Climate change, inadequate possessions, and land degradation all pose obstacles to modern agriculture. In the current scenario, the agriculture industry is mainly dependent on the use of chemical-based pesticides and fertilizers that impact soil health and crop productivity. Moreover, water scarcity leads farmers in drastically affected regions to use heavy metal-enriched water sources mainly originating from industrial sources for field crops irrigation. Soil pollutants can be carried into the human body via dust and water, creating negative health effects varying from simple symptoms, e.g., nausea and diarrhea and reaching death in critical cases. Thus, to clean soil contaminants, and improve soil fertility and agricultural production, alternatives to chemical fertilizers must be developed. Therefore, using beneficial microbes found in plant-associated soil microorganisms offers an effective strategy to alleviate some of these challenges, improving soil fertility, and crop yield, and protecting plants from stress conditions. Through the use of synergistic interactions, the synthetic consortium strategy seeks to improve the stability of microbial communities. In this review, synthetic consortia and their potential use in agriculture were discussed. Further, engineering new effective synthetic consortia was suggested as an effective approach in the concept of environmental bioremediation of soil pollutants and contaminants.

Irrigation of crops with domestic wastewater (DW) is a common practice in developing countries like India. However, domestic wastewater irrigation poses a risk of migration of toxic heavy metals to edible parts of crops, which requires serious measures to prevent their uptake. In this study, the effect of DW irrigation in comparison with Sarbal Lake water (SLW) and borewell water (BW) on soil characteristics and cultivated saffron (Crocus sativus L.) was investigated. For this purpose, samples of water, soil, and saffron (corm, petal, and stigma) were collected from the suburban area of Pampore, Srinagar district, Jammu and Kashmir, India. The results showed that DW irrigation had the maximum significant (p < 0.05) influence on the physico-chemical and nutrient characteristics of the soil, followed by SLW and BW irrigation, respectively. The growth and yield parameters of saffron were also significantly (p < 0.05) increased in the case of DW irrigation as compared to SLW and BW. The quality ranking of the cultivated saffron was found to be in accordance with the ISO standard (III: BW and II: DW and SLW). On the other hand, DW irrigation showed a significant increase in heavy metal contents (mg/kg) of saffron plant parts such as As (0.21–0.40), Cd (0.04–0.09), Cr (0.16–0.41), Cu (7.31–14. 75), Fe (142.38–303.15), Pb (0.18–0.31), Mn (15.26–22.81), Hg (0.18–0.25), Ni (0.74–1.18), Se (0.13–0.22), and Zn (3.44–4.59), followed by SLW and BW. However, the levels of heavy metals did not exceed the FAO/WHO safe limits. Bioaccumulation factor (BAF), dietary intake modeling (DIM<0.006496), health risk assessment (HRI<0.028571), and target hazard quotient (THQ<1) analyses showed no potential health hazard associated with the consumption of saffron irrigated with DW and SLW. Therefore, the results of this study provide valuable insights into the optimization of irrigation sources for saffron cultivation.

Currently, wastewater treatment plants produce large amounts of sewage sludge. Due to the rich content of organic matter and minerals, sewage sludge can be used as soil amendments for eroded soils. The aim of this work was to assess sewage sludge (SS) in combination with an eroded soil (ES) collected from the North Eastern Romania as growth substrate for sweet basil, and their effect on basil growth and physiology. The experiment was conducted in a greenhouse under controlled environment conditions. The tested substrates were: (1) eroded soil, ES; (2) mixture of eroded soil (15%) + sewage sludge, ES + SS (85%); and (3) sewage sludge, SS (100%). Three types of parameters were studied: morphological traits, physiological, and biochemical parameters. The maximum quantum yield of Photosystem II Fv/Fm was reduced in basil leaves grown on eroded soil (0.80) and was close to the normal value in ES + SS (0.83). Chlorophyll a and the carotenoids content were higher for plants grown on SS and significantly higher for those grown in ES + SS compared with the one of plants grown on ES. The fresh biomass yield and height of basil increased with 44% and 34.5% under ES + SS over ES. Total phenolic content was higher in plants grown on ES (7.34 mg/g dry weight Gallic acid equivalent), which also led to an increased antioxidant activity (44.4%) evaluated by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. Fourier-Transform Infrared (FT-IR) (4000–400 cm⁻¹) spectra of basil did not show significant qualitative differences among the plants from different treatments. The results of this study demonstrated that SS application led to the improvement of the basil morpho-physiological parameters, allowing the growth of basil on ES + SS.