Disappearance of some pesticides in celery

The control of pesticide residues in Sardinia (Italy) from 1996 to 1999 sho wed that 16.4% of the celery samples exceeded the legal limit. Among the pe sticides used, some exceeded the le gal limit. This study was carried out t o evaluate whether this was due to an incorrect use of the pesticides (e.g. , high doses, non compliance with the preharvest interval), or to improperl y set legal limits. The data reported in this paper agree with those report ed in the literature, and show that use of chlorothalonil (legal limit 10 m g/kg) did not result in irregularities, and that the preharvest interval co uld also be reduced. Because with repeated treatments, anilazine and especi ally ziram could cause serious problems, it would be appropriate to increas e the preharvest interval or their legal limits. The residues of these thre e pesticides were distributed differently in the leaves and in the stem (ed ible part), being considerably less in the latter. In commercial use, the l eaves are partly removed: this shows that the residue data could be signifi cantly affected by the amount of leaves left on the plant, thus the same sa mple could be legal or illegal depending on the amount of leaves removed.