Assessing the Impact of Treated Wastewater Irrigation on Citrus Fruit Quality: Nutritional, Heavy Metal, and Phytochemical Analyses

Abstract

Amidst escalating global water scarcity and mounting pressures on freshwater resources, this study explores the viability of utilizing treated wastewater for citrus irrigation. Heavy metal analysis of the treated wastewater demonstrates that cadmium (Cd) levels are comfortably below the recommended limit of 0.05 mg/l, ensuring safe agricultural use. Comparative analysis of citrus fruits irrigated with treated wastewater versus freshwater reveals quantitative insights. Citrus fruits irrigated with treated wastewater exhibit a decline in dry matter, with a significant reduction in vitamin C concentration from 53.23 mg/L to 25.15 mg/L. Conversely, these fruits show higher sugar (glucose) levels, which increase from 2.3 g/100g to 2.9 g/100g, potentially enhancing taste and sweetness. Furthermore, the study reveals a remarkable increase in polyphenol content, rising from 81.2 mg GAE/g to 275.64 mg GAE/g, suggesting a stress-induced phytochemical response. However, the flavonoid levels exhibit a contrasting trend, decreasing from 7.74 mg Eq QE/g to 4.23 mg Eq QE/g. These quantitative findings underscore the importance of careful management of treated wastewater quality for irrigation, balancing the potential benefits of improved taste and enhanced polyphenols against the reduction in vitamin C and flavonoids. This research contributes essential numeric data to the discourse on sustainable agricultural practices and water resource management, addressing global water scarcity challenges while safeguarding citrus fruit quality.