Case study of groundwater pollution in a critical area of the Southern-Friuli exposed to agricultural and landfill pressures.
Groundwater of the Southern-Friuli displays high levels of agricultural pollutants, such as nitrates and triazinic herbicides not only in the surficial layers, but also in the deeper ones, below 150 m. Some wells of the district of Gonars was monitored. The examined waters, used for irrigation but also for drinkable use, are exposed to environmental risk due to both agricultural practices and presence of many waste disposal sites. Heavy metals, nitrates and triazinic herbicides were measured in samples taken at four wells in three periods having different rain conditions. We found that groundwater quality is affected mainly by agricultural practices: nitrates and triazines are present at levels very near as well as superior to the maximum concentration allowable by Italian law. These agricultural contaminants have similar levels at all sampled sites: no difference was detected between dry periods and rain ones. Heavy metal contents are negligible in all cases; this fact suggests that ion-exchange, sorbing and complexing properties of the soils hinder the way of the metal leachates towards underlying groundwater. Zinc constitutes an exception; it is found at levels near or superior to the maximum allowable concentration (CMA), and the highest contents are observed in rain periods; different sites display different zinc levels, suggesting that this metal could have various point sources. Nitrates fertilisers were found in all sites at similar levels, very near to CMA (50 mg/L). Triazines are specific herbicides for corn growing, highly diffused here: their use in recent years is forbidden by Italian law, but the presence in groundwater of parent triazines and metabolites is a persistent problem of this area. The Italian law indicates a CMA of 0.10 microgram/L for the sum of atrazine and desethylatrazine, but we found that desethylatrazine by itself exceeds largely CMA in all sites.
Adami
G
G
Department of Chemical Sciences, University of Trieste, Via Giorgieri 1, 34127 Trieste, Italy. adami@dsch.univ.trieste.it
Siviero
P
P
Barbieri
P
P
Piselli
S
S
Reisenhofer
E
E
D000383:Agriculture; D004784:Environmental Monitoring; D006540:Herbicides / Q000032:analysis; D006801:Humans; D007558:Italy; D019216:Metals, Heavy / Q000032:analysis; D011634:Public Health; D011640:Public Policy; D011891:Rain; D012037:Refuse Disposal; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis*; D014227:Triazines; D014872:Water Movements; D014873:Water Pollutants / Q000032:analysis*; D014881:Water Supply
D006540:Herbicides; D019216:Metals, Heavy; D012989:Soil Pollutants; D014227:Triazines; D014873:Water Pollutants