Determination Of Trace N-nitrosamines In Environmental Water In Pearl River Delta And Study On The Relationship Between The Nitrosamines And Cancer Incidence

The cancer is one of the most common malignant tumor in the world.Its regional and zonal distribution has a high incidence of concentrated in phenomenon.The typical local cancer in the Pearl River Delta region of China is hepatocellular carcinoma and nasopharyngeal carcinoma,and the incidence of nasopharyngeal cancer ranks first in the world.90% of cancers are currently considered to exposure to cancer-causing chemicals.The N-nitrosamines compounds are recognized as strong carcinogens.According to the characteristics of low water content and hydrophilic of most N-nitrosamines,a solid-phase extraction(SPE)method that suitable for gas chromatography with mass spectrometry(GC-MS)to detect trace nine N-nitrosamines in environmental water was developed in this paper.As a representative of two local cancer high-risk area in Shunde and Sihui,we analysis of different water bodies in the area of the content and distribution law of nitrosamines compounds to explore its relationship with the local cancer incidence.We draw the following conclusions:(1)We adopted 4L for water sampling on the premise of allowable recovery.The coconut shell activated carbon was used as filler for N-nitrosamines extraction column in this method.The time passing the column was optimized to 0.5h/500 m L.The eluents directly blowed nitrogen to concentrate to 0.2 m L,and the enrichment ratio is 20 000 times.(2)N-nitrosamines were separated using gas chromatography with mass spectrometry(GC-MS),performed with DB-35 MS separation capillary,with high purity helium as reagent gas.Injection volume was 2μL.The instrument was equipped with electron impact ion source to detect and selected ion mode(SIM)to analysis.The recovery of 8 kinds of nitrosamine compounds recovery was 74%-124% except NDPh A.The detection limits ranged from 0.34 to 2.19ng·L-1 which basiclly met the requirements of the EPA 521 method.Furthermore,it was easy to operate and reproduce well.(3)According to the results of testing N-nitrosamines,NDMA were the main pollutants.Other nitrosamines are also detected,but the content was low.Lack of oxygen in water and water reducing environment might be one of the conditions of NDMA formation.(4)Since 1960 s to change water in Shunde and Sihui,the local people drank tap water instead of directly drinking pond water.However,we detectde with high nitrosamines NDMA in the fishing pond.The water content of nitrosamines were associated with engineering assignments and other human activities.The water in serious environmental pollution will become a hot spot.(5)High incidence of cancer of the groundwater is polluted by N-nitrosamines compounds,and the content is relatively close.Nitrosamines are widely distributed,forming ways,may be associated with local geological environment.(6)Although the pollution by nitrosamines in Shunde and Sihui area was different,the source pattern of precursor substance nitrates,nitrates,nitrites and amines in formation of the water nitrosamines is consistent.It leads to two local high cancer incidence region,certainly will cause people more attentions in terms of safe drinking water.