Adami G, Siviero P, Barbieri P, Piselli S, Reisenhofer E
Department of Chemical Sciences, University of Trieste, Via Giorgieri 1, 34127 Trieste, Italy.
Ann Chim. 2001 Sep-Oct;91(9-10):531-40.
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.
弗留利南部的地下水不仅在地表层，而且在150米以下的深层都含有高浓度的农业污染物，如硝酸盐和三嗪类除草剂。对戈纳尔斯地区的一些水井进行了监测。所检测的水既用于灌溉也用于饮用，由于农业活动和众多垃圾处理场的存在，面临环境风险。在三个不同降雨条件时期，从四口井采集的样本中测量了重金属、硝酸盐和三嗪类除草剂。我们发现，地下水质量主要受农业活动影响：硝酸盐和三嗪类物质的含量非常接近甚至超过了意大利法律允许的最大浓度。所有采样点的这些农业污染物含量相似：干旱期和降雨期之间未检测到差异。在所有情况下，重金属含量均可忽略不计；这一事实表明，土壤的离子交换、吸附和络合特性阻碍了金属渗滤液进入下层地下水。锌是个例外；其含量接近或超过最大允许浓度（CMA），且在降雨期观察到的含量最高；不同地点的锌含量不同，表明这种金属可能有多种点源。所有地点的硝酸盐肥料含量相似，非常接近CMA（50毫克/升）。三嗪类是用于玉米种植的特定除草剂，在这里广泛使用：近年来意大利法律已禁止使用，但母体三嗪及其代谢物在地下水中的存在是该地区一个持续存在的问题。意大利法律规定阿特拉津和去乙基阿特拉津总量的CMA为0.10微克/升，但我们发现所有地点仅去乙基阿特拉津本身就大大超过了CMA。
