A large percentage of flunixin, a nonsteroidal anti-inflammatory drug widely used for treating livestock, is excreted in intact form and thus potentially available for environmental transport. As the fate of flunixin in the environment is unknown, our objective was to quantify sorption, desorption, and transformation in five agricultural soils and manure using batch equilibrium methods. Concentrations of flunixin and degradation products were determined by high performance liquid chromatography time of flight mass spectrometry. For all studied soils, sorption of flunixin exhibited linear character, with both linear and Freundlich models providing adequate fit. Linear sorption coefficients varied from 8 to 112 L kg⁻¹. The strongest Pearson correlations with sorption coefficients were for clay content (r = 0.8693), total nitrogen (r = 0.7998), and organic carbon (r = 0.6291). Desorption of the reversibly bound fraction (3–10% of total sorbed flunixin) from all five studied soils exhibited non-hysteretic character suggesting low affinity of this fraction of flunixin to soil. Flunixin degradation in soils was relatively slow, exhibiting half-lives of 39–203 days, thus providing time for off-site transport and environmental contamination. The biological impacts of flunixin at environmentally relevant concentrations must be determined given its environmental behavior and extensive use as a nonsteroidal anti-inflammatory drug in livestock.

Graphical abstract

氟尼辛是一种广泛用于治疗牲畜的非甾体类抗炎药，大部分以完整形式排泄，因此有可能用于环境运输。由于氟尼辛在环境中的命运尚不清楚，因此我们的目标是使用分批平衡方法来量化五种农业土壤和肥料中的吸附，解吸和转化。氟尼辛和降解产物的浓度通过高效液相色谱飞行时间质谱法测定。对于所有研究的土壤，氟尼辛的吸附均表现出线性特征，线性模型和Freundlich模型均可提供足够的拟合度。线性吸附系数在8至112 L kg ^{-1之间变化}。与吸附系数最强的Pearson相关性是粘土含量（r  = 0.8693），总氮（r  = 0.7998）和有机碳（r  = 0.6291）。从所有五个研究过的土壤中可逆结合部分（总吸附的氟尼辛的3-10％）的解吸显示出非滞后性，表明氟尼辛的这一部分对土壤的亲和力很低。氟尼辛在土壤中的降解相对较慢，半衰期为39-203天，因此为异地运输和环境污染提供了时间。鉴于氟尼辛的环境行为和在牲畜中作为非甾体类抗炎药的广泛应用，必须确定氟尼辛在环境相关浓度下的生物影响。

图形概要