Abstract

Fadoua El- Makhoukhi^{1, 2}, Abdelmalek Dahchour², Fatiha Bentata³, Ilyass Maafa⁴ and Mohamed Alaoui El-Belguiti¹

DOI : http://dx.doi.org/10.13005/ojc/330347

The reuse of treated wastewater (TWW) is considered as one of the alternative solutions to limit the shortage and preserve the natural resource. The water potential in Morocco is estimated at 22 billion m3 per year, equivalent to 700 m3 / inhabitant / year. This quantity of water could fall to 500 m3 by 2030 under the pressure, in particular, of climate change and population growth. Irrigation with TWW has been shown to be beneficial in terms of stabilizing soil structure, enriching mineral nutrients for crops and increasing production. However, the use of TWW may coincide with the presence of pollutants such as pesticides and heavy metals in the soil. This situation can improve or reduce the transfer of pollutants to groundwater. Fenoxayprop ethyl (FPE) is an herbicide commonly used to control annual grasses and perennials in cereals. Published result on its behavior in the environment are controversial, varying from enhancement and reduction of its mobility. Mobility test of FPE was carried out in the Gharb region which is an important agricultural zone in Morocco known for its sandy and clayey soil. The mobility assessment was done by a bioassay based on the growth of barley seeds. This test was carried out in PVC columns 30 cm in length and 7.5 cm in diameter. Each column is composed of 6 sections of 5 cm height. 300 g of air-dried and sieved (2mm) soil was introduced into each column.  Muslin tissue was attached to the bottom of the column to retain the soil. The herbicide was applied on the top of each column. Three columns were used for the test. One column was eluted with distilled water and used as a control. The other columns were irrigated with TWW at a flow rate of 1.5 ml / min. The residue of the herbicide was analyzed in the percolated water and sections of the columns. The results show a marked increase in soil conductivity and a slight decrease in pH. Residue analysis showed that the movement of the herbicide increased in the percolated column with the wastewater compared to the control and moved from section 1 to section 6 in the TWW leached column. This may be due to the leaching of the herbicide in adsorbed form by the organic matter of the waste water. No residues were detected in the percolated water from all treated columns and from the control.

bioassay; fenoxayprop-ethyl; herbicide; mobility; wastewater

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