drinking water treatment by UV Light, are we increasing the problem.
IN Pakistan we are using UV LAMPS for drinking water
treatment, thinking exposure to uv light kills bacteria, virus .
some who know a little more think that rather than killing it
stalls the further multiplication, so for so good. today i came across this
mutation effect that scares me to think . rather than making our wter safe we may be adding several types of mutated bacteria and virus to our system . these microorganisms are of unknown nature may be more dangerous than the ones we are trying to get rid of and much more resistant to what we know of controlling them.
‘Acquired (or somatic) mutations occur in the DNA of individual cells at some time during a person’s life. These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if a mistake is made as DNA copies itself during cell division. Acquired mutations in somatic cells (cells other than sperm and egg cells) cannot be passed on to the next generation.’
hope microbiologists and molecular/ biological engineers can help me get rid of this negative thinking
July 19, 2011 at 11:58 pm
July 22, 2011 at 7:55 amadmin
link | author
Sheherzad Akhtar to me
show details Jul 20 (2 days ago)
Dear jahangir sb,
AA,
this is absolutely true what ever is written, inadequate ultaviolet light mutates the bacteria instead of killing it., usually the bacteria get weakened but any of them can mutate to become lethal. Its also true that by adulthood many of our own cells have mutated DNA.
im sorry i was out of office all day today and am now checking my mail from home. Ill be there tomorrow morning in case i can do anything for you.
With best regards,
sheherzad
office: 051 2213102
cell: 03335444192
August 8, 2011 at 6:25 pmadmin
link | author
Luzi, Samuel to me, Jamila, Sheherzad, Dr
show details Aug 5 (3 days ago)
Dear Mr. Jahangir
Thank you for your e-mail, good to hear from you after such a long time. I hope everything is fine with you!
Good to see also that your water website is up and running.
Regarding the issues of UV treatment (sorry for the late reply, I was on vacation):
I just talked to Prof. Thomas Egli from the Microbiology Department of Eawag. He says that mutations due to UV-C irradiation (lamps) for water treatment making pathogenic organisms more resistant against such radiation have not been observed so far. Bacteria do have well known repair mechanisms to repair damage to DNA caused by UV-C radiation (or other mutagens, or occurring naturally independent of external influences). At UV-C doses applied in water treatment plants, these repair mechanism are overwhelmed, however, thus irreversibly inactivating the pathogenic organisms. The risk for mutations to occur that would make cells more resistant (i.e. produce more effective repair systems) is very low, as the repair mechanisms are complex and not dependent on single genes à several mutations would have to occur at the same time), which may explain why no such mutations have been observed in decades of water treatment with UV-C.
In the case of SODIS, inactivation of pathogens does not occur through damage to DNA, but rather damage to proteins, mainly of the respiratory system in the cell membrane (e.g. http://www.ncbi.nlm.nih.gov/pubmed/20395268). UV-A is not directly mutagenic. Again, no resistances after the irradiation with sunlight (or artificial UV-A) have been observed, bacteria cultivated after exposure non-lethal doses of UV-A light are just as sensitive to damage from sunlight as the original population.
One further factor relates to selection: Even in the unlikely case that a mutant with enhanced resistance to UV radiation was created (by spontaneous or induced mutation), this pathogen would still have to out-compete other individuals without this mutation, and do so under conditions where the enhanced UV resistance does not provide an advantage (i.e. the digestive system). The likelihood of a proliferation of such an (already unlikely) mutation is thus very low.
Hope this is useful.
And best regards! Samy