Translating wastewater reuse for irrigation from OECD Guidelines: Tramadol sorption and desorption in soil-water matrices.

Garduño-Jiménez, Andrea Lorena; Durán-Álvarez, Juan Carlos; Cortés-Lagunes, Ruth Silvana; Barrett, David A.; Gomes, Rachel L.

Abstract

Treated and untreated wastewater is often used for agricultural irrigation and, despite the many benefits of this practice, it poses the risk of biologically active chemical pollutants (such as pharmaceuticals, like tramadol) entering the environment. The partitioning of tramadol between soil/water at environmentally relevant concentrations is important to understand its environmental toxicity. Kinetics and isotherm sorption studies based on the Organisation for Economic Cooperation and Development (OECD) 106 Guideline were undertaken, ensuring comparability to previous studies. Studies were undertaken in three soils of different characteristics using aqueous concentrations of tramadol from 500 ng L−1 (environmentally relevant) to 100 μg L−1 (comparable to previous studies). Two of the soils presented a significantly (p < 0.05) higher sorption at a lower initial tramadol concentration (5000 ng L−1), compared to 20,000 ng L−1. Hysteresis was observed in all studied soils, indicating the accumulation of tramadol. Higher sorption to soils correlated with higher clay content, with soil/water partitioning coefficients (Kd) of 5.5 ± 13.3, 2.5 ± 3.8 and 0.9 ± 3.0 L kg1 for soils with clay contents of 41.9%, 24.5% and 7.4%, respectively. Cation exchange was proposed as the main sorption mechanism for tramadol to soils when the pH was below tramadol's pKa values (9.41 and 13.08). A comparative kinetics study between tramadol in soil/calcium chloride buffer and soil/wastewater effluent demonstrated significantly higher (p < 0.05) tramadol sorption to soil from wastewater effluent. This has the environmental implication that clay soils will be able to retain tramadol from irrigation water, despite the organic content of the irrigation water. Therefore, our studies show that tramadol soil sorption is likely to be higher in agricultural environments reusing wastewater than that predicted from experiments using the OECD 106 Guideline calcium chloride buffer.

• Journal Article Type: Article
• Acceptance Date: May 17, 2022
• Online Publication Date: May 20, 2022
• Publication Date: Jun 28, 2022
• Deposit Date: Jun 27, 2022
• Publicly Available Date: Jun 29, 2022
• Journal: Chemosphere
• Print ISSN: 0045-6535
• Electronic ISSN: 1879-1298
• Publisher: Elsevier BV
• Peer Reviewed: Peer Reviewed
• Volume: 305
• Article Number: 135031
• DOI: https://doi.org/10.1016/j.chemosphere.2022.135031
• Keywords: General Medicine; General Chemistry; Environmental Chemistry; Environmental Engineering; Pollution; Health, Toxicology and Mutagenesis; Public Health, Environmental and Occupational Health
• Public URL: https://nottingham-repository.worktribe.com/output/8132139
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0045653522015247