Fate and transport of the β-adrenergic agonist ractopamine hydrochloride in soil-water systems

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• 作者：Heldur Hakk¹ ; ^{heldur.hakk@ars.usda.gov" class="auth_mail" title="E-mail the corresponding author} ; Weilin L. Shelver¹ ; Francis X.M. Casey²
• 关键词：Ractopamine ; ractopamine hydrochloride ; C/C0 ; relative concentration ; Kd ; soil&ndash ; water adsorption coefficient ; Koc ; soil organic carbon&ndash ; water partitioning coefficient ; TRR ; total radioactive residues ; OM ; soil organic matter ; NSB ; non-specific binding
• 刊名：Journal of Environmental Sciences
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：45
• 期：Complete
• 页码：40-48
• 全文大小：714 K

文摘

The feed additive ractopamine hydrochloride was fortified at four concentrations into batch vials containing soils that differed in both biological activity and organic matter (OM). Sampling of the liquid layer for 14 days demonstrated that ractopamine rapidly dissipated from the liquid layer. Less than 20% of the fortified dose remained in the liquid layer after 4 hr, and recoveries of dosed ractopamine ranged from 8 to 18% in the liquid layer at 336 hr. Sorption to soil was the major fate for ractopamine in soil:water systems, i.e., 42%–51% of the dose at 14 days. The major portion of the sorbed fraction was comprised of non-extractables; a smaller fraction of the sorbed dose was extracted into water and acetone, portions which would be potentially mobile in the environment. Partitioning coefficients for all soils suggested strong sorption of ractopamine to soil which is governed by hydrophobic interactions and cation exchange complexes within the soil OM. Ractopamine degradation was observed, but to mostly non-polar compounds which had a higher potential than ractopamine to sorb to soil. The formation of volatiles was also suggested. Therefore, despite rapid and extensive soil sorption, these studies indicated a portion of ractopamine, present in manures used to fertilize soils, may be mobile in the environment via water-borne events.