Abstract
Wastewater (WW) produced from different activities can be a useful resource or an environmental issue depending on its use. If used properly, WW can be a good source of irrigation/nutrients for plants. Otherwise, it may endure environmental/plant health issues due to the presence of pollutants. Mixing of WW with freshwaters can dilute pollutant concentration and thereby their toxic effects. This study evaluated WW toxicity to plant health by mixing it with canal water (CW) or tube-well water (TW). Results indicated that mixing of CW with three types of WWs (collected from three different areas), overall increased H2O2 contents by 61% and 25%, while TW mixing increased H2O2 contents by 4% and 25%, respectively in cabbage and maize roots. However, CW and TW mixing with WWs decreased H2O2 contents by 13% and 2% in cabbage shoot, while increased by 4% and 22% in maize shoot, respectively. In case of lipid peroxidation (LPO), TW mixing caused a decreased, while CW mixing caused an increased in root and shoot tissues of both the crops. Moreover, mixed treatments overall decreased Chl-a + b contents by 20% in cabbage, but increased by 2% in maize. Conclusively, the effects of mixed treatments greatly varied with the types of plants (maize vs cabbage), plant tissues (root vs shoot) and quality/type of mixing waters (alone vs mixed). Principal component analysis traced general trends in data based on covariance/correlation of plant response variables and irrigation treatments. Sewage and fresh waters may be monitored against quality criteria before being used for crop irrigation.