The power lines saga - again

Asolepius

Graduate Poster
Asolepius
Joined
Jul 5, 2004
Messages
1,150
This has come up yet again in my local newspaper. Can anyone direct me to the most up to date data on EMF and the risk of childhood leukaemia? Someone is citing the 1999 US study and I'm sure there's something later than that. Nothing on the MRC site. The trouble is that the usual web searches dredge up so much rubbish.
 
Les Rose said:
This has come up yet again in my local newspaper. Can anyone direct me to the most up to date data on EMF and the risk of childhood leukaemia? Someone is citing the 1999 US study and I'm sure there's something later than that. Nothing on the MRC site. The trouble is that the usual web searches dredge up so much rubbish.
Click to expand...

I'll have to look around, but EXACTLY which study did they quote in your newspaper? It'll be worth looking up just to see if anyone else has demolished it (and if not it may be time to give the old wrecking ball a workout!) :)

Also how about a short precis of what was in the newspaper? There may be other elements there worth following up.
 
It was just a letter to the editor. It mentions the `1999 study by the US Institute of Environmental Health Sciences', which allegedly took 6 years and cost $60m, and found `an increased risk of childhood leukaemia with exposure to electromagnetic fields'. The writer says that as a result, new US homes are not allowed near power lines. Also cites research by Profs Denis Henshaw and Dr Peter Fews. They apparently found that power lines produce charged particles that attach themselves to pollutants, giving them an electrical charge and increasing the risk of lung deposition. Henshaw is said to have concluded that magnetic fields surrounding power lines can triple the the amount of cancer-causing pollutants in the air.
 
Les Rose said:
It was just a letter to the editor. It mentions the `1999 study by the US Institute of Environmental Health Sciences', which allegedly took 6 years and cost $60m, and found `an increased risk of childhood leukaemia with exposure to electromagnetic fields'. The writer says that as a result, new US homes are not allowed near power lines. Also cites research by Profs Denis Henshaw and Dr Peter Fews. They apparently found that power lines produce charged particles that attach themselves to pollutants, giving them an electrical charge and increasing the risk of lung deposition. Henshaw is said to have concluded that magnetic fields surrounding power lines can triple the the amount of cancer-causing pollutants in the air.
Click to expand...

Thanks, interesting. You know that Henshaw is one of Coghill's "associates" don't you? Henshaw seems fairly respectable but he also appears to have an agenda. Last I heard his pollutant theory was just that - theory only. I've never heard of Fews. Who was the writer by the way? I've got to know the names of many of Coghill's friends, maybe it's some name I'll recognise.

In the meantime here are a couple of studies for you:

Br J Cancer 2000 Dec;83(11):1573-80
Childhood cancer and residential proximity to power lines. UK Childhood Cancer Study Investigators.

http://www.ncbi.nlm.nih.gov/entrez/...ve&db=pubmed&dopt=Abstract&list_uids=11076671

"There was no evidence that either proximity to electrical installations or the magnetic field levels they produce in the UK is associated with increased risk of childhood leukaemia or any other cancer."

Lagorio S, Salvan A. Infantile leukemia and exposure to 50/60 Hz magnetic fields: review of epidemiologic evidence in 2000 Ann Ist Super Sanita. 2001;37(2):213-24.

http://www.ncbi.nlm.nih.gov/entrez/...ve&db=pubmed&dopt=Abstract&list_uids=11758279

"We review the epidemiological evidence on childhood leukemia and residential exposure to 50/60 Hz magnetic fields. The possibility of carcinogenic effects of power frequency magnetic fields (ELF-EMF), at levels below units of micro tesla (microT), was first raised in 1979 by a case-control study on childhood cancer carried out in Denver, USA. In that study, excess risks of total cancer and leukemia were observed among children living in homes with "high or very high current configuration", as categorised on the basis of proximity to electric lines and transformers. Many other epidemiological studies have been published since then, characterised by improved--although still not optimal--methods of exposure assessment. At the end of 2000, the epidemiological evidence to support the association between exposure to extremely-low-frequency magnetic fields and the risk of childhood leukemia is less consistent than what was observed in the mid 90s. At the same time, a growing body of experimental evidence has accumulated against both a direct and a promoting carcinogenic effect of ELF-EMF. Such "negative" experimental evidence hampers a causal interpretation of the "positive" epidemiological studies."

I'll check out the site you mentioned and get back to you.
 
There's a whole list of studies, many of which "softly" conclude a demonstrable effect, that can be found on PubMed by typing in "EMF leukemia" into the search field.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?SUBMIT=y

At first blush, however, it appears that a lot of the abstracts are editorializing and re-stating conclusions from previous studies.

To clear this up, someone (or some group) has to come up with a definitive, non-speculative mechanism as to how non-ionizing electromagnetic radiation can induce cancer. There appears to be some data that suggest that ELF can induce immune cells to release free radicals, but it appears that this theory is still somewhat superficial and has involved some post hoc stringing together of the few observations they've seen in the test tube.

Interesting debate. IMHO, it's too soon to come down too hard on either side of it just yet, but I'm currently leaning towards "no effect" myself (until a better, more plausible mechanism can be elucidated).

