River Carnon Wheal Jane Mine hydrochemistry data

The River Carnon was sampled just downstream of the main Wheal Jane mine discharge using a polythene bucket attached to a nylon chord. Samples were returned to the Wallingford Laboratories for processing. Unfiltered samples were used for pH and alkalinity determination and samples were kept in filled glass bottles prior to analysis in order to minimise carbon dioxide changes (degassing in particular) that would affect the pH reading. Subsamples were filtered through 0.45 micrometer cellulose nitrate membranes and samples were stored prior to metal analysis after acidification to 1% with concentrated high purity nitric acid. For anions and nutrients (including silicon and ammonium), the samples were stored without acidification. Polypropylene bottles were used for storage and these bottles were cleaned with 10% hydrochloric acid and subsequently rinsed with distilled water. The samples were stored at 4 degrees C in the dark. Sampling and analysis was carried out by CEH in conjunction with the University of Reading. Water quality was monitored the River Carnon as part of a CEH science budget project. All the measurements and data collation were undertaken by CEH staff.