Monitoring of pesticides and heavy metals in cucumber fruits produced from different farming systems

A total of 216 kg of cucumber samples, representing three different types of farming production [e.g., conventional (C), greenhouse (G) and organic (O)], were collected from different locations in Giza governorate (Egypt), and subjected to pesticide residue and heavy metal analyses. Residues of some organochlorine pesticides (OCPs), such as hexachlorobenzene (HCB), heptachlor, aldrin, endrin, dieldrin and o,p′-DDT, as well as organophosphorus pesticides (OPPs), such as chlorpyrifos-methyl, thiometon and phorate were found in a number of samples at concentrations exceeding their MRLs. Lindane was detected in 33.3%, 50.0% and 25.0% of samples from C, G and O cucumber, respectively, without violation.

The insecticide methamidophos showed high frequency in the analyzed samples of C, G and O cucumber accounting to 66.7%, 41.7% and 50.0%, respectively, without violation. The majority of the analyzed samples contained detectable concentrations of Zn, Cu, Mn, Fe, Cd, Pb, Cr, Ni and Co. Only, Pb and Cd were found in a number of samples at concentrations exceeding their MLs. Contamination among the three types of cucumber either by pesticides or heavy metals varied from a season to another. Generally, the greenhouse cucumber contained the highest value of total pesticide residues (1.016 mg kg−1), followed by organic (0.442 mg kg−1) and then conventional (0.415 mg kg−1) cucumbers. Heavy metal contamination in the three cucumber types accounted to 4.968, 5.350 and 6.248 mg kg−1, respectively. The study shed light to the problem of multi toxicants in a food commodity such as cucumber; a common element in the daily human diet.