Assessment of the impact of irrigation with treated wastewater at different dilutions on growth, quality parameters and contamination transfer in strawberry fruits and soil: Health risk assessment

Industrial treated wastewater (TWW) could be an attractive alternative fto fresh water use in agriculture due to the shortage in water resource especially in the Mediterranean region. Furthermore, TWW could represent an efficient substitute for crop production thanks to its high load in nutrient. However, its high content of salts or mineral as well as organic pollutants can affect the crop safety, productivity and growth. A simple way to reduce the amount of chloride and salinity could be the dilution. In this study the irrigation of strawberry (Fragaria x ananassa cv Camarosa) using diluted TWW at three dilution ratios; D60 (40% TWW) D40 and D20 was performed and compared with the well water (WW) used as control. The use of TWW for the irrigation of strawberry plants was done for the first time in the city of Sfax located in the southeast of Tunisia. D20 registered the lowest strawberry yield and highest heavy metal contents in fruits compared to the other dilutions. Also, this dilution showed a toxic effect of high accumulation of chlorine, salts and metals by the apparition of brown edges in the leaves. However, D60 recorded the lowest soil salinity, the high plant growth and strawberry yield compared to the WW irrigated plants and showed lowest metal contents in soil, plants and fruits compared to other dilutions. Our study suggests the use of 60% diluted TWW for the irrigation of strawberry in order to obtain fruits matching international safety and quality standards.