Overall Duration of Sampling

How long should monitoring programs continue For the purposes of specifically answering the question What is the ecosystem response to changes in atmospheric loadings of mercuiy , some specific timeframes should be considered. 

Reductions in U.S. mercuiy emissions from medical and municipal waste incinerators and other industrial sectors have already occurred. Additional emission reductions from some coal-fired power plants have also already begun as co-benefits from technologies used to control SO2 and NO emissions. These mercury emissions from power plants are, however, expected to be reduced further over the next few decades. Meanwhile, changes in mercuiy emissions in other parts of the world may also affect some U.S. ecosystems. 

There is uncertainty concerning the length of time it will take for ecosystems to respond to reductions in mercuiy deposition. It is agreed, however, that it is important to continue monitoring until the majority of the ecosystem responses have been documented. If monitoring is discontinued before that point, the full response 

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