各位大佬，做河水检测的时候，有碰到过氨氮结果加硝酸盐氮结果比总氮高的吗，数据如下
[img=,900,187]https://ng1.17img.cn/bbsfiles/images/2019/03/201903281321076671_8254_3448414_3.png!w900x187.jpg[/img][img=,900,169]https://ng1.17img.cn/bbsfiles/images/2019/03/201903281321081791_3899_3448414_3.png!w900x169.jpg[/img][img=,900,154]https://ng1.17img.cn/bbsfiles/images/2019/03/201903281321084411_1442_3448414_3.png!w900x154.jpg[/img][img=,508,130]https://ng1.17img.cn/bbsfiles/images/2019/03/201903281321079998_9344_3448414_3.png!w508x130.jpg[/img]
另外问下，氨氮结果小于1mg/L时，是保留三位小数，1-10mg/L是保留两位小数，大于10mg/L是三位有效数吗？