0 present participle of discolour
1 to (cause something to) change from the original colour and therefore to look unpleasant:
The polluted mine water contaminates those sources, destroying wildlife and discolouring the water.
There are mines which have been discharging discolouring water, often for centuries, without causing serious damage.
However, if we accept that there is a problem with discolouring, there is a parallel with frozen mushrooms.
That provides the conditions for the textile industry to rise to the challenge and, to meet pollution reduction targets, to work on means of reducing discolouring emissions.
Experts believe that these low concentrations would not be a health hazard, even though they have unpleasant odours and are capable of discolouring some metals such as copper.
Especially in children, before the development of the permanent teeth, overdosage can lead to dental fluorosis, a discolouring and weakening of the enamel.
There were extensive signs of discolouring, which seemed to indicate extensive bruising.
Once harvested, sprouts last three to five weeks under ideal near-freezing conditions before wilting and discolouring, and about half as long at refrigerator temperature.
