Of course, to grow crop plants, you need land — and water

In his studies of soil-based pollution, Prof. Benny Chefetz. Photo by Sasson Tiram. Israel is a world leader in the utilization of treated wastewater in agriculture, yet this is not a problem-free solution to Israel’s water shortage: treated water leaves a range of organic pollutants in the soil, including pesticides, herbicides, and even antibiotics.

The first in Israel to identify residual pharmaceutical materials in treated wastewater used for crop irrigation, Prof. Benny Chefetz is studying how this residue gets into groundwater beneath agricultural fields. As the use of treated wastewater in agriculture escalates in Israel, this research is critical both for the development of water treatment methods and for national policy decisions on the use of wastewater, for example limiting use to specific crop plants, or in areas where groundwater cannot be contaminated.

Prof. Chefetz is also examining the uptake of organic pollutants by the plant cuticle, the waxy layer that covers all plant surfaces. While some scientists study the cuticle to elucidate how pesticides enter the foods we eat, Prof. Chefetz is concerned with the fate of these materials in the soil after plant decomposition. In another study, which focuses on soil-based pollution, he is examining Israel’s Kishon river, which flows from Mount Gilboa through the Jezreel Valley and empties into the sea at Haifa Bay — but not before sweeping up large quantities of industrial contaminants from bayside oil refineries, chemical plants and sewage treatment facilities. Looking at oil-based pollution hidden in the river’s underlying sediment, Prof. Chefetz has found that the Kishon riverbed suffers from two types of contamination. Sediment in the upper river is characterized by the particulates of air pollution, the result of incomplete burning of fossil fuels. But the closer one gets to Haifa, the sediment pollution changes, and there are more actual fuel residues.

Devising effective clean-up methods for the Kishon depends on effective cooperation between scientists from different disciplines. In a unique project linking plant sciences, environmental clean-up and profitable high tech, Prof. Chefetz has shown how the plant cuticle can help clean up polluted water — while creating an industrial component by-product that is valued by the electronics and photographic industries. Working together with Faculty colleague Professor Elisha Tel-Or and Professor Aharon Gedanken of Bar-Ilan University, Prof. Chefetz has devised a method in which plant cuticle materials absorb heavy metal ions which can then be transformed into metal nanoparticles using simple, microwave-based techniques. “It’s a cheap and effective strategy,” says Prof. Chefetz, “for turning environmental waste into ‘gold’.”