This review explores the hidden hazards associated with the reuse of treated wastewater and sewage sludge in agriculture while proposing mitigation strategies. It examines the origins and pathways of microplastics (MPs) in wastewater treatment plants and how these pollutants infiltrate agricultural ecosystems. The review assesses the effectiveness of MP removal from wastewater and its fate in soil after reuse, highlighting contamination dynamics and the need for proactive measures. Introducing soil remediation methods is crucial for addressing this issue. Alarming evidence of MPs in human blood, testis, semen, and placenta underscores the urgency for solutions, revealing significant threats to human health, particularly reproductive health. The review advocates for sustainable agricultural practices and effective soil remediation strategies to mitigate MP contamination, promoting environmental preservation, food safety, and human health protection. Graphical Abstract

The effects of ¹⁵N-labeled ammonium nitrate on yield, uptake of nitrogen (N) by sorghum (Sorghum sudanense, Piper), and on N remaining in the soil were studied in a field experiment with different N rates (0, 50, and 100 kg N ha⁻¹) and with two irrigation water qualities, well water (WW) and treated wastewater (TWW). Treated wastewater irrigation increased dry matter and N yield compared to WW. At equal N rates, recovery of ¹⁵N-labeled fertilizer by plants increased with TWW irrigation compared to WW (36% versus 23%). Neither fertilizer rate nor water quality had an effect on the ¹⁵N-labeled fertilizer remaining in the 0- to 60-cm layer of soil. On average 41% in the TWW treatment (49–33%) and 38% in WW treatment was mostly present in the surface 20-cm layer. Losses of ¹⁵N-labeled fertilizer were unaffected by irrigation water quality (35%) and increased with N application rate in TWW (4% versus 31%).

Under semi-arid conditions, irrigated agriculture faces hard competition for water. It is against this backdrop that appropriate management of irrigation techniques and water resources becomes a major concern. This study investigated the effect of surface (SDI) and subsurface drip irrigation (SSDI) with domestic treated wastewater (TWW) and fresh water (FW) on soil water dynamics, salinity, yield, and mineral nutrition of okra. The experimental design was set-up based on two adjacent plots according to the water quality: Fresh Water (FW) T₁ and domestic Treated Wastewater (TWW) T₂. Results showed that measured soil water contents (SWCs), under TWW treatment (T₂), were greater than their corresponding measurements under FW (T₁), and in particular at 35 cm depth. Meanwhile, for both water qualities, soil Electrical Conductivity (EC) registered at 5 cm depth was higher than those measured at 35 cm, with values ranging from 0.14 to 0.36 mS·cm⁻¹ and from 0.20 to 0.47 mS·cm^−m for T₁ and T₂, respectively. Regarding crop yield, a statistically significant increase (p = 0.05) in okra fresh yield was observed when TWW was used. Fresh yield in SDI was 2.55 t·ha⁻¹ and 3.9 t·ha⁻¹ in T₁ and T₂, respectively. Nevertheless, results indicated that lateral depth did not significantly affect okra fresh yield. Moreover, a significant higher irrigation water productivity (WP_irrig) with TWW (1.08 ± 0.26 and 1.23 ± 0.18 kg m⁻¹) was observed, which was nearly double those obtained with FW (0.72 ± 0.33 to 0.78 ± 0.18 kg m⁻¹). Appropriate use of SSDI with TWW stands as an irrigation management technique to improve yield and irrigation water productivity of okra crops.

Treated wastewater (TWW) is considered as an alternative for agricultural irrigation. The aim of this study was to understand the medium- and long-term effects of TWW on soil physicochemical parameters. Two perimeters (P₁ and P₂)receiving TWW for 38 and 20 years, respectively, in Tunisiawere selected for study. In each perimeter, two water types were adopted: TWW and groundwater (GW). Soil physicochemical traits (pH, EC, and concentrations of Na⁺, K⁺, Ca²⁺, and Mg²⁺) were measured up to 100 cm, and three indexes were calculated: sodium adsorption ratio (SAR), cation ratio of structural stability (CROSS), and cation exchange capacity (CEC). Overall, all soil parameters were significantly affected in the irrigation area using GW. However, in the case of TWW, only the pH was found to be affected, increasing by 4.7% from P₁ to P₂. Moreover, compared to GW, TWW enhanced the soil salinity by 127%, particularly at deeper subsoils. More interestingly, the results revealed an accumulation of Mg²⁺, Ca²⁺, and K⁺ and a depletion of Na⁺ at the soil surface. Notably, TWW showed the lowest CROSS and SAR indexes, indicating the benefits of applying TWW even after long-term use in improving soil physicochemical parameters such as sodicity and structural stability. Our results provide valuable information for decision-makers to use wastewater in irrigated marginal soils.