The Investigation Of Iodine Concentration In Salt,Water,Soil And Some Crops In Hangzhou

Objective: We aim to describe the environment iodine concentration in salt, water, soil and some crops along Hangzhou coast in the China foreland. It will be helpful for us to judge whether this area is insufficient in iodine and universal iodized salt is necessary or not. Methods: We collected iodized salt samples, drinking water samples (tap water in the towns, and well water or spring water in the villages), water samples from different sources (ditches, lakes, rivers), soil samples ,fresh green tea samples and fresh vegetables samples through randomly sampling in June, 2005. Salt water soil iodine and crops iodine was detected by arsenic-cerium redox method. Statistical analysis was expressed as x ± s by Windows SPSS13.0. Results: (1) The iodine concentration in salt was 27.90±4.33 mg/kg (n=108). (2) 75 water samples were collected. The water iodine value was 0.6- 84.8 μg/L, mean of 11.66 μg/L. The watershed along the QianTang River has significantly higher iodine content than the water in LinAn in mountain area (P<0.01). The iodine content and mean iodine content of tap water, well or springwater and natural waiter sources were 4.30±2.43 ug/L (n=34), 23.59±27.74 ug/L (n=19) and 12.72±10.72 \ig/L (n=22) respectively. This indicated that among environmental water sources, the ditch iodine content was the highest with river water iodine being the lowest (P<0.01). (3) Soil iodine value was 0.11" 2.93 mg/kg, mean of 1.32mg/kg. Though there was no statistical difference of soil iodine in different districts (P=0.131), soil iodine content correlated positively with water iodine content. (4) Green tea iodine (dry weight) in Hangzhou was 208.12±48.46|j,g/kg (n=15), around the tea field river water iodine was 10.42±11.75ng/L (n=15)and soil iodine was U5±0.67 mg/kg(n=15)o (5) Fresh vegetables iodine (dry weight) were below: green soy bean 135.03±50.311(ig/kg, kidney bean 167.90±61.99|ig/kg , carob 147.07± 68.74jig/kg , cabbage 330.12±177.50ug/kg ? Conclusions: Iodine concentration in salt accords with national policy of adding iodine in salt. Foreland has more iodine in water than mountain area. The data reflected that water and soil iodine in foreland area was not high, some crops ( such as green tea and vegetables) iodine concentrations were quite low, which suggests universal iodized salt should be necessary. Environment iodine has relatively close association with pollution.