Hellenic karst waters: geogenic and anthropogenic processes affecting their geochemistry and quality

Karst hydrosystems represent one of the largest global drinking water resources, but they are extremely vulnerable to pollution. Climate change, high population density, intensive industrial, and agricultural activities are the principal causes of deterioration, both in terms of quality and quantity, of these resources. Samples from 172 natural karst springs were collected in the whole territory of Greece. To identify any geogenic contamination and/or anthropogenic pollution, analyses of their chemical compositions, in terms of major ions and trace elements, were performed and compared to the EU limits for drinking water. Based on chloride content, the collected karst springs were divided into two groups: low-chloride (< 100 mg L− 1) and high-chloride content (> 100 mg L− 1). An additional group of springs with calcium-sulfate composition was recognised. Nitrate concentrations were always below the EU limit (50 mg L− 1), although some springs presented elevated concentrations. High contents in terms of trace elements, such as B, Sr, As, and Pb, sometimes exceeding the limits, were rarely found. The Greek karst waters can still be considered a good quality resource both for human consumption and for agriculture. The main issues derive from seawater intrusion in the aquifers along the coasts. Moreover, the main anthropogenic pollutant is nitrate, found in higher concentrations mostly in the same coastal areas where human activities are concentrated. Finally, high levels of potentially harmful trace elements (e.g. As, Se) are very limited and of natural origin (geothermal activity, ore deposits, etc.)

Neurotoxic metabolites of "commercial hexane" in the urine of shoe factory workers

Urinary metabolites were tested in 41 shoe-factory workers exposed to a mixture of 10 solvents among which "commercial hexane" was the prevailing component. Cyclohexanol, 2-methyl-2-pentanol, 3-methyl-2-pentanol, and trichloroethanol were determined in connection with exposure to cyclohexane, 2-methylpentane, 3-methylpentane, and trichloroethylene, respectively. 2-Hexanol, 2,5-hexanedione, 2,5-dimethylfuran, and gamma-valerolactone were all determined in connection with n-hexane exposure only. 2,5-Hexanedione was the principal n-hexane metabolite found in the workers' urine. This finding of the experimentally proven neurotoxin 2,5-hexanedione in the urine of shoe-factory workers exposed to "commercial hexane" is consistent with the idea that this compound is responsible for the development of neuropathy in this group of individuals

N-N-dimethylformamide concentration in environmental and alveolar air in an artificial leather factory.

N-N-Dimethylformamide was determined every hour during the eight hours of the work shift in the alveolar air of eight workers employed in an artificial leather factory and in the breathing zone of the eight workers. The alveolar ventilation of each worker was measured for 10 minutes during the work shift. Alveolar dimethylformamide concentration (Ca) was correlated with the environmental concentration (Ci) in six of the eight workers. The amount of dimethylformamide retained per litre of ventilated air, calculated as the difference (Ci - Ca), was correlated with environmental concentration in seven of the eight workers. Lung uptake of dimethylformamide per minute was correlated with environmental concentration in all eight workers. The ratios between alveolar and environmental concentration (Ca/Ci x 100) and the lung retention of dimethylformamide, calculated by the formula (1 - Ca/Ci) x 100, were 27.8% and 72.2% respectively. They did not show any correlation with environmental concentration, exposure time, or alveolar ventilation