Department of Environmenal and Biological Science

The performance of three filtering facepiece respirators (two models of N99 and one N95) challenged with an inert aerosol (NaCl) and three virus aerosols (enterobacteriophages MS2 and T4 and Bacillus subtilis phage)-all with significant ultrafine components-was examined using a manikin-based protocol with respirators sealed on manikins. Three inhalation flow rates, 30, 85, and 150 l min 21 , were tested. The filter penetration and the quality factor were determined. Between-respirator and within-respirator comparisons of penetration values were performed. At the most penetrating particle size (MPPS), >3% of MS2 virions penetrated through filters of both N99 models at an inhalation flow rate of 85 l min 21 . Inhalation airflow had a significant effect upon particle penetration through the tested respirator filters. The filter quality factor was found suitable for making relative performance comparisons. The MPPS for challenge aerosols was <0.1 mm in electrical mobility diameter for all tested respirators. Mean particle penetration (by count) was significantly increased when the size fraction of <0.1 mm was included as compared to particles >0.1 mm. The filtration performance of the N95 respirator approached that of the two models of N99 over the range of particle sizes tested ($0.02 to 0.5 mm). Filter penetration of the tested biological aerosols did not exceed that of inert NaCl aerosol. The results suggest that inert NaCl aerosols may generally be appropriate for modeling filter penetration of similarly sized virions.

Thermophilic aeration of cattle slurry and food industrial by-products was studied with the aim to improve hygienic qualities of the slurry so that it could be used as a safe fertiliser for berries to be eaten raw. We also wanted to study if the process would be energetically favourable in an arctic climate.

In this work alternative media for detection and enumeration of E. coli and coliform bacteria were compared to the reference method ISO 9308-1 (LTTC) using non-disinfected water samples with background flora. The alternative media included LES Endo agar medium (LES Endo), Colilert®-18 with 51-well Quanti-tray® (Colilert), Chromocult® Coliform agar (CC), Harlequin™ E. coli/Coliform medium (HECM) and Chromogenic Escherichia coli/Coliform medium (CECM). A total of 110 samples of groundwater, bathing water and spiked water was used. Our results revealed that confirmation of coliform bacteria counts is necessary, not only on lactose-based LTTC and LES Endo media, but also on the chromogenic agar media tested, due to the growth of oxidase positive colonies. LTTC and CC media also allowed the growth of some morphologically typical coliform colonies containing gram-positive bacteria. The recovery of coliform bacteria was lower on LES Endo than on LTTC. In most cases Colilert, CC, HECM and CECM gave higher coliform counts than LTTC. The use of the LTTC medium led to higher E. coli counts than obtained with any of the alternative mediums. There are three explanations for this: (1) high sensitivity of LTTC, (2) false positives on LTTC or (3) false negatives especially with Colilert, but also with chromogenic agar media. Although LTTC was found to be a very sensitive medium, the high degree of background growth of non-disinfected waters disturbed substantially the use of it. In conclusion, our results suggest that Colilert, CC and CECM are potential alternative media for detection of coliform bacteria and E. coli from non-disinfected water.

The study deals with the effect of common, annually-used pesticides on soil microorganisms, pesticide residues in soil, and carrot (Daucus carota) yields in Central Finland. Linuron residues in carrot roots were also analysed. Thiram+lindane and dimethoate were applied from 1973-1981 at the commercially recommended doses on experimental plots of carrots, linuron was applied at twice the recommended rate from 1973-1979 and at the normal rate thereafter and in addition TCA was applied in 1978. Maleic hydrazide was used in the years 1973-1976, and glyphosate after 1977. The numbers of different soil microorganisms, their activities and the pesticide residues were studied from autumn 1978 to 1981. The pesticide treatments reduced the growth of soil algae but increased the total number of microorganisms and the number of aerobic spore-forming bacteria. Linuron residues in the soil were 0.9-2.8mgkg-' in the growing season and 1.2-1.7mgkg-' in the autumn, 3 months after application. The residues of glyphosate in the soil were 0.7mg kg-l in the autumn, 41 days after the treatment, and had declined to a level of about 0.2mgkg-' by the following summer. In the pesticide-treated plots the carrot yield was only 2MO% of the yield in the hand-weeded plots. The herbicide programme controlled most of the annual weeds but not couchgrass Elyrnus repgns and milk sow-thistle Sonchus arvensis.

The occurrence and condition of Scots pine mycorrhizas were studied at different distances from a pulp mill in Central Finland. The chemical analyses of the soil humus layer in the vicinity of the mill revealed increased levels of ammonium-nitrogen, sulphur and calcium but unaltered concentrations of phosphorus and magnesium. Higher nitrate levels and nitrification were clearly detected at some sites which had recently been limed. Significant decreases in root ramification index and number of living mycorrhizas were found in a zone 0-0.6 km zone surrounding the factory but these parameters increased with increasing distance. Within a 2 km zone around the mill there were abundant Cenococcum geophilum and Paxillus involutus-type mycorrhizas while lowered frequencies of several other mycorrhizal types were detected. An ultrastructural study revealed changes in several types of mycorrhizas, the clearest of which were increased tannin deposition in cortical cells, intracellular growth of hyphae in cortical cells and the appearance of electron dense accumulations in the vacuoles of the fungal cells. The ultrastructural changes observed were distributed at least to a distance of 3 km from the mill and occurred in the roots of trees that had only a slight loss of needle mass. Nitrogen deposition is suspected to be the primary cause of root decline but atmospheric SO2 through the tree crown is also likely to be a contributing factor.

