Research and analysis

A WFD compatible approach to assess acidification using diatoms in UK and Irish rivers

This report describes a new Diatom Acidification Metric that offers a simple but effective way of assessing the ecological status of soft-waters vulnerable to acidification.

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A WFD compatible approach to assess acidification using diatoms in UK and Irish rivers

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There are two reasons why there are no suitable metrics for assessment of pH using diatoms for the Water Framework Directive (WFD): no current metric addresses the issue of ‘expected’ values of metrics, nor do any provide an ecological basis for setting quality status boundaries. The former issue is particularly significant as it is important that ecological status assessments can distinguish those water bodies that have been acidified by human causes from those that are naturally acid. An ecological rationale for setting boundaries is also important as the WFD provides ecological criteria by which ecological status should be assessed. The method described here will sit alongside the diatom metric that currently assesses the extent of eutrophication.

Published 17 October 2012