监测环境水样中总铬和铬(Ⅵ)的相关标准、规范存在问题及修订建议

日常工作发现,现行标准、规范在总铬、铬(Ⅵ)水质样品的采集、保存和监测环节存在不一致或不科学的问题。建议总铬、铬(Ⅵ)水质样品均采用非玻璃材质的采样容器和保存容器;1 000 mL总铬样品中添加入10 mL硝酸进行保存;鉴于铬(Ⅵ)样品的复杂性,其保存条件及保存期建议重新研究确定;排放标准中,污染物配套检测方法的规定不宜过于死板;采用二苯碳酰二肼分光光度法检测总铬和铬(Ⅵ)时,针对浊度、还原性物质、氧化性物质等干扰物的预处理需进一步完善。建议水质现行标准、规范在颁布实施后,长期公开征求修改建议并作相应修订。

Existing problems and revised suggestions on standards and criteria for monitoring total chromium and chromium(Ⅵ) in environmental water samples

In routine work, it was found that there were some inconsistent or unscientific problems in current standards and criteria for the collection, storage and monitoring of total chromium and chromium(Ⅵ) in water sample. Non-glass containers for sampling and storage were suggested for water samples which was used for monitoring total chromium and chromium(Ⅵ). 10 mL of nitric acid should be added into 1 000 mL sample of total chromium for storage. In consideration of complexity of chromium(Ⅵ) samples, the storage conditions and storage life should be restudied and confirmed. The regulations for the matching detection methods of pollutants in emission standard should not be too hidebound. During the determination of total chromium and chromium(Ⅵ) by diphenylcarbazide spectrophotometry, the pretreatment of interference materials such as turbidity, reducing substances and oxidizing substances should be further improved. It was suggested to seek long-term public opinions on amending advice and make corresponding revisions after issuing and implementing of existing standards and criterions for water quality.