福建省某县级市生活饮用自备水水质初步分析及评价-食品加工与安全专业论文.docxVIP

In section III, general chemical indexes (8 items in total, including pH, chlorides, iron, manganese, copper, zinc, and sulfates) are tested on 304 daily drinking water samples, and results of various items under tests are analyzed and pooled: of all 304 samples, 264 samples belong to soft water in terms of the total hardness and 40 belong to hard water, of which 2 samples above highly hard; 45 of all 304 samples fall in the range from pH=6.2 to pH=6.4, and 122 of all 304 samples exceeds the standard pH value, the non-conformity rate reaching up to 40/1%, which means that the water here tends to be acidic; 23 samples exceed the standard in terms of the content of manganese, the non-conformity rate being 7.6%; the conformity rate of other 6 items is high relatively and it exceeds 95%, that is, the conformity rate is 99.7% for total hardness, 99.3% for chlorides, 99.0% for iron, 100% for copper, 98.7% for zinc, and 100% for sulfates. In section IV, toxicological test is performed on 304 water samples collected from wells and springs for determining seven indexes (nitrogen of nitrates, lead, nitrogen of ammonia, nitrogen of nitrites, hexavalent chromium, and fluorides), and results of various items under tests are analyzed and pooled: the conformity rate of nitrogen of nitrates and hexavalent chromium is 100%; only one sample exceeds the standard in terms of nitrogen of nitrites, and therefore the conformity rate of this index is close to 100%; the conformity rate of the other three indexes exceeds 95%, that is, 95.7% for lead, 98.7% for nitrogen of ammonia, and 98.0% for fluorides. The conformity rate of all toxicological indexes exceeds 95%, and therefore the result of toxicological test on those 304 samples collected from wells and springs is satisfactory. Section V, Summary and suggestions： Including the analysis on the existing problem related to the daily water in Nan’An city, based on the pooled statistics for the quality of these 304 water samples, it may be co