The fertilizer value of human urine was compared with mineral fertilizer in pumpkin (Cucurbita maxima) cultivation at a dose of 113 kg N ha -1 with no-fertilization used as control. The growth of the vine was better in urine fertilized pumpkins than in mineral fertilized and non-fertilized pumpkins. Total fruit biomass was higher in mineral fertilized plants compared to urine fertilized and non-fertilized pumpkins. Urine fertilized pumpkins may have suffered from lower potassium or higher chloride, thus they produced fewer flowers and fruits. However, total fruit biomass and the number of fruits were slightly higher in urine fertilized plants than in their non-fertilized counterparts, i.e. 17.2 t ha -1 more pumpkin could be produced with urine fertilizer. The microbial hygiene quality as well as the contents of soluble sugars, protein and taste quality were similar in all treatments, but lower nitrate and higher chloride contents were recorded in urine fertilized pumpkins than other treatments. In conclusion, our study shows that the production rate of urine fertilized pumpkins was somewhat lower than mineral fertilized pumpkins but it was higher than non-fertilized pumpkins. The hygienic quality was equally good with all treatments.

Human urine obtained from separating toilets was tested as a fertiliser for cultivation of outdoor cucumber (Cucumis sativus L.) in a Nordic climate. The urine used contained high amounts of nitrogen with some phosphorus and potassium, but numbers of enteric microorganisms were low even though urine had not been preserved before sampling. The cucumber yield after urine fertilisation was similar or slightly better than the yield obtained from control rows fertilised with commercial mineral fertiliser. None of the cucumbers contained any enteric microorganisms (coliforms, enterococci, coliphages and clostridia). In the taste assessment, 11 out of 20 persons could recognise which cucumber of three cucumbers was diVerent but they did not prefer one over the other cucumber samples, since all of them were assessed as equally good.

Increased stabling of horses near to cities has led to interest in the environmental effects of paddocks. In this study, the contamination of horse paddocks was examined by determining the nutrient and micro-organism contents in the surface run-off waters and the electrical conductivity, pH and phosphorus, potassium and nitrate contents of top soils. Two open-stable paddocks were studied, one cleaned and the other left uncleaned, with a stocking density of 37.5 animals ha À1 in both. The feeding and drinking places were the most contaminated areas of both paddocks. In spring, after seven months of use, the nutrient concentrations in the surface run-off water from paddocks were 3.4-18.8 mg/l for total phosphorus, 3.0-15.0 mg/l for phosphate and 18.3-140.0 mg/l for total nitrogen, indicating a risk to surface waters. Summer rain generated surface run-off, especially from the feeding area of the stock-free uncleaned paddock.

A comparative, numerical, taxonomic analysis was carried out on 24 selected strains of Clostridium spp. isolated from cattle slurries and fresh forage grasses fertilized with slurries, as well as on 10 culture-collection Clostridium tyrobutyricum strains for reference. The results showed an unexpectedly low occurrence of the Clostridium tyrobutyricum, with only one of the 24 strains isolated from slurry belonging to this species. The majority of Clostridium strains isolated from grasses were identified as C. malenominatunt Although the predominant anaerobic, spore-forming colonizers of the cattle slurry belonged taxonomically to the genus Clostridium they could not be firmly identified, but appeared to show some resemblance to C. propionicurrL

The review discusses the aerobic treatments for farm slurry and food wastes and concentrates in particular on the thermophilic aerobic treatments. Methods are discussed under the heading of chemical, physical and other treatments. From those methods considered, the most suitable physical-microbiological treatment are aerobic thermophilic treatments. The main problem faced in aerobic thermophilic treatments could be the foaming formation during the process, and this could be solved by using different methods, mainly mechanical control method. Aerobic thermophilic treatments are also simple, economical and environmentally accepted. This method is known to have effects, and could be used to assist decontaminations on farms, as such technologies are already used in routine slurry treatment in many farms.

This study is based on a visual inspection and a questionnaire survey about sanitation in central Nepal. A total of 201 people from different groups were asked about their knowledge about eco-toilets, the fertilizer value of human urine and wood ash. Farmers were the least educated and least aware of most of the topics asked. Although the majority of educated people were aware about urine fertilizer, 68% of them were not interested in its use in their home, and 39% of them said that it might be not accepted. The visual inspection revealed that environmental hygiene depends on education. It is concluded that farmers need to receive practical demonstrations about the use of eco-toilets and wood ash to appreciate the direct benefits. It can be assumed that since urine fertilizer is a bonus obtained from eco-toilets, this could encourage even poor people to construct these kinds of facilities.