Phosphogypsum (PG) is a waste product (residue) from the production of phosphoric acid characterized by technologically enhanced natural radioactivity. Croatia’s largest PG deposition site is situated at the edge of Lonjsko Polje Nature Park, a sensitive ecosystem possibly endangered by PG particles. This field study investigates two aspects relevant for the general radiological impact of PG: risk assessment for the environment and risk assessment for occupationally exposed workers and local inhabitants. Activity concentrations of natural radionuclides ( U, U, Th, Ra, Pb, and K) were measured in the PG (at the deposition site), soil, and grass samples (in the vicinity of the site). The ERICA Assessment Tool was used to estimate the radiological impact of PG particles on non-human biota of the Lonjsko Polje Nature Park. The average annual effective dose for occupationally exposed workers was 0.4 mSv which was within the worldwide range. Fosfogips je nusproizvod koji nastaje tijekom proizvodnje fosforne kiseline, a karakteriziran je tehnološki povišenom prirodnom radioaktivnošću. Odlagalište fosfogipsa u Hrvatskoj nalazi se na rubu Parka prirode Lonjsko polje, osjetljivom ekosustavu potencijalno ugroženom od čestica fosfogipsa. Istraživanje opisano u ovom radu sagledava dva aspekta značajna za radiološki utjecaj fosfogipsa: procjenu rizika za okoliš te procjenu rizika za profesionalno izložene radnike i lokalno stanovništvo. Koncentracije aktivnosti prirodnih radionuklida ( U, U, Th, Ra, Pb i K) izmjerene su u uzorcima fosfogipsa uzetima s odlagališta te u uzorcima tla i trave uzetima u blizini odlagališta. Za modeliranje utjecaja fosfogipsa na okoliš (biotu) korišten je program ERICA Assessment Tool. Prosječna godišnja efektivna doza za profesionalno izložene radnike iznosila je 0,4 mSv, što je na razini svjetskog prosjeka.