Effects of aluminium water treatment residuals, used as a soil amendment to control phosphorus mobility in agricultural soils

Phosphorus (P) leaching from agricultural soils is a serious environmental concern. Application of aluminium water treatment residuals (Al-WTRs) at a rate of 20 Mg ha(-1) to clay soils from central Sweden significantly increased mean topsoil P sorption index (PSI) from 4.6 to 5.5 μmol kg(-1) soil. Mean degree of P saturation in ammonium lactate extract (DPS-AL) significantly decreased from 17 to 13%, as did plant-available P (P-AL). Concentrations of dissolved reactive P (DRP) decreased by 10-85% in leaching water with Al-WTR treatments after exposure of topsoil lysimeters to simulated rain. Soil aggregate stability (AgS) for 15 test soils rarely improved. Three soils (clay loam, silty loam and loam sand) were tested in greenhouse pot experiments. Aluminium-WTR application of 15 or 30 ton ha(-1) to loam sand and a clay loam with P-AL values of 80-100 mg kg(-1) soil significantly increased growth of Italian ryegrass when fertilised with P but did not significantly affect growth of spring barley on any soil. Al-WTR should only be applied to soils with high P fertility where improved crop production is not required.     

A statistical human resources costing and accounting model for analysing the economic effects of an intervention at a workplace

The study had two primary aims. The first aim was to combine a human resources costing and accounting approach (HRCA) with a quantitative statistical approach in order to get an integrated model. The second aim was to apply this integrated model in a quasi-experimental study in order to investigate whether preventive intervention affected sickness absence costs at the company level. The intervention studied contained occupational organizational measures, competence development, physical and psychosocial working environmental measures and individual and rehabilitation measures on both an individual and a group basis. The study is a quasi-experimental design with a non-randomized control group. Both groups involved cleaning jobs at predominantly female workplaces. The study plan involved carrying out before and after studies on both groups. The study included only those who were at the same workplace during the whole of the study period. In the HRCA model used here, the cost of sickness absence is the net difference between the costs, in the form of the value of the loss of production and the administrative cost, and the benefits in the form of lower labour costs. According to the HRCA model, the intervention used counteracted a rise in sickness absence costs at the company level, giving an average net effect of 266.5 Euros per person (full-time working) during an 8-month period. Using an analogue statistical analysis on the whole of the material, the contribution of the intervention counteracted a rise in sickness absence costs at the company level giving an average net effect of 283.2 Euros. Using a statistical method it was possible to study the regression coefficients in sub-groups and calculate the p-values for these coefficients; in the younger group the intervention gave a calculated net contribution of 605.6 Euros with a p-value of 0.073, while the intervention net contribution in the older group had a very high p-value. Using the statistical model it was also possible to study contributions of other variables and interactions. This study established that the HRCA model and the integrated model produced approximately the same monetary outcomes. The integrated model, however, allowed a deeper understanding of the various possible relationships and quantified the results with confidence intervals.     

Some Effects of Transit Gamma Radiation on Transistors

As a part of a study of nuclear radiation effects on shipboard electronic equipment, a large number of commonly used transistor types have been irradiated in similated transit radiation fields. A wide range was observed in the amount of radiation induced effects on gain and reverse leakage current, even within a group of one type of transistor. In general, only temporary changes were observed, with silicon types exhibiting smaller changes than the germanium units. For germanium types, reverse leakage current changed by a factor of 10-20 for some units while gain changed by a factor of 2 or less, with the change persisting in some types.     

Cadmium exposure pathways in a population living near a battery plant

OBJECTIVES: The objectives of the present study were to assess the relative impact of different pathways of environmental cadmium (Cd) exposure and to evaluate the contribution from locally produced vegetables and root crops to the total dietary intake of Cd. METHODS: Cadmium in urine was determined for 492 individuals living near a closed down battery factory in Sweden. For each individual we created an environmental exposure-index based on Cd emissions to ambient air and number of years living at various distances from the plant. This information as well as dietary data were collected via questionnaires. Samples of soil, carrots and/or potatoes were collected from 37 gardens and analysed for Cd concentration. RESULTS: Eating home grown vegetables/potatoes, environmental Cd-exposure-index, female gender, age above 30 years and smoking more than one pack of cigarettes daily for at least 10 years were found to be significantly associated with increased urine concentrations of Cd (UCd>1.0 nmol/mmol creatinine). We found a statistically significant relation between Cd in urine and environmental Cd-exposure-index in persons eating home grown vegetables/potatoes regularly. Cd concentrations in home grown carrots, potatoes and in garden soil were highest in the area closest to the factory. Daily consumption of potatoes and vegetables cultivated in the vicinity of the closed battery factory was estimated to increase Cd intake by 18-38%. CONCLUSION: The present study shows that consumption of locally grown vegetables and root crops was an important exposure pathway, in subjects living near a nickel-cadmium battery plant, whereas direct exposure via ambient air was less important.