Effects of CuO nanoparticles in composted sewage sludge on rice-soil systems and their potential human health risks

• Published in: Chemosphere (Oxford) 2023-10, Vol.338, p.139555-139555, Article 139555
• Main Authors: Duc Phung, Luc, Dhewi Afriani, Shinta, Aditya Padma Pertiwi, Putri, Ito, Hiroaki, Kumar, Arun, Watanabe, Toru
• Format: Article
• Language: English
• Subjects: biomass production; Biosolid reuse; Child; Composted sewage sludge; Copper - analysis; CuO nanoparticles; cupric oxide; Heavy metal accumulation; human health; Human health risks; Humans; Metal Nanoparticles - toxicity; Nanoparticles; nutritive value; Oryza; rice; Sewage; sewage sludge; Soil; soil amendments; soil fertility; Soil Pollutants - analysis; tillering; toxicity
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.139555

The release of metal-based nanoparticles (MNPs) into sewage systems is worrisome due to their potential impact on crop-soil systems that are amended with sewage sludge. This study aimed to investigate the effects of copper oxide nanoparticles (CuO NPs) in composted sewage sludge (CSS) on rice-soil systems and to assess the health risks associated with consuming CuO NP-contaminated rice produced by CSS amendment. CSS was treated with three doses of CuO NPs, resulting in Cu levels below the sludge limits (1500 mg Cu kg−1) for reuse as a soil amendment. Results showed that CuO NPs in CSS at environmentally acceptable levels had no negative effect on rice growth and yield. In fact, they enhanced biomass production, tillering capacity, and soil fertility by increasing N and K levels in the soil. In addition, CuO NPs in CSS (450–1450 mg Cu kg−1) promoted the accumulation of macro- and micro-minerals in rice grains, thereby improving the nutritional value of rice. However, Cu contamination in CSS led to elevated levels of toxic metals, especially As, in rice grains, posing potential health risks to both adults and children. In the presence of higher CuO NPs contamination in CSS, the hazard quotient of As exceeded one, indicating an increased risks of toxic metal exposure via rice consumption. This study raises concerns about potential long-term threats to human health posed by MNPs contamination in CSS and highlights the need to reevaluate the permissible limits of hazardous elements in sludge to ensure its safe reuse in agriculture. [Display omitted] •CuO nanoparticles (NPs) in sewage sludge didn't harm rice growth, yield or quality.•CuO NPs increased biomass production, tillering capacity, and soil N and K levels.•Elevated CuO NP contamination increased contents of potentially toxic metals in rice.•Hazard index values exceeded one and increased with CuO NPs levels in sludge.•It is critical to re-assess heavy metal limits in sludge for safe agricultural use.