Here’s an excerpt from Nicholas Kristof’s recent op-ed column, in the Sunday NY Times, titled “It’s time to learn from Frogs“. Thanks to Judith for this.
Deformed Frog. Photo Judy Helgen/Minnesota Pollution Control Agency
“Some of the first eerie signs of a potential health catastrophe came as bizarre deformities in water animals, often in their sexual organs.
Frogs, salamanders and other amphibians began to sprout extra legs. In heavily polluted Lake Apopka, one of the largest lakes in Florida, male alligators developed stunted genitals.
In the Potomac watershed near Washington, male smallmouth bass have rapidly transformed into “intersex fish” that display female characteristics. This was discovered only in 2003, but the latest survey found that more than 80 percent of the male smallmouth bass in the Potomac are producing eggs.
Now scientists are connecting the dots with evidence of increasing abnormalities among humans, particularly large increases in numbers of genital deformities among newborn boys. For example, up to 7 percent of boys are now born with undescended testicles, although this often self-corrects over time. And up to 1 percent of boys in the United States are now born with hypospadias, in which the urethra exits the penis improperly, such as at the base rather than the tip.
Apprehension is growing among many scientists that the cause of all this may be a class of chemicals called endocrine disruptors. They are very widely used in agriculture, industry and consumer products. Some also enter the water supply when estrogens in human urine — compounded when a woman is on the pill — pass through sewage systems and then through water treatment plants.
These endocrine disruptors have complex effects on the human body, particularly during fetal development of males.
“A lot of these compounds act as weak estrogen, so that’s why developing males — whether smallmouth bass or humans — tend to be more sensitive,” said Robert Lawrence, a professor of environmental health sciences at the Johns Hopkins Bloomberg School of Public Health. “It’s scary, very scary.”
The scientific case is still far from proven, as chemical companies emphasize, and the uncertainties for humans are vast. But there is accumulating evidence that male sperm count is dropping and that genital abnormalities in newborn boys are increasing. Some studies show correlations between these abnormalities and mothers who have greater exposure to these chemicals during pregnancy, through everything from hair spray to the water they drink.
Endocrine disruptors also affect females. It is now well established that DES, a synthetic estrogen given to many pregnant women from the 1930s to the 1970s to prevent miscarriages, caused abnormalities in the children. They seemed fine at birth, but girls born to those women have been more likely to develop misshaped sexual organs and cancer.
There is also some evidence from both humans and monkeys that endometriosis, a gynecological disorder, is linked to exposure to endocrine disruptors. Researchers also suspect that the disruptors can cause early puberty in girls.
A rush of new research has also tied endocrine disruptors to obesity, insulin resistance and diabetes, in both animals and humans. For example, mice exposed in utero even to low doses of endocrine disruptors appear normal at first but develop excess abdominal body fat as adults.
Among some scientists, there is real apprehension at the new findings — nothing is more terrifying than reading The Journal of Pediatric Urology — but there hasn’t been much public notice or government action.
This month, the Endocrine Society, an organization of scientists specializing in this field, issued a landmark 50-page statement. It should be a wake-up call.
“We present the evidence that endocrine disruptors have effects on male and female reproduction, breast development and cancer, prostate cancer, neuroendocrinology, thyroid, metabolism and obesity, and cardiovascular endocrinology,” the society declared.
“The rise in the incidence in obesity,” it added, “matches the rise in the use and distribution of industrial chemicals that may be playing a role in generation of obesity.”…”
Read the whole post on the NY Times website (may require free signup).
Nicholas Kristof adds the following to this story on his blog:
My Sunday column is unusual and has been in gestation for a couple of months, and frankly the research has been scary. We don’t know for sure that these chemicals are harmful, but the evidence is mounting. I only wish I had more space than the 750 words that the column allows.
I became interested in the issue when I saw Hedrick Smith’s Frontline special, “Poisoned Waters,” in April. I had vaguely known about amphibian and fish deformities, but that made me dig deeper — and it was like pulling at a ball of string.
This is a difficult kind of journalism to pull off successfully, and let me know if you think I blew it. On the one hand, we should call public attention to a potential public health hazard so that threats can be addressed. On the other hand, we have to acknowledge the uncertainties and avoid hysteria. The balance is particularly difficult with endocrine disruptors because the science is so complex (the causal pathways are particularly murky). One of the crucial questions is whether the effective of different chemicals is additive, so that low levels of particular substances — each harmless in and of itself — collectively create a threat, perhaps in conjunction with some genetic susceptibility. If it is additive, then studies based on exposure to a particular chemical are less reassuring.
In addition, the chemicals often interact with other elements in the environment. Perhaps the leading theory on the frog deformities today is that agricultural chemicals weaken their immune system, and then parasites actually trigger the deformities. But hermaphroditism in amphibians seems to be caused by chemicals alone.
Then there are measurement questions. There appears to be more hypospadia now, and more cases of undescended testicles, but is just that doctors are more meticulous about recording cases? It’s hard to be 100 percent certain. Likewise, some studies show declining sperm count, but some don’t. I used “up to 7 percent” for undescended testicles because a new Cambridge University study found 7 percent, up from 4 percent the last time it looked at the issue; more common figures are 4 to 5 percent. My figure of up to 1 percent for hypospadias comes from an article this year in Journal of Pediatric Urology, which estimated incidence at .3 to 1 percent of newborn boys….”
Read the whole post on Nicholas Kristof’s blog.
Journal of Andrology — photos of human male hypospadias (genital deformations). I tried posting this, but Photobucket deleted the picture, saying it conflicted with their “terms of service”.
Prague Declaration on Endocrine Disruption
Video of Nicholas Kristof, talking on Colbert Nation (available in USA only)
More Deformed Frog pictures from Judy Helgen
The last croak — pictures of deformed animals
The Bovine 