title: [Determination of copper, zinc, iron and calcium in wheat and maize and three nitrogen compounds in high and low risk areas of esophageal cancer].
abstract: This study reports the concentrations of copper, zinc, iron and calcium in wheat and maize from high risk area Linzhou and low risk area Yuzhou of esophageal cancer and three nitrogen compounds of four types of drinking water in Linzhou. The results showed that the concentrations of zinc and calcium in wheat and maize from Linzhou were significantly lower than these from Yuzhou, the copper concentrations in grains were higher and the iron in maize was lower. The nitrate-N concentrations in four types of drinking water from Linzhou were below the national standard but the nitrite and NH3-N concentrations were higher than the national limits. The results suggest that the low concentrations of zinc, iron and calcium and high concentrations of copper in grains as well as the high concentrations of nitrite and NH3-N may be related to the etiology of esophageal cancer.
authors.affiliation: Dept. of Nutrition and Food Hygiene, Henan Medical University, Zhengzhou, China.
authors.forename: W
authors.initials: W
authors.lastname: Li
authors.forename: W
authors.initials: W
authors.lastname: Lu
authors.forename: M
authors.initials: M
authors.lastname: Zhu
authors.forename: B
authors.initials: B
authors.lastname: Shi
mesh_terms: D002118:Calcium / Q000032:analysis; D003300:Copper / Q000032:analysis*; D004938:Esophageal Neoplasms / Q000209:etiology; D006801:Humans; D007501:Iron / Q000032:analysis; D017672:Nitrogen Compounds / Q000032:analysis*; D014908:Triticum / Q000737:chemistry*; D014881:Water Supply / Q000032:analysis*; D003313:Zea mays / Q000737:chemistry; D015032:Zinc / Q000032:analysis
chemical_list: D017672:Nitrogen Compounds; D003300:Copper; D007501:Iron; D015032:Zinc; D002118:Calcium