-TT
 
O.K. Les, that site you quoted looks O.K.

Here is the info on that 1999 US report.

Info on the report is at this site: http://www.niehs.nih.gov/emfrapid/

From the summary press release:

"Environmental Health Institute Report Concludes Evidence is 'Weak' that EMF's Cause Cancer

After six years of accelerated, Congressionally mandated research, the National Institute of Environmental Health Sciences today announced it has concluded that the evidence for a risk of cancer and other human disease from the electric and magnetic fields (EMF) around power lines is "weak."

NIEHS’ review and analysis of the existing data came in a report to Congress, released today. The report applies to the extremely low frequency electric and magnetic fields surrounding both the big power lines that distribute power and the smaller but closer electric lines in homes and appliances.

While sections of the report say EMF exposure "cannot be recognized as entirely safe," the report concludes: "The NIEHS believes that the probability that EMF exposure is truly a health hazard is currently small. The weak epidemiological associations and lack of any laboratory support for these associations provide only marginal scientific support that exposure to this agent is causing any degree of harm."

Research continues on some "lingering concerns," the report says, and efforts to reduce exposures should continue.

NIEHS said that the "strongest evidence" for health effects comes from statistical associations observed in human populations with childhood leukemia and chronic lymphocytic leukemia in occupationally exposed adults such as electric utility workers, machinists and welders. "While the support from individual studies is weak," according to the report, "these epidemiological studies demonstrate, for some methods of measuring exposure, a fairly consistent pattern of a small, increased risk with increasing exposure that is somewhat weaker for chronic lymphocytic leukemia than for childhood leukemia."

However, laboratory studies and investigations of basic biological function do not support these epidemiological associations, according to the report. It says, "Virtually all of the laboratory evidence in animals and humans and most of the mechanistic studies in cells fail to support a causal [cause and effect] relationship."

From the Q&A of the same organisation (2002):

"Q: Is there a link between EMF exposure and childhood leukemia?

A: Despite more than two decades of research to determine whether elevated EMF exposure, principally to magnetic fields, is related to an increased risk of childhood leukemia, there is still no definitive answer. Much progress has been made, however, with some lines of research leading to reasonably clear answers and others remaining unresolved. The best available evidence at this time leads to the following answers to specific questions about the link between EMF exposure and childhood leukemia:

* Is there an association between power line configurations (wire codes) and childhood leukemia? No.

* Is there an association between measured fields and childhood leukemia? Yes, but the association is weak, and it is not clear whether it represents a cause-and-effect relationship."
 
Thanks Pragmatist et al. The writer of the letter was D M Colcomb of Devizes. I didn't know about the Henshaw-Coghill connection - that says a lot. One final point to clear up - is it really true that there is US legislation against building homes near power lines? There might be silly little local laws, but I have never heard of any federal law.
 
ThirdTwin said:
There's a whole list of studies, many of which "softly" conclude a demonstrable effect, that can be found on PubMed by typing in "EMF leukemia" into the search field.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?SUBMIT=y

At first blush, however, it appears that a lot of the abstracts are editorializing and re-stating conclusions from previous studies.

To clear this up, someone (or some group) has to come up with a definitive, non-speculative mechanism as to how non-ionizing electromagnetic radiation can induce cancer. There appears to be some data that suggest that ELF can induce immune cells to release free radicals, but it appears that this theory is still somewhat superficial and has involved some post hoc stringing together of the few observations they've seen in the test tube.

Interesting debate. IMHO, it's too soon to come down too hard on either side of it just yet, but I'm currently leaning towards "no effect" myself (until a better, more plausible mechanism can be elucidated).

-TT
Click to expand...

Yes, this is quite typical. Lots of meta analyses of epi studies, but overall very little. Having looked at the electromagnetics angle of many of these studies I am not at all impressed or convinced that the data is meaningful. If you take a close look at the sample sizes, selection criteria etc., of many of them, most are suspect.

For what it's worth I believe that there is sufficient evidence that yes there is a level of risk. But that under normal environmental conditions the risk is extremely rare and minimal and doesn't require any urgent action. I wouldn't want to live directly under a 300KV power line, but at the same time I don't feel a sense of panic whenever I get near to my toaster! :)

What it usually comes down to is that there an apparent correlation but no obvious causation. This was discussed elsewhere and amongst the things that came up are other possible causal factors that could lead to possible associations between cancers and powerlines that have nothing to do with EMF's, for example defoliant chemicals sprayed along the routes of power lines (to prevent trees growing up into the lines), or PCB's used in electrical insulators on the lines which often leak... and so on.

But the power line "panic" is also big business for some. Take a look at the "biolelectromagnetics" thread in General Skepticism and the Paranormal for a truly disgusting example of the levels that some people stoop to - if you haven't already that is. Oh, and I disclaim any responsibility for headaches, nausea and sudden rage attacks caused by that thread...! :D
 
Les Rose said:
Thanks Pragmatist et al. The writer of the letter was D M Colcomb of Devizes. I didn't know about the Henshaw-Coghill connection - that says a lot. One final point to clear up - is it really true that there is US legislation against building homes near power lines? There might be silly little local laws, but I have never heard of any federal law.
Click to expand...

