Occupational exposure and indoor air quality monitoring in a composting facility.

The objective of this study was to investigate indoor air quality in a completely covered enclosure used for the aerobic composting of organic wastes originating from vegetable, fruit, and garden refuse. Samples of gases and vapors were taken in the ventilation exhaust ducts. Volatile organic compounds (VOCs) were collected on Tenax absorbent; after thermal desorption they were analyzed by gas chromatography/mass spectrometry. Hydrogen sulfide was determined using Dräger test tubes. Microbial samplings were conducted on four sites inside the hall. Microbes were collected using a modified Anderson high-volume sampler, consisting of two impactor stages. Results indicate that the concentrations of VOCs were rather low; only the limonene level was elevated, but it was still well below the current Dutch provisional threshold limit value. Hydrogen sulfide levels found were also far less than the Dutch threshold limit value. Both total bacteria and gram-negative bacterial counts exceeded the provisional Dutch guideline of 10,000 cfu/m3 for indoor air in the work environment. Furthermore, the number of fungi, for the larger part consisting of the genera Aspergillus and Penicillium, which are known to cause respiratory tract disorders, approached the hazardous exposure level.

[The PRIMOS household model]. / Het PRIMOS-huishoudenmodel.

The PRIMOS model, developed to forecast changes in household composition in the Netherlands, is applied to official data for the period 1977-1990. "The forecast results in an increasing number of households in the Netherlands, from 5.95 million in 1990 to 7.37 million in 2015." Projections by region are also included. (SUMMARY IN ENG)

Interrelationships between bioaccumulation of organic trace pollutants (PCBs, organochlorine pesticides and PAHs), and MFO-induction in fish.

1. Hydrophobic compounds that are more easily biotransformed (e.g. PAHs) generally show less bioaccumulation in fish than the more persistent PCBs and DDTs. 2. In lake Nieuwe Meer, with the highest levels of organic micropollutants, the hepatic MFO activity was elevated in three fish species. This indicates that MFO activity might be a sensitive indicator for organic micropollutants in the aquatic environment. 3. Activities of the 3-MC type inducible isozymes were most pronounced in all three fish species studied. Though further research is required, indications for the existence of a PB-type inducible enzyme system have been demonstrated for two fish species, i.e. pike and eel. 4. Fish liver enlargement as a consequence of MFO induction could not be demonstrated in fish from the most polluted lake. 5. In fish, a correlation was observed between PCB or OCP tissue concentrations on the one hand, and hepatic MFO activities on the other. The low PAH fish/sediment ratios are further reduced when MFO systems are induced due to organic micropollution. The interrelationship between bioaccumulation and enzyme induction demonstrates the importance of an integrated study of these phenomena in field research.

[Municipal household forecasts according to the PRIMOS-household model]. / Huishoudensprognoses per gemeente volgens het PRIMOS-huishoudenmodel.

PIP: The PRIMOS-household model is described. Its application to the formulation of household projections for the Netherlands is reviewed. Household projections up to the year 2000 are presented. (SUMMARY IN ENG)^ieng

[Municipal population forecasts according to the PRIMOS model]. / Bevolkingsprognoses op gemeentelijk niveau volgens het PRIMOS-model

PIP: Some results of recent population forecasts for all municipalities in the Netherlands are presented for the years 1983, 1985, and 1990. The forecasts are provided by region and municipality for ages 0-19, 20-64, and 65 and over and were prepared primarily to determine housing requirements. The projections include allowances for both internal and international migration. The PRIMOS model used is a cohort-component model developed by the Research Centre for Physical Planning. (summary in ENG)^ieng