Water Surveys

Too often in the preparation and Interpretation of geochemical surveys great emphasis is placed on the analytical methods used and recognition of any assodated sources of error. However, before a sample can be analysed it must be collected, and it is this aspect of the analytical programme than can be neglected; Bad sampling techniques can invalidate a survey and are far more costly to correct than analytical errors. Laboratory errors or mistakes can often be corrected by reanalysis of the sample, but if the sample is contaminated or unrepresentative, the analytical result will lack significance, regardless of the accuracy and precision of the analytical method used. This is not usually discovered until after the samples have been analysed and the data interpreted on a field-wide basis, possibly necessitating a re- sampling programme: bad sampling techniques are very costly. It is therefore worthwhile to adopt standardised methods of water sampling. This includes standardising the equipment to be used, and the correct preparation of that equipment in the laboratory several days before any field surveys are undertaken.