Thematerialhas been filtered at 0.45 µm and acidified with HNO3 toaroundpH1.5Certifiedvalues500 mLAl. 159 µg/kgCd.2.94 µg/kgPb . 7.78 µg/kgAs. 10.8 µg/kgCu.45.7 µg/kg