Sludge Watch ==> Sheep grazed on sludge fields - impacts on fetal ovarian development

[Maureen Reilly]

Sludgewatch Admin:

I think we need to look at the impacts of grazing sheep on sludged 
fields...like they do at Green Acres Farm in Kern County.
Those sheep are grazing on Los Angeles sewage sludge.
.................................

Science Daily

European Society for Human Reproduction and Embryology
Date: July 5, 2007
More on: Pregnancy and Childbirth, Fertility, Environmental Issues, 
Sustainability, Recycling and Waste, Diseases and Conditions

Common Environmental Chemicals In Diet Affect Fetal Ovarian Development

Science Daily — Exposing a developing female sheep fetus to low doses of 
chemicals commonly present in the environment can disturb the development of 
the ovary, a scientist told the 23rd annual conference of the European 
Society of Human Reproduction and Embryology (Wednesday 4 July). Dr. Paul 
Fowler, of the University of Aberdeen, Scotland, UK, said that this research 
would help to establish the importance of the effect of environmental 
chemicals for fertility.


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Over recent decades there has been a dramatic increase in the production of 
industrial and agricultural chemicals and heavy metals, and this has 
coincided with widespread reports of breeding problems in wild animals. 
Fertility also appears to be declining among humans and there has also been 
a rise in reproductive defects observed in newborn babies.

Until now, most studies have looked at a short-lived exposure to high doses 
of single compounds, and have usually done so in mice and rats. Dr. Fowler 
and his colleagues decided to study the effect of long-term, low-level 
exposure to a cocktail of chemicals and heavy metals in an animal which has 
a long pregnancy, therefore better replicating the situation in the human.

"Our 'real life' model exposed developing sheep fetuses by pasturing their 
mothers on fields fertilised with either inorganic fertiliser, the control 
group, or, in the case of the treatment group, with digested human sewage 
sludge, before and during pregnancy", said Dr. Fowler.

" We examined the ovaries from the fetuses at day 110 of gestation, the 
equivalent of week 27 in a human pregnancy, and found that the ovaries from 
the fetuses where the mother was grazing the sewage sludge fields contained 
fewer eggs and also a number of protein abnormalities. These differences 
could have implications for problems such as cancer in later life."

The scientists hope that their Wellcome Trust-funded study will help to 
pinpoint the stages of pregnancy at which the developing fetus is most 
sensitive to disruption and also to measure the degree to which fertility is 
affected in the offspring after puberty, following their exposure as fetuses 
to environmental concentrations of a mixture of pollutants. "Switching some 
mothers from sewage sludge fertilised to control pastures before conception 
will tell us whether maternal exposure either before or during pregnancy 
does most damage to the offspring", said Dr. Fowler. "The sheep model is 
quite novel, with relatively little research in the area currently being 
performed in this way. One of the collaborators in the project, Professor 
Richard Sharpe from the MRC Human Reproductive Sciences Unit in Edinburgh, 
UK, has already found reduced testosterone and testis cell numbers in the 
male fetus exposed to sewage sludge at day 110 of gestation.

The group has applied for further funding to look more closely at the 
implications of the sheep findings for humans, for instance by comparing 
quantities of chemicals in the human fetus with those seen in sheep, and 
investigating whether changes induced in the sheep fetus could be a problem 
for the developing human. They also intend to look at the mechanisms by 
which exposure to environmental chemicals can cause defects in reproductive 
development in order to determine what might be done to reduce risks for the 
human fetus.

There is still considerable debate around the level of importance of 
environmental chemicals in cancer, obesity, infertility and other complex 
diseases which have multiple causes. "We hope our research will help in the 
drive for evidence-based policy making on this issue", said Dr Fowler. "If 
we can definitely establish that environmental chemicals are important in 
triggering these diseases, then we might be able to produce better 
treatments, but it would also be important to devise legislation to begin 
reducing the levels of such chemicals. We would then look to work with 
chemical and agricultural industries to find safer chemicals by improving 
how they assess fetal development effects. If such measures helped to reduce 
the rates of cancer, obesity and infertility, there would be considerable 
benefits in terms of the costs of healthcare."

Note: This story has been adapted from a news release issued by European 
Society for Human Reproduction and Embryology.

http://www.sciencedaily.com/releases/2007/07/070704144531.htm