Ecotoxicological evaluation of cork-boiling wastewaters

Toxicity tests with Vibrio fischeri, Daphnia magna, and Lemna minor were used to evaluate acute and chronic toxicity of cork-boiling wastewaters and correlation analysis was performed with physicochemical parameters. Acute toxicity values (EC(50)) ranged from 2.3% to 24.2% in the Microtox test and from 4.4% to 29.5% in the Daphnia test. According to these values, 78% of the samples were classified as acutely toxic to the most sensitive species (V. fischeri). Significant correlation was obtained between EC(50) and chemical oxygen demand, biochemical oxygen demand after 5 days, total organic carbon, tannin and lignin and total solids. No significant correlation was found between the two acute tests. The D. magna chronic test showed significant differences between all tested concentrations and the control, with an EC(50) of 0.32%. An EC(50) value of 26.0% was calculated for L. minor. For the analysis of cork-boiling wastewater toxicity and routine biomonitoring, the use of the Microtox test is suggested, to afford greater environmental protection.

Ecotoxicological monitoring of remediation in a coke oven soil

Assessment of contaminated sites is usually based on chemical analyses of hazardous compounds in soil. This is enough either to assess the environmental hazard of contaminated soil nor to evaluate the efficiency of applied remediation techniques. Information on the bioavailability of complex mixtures of xenobiotics and degradation products cannot be provided by chemical analytical data, but results from bioassays can integrate the effects of pollutants in mixtures. In the preservation of human health and environmental quality, it is important to evaluate ecotoxicological effects of contaminated industrial soils to complement the techniques of analytical chemistry. The monitoring of a coke oven soil and the evaluation of the landfarming treatment technique, conducted on-site in a pilot scale installation, was done by a battery of ecotoxicological tests: acute, chronic, and genotoxicity tests. Contaminated soil samples revealed toxic effects for different species mainly due to high concentrations of polycyclic aromatic hydrocarbons (PAHs). After landfarming treatment, soil samples presented significant reduction in toxicity, confirming the effectiveness of the landfarming process pointed out by a significant reduction in low molecular weight PAH concentrations. Comparative analysis of the different ecotoxicological tests allowed the establishment and validation of a more suitable procedure for the monitoring of PAH contaminated soils.

Landfarming in a PAH-contaminated soil

The present work describes a coke oven soil treatability study by land-farming, conducted on-site in a field scale facility covering 100 m2. The soil contamination was mainly due to high concentrations of polynuclear aromatic hydrocarbons (PAHs) up to 1,140 mg/Kg dry weight (sigma EPA). Along the treatment process the soil was characterised at the chemical, microbiological and ecotoxicological levels. After 3 months a reduction of 63% in total PAHs concentration was observed, being detected a more pronounced reduction for PAHs with 2, 3 and 4 rings (79%). Concomitantly, a change in the composition of the microbial population was observed with a significant increase in the PAHs degrading and total heterotrophic colonies. Concerning the ecotoxicity and genotoxicity data no effect was detected in the treated soil samples eluates.

Unintentional fatal paraquat poisonings among agricultural workers in Costa Rica: report of 15 cases

This study analyzes the exposure circumstances of 15 fatal occupational paraquat poisonings. To evaluate the potential danger of dermal absorption and the amount needed to produce a fatal outcome in the event of oral intake, we reviewed the medical records and autopsy protocols and interviewed relatives. Five fatalities were due to ingestion of a mouthful of paraquat concentrate, and five to intake of a smaller amount; three cases were associated with dermal exposure, and in two, there was no evidence of either oral or dermal exposure. Several cases concerned diluted paraquat spray. The clinical and pathomorphological findings, including a "blinded" evaluation of lung slides, were consistent with paraquat poisoning in all cases. Difficulties in establishing the diagnosis and recognizing the exposure were identified, as well as classification of unintentional poisonings as suicides at autopsy. The findings suggest that paraquat may cause fatal poisonings by ingestion of small amounts, by dermal absorption of diluted paraquat, and possibly by inhalation. More conclusive studies are warranted.

Nurse, haemodialysis, patient: is our caring based within a helping relationship?

Due to our experience in haemodialysis (HD) we became interested in evaluating the quality of care given during HD treatment. In May 1994, we conducted a cross sectional survey comparing the assessment of the total interaction between nurses and haemodialysis patients in a Lisbon dialysis facility. Our purpose was to identify nurses' and patients' opinion on the total interaction established during the dialysis treatment among both groups.