Naval battles

[Prime-Evil]

There is a bit more to my statement about lack of harm from DDT etc. These products are fat soluble, as opposed to water soluble, and tend to end up in layers of fat or blubber. If injected into blood, they kill at quite low doses. However, when they enter the body in small amounts over a period of time, they accumulate in fatty tissues. They are stored there, and are, effectively, biologically inactive. While there is a lot of hysteria about the fact that animals such as polar bears have a lot of these products in their bodies, the chemicals are in fat layers, and evidence to show they interfere with normal metabolism is basically lacking. And that is not due to lack of studies.

Wasn't there a real problem with birds, particularly birds of prey, because of all the DDT and other spraying? Also, isn't there a problem that every generation we have a different perception of what is natural habitat? Every generation we have less natural habitat, and what we do have has less biomass, less biodiversity, and more contamination. But we always grow up thinking everything is normal. How will we ever know when things are no longer normal?

.

The other question has to be what we are really getting in return for all this.

Some of it is very good, but most of it does not seem neccessary.

.

[MattC]

Not to be too contentious, but there actually is a wealth of evidence to suggest that these compounds cause harm. It is irrelevant for this point that they are stored in the fat - that is true in whales just as much as in humans or in any other mammals, and you don't hear people talking about how the ddt (partial) ban is silly because it's stored in fat cells. Fat cells can be consumed, and the simple fact of the matter, as far as I can tell, is that strong correlations between high levels (in fat cells) of these compounds and health problems are universally accepted. In fact, I would challenge you to supply one reliable, reasonably recent scolarly article that suggests that it is reasonable to believe that a creature may accumulate high levels of these compounds without adverse health effects (excepting evidence that suggests that not every single creature with high levels suffers health effects - just as there are smokers that live to 95 and swear by a pack of smokes and a shot of whisky, there will be animals that live to ripe ages despite accumulations of these toxins).

I would be very interested to see such evidence, should it exist, as I have read numerous journal articles while doing research for my degree that suggested very strongly that not only were strong correlational effects present, but that also causal relationships had been determined with some degree of reliability (causal relationships can be very difficult to establish, of course, unless you are conducting a very controlled experiment - a feat difficult to do with something like, say, a whale, or in fact any reasonably large oceanic mammal).

On the off chance that I eat my words and you have just such a source, let me state that I am by no means convinced that you are wrong - it is just that I have seen in the past plenty of evidence to suggest that these compounds can safely be assumed (when at certain levels that are in fact common in nature) to have dangerous side effects. Additionally, my brief search for additional reliable sources to cite here has turned up a huge wealth of articles, none of which seem ambiguous about the matter (though there are definately calls for more research, for instance research into the mechanisms of these negative effects; I suspect these mechanisms will follow a more thorough understanding of the endocrine system [and other organs]).

 

Here are a few articles that address the topic:

http://taylorandfrancis.metapress.com/(bolfmpabvqdkyt552pq4ig3g)/app/home/contribution.asp?referrer=parent&backto=issue,2,2;journal,38,50;linkingpublicationresults,1:104774,1

http://entc.allenpress.com/entconline/?request=get-abstract&doi=10.1897/1551-5028(2002)021%3C2752:PRAORE%3E2.0.CO;2

http://www.epa.gov/endocrine/Pubs/kavlock.pdf

http://taylorandfrancis.metapress.com/(hcrlbgngdexrvznywuuvjr55)/app/home/contribution.asp?referrer=parent&backto=issue,4,11;journal,18,42;linkingpublicationresults,1:119813,1

This is by no means a comprehensive list of the research that has been conducted.

[Prime-Evil]

Somethings are more harmful than beneficial.

Somethings are more beneficial than harmful.

 

Should we be more sceptical of the harm of polution, or the need for so much of it?

Perhaps the best example of this is lawn care, but there are many many others.

 

Personally, I have grown sceptical of anyone who tries to sell me anything, including scepticism.

.

[wpenrose]

You know the big naval battles between germans and british and americans and japanese during WW2? I wonder, how big was the impact on the ocean environment? ships blowing tons of artillery straight to the water, massive sinking ships that must leak alot of petrol when they get hit and sunk by other ships artillery and also airplanes crashing into the water they too, leaking petrol. I have certainly not heard about it, but come to think of it it must have had a negative effect on the sea ecology, but how big?

 

The whole concept of stewardship of the earth didn't really get going until the 1960's. I'm sure that in a desperate battle for the future of civilization, Shamu was probably the last thing on anyone's mind. More likely, it was, "Will I get my ass blown off in the next 24 hours?"

 

While I was in the Canadian Navy reserve, we dumped our garbage straight in the ocean, which one sailor called, "The world's biggest garbage dump." Barely a day passed without encountering a dozen or so plastic bottles, steel barrels, pieces of lumber, oil slicks, etc. And this was 1962.

 

Dangerous Bill

[SkepticLance]

MattC.

I tried to read your references.

Out of four ...

Two I was apparently locked out of.

One was about dolphins, and 'calculated' an estimated risk from PCBs. Not what I call empirical evidence.

The last appears to be a request for research funds by referring to the need to evaluate the toxicity of a number of chemicals.

 

There are always lots of alarmist papers about. Actually nailing down risk is something else. I do not claim that DDT, PCB's etc carry no risk. That would be silly. All I said was that low level intake (sub-acute) led to accumulation within fat cells, where it seems to be rendered metabolically inactive. These chemicals render harm when in non fat tissue. I have lost the reference, but there was a well known study made of WW II veterans who had been 'deloused' with DDT. They had quite high levels of DDT in their fatty tissues, but a cancer rate no higher than a control group of veterans who had not been so treated.

