP concentrations in air and dust was found.

Vertical and horizontal variability of volatile organic compounds in homes in Eastern Germany.

A German study on Indoor Factors and Genetics in Asthma (INGA) will be conducted for 10 years in towns of Eastern and Western Germany. The study will include an indoor and outdoor exposure assessment of BTEX (BTEX=benzene, toluene, ethyl benzene, ortho-xylene, and meta- plus para-xylene) volatile organic compounds (VOCs). In a pilot study, which was conducted in Erfurt, a city in Eastern Germany, during the winter of 1994, vertical and horizontal variabilities of BTEX concentrations within the homes were examined in detail. Passive sampling was conducted in the living room (at 0.7, 1.2, and 2.0 m height), bedroom (2 m), kitchen (2 m), and outside the window of the living room, in 20 homes of randomly chosen adults. The 20 houses consisted often old concrete constructions ('Altneubauten'=OLD, constructed between 1960 and 1970) and ten new concrete constructions ('Neubauten'=NEW, constructed between 1970 and 1980). At each apartment, Organic Vapour Monitor (OVM) 3500 passive sampling devices (3M Company) were exposed for 7 days. After elution with carbon disulfide (CS2), the samples were analyzed with dual column gas chromatography (GC) with flame ionization detector (FID). No significant differences between the median values of the weekly average air concentrations of the BTEX VOCs in the different heights of measurement in the living rooms could be detected. Kitchen and living room median BTEX concentrations were equal and both significantly higher than the bedroom concentrations (except benzene). The indoor BTEX air concentrations were significantly higher than the outdoor concentrations (except benzene). Significant differences in BTEX indoor concentrations between OLD and NEW buildings could not be detected (except toluene).

Pentachlorophenol in indoor environments. Does a single measurement of air and dust concentrations represent the contamination?

In order to be able to make a decision, as to whether a room or building has a health-endangering pentachlorophenol (PCP) concentration, usually the PCP concentrations in air and settled dust are measured. The variability of the PCP concentration in indoor air and dust was studied. Air and dust samples were taken from 75 rooms in 30 buildings with suspicion of application of PCP-containing wood preservatives. Sampling was repeated four times within 18 months. Thirty-six rooms were reconstructed within the study; 39 rooms had unchanged contamination status during the study. The four times repeated measurements of PCP concentrations in air and dust in these rooms showed large variations of the measured values. The variability of the results is to a large extent in the same range as the measured values. The observed relative standard deviation of the PCP concentrations in air and dust does not depend on the average PCP concentration detected in the individual rooms.

The effect of wind direction on the observed size distribution of particle adsorbed polycyclic aromatic hydrocarbons on an inner city sampling site.

An investigation of the variability in the size distribution of particle adsorbed polycyclic aromatic hydrocarbons (PAHs) on an inner city sampling site showed differences depending on the wind direction. Particle size distributions of PAHs from outdoor air sampling were measured in Munich from 1994 to 1997. The sampling site is located northeast of a crossing with heavy traffic and southwest of a large inner city park. Depending on the wind direction, three different size distributions of particle adsorbed PAHs were observed. The maximum PAH concentration on very small particles (geometric mean diameter 75 nm) was observed with wind from west to southwest coming directly from the crossing area or the roads with heavy traffic. The maximum PAH concentration on particles with geometric mean diameter of 260 nm was found on days with wind from the built-up area north of the sampling site. On particles with geometric mean diameter of 920 nm the maximum PAH concentration was found on days with main wind directions from northeast to east. On these days the wind is blowing from the direction of the city park nearby. The distribution of particle adsorbed PAHs within different particle size classes is substantially influenced by the distance of the sampling site from strong sources of PAH loaded particulate matter.

The relevance of fat content in toxicity of lipophilic chemicals to terrestrial animals with special reference to dieldrin and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

Lipophilic chemicals such as chlorinated hydrocarbon insecticides and other persistent chemicals such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are fat soluble chemicals and are readily bioconcentrated in animal fat depots. The modifying role of the body fat content in the toxicity of chlorinated cyclodiene insecticides to insects and in the toxicity of TCDD to different mammals was investigated. The single oral acute 30-day LD50 data of TCDD in different mammals are presented and correlated with their total body fat content. A two linear regression equation with log/log values was obtained. It is concluded that the storage of TCDD and other related lipophilic and persistent chemicals in lipids of organisms is, in a sense, a detoxication mechanism by which the compounds are removed from sites of action and/or receptors. Therefore, terrestrial organisms such as insects and mammals with higher total body fat content can accumulate and tolerate higher chlorinated hydrocarbon insecticide and TCDD doses than organisms with lower fat content. The different sensitivity of mammals of various species, strains, body weight, sex, age, etc. to acute toxicity of TCDD and related lipophilic persistent chemicals can mainly be explained by differences in total body fat content.

[Organochlorine compounds in human milk]. / Organochlorverbindungen in Frauenmilch.

The impact of life style characteristics and chemical exposure conditions of about 80 nursing women on the contents of Organochlorine compounds (OCC) in their breast milk is analyzed and described by a robust statistical procedure. Information on independent variables such as age, diet, smoking, occupation and chemical exposures is obtained by a questionnaire. Concentrations of HCB alpha-, beta-, gamma-HCH, Heptachlorepoxide, Dieldrin, DDE and PCB in milk samples are measured and serve as dependent variables. By logistic regression we quantify the influence of combinations of several independent variables on the probability of being extremely contaminated with at least one OCC. We also study the pattern in which OCC are associated with each other. There are distinct pairwise correlations of the four main contaminants: HCB, beta-HCH, DDE and PCB. These correlations entail that a woman with a high PCB concentration, for example, is more likely of being also contaminated above average with the remaining contaminants. We define a simple load score and compare its different theoretical distributions under the assumption of presence or absence of the correlations. By this we can show that the proportion of heavily contaminated women is underestimated, if the OCC associations are ignored. We therefore recommend that the pattern of OCC-correlations in human milk is further studied in more representative samples. These investigations should also comprise occupationally exposed women.