title: Fate of the antiretroviral drug tenofovir in agricultural soil.
abstract: Tenofovir (9-(R)-(2-phosphonylmethoxypropyl)-adenine) is an antiretroviral drug widely used for the treatment of human immunodeficiency virus (HIV-1) and Hepatitis B virus (HBV) infections. Tenofovir is extensively and rapidly excreted unchanged in the urine. In the expectation that tenofovir could potentially reach agricultural lands through the application of municipal biosolids or wastewater, and in the absence of any environmental fate data, we evaluated its persistence in selected agricultural soils. Less than 10% of [adenine-8-(14)C]-tenofovir added to soils varying widely in texture (sand, loam, clay loam) was mineralized in a 2-month incubation under laboratory conditions. Tenofovir was less readily extractable from clay soils than from a loam or a sandy loam soil. Radioactive residues of tenofovir were removed from the soil extractable fraction with DT(50)s ranging from 24±2 to 67+22days (first order kinetic model) or 44+9 to 127+55days (zero order model). No extractable transformation products were detectable by HPLC. Tenofovir mineralization in the loam soil increased with temperature (range 4°C to 30°C), and did not occur in autoclaved soil, suggesting a microbial basis. Mineralization rates increased with soil moisture content, ranging from air-dried to saturated. In summary, tenofovir was relatively persistent in soils, there were no extractable transformation products detected, and the response of [adenine-8-(14)C]-tenofovir mineralization to soil temperature and heat sterilization indicated that the molecule was biodegraded by aerobic microorganisms. Sorption isotherms with dewatered biosolids suggested that tenofovir residues could potentially partition into the particulate fraction during sewage treatment.
authors.affiliation: Agriculture and Agri-Food Canada, London, ON, N5V 4T3 Canada.
authors.forename: Abdul Jabbar
authors.initials: AJ
authors.lastname: Al-Rajab
authors.forename: Lyne
authors.initials: L
authors.lastname: Sabourin
authors.forename: Ralph
authors.initials: R
authors.lastname: Chapman
authors.forename: David R
authors.initials: DR
authors.lastname: Lapen
authors.forename: Edward
authors.initials: E
authors.lastname: Topp
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D000327:Adsorption; D000383:Agriculture; D044966:Anti-Retroviral Agents / Q000032:analysis* / Q000737:chemistry; D004784:Environmental Monitoring; D007700:Kinetics; D063065:Organophosphonates / Q000032:analysis* / Q000737:chemistry; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis*; D013696:Temperature; D000068698:Tenofovir; D014865:Waste Disposal, Fluid
chemical_list: D044966:Anti-Retroviral Agents; D063065:Organophosphonates; D012987:Soil; D012989:Soil Pollutants; D000068698:Tenofovir; D000225:Adenine