Chenghai Lake (Chinese: 程海) is a plateau lake in Yunnan Province，southwest of China. The lake has a total area of about 77.22 square kilometers. The average depth is 25.7 m, with an elevation of 1503 m. the water storage capacity is about 19.87×108m3.[1] Chenghai Lake is one of only three lakes in the world where Spirulina is found naturally.

Recent tests by China's State Food and Drug Administration (SFDA) have revealed that several brands of the medicinal algae spirulina contain dangerous amounts of lead. These results have led to a recall by the SFDA of all tainted spirulina products.

Spirulina from eight different companies was bought in drug stores in northeast China and tested for heavy metals. Six of the eight brands contained unhealthy levels of lead. One US brand, Cont-healthy, had lead levels exceeding Chinese governmental standards by 820 percent, according to a Xinhua news report.

The report of lead contamination could have a negative impact on Lijiang's economy. Chenghai Lake (程海) near Lijiang is one of only three lakes in the world where spirulina grows naturally, the other two being Lake Chad in Africa and Lake Texcoco in Mexico. Farms on Chenghai Lake produce 40 percent of the world's spirulina supply.

Two Chinese companies whose products tested positive for contamination, U-Ways (尤维斯) and Green-A (绿A), source their spirulina exclusively from Chenghai Lake.

Generally sold as a dietary supplement, spirulina is a blue-green algae rich in protein, vitamins and amino acids. It is sold in powder or tablet form and is marketed in China as a weight loss product, a palliative for heart disease, an anti-cancer agent and as a health supplement for pregnant women.

The high levels of lead may have come from companies putting additives into their products. The Xinhua report quoted an industry insider in Yunnan who said it is common that manufactures use cheaper and substandard spirulina powder to cut costs.