The effect of irrigation of pickling cucumber with urban wastewater on product quality and heavy metal accumulation

Abstract

Pickled cucumber is one of the vegetables that needs water frequently during its cultivation and is processed and evaluated, and it is consumed high all over the world. In arid and semi-arid regions, wastewater is commonly used for vegetables and forage crop irrigation. In this study, a comparative field study was carried out using untreated wastewater (U), treated wastewater (T), and tap water for control (C) irrigation for the growing of cucumber pickled plants. Plant phenological and some growth parameters, fruit quality parameters, fruit, and leaf color, photosynthetic pigments, phenolic compound, vitamin C and heavy metal (HM) contents (Cr, Ni, Cd, Pb, Cu) in different parts of the plant were defined. In addition, crop productivity was measured by the means of fruit weight and diameter, and length. The results show that plant length and yield of pickling cucumbers increased by 40.90% in U, and 4.39% in T. The plants in U applications were started to harvest 5 days ago when compared with the others. On a positive note, U led to an increase in vitamin C levels and phenolic compounds. Collectively, the data suggest that U can help add value to pickling cucumber by increasing its antioxidant activity as compared to other irrigation water sources. The accumulation in the leaves was Ni > Cr > Cu > Pb > Cd, respectively. Based on the results, this study concludes that it is possible to use wastewater for cucumber irrigation. Since the edible parts of pickling cucumber are consumed after processing, they do not pose a risk to public health. This study may provide a basis for application of using untreated wastewater in high quality cucumber production.