Organic xenobiotics

Abstract

As well as fertilizer benefits, reutilization of phosphor (P) from secondary sources and recycling materials such as sewage sludge, farmyard manures, composts, biogas residues or meat and bone meal products on agricultural soils bears the great risk of contaminating farm sites with organic xenobiotics. Contamination of groundwater, surface and drinking water as well as of aquatic sediments and soils with pharmaceuticals has been reported (Hamscher et al. in Analytical Chemistry 74:1509–1518, 2002; Hirsch et al. in Science of the Total Environment 225:109–118, 1999; Kümmerer in Pharmaceuticals in the environment. Sources, fate, effects and risks. Springer, Heidelberg, 2001b; Ternes in Water Research 32:3245–3260, 1998). According to available data, biodegradation is more the exception than the rule, which is one reason for the widespread occurrence of these compounds in the environment (Kümmerer in Chemosphere 45:957–969, 2001a). Antibiotics and disinfectants are especially designed to have a strong impact on microorganisms, making environmental effects very likely to occur. Therefore it is necessary to consider possible risks of using secondary raw materials containing such xenobiotics despite their advantages as a fertilizer or source of organic material. For many organic contaminants no environmental risk assessment (ERA) is available. For veterinary drugs, a note of guidance on ERA was issued in January 1998 but hardly any eco-toxicological data are available for products approved before 1998 (Baguer et al. in Chemosphere 40:751–757, 2000; EU in EMEA/CVMP/055/96. EMEA, London, 1996) or for human therapeutics. For many pharmaceuticals as well as organic chemicals their environmental effects are quite unknown, particularly any interactions. New technologies enabling the detection of traces of organic xenobiotics and their metabolites even in critical matrices (slurry, sewage sludge) are partly responsible for the higher awareness of possible risks. Environmental tests on the effects of xenobiotics are still rare and have only been performed in the last decade and mainly for aquatic organisms. It is the aim of this chapter to give an overview of the different classes of organic contamination that are relevant in organic P fertilizers. Moreover technical solutions to decrease or minimize the risk of soil contaminations by using organic P fertilizers are discussed and the different recycling materials are evaluated with respect to their environmental risks. It is not possible to address all different organic compounds and their impact on the environment in one chapter because of the sheer number of compounds and metabolites. The focus was put on the input of pharmaceutical contamination into agriculture because sewage sludge and farmyard manures are important organic P fertilizers, which can contain high amounts of pharmaceuticals. But even so this field is too large to cover the whole spectrum taking into account that in Germany alone 50,000 drugs are registered for human use, containing more than 3000 different active compounds (Kümmerer in Pharmaceuticals in the environment. Sources, fate, effects and risks. Springer, Heidelberg, 2001b). In order to illustrate the general problems arising from field application of environmentally relevant substances, two main classes of contaminants were discussed in detail: antibiotics and substances with an endocrine potential. For more detailed information several extensive review articles and books are available covering the different aspects of pharmaceutical drugs in the environment, their occurrence and behavior in the environment, their chemical characteristics, and their impact on soil organisms, plant growth and aquatic life (Boxall et al. in Reviews of environmental contamination and toxicology 180:1–91, 2004; Halling-Sørensen et al. in Chemosphere 36:357–393, 1998; Kümmerer in Pharmaceuticals in the environment. Sources, fate, effects and risks. Springer, Heidelberg, 2001b; Kumar et al. in Advances in Agronomy 87:1–54, 2005a; Sarmah et al. in Chemosphere 65:725–759, 2006). Pathogens, another important possible organic contamination of secondary P fertilizers, were also not addressed in detail, as the topic is comprehensive enough to fill books on its own (e.g. Bowman in Manure pathogens: manure management, regulations, and water quality protection. WEF Press, United States, 2009).