摘要
高锰酸盐指数(CODMn)、硝酸根(NO-3)、铵根(NH+4)是判断水体是否受到三氮污染的重要指标。对于测定这三个指标的水样保存方式和时间,地质行业标准和国内外主要国家标准间存在明显差异。地质行业标准规定地下水样品原水室温保存,CODMn和NH+4在3天内测定;NO-3在20天内测定;国家标准和美国标准推荐样品硫酸酸化,避光或冷藏保存,在2~7天内完成CODMn和NO-3和1~7天内完成NH+4测试。为了分析各类标准在样品保存要求上的差异对检测结果的影响,确保检测数据能真实地反映水体污染状况,找寻简便的保存方式,本文在广州地区采集地下水,按照地质行业标准与国家标准进行处理和保存,并在不同时间段对三个指标进行测试。分析验证结果表明:地质行业标准与国家和美国标准关于水样的保存方法均非常可靠。地质行业标准主要针对静态地下水,保存方法相对宽松;国家标准和美国标准适用范围除了地下水,还包括动态的地表水和废水,采样对象成分更为复杂,更不稳定,更容易受外界影响发生变化,故保存条件高于地质标准。在广州地区,采用原水室温避光保存水样,CODMn、NH+4保存时间可为5天,NO-3保存时间可为30天;采用酸化水室温保存水样,CODMn、NO-3和NH+4保存时间可长达30天。这两种方式均比地质行业标准和国家标准推荐的有效时间长,且原水和酸化水室温保存方式相对于冷藏保存方式更为方便。本文提出,如果采集的水样能方便、快速送达实验室,可采用原水保存;如果不能在短时间内送达实验室检测,可采用硫酸酸化保存。
CODMn , NO^-3 and NH^＋4 are important indicators to nitrite, nitrate and ammonia pollution in groundwater. There are significant differences between geological industry standards and national-international standards about the storage ways and time for these three indexes. Geological industry standards prescribed that when samples are stored at room temperature without adding any reagent,CODMn and NH^＋4 should be tested in 3 days while NO^-3 in 20 days. National and international standards proposed that when samples are kept in dark places or in the refrigerator with addition of sulfuric acid,it is better to detect CODMn and NO^-3 within 2-7 days while NH^＋4 within 1 -7 days. In order to analyze the differences of the storage condition of the various types of standards about groundwater,and to make sure getting accurate testing results,stability research of CODMn ,NO^-3and NH^＋4 in groundwater of Guangzhou Region were studied. Under the two kinds of preservation conditions with adding sulfuric acid and adding nothing in groundwater,testing of the three indexes by using new sealed samples at different time. The results showed that all standard methods about water preservation are reliable. Preservation conditions in geological industry standards that are applied to static groundwater are relatively less critical,while preservation conditions in national and international standards that are available to surface water and waste water, which are more complicated,unstable and changeable,are relative more stringency. In addition,in Guangzhou region,under the condition of keeping samples in dark places,CODMn and NH^＋4 could be obtained accurate data both for testing samples with addition of acid for 30 days and without any addition for 5 days. The content of NO^-3was nearly the same under the two kinds of storage conditions in 30 days. Both two methods are more effective than geological industry and national standards, and it is easier to keep samples in dark places than keep in refrigeration. At last,we proposed that groundwater can be stored without any addition when it is easy and quick to take samples back to the laboratory,alternatively,groundwater can be stored with addition of sulfuric acid.
出处
《岩矿测试》
CAS
CSCD
北大核心
2014年第3期419-425,共7页
Rock and Mineral Analysis
