| The heavy metals contents of irrigation water, including Cd, Hg, As, Pb, Cr, Cu, Zn and Ni, in the
agro-producing areas of Hainan Province were investigated by random sampling. Environmental quality conditions of
the heavy metals were evaluated by methods of single quality index and complex quality index. Results showed that
the average contents of metals were all under the limiting values prescribed by "HJ 3322006 Farmland
environmental quality evaluation standards for edible agricultural products". Single quality indices of the eight
elements were all lower than or equal to 0.5, and complex quality index of the eight elements was 0.17. Irrigation
water environmental quality in the three study places (Sanya, Qionghai, Dongfang) were all set at the first class
belonging to clean level, being fit for planting non-pollution agricultural products. However, the contents of heavy
metals in some areas were beyond the limiting values, such as the contents of Hg from individual Sanya and Qionghai
samples, the contents of Ni from individual Dongfang samples. For most heavy metals, they were positively correlated
with one another in contents. For instance, there was a very significant correlation between the content of Cd and the
content of Pb, there was a significant correlation between the content of As and the content of Ni. |
