From the early 1950s until a market collapse in 1971, Uranium (U) mining was an active business in Southwestern U.S. Mining has been concentrated in the Four Corners region and the Navajo reservation. To this day, abandoned mines are heavy polluters and “10,000 gallons of U-contaminated water seeps into the Colorado (River) daily”. Of the 226 water sources for the Navajo people, 90 are contaminated with U.
U is a heavy metal which can impair human health as a result of problems with either radioactivity or heavy metal properties. Studies in the past have primarily addressed kidney damage and respiratory disease from inhalation or ingestion of U. The resultant diseases are sometimes malignant and sometimes not.
It is known that mice fed uranium have reproduction problems. The present study was about the estrogen activity of U as heavy metals are known to have estrogenic activity. Mice which were pregnant and mice with their ovaries removed were given U in their drinking water. The concentration in the water was from 0.5 to 28 mg/L. The results of the U fed mice were compared to mice fed DES (diethylstilbesterol) as a control.
Female mice which drank water with U or synthetic estrogen developed specific abnormalities, including a decreased amount of ovarian follicles, increased weight of the uterus and abnormal vaginal cells. Treatment with an anti-estrogen drug while drinking uranium water blocked the abnormal responses usually seen with U. The female mice that drank U water had offspring which seemed normal, but had “significantly fewer primordial follicles” compared to females which drank tap water. Of interest, mice treated with U before birth (because their mothers were treated with U) had reduced numbers of ovarian follicles.
Mice with their ovaries removed were given either U or DES, which caused estrogen-related changes in the uterus even though they were unable to produce natural estrogen of their own. This reaction was blocked by estrogen receptor blockers showing that the effect was the result of estrogen activity. U and DES caused accelerated puberty in mice due to estrogen activity. The mice were tested in numerous ways to demonstrate the estrogen activity of U.
CONCLUSION: The major finding of this study is that U has estrogen activity, as do other heavy metals, such as cadmium. The estrogen effect scan be seen below the EPA safe drinking water level of 30 microg/L. People exposed to U in the environment may develop fertility problems and reproductive cancers. Previous studies have shown that environmental estrogens, DES and bisphenol A may contribute to reproductive abnormalities and cancer late in life.
NOTES: Reproductive cancers would include breast, ovarian and prostate cancers. Endocrine disruptors are chemicals which have hormone-like activity and alter the normal balance of hormones. Most have estrogen activity and increase estrogen activity in both males and females. One result is that male fish in the Potomac River now produce eggs due to pollution.
The Four Corners region includes the area where the states of New Mexico, Arizona, Colorado and Utah meet.
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PMID: 18087588. nutrientmedicine