title: Sorption of selected veterinary antibiotics onto dairy farming soils of contrasting nature.
abstract: The sorption potential for three sulfonamides (SAs), sulfamethoxazole (SMO), sulfachloropyridazine (SCP) and sulfamethazine (SM) and a macrolide, tylosin tartrate (TT) was assessed on six New Zealand dairy farming soils of contrasting physico-chemical properties. Kinetics studies showed that the sorption was rapid in the first few hours of the contact time (0-2h for SA and 0-4h for TT) and thereafter apparent equilibrium was achieved. Batch sorption isotherm data revealed that the degree of isotherm linearity (N) for SCP and SM varied between 0.50 and 1.08 in the six soils. Isotherms of both TT and SMO were mostly non-linear with the degree of non-linearity for TT (N=0.38-0.71) being greater than for SMO (0.42-0.75) in all soils except Manawatu (TT) and Te Kowhai (SMO) where a linear pattern was observed. Concentration-dependent effective distribution coefficient (Kd(eff)) values for the SMO, SCP and SM antibiotics in the soils ranged from 0.85 to 16.35 L kg(-1), while that for TT was 1.6 to 1,042 L kg(-1). The sorption affinity for all soils followed an order: TT>SCP>SM>SMO. Remarkable high sorption for tylosin in Matawhero soil as compared to other soils was attributed to the presence of oxygen containing acidic polar functional groups as evident in the FT-IR spectra of the soil. Furthermore, it was hypothesised that sorption of TT onto soils was mostly driven by metal oxide-surface mediated transformations whereas for sulfonamides it was primarily due to hydrophobic interactions.
authors: Department of Civil & Environmental Engineering, Faculty of Engineering, The University of Auckland, Private Bag 92019, Auckland, New Zealand; Landcare Research, Private Bag 3127, Hamilton, New Zealand.
authors: Prakash
authors: P
authors: Srinivasan
authors: Department of Civil & Environmental Engineering, Faculty of Engineering, The University of Auckland, Private Bag 92019, Auckland, New Zealand. Electronic address: a.sarmah@auckland.ac.nz.
authors: Ajit K
authors: AK
authors: Sarmah
authors: Chemistry Department, University of Waikato, Private Bag 3105, Hamilton, New Zealand.
authors: Merilyn
authors: M
authors: Manley-Harris
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000737:chemistry*; D003612:Dairying; D008956:Models, Chemical; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D013410:Sulfachlorpyridazine / Q000032:analysis / Q000737:chemistry; D013418:Sulfamethazine / Q000032:analysis / Q000737:chemistry; D013420:Sulfamethoxazole / Q000032:analysis / Q000737:chemistry; D015645:Tylosin / Q000032:analysis / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D012987:Soil; D012989:Soil Pollutants; D013418:Sulfamethazine; D013420:Sulfamethoxazole; D013410:Sulfachlorpyridazine; D015645:Tylosin
keywords: Freundlich isotherm; Macrolide; Partition coefficient; Sorption; Sulfonamide