When the bituminised matrix has been altered by swelling, encapsulated radionuclides are easily leached by the contact of ground water and released in the geosphere.
wˌɛn ðə baɪtˈuːmɪnˌaɪzd mˈeɪtɹɪks hˈæzbiːn ˈɔltɚd baɪ swˈɛlɪŋ, ɛŋkˈæpsjʊlˌeɪɾᵻd ɹˌeɪdɪoʊnˈuːklaɪdz ɑːɹ ˈiːzili lˈiːtʃt baɪ ðə kˈɑːntækt ʌv ɡɹˈaʊnd wˈɔːɾɚ ænd ɹᵻlˈiːst ɪnðə dʒˌiːoʊsfˈɪɹ.