Intercomparison 9913 of the International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes (ICP Waters report 51/1999)
MetadataShow full item record
- NIVA-rapport 
57 laboratories in 24 countries participated in intercomparison 9913. Two sample sets were used, one for the determination of major ions and one for organic matter and aluminium fractions. Based on the general target accuracy of ± 20 %, 78 % of the results were acceptable. More than 80 % of the result pairs were acceptable for conductivity, chloride, sulfate, magnesium, sodium, and dissolved organic carbon. For pH only 57 % of the result pairs were acceptable in relation to the extended target accuracy of ± 0.2 units. For three analytical variables it was decided not to evaluate the reported results, reactive and non-labile aluminium because of the great spread between the results from the few participants, and nitrate + nitrite because of the instability of sample A. Normalization of the methods is necessary to improve the comparability for pH and aluminium fractions. Manual methods are generally less sensitive compared to instrumental methods, and are not always suitable for acid rain monitoring.
PublisherNorsk institutt for vannforskning
ICP Waters report;51/1999