Pharmaceutical and personal care products in tile drainage following surface spreading and injection of dewatered municipal biosolids to an agricultural field

Abstract

Land application of municipal biosolids can be a source of environmental contamination by pharmaceutical and personal care products (PPCPs). This study examined PPCP concentrations/temporally discrete mass loads in agricultural tile drainage systems where two applications of biosolids had previously taken place. The field plots received liquid municipal biosolids (LMB) in the fall of 2005 at an application rate of ∼ 93,500 L ha − 1 , and a second land application was conducted using dewatered municipal biosolids (DMB) applied at a rate of ∼ 8 Mt dw ha − 1 in the summer of 2006. The DMB land application treatments consisted of direct injection (DI) of the DMB beneath the soil surface at a nominal depth of ∼ 0.11 m, and surface spreading (SS) plus subsequent tillage incorporation of DMB in the topsoil (∼ 0.10 m depth). The PPCPs examined included eight pharmaceuticals (acetaminophen, fluoxetine, ibuprofen, gemfibrozil, naproxen, carbamazepine, atenolol, sulfamethoxazole), the nicotine metabolite cotinine, and two antibacterial personal care products triclosan and triclocarban. Residues of naproxen, cotinine, atenolol and triclosan originating from the fall 2005 LMB application were detected in tile water nearly nine months after application (triclocarban was not measured in 2005). There were no significant differences ( p > 0.05) in PPCP mass loads among the two DMB land application treatments (i.e., SS vs. DI); although, average PPCP mass loads late in the study season (> 100 days after application) were consistently higher for the DI treatment relative to the SS treatment. While the concentration of triclosan (∼ 14,000 ng g − 1 dw) in DMB was about twice that of triclocarban (∼ 8000 ng g − 1 dw), the average tile water concentrations for triclosan were much higher (43 ± 5 ng L − 1 ) than they were for triclocarban (0.73 ± 0.14 ng L − 1 ). Triclosan concentrations (maximum observed in 2006 ∼ 235 ng L − 1 ) in tile water resulting from land applications may warrant attention from a toxicological perspective.