# Pesticides in drinking water: Atrazine

On this web page you can see how many carcinogen molecules you ingest on a normal day by drinking two liters of water with only 1 ppb (parts per billion) of Atrazine.
The formula of Atrazine is C8H14ClN5. In the table bellow you can see a picture of the Atrazine molecule with the calculation of the molar mass.

 =12,01 g/mol =1,01 g/mol =34,45 g/mol =14,01 g/mol
Calculation of the molar mass of Atrazine
g/mol

1 ppb (by mass) of Atrazine means 10-9 kg of Atrazine for 1 kg of water. The number of moles of Atrazine can be calculated with formula (1):

 (1)
 where: = quantity of matter (mol) = mass of element (g) = molar mass (g/mol)

The number of molecules in a certain quantity of matter can be calculated with formula (2)

 (2)
 where: = number of molecules = quantity of matter (mol) = Avogadro number = 6,02·1023 (mol-1)

The combination of equation (1) with equation (2) gives (3):

 (3)

The mass of Atrazine present in one liter of water with 1 ppb of Atrazine is 10-9·103 g.
All the parameters for formula (3) are now known.

 =10-9·103 g =215,72 g/mol =6,02·1023 mol-1 molecules of Atrazine for 1 liter with 1 ppb

The French limit for Atrazine in drink water is 0,2 ppb this comes over with 5,58·1014 molecules in one liter. Imagine that you drink 2 liter of this water a day, it means that you ingest 1,1·1015 molecules of this pesticide every day.

Experimentation in labs on animals shows that Atrazine is carcinogen. Direct experimentation on human beans is not done but there are several epidemiological studies that conclude that Atrazine is carcinogen.

For further information take a look at the websites mentioned bellow:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15367570&dopt=Abstract