| Abstract
| - Total annual Gd emission of a hospital offering a maximumspectrum medical services using Gd complexes inmagnetic resonance imaging was computed and independently measured by ICP/MS. The Gd emission wasbetween 2.1 and 4.2 kg per year, yielding a theoreticalconcentration of 8.5−30.1 μg per L in the hospital's effluent.Gd concentrations measured on different days werebelow detection limit (1 μg per L) and 55 μg per L, andannual average concentrations were between 10.5 and 20.5μg per L as calculated from analytical results, waterflow, and total water consumption. The concentrations inthe influent of the municipal sewage treatment plant(STP) receiving the effluent were always below detectionlimit indicating that there was no other major dischargeof Gd. Based on consumption data, total Gd input by Germanhospitals is estimated to be roughly 132 kg per year. Anelevation of the natural concentration of Gd in German surfacewaters by 0.003−0.004 μg per L will result from thisamount, if there is no elimination in sewage treatmentplants. Using the number of MRI apparatus used in Germanythe annual emission by hospitals is 484 and 1160 kg byhospitals and practices, resulting in an additional Gdconcentration in German surface water of 0.011 and 0.026μg per L, respectively. Therefore, the emission of Gdcompounds used in magnetic resonance imaging have tobe considered as one source among others of anthropogenic Gd anomaly in surface waters.
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