Ken Wilkins

Volatile metabolites from some gram-negative bacteria

A survey of volatile organic compounds (VOCs) excreted from various Gram-negative bacteria (Pseudomonas spp., Serratia spp. and Enterobacter spp.) was carried out. Compounds were identified by gas chromatography-mass spectrometry. VOCs identified included dimethyl disulphide, dimethyl trisulphide and isoprene.

Sorting and recycling of domestic waste. Review of occupational health problems and their possible causes

In order to reduce the strain on the environment from the deposition of waste in landfills and combustion at incineration plants, several governments throughout the industrialized world have planned greatly increased recycling of domestic waste by the turn of the millennium. To implement the plans, new waste recycling facilities are to be built and the number of workers involved in waste sorting and recycling will increase steadily during the next decade. Several studies have reinforced the hypothesis that exposure to airborne microorganisms and the toxic products thereof are important factors causing a multitude of health problems among workers at waste sorting and recycling plants. Workers at transfer stations, landfills and incineration plants may experience an increased risk of pulmonary disorders and gastrointestinal problems. High concentrations of total airborne dust, bacteria, faecal coliform bacteria and fungal spores have been reported. The concentrations are considered to be sufficiently high to cause adverse health effects. In addition, a high incidence of lower back injuries, probably due to heavy lifting during work, has been reported among workers at landfills and incineration plants. Workers involved in manual sorting of unseparated domestic waste, as well as workers at compost plants experience more or less frequent symptoms of organic dust toxic syndrome (ODTS) (cough, chest-tightness, dyspnoea, influenza-like symptoms such as chills, fever, muscle ache, joint pain, fatigue and headache), gastrointestinal problems such as nausea and diarrhoea, irritation of the skin, eye and mucous membranes of the nose and upper airways, etc. In addition cases of severe occupational pulmonary diseases (asthma, alveolitis, bronchitis) have been reported. Manual sorting of unseparated domestic waste may be associated with exposures to large quantities of airborne bacteria and endotoxin. Several work functions in compost plants can result in very high exposure to airborne fungal spores and thermophilic actinomycetes. At plants sorting separated domestic waste, e.g. the combustible fraction of waste composed of paper, cardboard and plastics, the workers may have an increased risk of gastrointestinal symptoms and irritation of the eyes and skin. At such plants the bioaerosol exposure levels are in general low, but at some work tasks, e.g. manual sorting and work near the balers, exposure levels may occasionally be high enough to be potentially harmful. Workers handling the source-sorted paper or cardboard fraction do not appear to have an elevated risk of occupational health problems related to bioaerosol exposure, and the bioaerosol exposure is generally low.(ABSTRACT TRUNCATED AT 400 WORDS)

Volatile metabolites from mold growth on building materials and synthetic media

Mold species which were isolated from damp buildings were grown on sterile building materials and some synthetic media in order to study the microbial volatile organic compounds produced. Patterns of the microbial volatile organic compounds (MVOC) were very media dependent but media which favor terpene biosynthesis may give patterns unique enough for identification of dominant indoor molds.

Volatile metabolites from actinomycetes

Dimethyl disulfide, dimethyl trisulfide, aliphatic alcohols, ketones, esters, thioesters, and isopreniods (C10, C11, C12, C15) were identified from the growth on a laboratory substrate of 7 isolates of actinomycetes, some of which have been associated with farmers lung.

Variation of volatile organic compound patterns of mold species from damp buildings

The use of volatile organic compounds (VOCs) to detect mold growth in damp buildings depends on a comprehensive knowledge of the biosynthetic pathways available to indoor molds as well as their biological variation. Recent reports concerning (VOCs) formed during the growth of molds from damp buildings on laboratory substrates indicate considerable variation, presumably because of the sensitivity of mold VOC biosynthesis to environmental conditions or large biological variation.

Volatile organic compounds from household waste.

Ninety volatile organic compounds were identified in the headspace of biodegradable and mixed household waste by GC/MS. Most of them could be attributed to biological waste, microbiological growth in biological waste or packaging materials. Although none of the compounds were present at concentrations exceeding their threshold limit values, it is possible that in closed garbage cans or containers organic sulfur compounds could contribute to the reported gastrointestinal problems of collection personnel.

Gas chromatographic analysis of free fatty acids and fatty acid salts extracted with neutral and acidified dichloromethane from office floor dust

A gas chromatographic method for estimation of fatty acid salts (FASs) in house dust has been developed. The difference between results for acidic and neutral extractions gives the FAS content of a sample. The method was designed to handle the inhomogeneity of the dust and to avoid false positive results due to low concentrations. The absolute recoveries of the model compounds octadecanoic acid and sodium octadecanoate were 91% and 77%, respectively. Problems with the internal standard and the inhomogeneity of floor dust, however, resulted in large variations and somewhat underestimated concentrations. The content of total FASs in eight samples of office floor dust were up to at least 0.5% in the fine particle fraction.

Volatile organic compounds from garden waste

Abstract About 170 compounds were identified in the headspace or liquid exudate from garden waste. Typical for microbiological growth were branched and straight chain alcohols, carboxylic acids and esters C 2 –C 8 . Several of the substances have been identified in early studies of compost For some waste samples the organosulfur compound concentration (C 1 and C 3 mono-, di- and trisulfides) was ca. 10 mg/m 3 which suggests that these substances may contribute to mucous membrane irritation or nausea reported by waste collection personnel.

Detection of ciliostatic activity in fungal growth on building materials

Varying ciliostatic activity was found in extracts of biomass from building materials inoculated with pure isolates of some molds previously isolated from buildings. Extracts from growth on materials composed of finely divided cellulose (plaster board and construction cardboard) were more active than those from growth on Rockwool. Extracts of biomass from all three materials demonstrated an activity greater than control samples. Based on the activity observed here, it is conceivable that the measurement of ciliostatic activity of biomass scraped from contaminated building materials could be useful for planning removal strategies.

Volatile sesquiterpenes from Stachybotrys chartarum: Indicators for trichothecene producing mold species?

Trichodiene, a volatile sesquiterpene which is structurally related to trichothecene mycotoxins, has been identified in the headspace of growing Stachybotrys chartarum by GC/MS. It is possible that volatile sesquiterpene patterns can be used to characterize S. chartarum and related mold isolates as trichothecene producers, thus providing clear criteria for decisions concerning the occupancy and renovation of contaminated buildings.