But because factories were allowed to -- allowing warm water to run back into the river, the temperature was becoming too high for the salmon to survive.

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The government has put up posters and organised talks to explain to the villagers that urinating in the water can make them sick, and that they should avoid bathing in the river at noon - the snails come out when the temperature is highest.

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Atoms of elements with boiling points below the temperature of a particular plate pass over it, just as water runs over a warm river-bed.

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