Environment Process And Toxicological Effects Of The N-nitrosodimethylamine (NDMA)

N-nitrosodimethylamine (NDMA) is an industrial and environmental pollutant,which has strong carcinogenicity, mutagenicity, and teratogenicity. NDMA has beendemonstrated to cause cancers in organs, including liver, lung, and kidney, in animals.NDMA aroused great attention resulting from the widely distribution in environments.However, the toxicological data of NDMA are still deficient, especially data ofdomestic aquatic toxicology lacking. This paper summarized the sources, forms andexposure pathways of NDMA, and analyzed the toxicological effects of NDMA tohuman and animals. The acute toxicity tests of NDMA on Pseudokirchneriellasubcapitata and Daphnia magna Straus was investigated to classify the toxicity levelof NDMA. The main contents are as follows:1. Environment process and toxicological effects of NDMANDMA was detected in products (such as fuel, lubricating oil, tobacco,herbicides, pesticides, rubber etc.) as well as food processing, storage andtransportation. The various pollution sources and diverse releases had led to humanmultiple exposure pathways. Human beings can be exposed to NDMA through itspresence in food, water, air, and consumer products. In the appropriate conditions,NDMA can be formed in vivo. Many studies conducted with laboratory animalsindicate that NDMA is absorbed rapidly and extensively, primarily from the lowerintestinal tract (>90%). And also NDMA can be passed to offspring through breastmilk. The relevant epidemiological studies reported that NDMA can cause cancers,such as liver, gastric, tract and lung cancer, in both acute toxicity and chronic toxicityexperiments of animals (including rats, mice, hamsters, guinea pigs, monkeys, etc.).Many studies have shown that NDMA can increased frequencies of gene mutations,chromosomal damage, and unscheduled DNA synthesis.2. Acute toxicology tests of NDMAAccording to the procedures of "Chemicals-algal growth inhibition test" and"Water quality-Determination of the acute toxicity of substance to material onDaphnia (Daphnia magna straus)”, the experiments of72h algae growth inhibitiontest and24h acute toxicity of Daphnia magna Straus were carried out respectively.The test conditions, such as pH, DO, temperature, light cycle as well as the testsolution concentration accuracy were under strict control. The EC50s were calculated through the analysis of chlorophyll, biomass, inhibition rate, and the number of deaths.The24h-EC50,48h-EC5072h-EC50of Pseudokirchneriella subcapitata were4.49,0.18,0.33g/L respectively, and the95%confidence intervals were1.48-1.66,0.12-0.24,0.26-0.41g/L respectively. The EC50of Daphnia magna Straus was4.22g/L, and the95%confidence interval was3.195-5.574g/L. According to the “Theguildlines for the hazard evaluation of new chemical substances”, hazard of NDMA’secological toxicity was graded which was low level, but the chronic toxicity remainsto be studied.