Bioaerosols from the land application of biosolids in the desert southwest USA.

This study evaluated bioaerosol emissions during land application of Class B biosolids in and around Tucson, Arizona, to aid in developing models of the fate and transport of bioaerosols generated from the land application of biosolids. Samples were collected for 20 min at distances between 2 m and 20 m downwind of point sources, using an SKC BioSampler impinger. A total of six samples were collected per sampling event, which consisted of a biosolid spray applicator applying liquid biosolids to a cotton field. Each application represented one exposure. Samples were collected in deionised water amended with peptone and antifoam agent. Ambient weather conditions were also monitored every 10 min following initiation of sampling. Concurrently with downwind samples, background (ambient) air samples were collected to compensate for any ambient airborne microorganisms. In addition, biosolids samples were collected for analysis of target indicator and pathogenic organisms. Soil samples were also collected and analysed. Significant numbers of heterotrophic plate count (HPC) bacteria were found in air samples collected during the biosolid application process. These could have arisen from soil particles being aerosolised during the land application process. Aerosolised soil may contribute significantly to the amount of aerosolised microorganisms. Soil particles may be able to more readily aerosolise, due to their low density, small particle size and low mass. Aerosolised HPC bacteria found during biosolids land application were similar to those found during normal tractor operation on non-biosolids applied fields. Coliforms and coliphages were not routinely detected even though they were found to be present in the biosolids at relatively high concentrations, 10(6) and 10(4)/g (dry weight) of biosolids respectively. This could be due to the die-off rate of aerosolised Gram-negative bacteria or sorption to the solid portion of the biosolids. Low numbers of aerosolised coliphages may likewise be due to sorption phenomena. We theorise that only organisms in the aqueous phase of the biosolids were available to desorb and be aerosolised. Animal viruses, which were not detected in the biosolids, were likewise not detected in the aerosol samples. Clostridium perfringens was detected in only a small percent of aerosol samples although it was detected during all weather conditions; other microorganisms were detected during more favourable environmental conditions (relative humidity >10%). Despite the fact that many of these organisms were present in the biosolids at significant concentrations, their presence in bioaerosols generated during the land application of biosolids was limited to only a small percentage of samples. Bacteria as well as viruses may sorb to biosolids, which contain a high percentage of organic matter, and desorption during land application of biosolids may not readily take place; therefore, these microorganisms may not be readily aerosolised.     

Illustrative Benchmarking Rework and Rework Costs in Swedish Construction Industry

Following several studies investigating the causes of construction rework among some projects in the Swedish construction industry, we conducted this study in cooperation with R&D West, a group of construction companies in Sweden, to measure the costs of rework in construction projects. Rework has become an endemic feature of the procurement process in construction that invariably leads to time and cost overruns in projects. Thus, in order to improve the performance of projects, it is necessary to identify the causes and costs of construction rework. The research presented in this paper identifies, analyzes, and discusses the causes, magnitudes, and costs of rework experienced in seven Swedish construction projects. The findings revealed that the costs of rework for the case study projects were 4.4% of the construction values of the observation period, and the time needed to correct them was 7.1% of the total work time. The construction errors that generated rework were further analyzed according to their origins, types, and positions, causes of construction rework were identified and discussed, and preventive actions were suggested.     

Long-term outcome of kidney-pancreas transplant recipients with good graft function at one year

