Global water scarcity entailed the use of treated wastewater (TWW) in agriculture, however, this water can vehiculate numerous pollutants into soil and further crops such as microplastics (MPs). To date, few studies had quantified the accumulation of MPs in soils and earthworms after irrigation with TWW as well as their toxicological effects. Hence, the main objective of the present work is to evaluate the toxicity of MPs using Lumbricus sp. earthworms collected from TWW irrigated soils with an increasing gradient of time (5 years, 16 years and 24 years). MPs determination in soil, as well as in earthworms were performed. The intestinal mucus was quantified, and cytotoxicity (Lysosomal membrane stability (LMS), Catalase (CAT) and glutathione-S-Transferase (GST) activities), neurotoxicity (Acetylcholinesterase activity (AChE)) and genotoxicity (Micronuclei frequency (MNi)) biomarker were assessed. Our results revealed that the use of TWW rendered MPs accumulation in earthworms' tissues and induce alteration on the intestinal mucus. An important cytotoxicity time-depending was observed being associated with an increase on genotoxicity. Overall, the present investigation highlights the ecotoxicological risk associated with the use of TWWs as an important driver of MPs and consequently measures are necessary to reduce MPs in wastewater treatment plans to improve this non-conventional water quality.

The potential for a global water crisis looms in the face of declining precipitation and growing population. Immediate action is required to address the issue of water shortage. Water recycling and reuse of treated wastewater (TWW) in practical applications holds the potential to facilitate this problem. TWW refers to the wastewater being treated at a sewage treatment plant to meet the required safety standards. One such application of TWW is using it as a replacement for potable water in road construction. A typical road construction requires huge amount of water for various purposes, such as soil compaction, dust control operations, concrete production, curing, etc. The primary focus of this review is to highlight the feasibility of using alternative water sources in road construction activities. The effect of water treatment level on pavement material properties has been reviewed. Further, the influence of toxic chemical compounds present in TWW on the fresh and hardened properties of concrete is thoroughly discussed. The fundamental reasons behind the change in mechanical properties of subgrade and granular layers with the application of TWW are highlighted. Additionally, data on the chemical characteristics of non-potable water and their effect on pavement durability are surveyed and summarized. The review indicates that there is a need to explore the use of TWW in subgrade and granular layers. Further, the effect of source and treatment level on the mechanical properties of different pavement layers should be investigated with more rigor. Life cycle assessment (LCA) and field evaluation of pavements constructed using different sources of TWW will build more confidence in its use as a sustainable construction material.