znni 63. Ckbiirtstag gewidmet .S/CJU J I E W~J : Eight. urea herbicides, a s are used for weed cont.rol, me investiptrd for their effect on the green alga ;Lnkisti.otlrs//~ rt,s jnlccifus and the wa.rm-water fish Po~ci2ia reticirlatu and found to be highly tosic for the test alga or highly to moderately tosic for t,lie fish. If other criteria (acnte tosicity to warm-blooded animals, carcinogenicity and bioclieinical degrsdability) are taken into account too, the test'ecl herbicides have to be classified as very &nperous water pollutants. Legal sanct,ions to be applied in cases of exceeded limiting values are discussed..Iota hydrochim. hyrlrobiol. 15 (198.5) 4 496 Kategorisierung Ton Wasserschadstoff en S a c h der Definition iiii WASSERSCHADSTOFF-KATALOC: sind Wasserschadstoffe Siihstanzen, die hereits in geringen Konzentrat,ionen