Pharmaceutical antibiotic compounds in soils - a review - Susane.info

146 Thiele-Bruhn J. Plant Nutr. Soil Sci. 2003, 166, 145±167
the environment. Contamination of surface, ground and
drinking water, of aquatic sediments and soils with
pharmaceuticals have been reported (Richardson and Bowron,
1985; Heberer and Stan, 1998; Hirsch et al., 1999;
Kümmerer, 2001a; Hamscher et al., 2002a). Soil residues
result mostly from the use of contaminated excrements as
fertilizer on agricultural land. It has been estimated that loads
of up to kilograms per hectare may enter agricultural soils and
that a concentration level of antibiotics similar to pesticides is
easily reached (van Gool, 1993; Winckler and Grafe, 2000).
Due to surface runoff and leaching, soils can even act as a
source of antibiotic contaminants for the aqueous environment
(Alder et al., 2001). Residues of pharmaceutical
antibiotics can provoke resistance in pathogens either directly
or indirectly by transfer of plasmids from non-pathogens to
pathogenic microorganisms (Wegener et al., 1998). The
resulting antibiotic residues and resistant microorganisms
can affect the natural soil microbial community and soil
functions and may even harm animals and humans via the
food chain (Richter et al., 1996; Kennedy et al., 2000). In
addition, infections by resistant pathogens lower the
efficiency of pharmacotherapies for humans and animals
(Richter et al., 1996).
However, no regulations exist for concentration limits of
antibiotics in soils or soil water. Following the lead of the USA,
an environmental risk assessment of veterinary pharmaceuticals
was prescribed in the EU in 1998 with the EU directives
81/852/EEC and 92/18/EEC (EMEA, 1997). Thereby, predicted
environmental concentrations (PEC) are calculated
with the help of a balancing model (Spaepen et al., 1997).
The PEC are compared with predicted, biologically noneffective
concentrations (PNEC). First, the exposition is
evaluated and PEC are compared with trigger values. These
trigger values have been set at 10 lg kg ±1 for the faeces of
grazing livestock, at 100 lg kg ±1 for dung and soils and at 0.1
lg l ±1 for groundwater. When PEC exceed these trigger
values or antibiotics are directly applied to surface water for
the treatment of fish, experimental testing in the tiered second
phase becomes necessary. Legislation and methods for an
environmental risk assessment of pharmaceuticals are dealt
with in detail in the book edited by Kümmerer (2001b). There,
alternative concepts to the model by Spaepen et al. (1997)
are also presented. Therefore, this topic is not addressed in
this review.
The occurrence and effects of pharmaceuticals in different
environmental compartments, especially water, were
reviewed by Halling-Sùrensen et al. (1998), Daughton and
Ternes (1999), and Kümmerer (2000). Another review deals
with the adsorption of veterinary pharmaceuticals in soils
(Tolls, 2001), while Richardson and Bowron (1985) and
Hirsch et al. (1999) combined overviews on antibiotics in
water with results from their own investigations. However,
research and publications on these topics have increased
remarkably in the last few years, justifying a review focusing
on the input and fate of pharmaceutical antibiotics in soils.
2 Consumption and physicochemical
properties of antibiotics
Antibiotics are defined as chemical compounds that are
synthesized through the secondary metabolism of living
organisms, with exceptions for semi- or completely synthetic
substances. Antibiotics inhibit the activity of microorganisms,
viruses, and eucaryotic cells, respectively (Lancini and
Parenti, 1982). In human medicine, antibiotics pose the third
biggest group among all pharmaceuticals making up more
than 6 % of all prescriptions (Schwabe and Paffrath, 2001). In
veterinary medicine, more than 70 % of all consumed
pharmaceuticals are antibiotic agents (Halling-Sùrensen et
al., 1998). In Europe, two thirds of all pharmaceutical
Table 1: Annual consumption of antibiotics for veterinary medicine, especially livestock, in the European Union, European countries and
regions of Germany (without coccidiostatics).
Tabelle 1: Jährlicher Verbrauch an Antibiotika in der Veterinärmedizin, v.a. für landwirtschaftliche Nutztiere, in der Europäischen Union,
europäischen Staaten und Regionen in Deutschland (ohne Kokzidiostatika).
EU
1999 a
France
1980 b
Sweden
1996 c
Denmark
1997 d
Switzerland
1997 e
UK
2000 f
Weser-Ems
1997 g
Brandenburg
1998/99 h
t % t % t % t % t % t % t % t % t %
Therapeutics 3902 625 20 57 14 437 88 j 6.6 j 10 j
Mecklenburg-
Vorpommern
2001 i
Tetracyclines 2575 66 117 19 2.7 13 13 23 1.0 7 228 52 40 57 4.6 69 6.4 41
Sulfonamidesk 78 2 139 22 2.2 11 13 23 n.a. 94 22 14 21 0.9 14 2.5 16
Aminoglycosides 1564 57 9 1.1 5 7.7 14 n.a. 12 3 7.1 10 0.2 3 0.2 2
b-Lactams 351 9 50 8 n.a. 15 26 9.2 64 49 11 3.8 5 0.2 3 0.1 1
Macrolides 468 12 37 6 1.5 7 1.7 3 0.3 2 41 9 0.2 0.3 0.01 0.1 0.1 1
others 234 6 226 36 n.a. 6.5 11 3.8 27 12 3 4.5 6 0.7 10 0.8 8
Ergotropics 786 n.a. n.a. 107 36 24 18 0.1 n.a.
a FEDESA (2001), data for percentages of compound classes from 1997; b Espinasse (1993); c Mudd et al. (1998); d Halling-Sùrensen et al.
(2002a); e Swiss Importers of Antibiotics (1998) cited in Alder et al. 2001; f NOAH (2002); g Winckler and Grafe (2000); h Linke and Kratz
(2001); i Thiele-Bruhn et al. (2003a); j veterinary prescriptions for feed antibiotics only; k incl. trimethoprim; n.a. = no data available