Heavy metals in Palestinian Agriculture (HEMiPA): A pilot study in the Jenin Governorate

Swiss partners
-
ETH Zürich: Matthias Wiggenhauser (main applicant)
Partners in the MENA region
- Al-Quds Open University, Palestine: Aziz Salameh (main applicant)
- National Agricultural Research Centre NARC, Palestine: Zaher Barghhouti
Other partners
- John Innes Institute Norwich, United Kingdom: Lukas Kronenberg
Presentation of the projet
In many agricultural systems, heavy metals are inadvertently applied to soils, thereby potentially impairing the quality of soils, freshwater, and crops. While Switzerland has a tight-knit soil data base that has identified major heavy metal inputs into agroecosystems, there is no such risk assessment data for the Occupied Palestinian Territory. For this project, we aimed to assess the risk of heavy metal fluxes by identifying major sources, pathways, and soil mass balances of heavy metals in Palestinian agroecosystems. To this end, we sampled soil, crop (wheat, squash, olives), fertilizer, and irrigation water samples in 40 farms of the region of Jenin in spring/summer 2023. In addition, data on soil fertilization and management practices were collected. The samples were shipped to ETH Zurich, processed, and analyzed for heavy metals such as zinc, copper, cadmium, uranium, and nickel.
Heavy metal analyses (As, Cd, Cr, Cu, Fe, Mn, Ni, Zn, Tl, Pb, U) in the fruits revealed that none of the fruit samples (i.e. edible plant parts) exceeded critical threshold set by the FAO/WHO or by comparing with literature data. This indicates that current heavy metals levels in the crops are generally not concerning within the sampling region. This observation corresponded with soil analyses that revealed that for almost all soils, the heavy metals were present, but not at harmful concentrations. With the data available, we semi-quantitatively modelled typical soil mass balances for the different heavy metals. Such mass balances allow to asses if the current agricultural practices are ecologically sustainable. Exemplified for cadmium (Cd), a very toxic and mobile element in soilcrop systems, the soil mass balance showed that with the current agricultural practice, Cd has a tendency accumulate in the soils. The main driver of the accumulation is mineral phosphorus fertilizer that contains high concentrations of Cd and also irrigation water. In the latter, the Cd concentration was low, but the high application rates lead to a high input of Cd. Based on our outcomes, we can recommend that farmers strive towards low mineral phosphorus fertilizer inputs, in best case with mineral phosphorus fertilizer that contain little quantities of Cd. In addition, we further recommend to dosage irrigation to the minimum level required to avoid Cd accumulation.
Building up on this report, the project team will submit a manuscript to a peer-reviewed open-access journal. Initially, it was planned to present the results and discuss the agricultural consequences of them with agricultural stakeholders in a work-shop. Since the escalating conflict in the region does not allow such as work-shop, we will provide a poster that includes results and our recommendations regarding agricultural practices and will disseminate it via the social media channels of the National Agricultural Research Centre in Palestine. Finally, based on the successful generation of the results under challenging conditions as well as the fruitful two-way exchanges and visits of both partners, a follow-up project idea has already set-up that focuses on pollutant and nutrient fluxes in irrigated date-palm systems in the region of Jericho. This research idea will be further developed and submitted for funding as soon as the conflicts reduces the risks on a successful implementation on research with field work onsite.