Cr(VI) reduction into Cr(III) as a mechanism to explain the low sensitivity of Vibrio fischeri bioassay to detect chromium pollution

Vibrio fischeri bacteria, used as a biological target in either acute or chronic toxicity tests, display a low sensitivity to Cr(VI). This phenomenon could be due to the capacity of these bacteria to reduce Cr(VI) into Cr(III). This reducing capacity was found to depend on culture medium composition, pH value, incubation time and the presence of a carbon source. It also depends on the nature of the carbon source, glucose being more efficient than glycerol. This is probably related to differences in bacterial metabolism when given either glucose or glycerol. The thermostable Cr(VI)-reducing activity found in the supernatants of V. fischeri cultures grown on glucose suggests that, under these conditions, the bacteria release non-proteic reducing substances which have not been identified yet.     

Ecotoxicity, phytotoxicity and extractability of heavy metals from different stabilised sewage sludges

The presence of heavy metals in the sludges produced in wastewater treatment plants restricts their use for agricultural purposes. This study compares different types of sludges (aerobic, anaerobic, unstabilised and sludge from a waste stabilisation pond) in order to assess the extractability of heavy metals using simple extraction, water and DTPA. The stabilisation treatment undergone by the sludges influenced the heavy metals extractability. The least mineralised sludges (unstabilised and aerobic) showed higher metal extractability. The sewage sludges were subjected to chemical characterisation and toxicity testing (ecotoxicity and phytotoxicity assays) in absence of substrate, to provide a preliminary assessment of their suitability for land application. The ecotoxicity assays confirmed that no sludge constituted a hazardous waste. The sludge extracts had significant adverse effect on the germination index (GI) of barley (Hordeum vulgare L.) and cress (Lepidium sativum L.), a fact which indicates that some characteristics affected root growth.     

Report: New guidelines for characterization of municipal solid waste: the Portuguese case

This report proposes a new set of guidelines for the characterization of municipal solid waste. It is based on an analysis of reference methodologies, used internationally, and a case study of Valorsul (a company that handles recovery and treatment of solid waste in the North Lisbon Metropolitan Area). In particular, the suggested guidelines present a new definition of the waste to be analysed, change the sampling unit and establish statistical standards for the results obtained. In these new guidelines, the sampling level is the waste collection vehicle and contamination and moisture are taken into consideration. Finally, focus is on the quality of the resulting data, which is essential for comparability of data between countries. These new guidelines may also be applicable outside Portugal because the methodology includes, besides municipal mixed waste, separately collected fractions of municipal waste. They are a response to the need for information concerning Portugal (e.g. Eurostat or OECD inquiries) and follow European Union municipal solid waste management policies (e.g. packaging waste recovery and recycling targets and the reduction of biodegradable waste going to landfill).     

The role of human capital,motivation and supervisor sponsorship in predicting career success

Based on Turner's (1960) contest‐ and sponsored‐mobility systems, a comprehensive model of the determinants of career success was examined. Human capital and motivational variables represented the contest‐mobility system whereas leader–member exchange and supervisor career mentoring represented the sponsored‐mobility system. Results based on data from 245 supervisor–subordinate dyads indicated limited support for the contest‐mobility system and strong support for the sponsored‐mobility system. Interestingly, the two forms of sponsorship were differentially related to career outcomes. Specifically, leader–member exchange was positively related to salary progression, promotability, and career satisfaction. Career mentoring, however, was only related to promotability. Copyright © 1999 John Wiley & Sons, Ltd.     

Symptomatic profile and health‐related quality of life of persons affected by the Prestige catastrophe

This study analyses the impact of the Prestige oil spill on the mental health and the perception of physical health and functional capacity in the affected population. The sample comprised 926 residents from the section of the Spanish coast affected by the oil spill. The data was collected slightly more than one year after the accident. Scales referring to clinical symptoms (SCL‐36) and health‐related quality of life (SF‐36) were administered. The results suggest that individuals with higher degrees of exposure or residing in areas closest to the spill show lower levels of mental health in comparison to those with lower levels of exposure or living in areas farther away from the spill. This study also finds that women and fishermen tend to suffer more from the consequences of these types of disaster.     

Modified CDKN2B (p15) and CDKN2A (p16) DNA methylation profiles in urban pesticide applicators

Environmental Science and Pollution Research - Gene-specific changes in DNA methylation by pesticides in occupationally exposed populations have not been studied extensively. Of particular concern...