Water quality in Wuliangsuhai Lake, China, is crucial for human health and the environment. A study analyzed 24 water quality factors in samples from 19 sites during irrigation and non-irrigation periods. They found that pollution levels were higher in the middle of the lake during irrigation, mainly from agricultural and industrial wastewater. In the non-irrigation period, pollution levels decreased significantly, with run-off from the Hetao irrigation area being the main pollution source.