in the trenches/endocrine disrupters
5. New in the Literature
Sperm flap flip flop a downer
Sperm wiggled back into the spotlight in November and the news is not encouraging. A sophisticated re-analysis of sperm count data shows a sharp decline, perhaps greater than previously estimated. In 1992 Danish researchers reported a drop in sperm counts and triggered a flurry of debate about results, methods and interpretations. It didn't help that studies published since then have contradicted each other.This latest report is intended to be definitive. According to Reuters news, the study's lead author, Shanna Swan, chief of the reproductive epidemiology section at the California Department of Health Services, said, ``I think this study will change the debate about sperm decline from 'if' to 'why'.'' Swan, who is also a member of the National Academy of Science panel examining hormonally active agents in the environment, says the concern isn't fertility. But dropping sperm counts are a red flag for other problems such as testicular cancer.
You can read a press release summarizing this research. For the abstract of the research article, see Have Sperm Densities Declined? A Reanalysis of Global Trend Data in Environmental Health Perspectives.
Possibly related sperm news: an estrogen link
Estrogen turns out to be vital to male fertility -- specifically to sperm count. "If there is a normal function for estrogen in the male, and that function is required for normal fertility, then it is logical to hypothesize that chemicals that interfere with estrogen receptors may interfere with fertility," said lead author Rex A. Hess, according to the University of Illinois press release announcing the study, Estrogen Linked To Sperm Count, Male Fertility "Until now, there has been no known function for estrogen in the male. We have had nothing to focus on. Now we can ask the question: Does this chemical or that chemical interfere?" Hess said. Summaries of the article in the journal Nature, and of news commentary about the study are available online. (Nature requires a free registration.)More bad news for boys and men (and the girls and women who love them) Hypospadias -- congenital birth defects of the penis, in which the urinary opening is not at the end where it belongs -- are increasing. In fact the rate has nearly doubled in the US and now affects about 1 of every 100 boys. And it's apparently not due to better surveillance and reporting as previously thought. No one knows for sure what causes it, but hormone disruption is one logical suspect. For more info, read the CDC backgrounder on the study, recently published in the journal Pediatrics.
Bad news for girls and women (and the boys and men who love them)
A fish/fertility link
Eating contaminated sport fish from Lake Ontario is associated with shortened menstrual cycles, according to a recent study. Fish consumption was also associated with a small, but statistically insignificant, delay in the time it took women to become pregnant. Read more about the study in a press release from the University of Buffalo.Early puberty in girls
Two recent articles follow up on research reported last spring. E/The Environmental Magazine offers the short, easy-to-read piece, Premature Puberty -- Is Early sexual development the price of pollution? And Rachel's Environment & Health Weekly delivers another well researched and footnoted article, Girls Are Reaching Puberty Early.Breast cancer
October was Breast Cancer Awareness month and Rachel's Environment & Health Weekly just concluded a 5-part series on breast cancer. Start with The Truth About Breast Cancer--Part 1. Once you're there, you can click the arrow button in the margin to read successive articles. (You can also navigate by clicking the Index button and choosing the article you're interested in. The buttons are only visible at the beginning of articles.)On the deformed frog front
Just as the Minnesota school kids suspected, it's the water, according to preliminary studies. But researchers still don't know exactly what it is in the water that's causing the problems, or whether people are also at risk. ScienceNewsOnline outlines the issue in Water link to frog deformities strengthened. See also the Joint News Release from the Minnesota Pollution Control Agency and the National Institute of Environmental Health Sciences, NIH. (You may also want to check out the Statement from the Director, Environmental Toxicology Program at NIEHS, available from a link at the bottom of the release.) A news article in Environmental Health Perspectives, Frog Deformities Research Not Leaping to Conclusions gives more background on the research effort. However, there have since been some grumblings that the announcement of preliminary findings was premature.CDC and NIH team up for testing
NIH's National Institute of Environmental Health Sciences and the Centers for Disease Control and Prevention's National Center for Environmental Health have launched a study of blood and urine samples to determine Americans' level of exposure to environmental estrogens. See CDC and NIH Join in Testing Exposure of Americans to Environmental Estrogens and Other ChemicalsEPA and clean water
In celebration of the 25th anniversary of the Clean Water Act, EPA has put up several pages of history, background, and information, including a link to pages highlighting the "Adopt Your Watershed" campaign. While you're surfing the EPA you might want to check out the Index of Watershed Indicators, which organizes and presents aquatic resource information on a watershed basis. On the Surf Your Watershed page EPA invites you to "locate your watershed, get information, link your information, speak out!" Also of interest is a 23-page report: Water On Tap: A Consumer's Guide to the Nation's Drinking Water available online or in PDF format.Smile?
Hormone-mimicking chemicals may leach out of tooth sealants used to prevent cavities. Then again, maybe they don't. Or maybe they do, but the chemicals are different ones than people thought. For the latest, sink your teeth into Dental Sealant Safety Reconsidered at ScienceNewsOnline.As the tern turns
A recent study adds another chapter in the continuing saga of gender-bent aquatic birds, showing that feminized terns carried higher levels of toxic dioxin-like compounds than normal birds. Tern Trouble capsulizes the research.Maine papers pounce on mercury menace
Power plants and waste incinerators spew toxics and endocrine disrupters such as dioxin and mercury into the air. The Portland Press Herald and Maine Sunday Telegram exposed the Mercury Menace in a recent series of articles. For a little more background check out EPA's Mercury in Medical Waste - Use of Alternative Products and related links.Living downstream
Rachel's Environment & Health Weekly, # 565 discusses Sandra Steingraber's new book, Living Downstream --An Ecologist Looks At Cancer and The Environment, and the press reaction -- or rather, significant lack thereof.
Environmental Health Perspectives
EHP, the journal published by NIEHS, is a major source of research information on endocrine disruption. Though EHP is still behind in publishing the paper version (the September issue arrived the first week of December), the online edition is becoming increasingly timely. Here are some articles of interest from recent issues.
September
The news story Estrogens in the Environment discusses NIEHS's latest conference on this topic. And a guest editorial, Interactive Hormonal Activity of Chemical Mixtures, reflects on research efforts overly focused on estrogenic activity as well as the problem of chemical mixtures.October
Researchers are adding to the list of possible chemical culprits responsible for the reproductive problems of Florida alligators. See Reproductive Toxins and Alligator Abnormalities at Lake Apopka, Florida to read the abstract of a commentary paper.November
An Enlightened Approach to Screening for Dioxins is a news brief describing a new technique that employs bioluminescence to screen for dioxin. There are also research articles examining links between Herbicides and Breast Cancer and between Household Pesticides and Risk of Pediatric Brain Tumors.Toxics
The latest Program Report from the Environmental Defense Fund, "Toxic Ignorance--The Continuing Absence Of Basic Health Testing For Top-Selling Chemicals In The United States" is available from EDF's website. Rachel's Environment & Health Weekly discusses the report and the law behind it in The Toxic Substances Control Act.The agency for Toxic Substances and Disease Registry (ATSDR) just updated its list of the Top 20 Hazardous Substances. 1997 CERCLA Priority List of Hazardous Substances lists the chemicals and provides background on how the list is compiled.
An interesting twist
An insect equivalent of endocrine disruption can be used as a weapon against pests. See Researcher Designs Pill To Control Mosquitoes. What's not mentioned is whether this clever approach could also end up being an unwelcome starvation diet for fish, frogs, birds and other creatures that depend on mosquitoes for food.
Archives of "New in the Literature:"
Archived 1/5/98
Archived 9/25/97
Archived 8/04/97
Archived 6/30/97
Archived 6/02/97
More on Endocrines:
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