BISPHENOL A AND NONYLPHENOL TRANSFER TO VEGETABLES CULTIVATED ON CONTAMINATED SOIL

A research program, financed by the Italian Ministry of Education, University and Research, started early 2013 to investigate the occurrence and fate of selected emerging contaminants in soil, water, sediments and food in Italy, in order to assess health risks and to develop control measures. Bisphenol A (BPA) and Nonylphenol (NP) are both emerging pollutants listed as endocrine disrupters, for which diet seems the major exposure route for humans. In this specific work, the transfer of BPA and NP 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 BPA or 4-NP and in pots with uncontaminated soil (blank pots). After filling (time T0), the pots were located in greenhouses, daily monitored and periodically watered. Lettuce was cultivated for about 55 d (T1). Tomatoes were collected at different times (T1 = 52 d, T2 = 66 d, T3 = 79 d and T4 = 89 d) due to the different ripening time of the fruits. Soil samples were also collected, by coring the soil next to the plants. Commercial pre-washed lettuce, raw lettuce and tomatoes from conventional farming and organic farming were also bought at a local store and analyzed for BPA and 4-NP quantification. Contamination of soil with BPA resulted in a very rapid (2 days) degradation of this contaminant and the production of two byproducts (p-HBA and p-HAP). No BPA was found at all sampling times in the vegetables from either the blank pots or the BPA pots. p-HBA was found at high concentrations in the vegetables from the contaminated pots; the concentration in the lettuce produced in the experiment was higher than in the commercial samples. Though p-HAP was found in some soil samples from the contaminated pots, it was never found in the vegetables. As for 4-NP pots, a huge decrease in 4-NP concentration occurred in the contaminated soils between T0 and T1. Vegetables from the contaminated pots had high 4-NP concentrations. p-Cresol was the most frequently detected byproduct, which was found in the vegetables from the contaminated pots at concentrations higher than in the commercial samples. Phenol was found in the tomatoes from the contaminated pot, at concentrations higher than in the commercial tomatoes.