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agrocks
Visitor

Anybody knowledgeable in DDT?

I'm sorry to bother everyone and I hope I'm not too disruptive with this post.

 

I'm an American considering moving to the Canary Islands (Spain) with my wife to have a baby.  I found a study from 2004 which found very high levels of DDT pesticide in the people on those islands.  Now I'm reconsidering everything and I'm hoping someone here knows enough about the substance to tell me how to make this move safely or if I should forget the whole thing.  We're headed to the capital city (Las Palmas de Gran Canaria) and the study finds particularly high levels on that island and in urban areas so we must be headed to the worst possible spot for it.  Why would DDT levels be so high in urban areas?

 

In case anyone's curious, here's a link to the study in PDF form:

 

http://www.atan.org/contaminacion/pesticidas/DDT-people.pdf

 

and here you can view the PDF in Google Viewer so you don't have to handle the PDF:

 

http://docs.google.com/viewer?url=http%3A%2F%2Fwww.atan.org%2Fcontaminacion%2Fpesticidas%2FDDT-peopl...

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8 Replies
JacobMcCandless
Senior Contributor

Re: Anybody knowledgeable in DDT?

This research you have linked measured DDT and the metabolite DDE and DDDwhich have a very long half life.

 

The results are below those of Americans and Mexicans.

The ratio of DDT to DDE/DDD is high which indicates that there have been recent exposures.

 

It doesn't look to me that there were any agricultural applictions on these island because there is no radially decreasing high point.  There are no very high level in a few members of the population.

 

Most of the participants have at least some exposure so while it may be food born exposure it is somewhat unlikely.

 

There is an age group and gender trend.  The island to island trend is ambiguous.

 

Plausible explainations would be water source, or something along the lines of areial spraying probably in Africa, maybe on the Islands themselves.  I'm not sure if there is enough information as to whether or not the exposure was aeresol or if it precipitated.

 

Due to the gender trend I would estimate it was sprayed mid-july-ish in the morning.

 

If DDT is what you are worried about do not go to Tanzania, Mexico or the United States.  These countries probably use DDT that you will be exposed to most severly.  

Canary Island exposure is not a strong threat.

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agrocks
Visitor

Re: Anybody knowledgeable in DDT?

Hi Jacob, thank you for taking the time to write. Since p, p' -DDT has a relatively short half-life, isn't it a good indicator of whether or not there has been recent exposure to DDT?  Here are the comparitive levels of p, p' -DDT (table 5 on page 58):

 

Tanzania: 3034
Mexico: 190 - 356

*Gran Canaria: 280

*Tenerife: 248
Sweden: 20.4

*La Gomera: 32.4

Canada: 11 - 12.6

*La Palma: 8.9

*El Hierro: 7.8

*Lanzarote: 5.7

Egypt: 3.9
*Fuerteventura: 0

 

* Canary Islands

 

To me this looks like an indication of an ongoing DDT problem on Gran Canaria and Tenerife.  Could you point out my misunderstanding?

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Husker-J
Senior Contributor

Re: Anybody knowledgeable in DDT?

DDT is still in use in many countries, as an insecticide against insects that have the potential to spread disease (I think one of the first uses of DDT, was to control mosquitos that were found to spread malaria).

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agrocks
Visitor

Re: Anybody knowledgeable in DDT?

Very true, in some countries the threat of malaria is more severe than the threat posed by DDT.  Not in Spain though where DDT has been prohibited since 1977.

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JacobMcCandless
Senior Contributor

Re: Anybody knowledgeable in DDT?

It seemed to me that the levels were lower than the reference data (bear in mind I've assumed the data requires no adjustments or speculation). It would suggest that this was a one time occurrence, or the DDT is being applied sparingly. From what I understand, DDT is only an effective Ausgang when it is applied intensely and thoroughly. Specifically, the DDE/DDD data is what brings me to this conclusion.


The levels of DDT are clearly detectable.  Even adding the DDE/DDD and DDT together these are comparatively low levels.

 

The levels are actually so low I'd accept that there may not be any direct or drift exposure at all.

 

Islands typically do not have mosquitoes.

 

I'll tell you what a good remedy is.  And then you can laugh at me.  Testosterone.  The females do not form mouths and the diesese is not spread.  Four gallons of hard piss in the spring could do it.

 

You can add that to a light bulb and some fly tape.

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agrocks
Visitor

Re: Anybody knowledgeable in DDT?

I'm sorry but I don't follow.  The DDT levels on Gran Canaria and Tenerife look comparatively high to me, at least compared to countries other than Mexico and Tanzania where DDT was not prohibited at the time samples were gathered.

 

Tanzania: 3034
Mexico: 190 - 356
Gran Canaria: 280
Tenerife: 248
Sweden: 20.4
La Gomera: 32.4
Canada: 11 - 12.6
La Palma: 8.9
El Hierro: 7.8
Lanzarote: 5.7
Egypt: 3.9
Fuerteventura: 0

 

These are the p, p' -DDT levels.  p, p' -DDT seems most appropriate for examining recent exposure to DDT since it has the shortest half-life.

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JacobMcCandless
Senior Contributor

Re: Anybody knowledgeable in DDT?

I would have expected variances amongst the population to be at least an order of magnitude due to the nature of areas of concentrated application. Ordinarily, we would expect as much as half of the DDT to be in a very localized area. A few people should be highly exposed.

Certain crops are not eaten by some and eaten often by others, although I do not know what the dietary habits are like in this part of the world. There should almost invariably be a large subsection with 0 exposure.

Men on average eat more than do women, even double. I would be expect "industrial exposure" to be on the list of possibilities but it is not.

Direct potable water supply exposure is a possiblity.

I'd like to see what studys of other populations have found.  Obviously there is exposure.  It certianly would be a concern if it came off the the tradewinds of the African continent.

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agrocks
Visitor

Re: Anybody knowledgeable in DDT?

Doesn't the fact that p, p' -DDT is concentrated on only 2 of the 7 Canary Islands indicate that the chemical did not blow over from the African continent?  In fact, the two islands closest to the continent don't show any p, p' -DDT at all.

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