Occurrence of Zearalenone on Fusarium graminearum Infected Wheat and Maize Fields in Crop Organs, Soil, and Drainage Water NICCOLO HARTMANN, †,‡ MARIANNE ERBS, †,§ HANS-RUDOLF FORRER, † SUSANNE VOGELGSANG, † FELIX E. WETTSTEIN, † REN ´ E P. SCHWARZENBACH, ‡ AND THOMAS D. BUCHELI* ,† Agroscope Reckenholz-Ta ¨nikon, Research Station Reckenholz, 8046 Zu ¨ rich, Switzerland, and Institute of Biogeochemistry and Pollutant Dynamics, ETH Zu ¨ rich, CH-8092 Zu ¨ rich, Switzerland Received March 13, 2008. Revised manuscript received May 13, 2008. Accepted May 19, 2008. The mycotoxin zearalenone (ZON) is a very potent natural endocrine disrupting chemical, produced by Fusarium graminearum fungi growing on crops such as wheat and maize. Although it is well-investigated in food and feed, very little is known about its environmental fate and behavior. Here, we report the occurrence of ZON on F. graminearum infected wheat and maize fields in crop organs and soil and its emission via drainage water. ZON amounts in the investigated crops and topsoil were between 6.1 and 25.0 and up to 5.6 g/ha, respectively. ZON concentrations in drainage water were in the low nanogram per liter range with a maximum of 35 ng/ L. Cumulated ZON amounts emitted via drainage water ranged from 0.1 to 4.3 mg/ha, depending on the crop cultivated in the respective period. This corresponds to fractions between 0.001 and 0.070% of the initially present ZON amount in the plants. Because of the low concentrations emitted via drainage water, it can be assumed that ZON contributes little if at all to the overall estrogenicity of major surface water bodies. However, in small creeks, mainly fed by agricultural runoff, ZON might be present in environmentally critical concentrations at times of F. graminearum infections. Introduction Zearalenone (ZON) is known as a very potent endocrine disrupting chemical. Its relative estrogenic potency (1) and binding affinity to the estrogen receptor (2) are close to that of 17-estradiol and orders of magnitudes higher than for notorious synthetic endocrine disruptors such as bisphenol A, DDT, or atrazine (1). ZON is the most prominent representative of the resorcyclic acid lactones (RALs) (see Supporting Information Figure S1). It is produced by Fusar- ium fungi, in particular, by Fusarium graminearum growing on maize, wheat, and other cereals (3), which cause Fusarium head blight on wheat and ear/stalk rot on maize. Because both maize and wheat crops can be infected by F. graminearum, the crop rotation of wheat after maize is problematic due to fungi survival on maize plant debris remaining after harvest in the field, from which infestation of the following wheat takes place. The extent of F. graminearum infection on wheat and maize and subsequent ZON contamination is determined by several factors: (i) climatic conditions, (ii) crop rotation, (iii) soil cultivation, and (iv) susceptibility of crop varieties (4). In recent years, the problem has worsened probably due to the alteration of the cropping system, reduced soil tillage, and, possibly, changing climatic conditions (4). Plenty of effort has been spent on investigating the occurrence and fate of ZON in food and feed products and its estrogenic effects, particularly in domestic animals. ZON was reported to occur regularly in agricultural food and feed products around the world (5, 6). An overview in Switzerland (5) showed that 13% of the investigated samples contained ZON, mostly in the low microgram per kilogram range. F. graminearum infested feeding or litter can cause severe reproductive and infertility problems in husbandry animals (7, 8), particularly in swine. In contrast to extensive investigations in the agricultural and food context, very little is known about the environmental distribution of ZON. Several publications reported the occurrence of ZON in surface waters (9, 10) and in- and effluents of wastewater treatment plants (9, 11, 12). Con- centrations ranged from below the detection limit up to 60 ng/L for individual samples. In some cases, other RALs such as R-zearalenol (R-ZOL), R-zearalanol (R-ZAL), and -zear- alanol (-ZAL) were detected at similar levels as ZON (10, 11, 13). Unfortunately, in most of these publications, possible sources of RALs were not elucidated. In one case, the presence of RALs was associated with the excretion of cattle fed with growth promoters (9). However, the envi- ronmental distribution of ZON and its emission from F. graminearum infected wheat and maize fields into the aqueous and nonaqueous environment have not yet been investigated. All six RALs were investigated in this field study. Table 1 compiles available physicochemical data for ZON, R-ZAL, and for 17-estradiol. This comparison is of interest since their aqueous solubilities and octanol-water partition constants (Kow ) are in the same order of magnitude (14) and because the estrogenicity of endocrine disruptors is often related to those of natural steroid hormones. Test results of different cereal washing procedures revealed that up to 61% of ZON desorbed from contaminated maize kernels into distilled water (15). This indicates some environmental aqueous phase mobility. Simultaneously, with an estimated log K ow of 3.58 and calculated log K oc of 3.89 (Table 1), the compound very likely exhibits a certain potential for sorption and retention in soil systems, depending among other potential sorbents assumed on the organic carbon fraction (foc ). Its abiotic stability during milling, food processing, heating, etc. is considerable (16), and it must be assumed that ZON could be rather chemically persistent in the environment as well. Data on biotic transformation of ZON generally indicate as a main metabolization pathway the reduction of the 6′-keton to yield R- and -ZOL (17). Mortensen et al. (18) described the fate of ZON in soils and reported an overall dissipation half-life of 6-11 days, including degradation and irreversible sorption, but without quantifying degradation products. * Corresponding author e-mail: thomas.bucheli@art.admin.ch. † Agroscope Reckenholz-Ta ¨nikon. ‡ Institute of Biogeochemistry and Pollutant Dynamics. § Present address: MDS Pharma Services Switzerland AG, CH- 8320 Fehraltorf, Switzerland. Environ. Sci. Technol. 2008, 42, 5455–5460 10.1021/es8007326 CCC: $40.75  2008 American Chemical Society VOL. 42, NO. 15, 2008 / ENVIRONMENTAL SCIENCE & TECHNOLOGY 9 5455 Published on Web 06/27/2008