[MattC]

My apologies for my references - I was posting from the library at my university, where we have access (access is restricted by IP).

 

I believe I understand what you are saying - I still have to disagree. I do agree, however, that the empirical evidence of, specifically, the harm caused by these compounds as they are in fat cells will be difficult to "nail down." Large studies (which would be necessary) would have to involve long-lived marine animals, in order to determine the effect of very low doses that accumulate to large quantities in fat. Studies like this would need to be conducted on whales or similar long-lived marine mammals (and some equally long lived fish), and this probably won't happen.

 

My argument is that, as there is no shortage of evidence showing health consequences associated (correlational effects, granted, but all we have, and statistically sigificant to high degrees of certainty) with high levels found in fat cells (where the phrase "high levels" refers to high levels as found in creature in natural aquatic environments, not artificially high levels - just high levels as compared to levels in some other creatures which seem to have less significant levels of buildup), it is silly to assume that there are no health consequences associated with even low-level intake (unless, of course, you define low level as those levels that do not result in fat accumulation levels that exceed the values that have been correlated with disruption of biological processes. The mechanism needs research - this is one of the points of the second of the two articles you were able to access (this article, which I would have assumed you would like, is both skeptical, in that they do not assume anything that has not been absolutely proven, and simultaneously unambiguous about the concensus that there is a problem with these compounds, though the problem is not fully understood yet).

I have to object to your choice of the word "alarmist," apparently in reference to the papers I cited (none of which were remotely alarmist), but perhaps you were making the assumption that my opinions come from journalistic articles (as opposed to scholarly), and while it is not true in this case it is definately a safe assumption to make, most of the time, given the horde of alarmist papers (on nearly every topic) in the media.

Finally, there actually *is* evidence that these and other chemicals that reside in fat cells play active roles, for instance in pregnant mammals (which have been shown to pass some of these compounds through milk. While it is possible that the effect is due to concentration of recently ingested compounds, nevertheless the amounts found in fetuses and in milk suggest that fat-stored compounds may be passed along, and this certainly does not conflict with our understanding of the purpose of fat cells, which do not just sit there indefinately once they are formed, but rather act as reserves for times of need.

 

I will be the first to admit that I am not an expert in this particular field - that does not mean, however, that I will ignore the opinions of those who are experts. I also do not want to imply that DDT has no benefits - in the fight against malaria and other diseases borne by very DDT-vulnerable organisms, it seems highly probably that, at least in a small, closed system (for instance, when we just consider the effects of DDT delousing on the people deloused), the benefits vastly outweigh the consequences. That is not to say that there are no consequences, and a lack of a significant increase in cancer (which, I believe, is not even the most significant adverse effect associated with DDT, which disrupts a number of glands) should not be taken as a bill of safe health. Not that I was able to find the study you cited - though I have not looked very hard.

 

I have some more to say about this topic, and I am appreciating your skepticism (which, in my opinion, is a vital factor in creating true scientific discourse), but I am out of time. I will attempt to obtain sources that are more accessible and I will discuss a few related points on Thursday, as I am going to be at work and in a lab for the rest of today. I especially want to discuss the ambiguous evidence regarding the effects of fat-stored DDT, though it would be nice to keep the topic a little more broad (as we started out discussing a number of toxins).

Have an excellent day, and if you get the chance run by a UC or other university library and you should be able to gain access to a great deal of scholarly journals!

[SkepticLance]

MattC.

It is nice to debate with someone like you, who keeps it polite and friendly.

 

I have had a number of 'discussions', which do not always stay unheated, with certain extreme environmentalists who regard any synthetic chemical as evil incarnate. Surprising how they regard 'natural' chemicals that are far more toxic as being OK. One example of the 'evil synthetic' is dioxins.

 

Now, dioxins are nasty. No doubt about that. 2,3,7.8 TCDD is the worst, and is the most toxic man made chemical ever. However, there is a low level, even for that product, where it becomes harmless. The USEPA in at least one reference suggests the lowest level likely to harm a human is 20 parts per billion.

 

Here in New Zealand, there has recently been a bit of a furore over dioxin residues left at a plant that once made the phenolic herbicide, 2,4,5 T. Locals had their blood tested. Dioxin levels ranged from 1 to 35 parts per trillion. (every reading, except one person, was below 20 ppt). Immediately they were rushing out to sue the company for millions! We are talking amounts 1000 times lower than the minimum considered to be potentially harmful!

 

Naturally, Greenpeace was in there, swinging. Other pressure groups formed to push for compensation. Human greed and sheer stupidity are among the things that makes me so skeptical!

 

As a result of this, and numerous other situations, I tend to look hard at claims of toxicity from synthetic chemicals. My own observations would indicate that most claims of harm are not correct.

 

DDT is a good example. It is frequently claimed that it is highly carcinogenic. However, epidemiological evidence among humans is pretty much absent. Yet lots of people have been exposed to it. In the case of returning WWII veterans, they were literally covered with DDT dust to delouse them.

 

I have read of one interesting case of DDT poisoning, however. It is a long time ago, and I cannot guarantee that the details are accurate. Apparently, this guy was very fat, and had been a spray contractor, spraying DDT. The DDT ended up in his fat tissue, and he lived a pretty healthy life, in spite of lots of DDT in his fat cells. The proverbial hit the fan when he became ill with an infection. High fever, and sudden loss of weight. He died of DDT poisoning, due to the release of chemical from fat cells when the fat disappeared. DDT in blood is far worse than DDT in fat. This case does suggest that high levels of DDT in fat cells do not necessarily mean ill health.

 

While we should, of course, be aware of the harmful effects of pollution, we should not be sucked in by alarmist groups such as Greenpeace. Good, scientific data is needed before jumping to conclusions.