To assess the long-term outcome of kidney/pancreas transplantation, patients were identified who had good graft function at one year posttransplant and a minimum of 3 years' follow-up. Fifty recipients from 1987-92 met these criteria. Records were reviewed for graft survival, graft function, readmissions, and medical complications. Psychosocial adjustment and quality of life were assessed using the SCL-90-R and SIP surveys, respectively. Patient, kidney, and pancreas survivals were 94%, 86%, and 85% at five years (Kaplan-Meier), with a mean follow-up of 4.3 years. The 3 deaths were due to 2 sudden arrests at home (presumed to be cardiac events) and 1 episode of sepsis. Other graft losses were due to rejection, except for one case of sepsis. The remaining patients are normoglycemic (glucose 92 +/- 23 mg/dl) and have a creatinine of 1.8 +/- 0.6 mg/dl. Mortality after the first year was 0.9%/year. Estimated kidney and pancreas half-lives were 15 +/- 2 and 23 +/- 7 years, respectively. Hospitalization, acute rejection, graft pancreatitis, dehydration, and severe infections all decreased dramatically after the first year. While CMV was the most common infection in the first year, foot infections predominated thereafter. Retinal hemorrhage was infrequent. Sudden death (presumably cardiac) was the chief cause of mortality, while peripheral vascular disease resulted in several amputations. Fractures were common, suggesting the need for increased attention to bone demineralization. Psychosocial and quality of life evaluations were within normal limits. In conclusion, most complications specifically related to transplantation occur in the first year, but underlying disease renders these patients susceptible to a variety of cardiovascular, bone, and other disorders.     

Role of transferrin in determining internal iron distribution

The behavior in vivo of transferrin in loading and unloading iron from its two sites was examined in rats. Radioiron entering the plasma from the gastrointestinal tract in iron-deficient, normal and iron-loaded rats did not differ in its subsequent tissue distribution between erythroid marrow and liver of normal recipients from a second isotope added to the same plasma in vitro. Loading studies in vitro were then carried out employing a reticulocyte incubation model designed to place one isotope predominantly on one site of transferrin, more available to the erythron, and the second isotope on the other site, more available to the liver. In 15 groups of animals in which 3 different iron salts were employed to load transferrin with iron, the mean isotope ratio in the erythron was 1.03 (+/-0.06 SD) and the mean liver ratio was 0.75 (+/-0.21 SD). It was found that the incubation of plasma with reticulocytes resulted in contamination of the plasma by radioactive hemoglobin. After allowance was made for hepatic uptake of radiohemoglobin in the 13 groups in which proper correction could be made, the isotope ratio in the liver became 0.97 (+/-0.17 SD). It is concluded that iron atoms from the two sites of transferrin have similar tissue distributions in vivo in the experimental situations examined.     

Musculoskeletal symptoms and job strain among nursing personnel: a study over a three year period

OBJECTIVES: To examine the variation of symptoms from the neck, shoulders, and back over a three year period among female nursing personnel and the relation between job strain and musculoskeletal symptoms. METHODS: At a county hospital the female nursing personnel answered a questionnaire at baseline and then once a year over a period of three years. There were 565, 553, 562, and 419 subjects who answered the questionnaire at the first, second, third, and fourth survey, respectively. Of the study group, 285 nursing personnel answered the questionnaire on four occasions. Ongoing symptoms of the neck, shoulders, and back were assessed by means of a 10 point (0-9) scale with the verbal end points "no symptoms" and "very intense symptoms." Cases were defined as nursing personnel reporting ongoing symptoms, score > 6, from at least one of the body regions. For assessments of job strain, a Swedish version of Karasek and Theorell's model was used. RESULTS: Of the 285 subjects, 13% were defined as cases at all four assessments, and 46% varied between cases and not cases during the study period. In the repeated cross sectional surveys the estimated rate ratio (RR) for being a case was between 1.1 and 1.5 when comparing the group with job strain and the group without job strain. For the combination of job strain and perceived high physical exertion the estimated RR was between 1.5 and 2.1. When the potential risk factors were assessed one, two, or three years before the assessment of symptoms the estimated RR for becoming a case was between 1.4 and 2.2 when comparing the group with job strain and the group without job strain. CONCLUSION: Almost half of the healthcare workers varied between being a case and not, over a three year period. The analysis indicated that job strain is a risk factor for musculoskeletal symptoms and that the risk is higher when it is combined with perceived high physical exertion.