Phytotoxic effects and environmental risk assessment of petunia hybrida irrigated with reclaimed water from the chip industry

Regeneration and utilization of wastewater in the chip industry is of great significance to reduce water pollution, alleviate water shortage and promote the green development of the chip industry. In order to clarify the phytotoxic effects of reclaimed water from the chip industry on plants, petunia hybrida was used as a model organism to analyze the response characteristics of growth morphology, total protein, chlorophyll, antioxidant system and energy system biomarkers, and to evaluate environmental risks based on the second-generation Integrated Biological Responses version 2 (IBRv2) during irrigation with two types of reclaimed water. The results showed that there was no obvious adverse effect on the growth and morphology of petunia hybrida irrigated with two kinds of reclaimed water. At the middle stage of irrigation (9 days), the total protein and chlorophyll of petunia hybrida were significantly induced, and then the induction was relieved and the inhibition began to appear. At the middle and late stage of irrigation (9-15 days), the antioxidant biomarkers of petunia hybrida were mainly inhibited, but no obvious oxidative damage to petunia hybrida occurred. The response patterns of energy system biomarkers were inconsistent during irrigation. The average values of IBRv2 for the two types of reclaimed water from chip industry were between 0.85 and 1.72, and the environmental risk level was low. However, because the reclaimed water still contained high concentrations of chloride ion and total dissolved solids (TDSs), the sensitive biomarker combination of glutamate dehydrogenase, pyruvate kinase, malondialdehyde (MDA) or superoxide dismutase, MDA could be selected to monitor and control the environmental risk. It was recommended to further research and develop the treatment process which could effectively reduce the concentration of chloride ion and TDS in the reclaimed water of chip industry, so as to ensure the ecological environment safety of the reclaimed water for green irrigation.