Occurrence and fate of phthalates in soil and plants

Abstract

Phthalate concentrations (di-(2-ethylhexyl)phthalate, dibutylphthalate and butylbenzylphthalate) were measured in the neighbourhood of phthalate-emitting plants and in unpolluted areas in soil and maize. Special emphasis was given to differentiate between deposition and contamination via the soil-root pathway. Therefore the environmental analysis program was extended by model experiments. Plots were fertilized with phthalate-containing sewage sludge prior to the cultivation of maize, oats and potatoes. In another experiment plants were exposed to phthalate-treated dust. Degradation and uptake by plants of the three phthalates were studied. The results show that phthalates are general air contaminants and can be found in unpolluted areas, too. The concentrations ranged from background levels to peak values of 490 mg/kg for DEHP and 560 mg/kg for DBP in soil and 20 ppm DBP in plants. The model experiments suggest that surface accumulation of phthalates in plants and transport of the substances into other parts of the plants was not detectable. Uptake of phthalates via the soil path was not detected, either. The results confirm that the accumulation of airborne phthalates in plant cuticles may be an important path, whereas the bioavailability of phthalates in soil and from leaves can be ignored.