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Potentially toxic elements are widespread soil contaminants, whose occurrence could entail a concern for human health upon ingestion of fruit and vegetables harvested in a polluted area. This work set out to evaluate the concentrations of lead and cadmium as well as the levels of thirteen heavy metals for which a limit value is yet to be established by the food safety authorities, in order to perform a risk characterization related to the dietary intake of these metals and to provide a scientific opinion with wider relevance in the light of current worldwide regulatory issues. The sampling consisted of fruit and vegetables grown in a potentially contaminated area of southern Italy due to the illegal dump of hazardous wastes. An evaluation of the dietary exposure through the calculation of the Hazard Index (HI), the Maximum Cumulative Ratio (MCR) and the Target Cancer Risk (TCR) was adopted to this end. The results revealed that about the 30% of samples showed quantifiable levels of chemicals and no significant difference emerged between the potentially polluted area and the nearby cities that were selected as a control landfill site. The overall risk characterization for non-carcinogenic endpoints showed that the HI did not reach unsafe values, except for a small number of samples mainly because of aberrant occurrences and, in any case, the cumulative toxicity was mainly driven by thallium and vanadium. As far as the carcinogenic effects of arsenic are concerned, the distribution of TCR values broadly lay below the safety threshold; a certain percentage of data, however, exceeded this limit and should be taken into account for the enforcement of future regulatory thresholds.

Two clones of white clover (Trifolium repens L.) differing in ozone tolerance were grown in southern Italy during 1997 and 1998 to study the effects of ambient ozone exposure on yield, leaf morphology and water use. Ambient ozone levels were high in both years with values exceeding the threshold for leaf injury reported in the literature. In both years ozone injury was observed on the sensitive clone (NC-S) but not on the resistant one (NC-R), and leaf and stolon dry matter production was significantly lower in NC-S than in NC-R. However, it cannot be excluded that other factors, such as high temperature, interacted with the effect of ozone on biomass production. The clones differed in morphological characteristics. Lower total leaf area in NC-S plants was due to a smaller number of leaves per plant, but the average area per leaf was higher in NC-S. Specific leaf weight and net assimilation rate were higher in the more productive clone (NC-R). Cumulative plant water use was higher in NC-R in each growth period because of the larger leaf area; by contrast, water use per unit leaf area was higher in NC-S, indicating higher leaf conductance to water vapour. The results suggest that ozone significantly reduces the yield of sensitive white clover plants under well-watered conditions, and that the difference in ozone tolerance between clover clones is related to differences in leaf morphology and water use.