It appears that D M Colcomb is one David Colcomb, a campaigner and activist who is opposed to a plan to make a heritage centre and records office in Chippenham. The proposed site is apparently next door to an electricity substation, and from what I can piece together from various reports I gather that he's fishing for any excuse to throw a spanner into the works because he wants the centre to be built in Devizes. It appears that the EM radiation issue is just an excuse to that end.

http://www.thisiswiltshire.co.uk/wiltshire/archive/2004/09/03/chip_news_local24ZM.html

"CHIPPENHAM NEWS: THE county council has dismissed fears that the site of the proposed Wiltshire and Swindon Record Office is a health risk.

Research carried out by campaigners reveal staff and visitors to the record office at Cocklebury Road, Chippenham, would be threatened by cancer caused by a neighbouring power station.

But a study carried out by Wiltshire County Council disputes the report claiming the site is out of range of possible radiation. "

If you enter "Colcomb" into the search box on the above site, you'll find 40 odd rants on the same subject by Colcomb, including a few contradictions. One of his arguments is that the site is dangerous because of EM, another is that the people of Chippenham are being denied the use of the valuable site for other projects...go figure! :)

He doesn't seem to be one of Coghill's cronies - if he was, Coghill would be there already lapping up the publicity. But either way it's worth nipping in the bud.

It would be worth finding out the voltage on the feed lines to the substation, it may not be very high, and if it isn't then Henshaw's work isn't going to be relevant anyway.

As for Henshaw himself, Darat actually wrote to him and asked him directly about some of Coghill's claims. He didn't reply. But Coghill keeps citing him, and claims in the Bioelectromagnetics thread that he's one of his supporters. Henshaw also turns up at the same venues as Coghill and gives talks with him. He also staged a rather theatrical protest near Bristol with a field full of fluorescent tubes. If you do a search for him you'll find the details.

Peter Fews is apparently a collegue of Henshaw's (University of Bristol), they've published a lot of papers together.

I can't find any evidence of any Federal Building Codes in the US relating to new homes and power lines, I've looked at various sites on codes and regulations but found nothing. However that doesn't mean there aren't any. As you said, if there are any they are likely to be at state or county level rather than Federal. Maybe the best approach in this case would be a demand for evidence.
 
Well I am most impressed by the command of the web you guys seem to have! I will put together a suitable rebuttal for the Salisbury Journal (although they are already getting a steady stream of woo debunking from me).

Thanks again.
 
I have now found out that the voltage at the Chippenham substation is 33kv. All the work by Henshaw et al was on main grid voltage, ie 400kv. The famous demo, with the fluorescent tubes lighting up, was actually done on top of an uninhabited hill in the Cotswolds where the towers were abnormally low, to keep a low profile for aesthetic reasons. They won't light up under normal towers. Time for another letter to the Salisbury Journal.
 
Is it 33kv on the input side and what- 480v out? Or is 33kv the output voltage? Just curious.
 
I was told that 33kv is the input. Local distribution also uses 250kv apparently but not at this site.
 
Asolepius said:
I have now found out that the voltage at the Chippenham substation is 33kv. All the work by Henshaw et al was on main grid voltage, ie 400kv. The famous demo, with the fluorescent tubes lighting up, was actually done on top of an uninhabited hill in the Cotswolds where the towers were abnormally low, to keep a low profile for aesthetic reasons. They won't light up under normal towers. Time for another letter to the Salisbury Journal.
Click to expand...

Ah, well done. Just as I suspected.

To answer Soapy Sam's question, in the UK I believe the main distribution grid is 400KV, and in some areas there are smaller sub grids at 275KV. But usually these very high voltages run to major substations on the outskirts of towns or in the countryside. Those substations convert to 33KV which is then run to secondary substations within the town, but the wires don't necessarily have to be overhead, they may run underground from that point. The 33KV secondary substations down convert to 11KV, and 11KV sub-sub stations convert down to domestic levels.

So it sounds like the Chippenham station is a 33KV/11KV secondary station.

The UK grid map shows a 400KV line to Melksham, and presumably a primary substation from there provides a 33KV feed to Chippenham.

Here is a link to some pictures of typical substations:

http://www.central-networks.co.uk/Content/Safety/safety_substations.aspx
 
Pragmatist said:
...
For what it's worth I believe that there is sufficient evidence that yes there is a level of risk. But that under normal environmental conditions the risk is extremely rare and minimal and doesn't require any urgent action. I wouldn't want to live directly under a 300KV power line, but at the same time I don't feel a sense of panic whenever I get near to my toaster! :)
Click to expand...

The risk estimate I have seen is 20% increase, so instead of 10 cases per 100 000 people you get 12 cases. Not enough to tear down all power lines and live in caves again if you ask me. Then again there is no point in stubbornly denying that there is a risk by saying 20% isnt "significant" or there is no plausible mechanism so it must be rubbish.
 
You must log in or register to reply here.

Back
Top Bottom