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The characteristics of ammonia in drinking water sources in China were evaluated during 2005-2009.The spatial distribution and seasonal changes of ammonia in different types of drinking water sources of 22 provinces,5 autonomous regions and 4 municipalities were investigated.The levels of ammonia in drinking water sources follow the order of river ＞ lake/reservoir ＞ groundwater.The levels of ammonia concentration in river sources gradually decreased from 2005 t0 2008,while no obvious change was observed in the lakes/reservoirs and groundwater drinking water sources.The proportion of the type of drinking water sources is different in different regions.In river drinking water sources,the ammonia level was varied in different regions and changed seasonally.The highest value and wide range of annual ammonia was found in South East region,while the lowest value was found in Southwest region.In lake/reservoir drinking water sources,the ammonia levels were not varied obviously in different regions.In underground drinking water sources,the ammonia levels were varied obviously in different regions due to the geological permeability and the natural features of regions.In the drinking water sources with higher ammonia levels,there are enterprises and wastewater drainages in the protected areas of the drinking water sources.