Collected from the River Thames downstream of Henley-on-Thames at Aston, U.K. Filtered at 0.7 mm and then at0.45 mm. Stabilised at pH 2 by the addition of concentrated HNO3.Certified valuesAl . 73 mg/L Cu .15.4 mg/L Na . 24.7 mg/LCa .mg/L Fe .287 mg/L Pb.
