Transfer of Benzophenones from Soil to Plants

Benzophenones (BPs) include different compounds whose molecular structure is based on diphenyl ketone (benzophenone, BP). Some benzophenones have been reported to have estrogenic activity and some compounds have been classified as possibly carcinogenic to humans. Specific studies should be carried out about possible pollution of soils due to the use of biosolids and/or treated wastewater in agriculture practices, in particular to understand the transport of BPs to the edible parts of plants and risk for humans due to their consumption. In this work, the transfer of BP and BP-3 to edible vegetables cultivated on polluted soil was investigated. Lettuce and tomatoes were selected due to their high worldwide per capita consumption rates. Plants were cultivated in pots filled with agricultural soil artificially contaminated with BP or BP-3 and in pots with uncontaminated soil (blank pots). At the beginning of tests (time T0) three soil samples from each pot were collected and analyzed. Lettuce was cultivated for about 55 d; at the end of this period (time T1), the edible part of each plant was collected and analyzed. Tomatoes were collected at different times (T1 = 54 d, T2 = 70 d, T3 = 83 d and T4 = 92 d) due to the different ripening time of the fruits; in the BP-3 pot, tomatoes could be collected only at time T3 and T4, because no ripe fruits were available before. Soil samples were also collected at the different times, by coring the soil next to the lettuce plant roots or the plants from which tomatoes had been grabbed. Commercial pre-washed lettuce, raw lettuce and tomatoes from conventional farming and organic farming were also bought at a local store and analyzed. BP concentrations in the contaminated soils remained constant over time except for the tomato pot from time T3, while BP-3 concentrations decreased over time. As for the vegetables, BP (at T2) and BP-3 (at T3 and T4) in tomatoes were higher than in the Blank. BP and BP-3 concentrations found in the vegetables cultivated in this study were similar to those measured in the commercial vegetables, except for BP-3 in tomatoes at T3.