dˈuː tʊ ɪts ɹˈɛlətˌɪvli lˈoʊ ɹɪɐktˈɪvᵻɾi, ɪt kæn biː fˈaʊnd ɪn sˈiːwɔːɾɚɹ ɪn lˈɑːɹdʒ ɐmˈaʊnts; ɪɾ ɪz ˈɛstᵻmˌeɪɾᵻd ðæt sˈiːwɔːɾɚɹ ɪz ɐpɹˈɑːksɪmətli zˈiəɹoʊ.fˈoːɹtiːn tə zˈiəɹoʊ.twˈɛnti fˈaɪv pˈɑːɹts pɜː mˈɪliən pˌiːpˌiːˈɛm ɔːɹ twˈɛnti fˈaɪv mˈaɪkɹoʊmˌoʊlɚ.
Due to its relatively low reactivity, it can be found in seawater in large amounts; it is estimated that seawater is approximately 0.14 to 0.25 parts per million (ppm) or 25 micromolar.