Together with calcium, magnesium plays an integral role in tooth and bone hardness.

再加上钙，镁起着牙齿和骨骼硬度不可或缺的作用。

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Is mainly composed of calcium magnesium sulfate, chloride and nitrate as the hardness of the form salts.

主要是由钙镁的硫酸盐、氯化物和硝酸盐等盐类所形成的硬度。

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Major Inorganic Components: Sodium, potassium, chloride, calcium, magnesium, alkalinity, total hardness, total phosphorus, fluoride, sulphate.

主要无机成分：钠，钾，氯，钙，镁，碱度，总硬度，总磷，氟化物，硫酸盐。

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Other values recorded include ammonia, chlorine, water hardness (calcium and magnesium), dissolved oxygen and organic carbon.

BBC: Thames archive reveals long nitrate rise