Transcript impacts of metals on aquatic ecosystems and human health

IMPACTS OF ENDOCRINE DISRUPTER
CHEMICALS ON AQUATIC
ORGANISMS AND HUMAN HEALTH
Dr. Fran Solomon
[email protected]
February 3, 2009
TOPICS TO BE COVERED
What are endocrine disrupter
chemicals (EDCs) and how do they act?
Properties and sources of EDCs
Exposure pathways
Impacts of specific groups and
mixtures of EDCs
How to reduce exposure
TOXIC CHEMICALS
Chemicals that have negative impacts
on an organism’s survival, activity,
growth, metabolism or reproduction
Include over 200,000 human-made
organic chemicals (contain carbon)
EDCs are recent chemicals of concern.
ENDOCRINE DISRUPTION
Endocrine disrupter chemical (EDC) is
“any chemical with the potential to alter
hormonally mediated signals in plants
or animals.”
Hormone receptor – site on surface or
interior of a cell that is activated or
triggered by a hormone.
ENDOCRINE DISRUPTION
H
EDC
H
EDC
H
Hormones bind to
cell receptors and
induce a response

EDCs bind to receptors and
 MIMIC a hormone
 BLOCK hormone binding
INTERFERE with hormone
synthesis, transport or
degradation

KNOWN OR SUSPECTED EDCS
Pesticides
Polychlorinated
biphenyls (PCBs)
Polybrominated
diphenyl ethers
(PBDEs)
Bisphenol-A (BPA)
Phthalates
PROPERTIES OF EDCs
Resistant to degradation
Can be transported long distances.
Lipophilic – fat soluble, therefore rapid
absorption through cell membranes
and accumulation in fatty tissues
Bioconcentration
Biomagnification
BIOMAGNIFICATION
SOURCES OF EDCs
Sewage
Urban stormwater runoff
Agricultural stormwater runoff
Industrial waste
Atmospheric deposition
Oil spills
Household products
TOXIC CHEMICAL EXPOSURE
PATHWAYS IN FISH
Gills – diffusion across membranes
into bloodstream
Skin – diffusion into bloodstream
Drinking polluted water
Ingestion of sediments
Food chain
FISH GILLS (www.sci.sdsu.edu;
www.diatribune.com/marine-life-series)
TOXIC CHEMICAL EXPOSURE
PATHWAYS IN HUMANS
Lungs – inhaled particulates
Skin
Drinking contaminated water
Food chain
TOXICITY AND AGE/BODY SIZE
Developmental and young life stages of all
species are especially sensitive to EDCs.
Larger surface area/volume ratio → faster
EDC uptake per unit weight
Higher breathing, metabolic, and growth
rates → faster and more uptake of EDCs
Young animals and humans are not able to
detoxify EDCs as well as adults.
PESTICIDES
Synthetic chemical compounds used to
destroy or control pest organisms
5 billion tons applied annually
worldwide
30-fold increase in pesticide use in U.S.
since 1945
Found in surface waterbodies and
groundwater, including drinking water
wells.
CHLORINATED HYDROCARBONS
Examples – DDT, DDE, dieldrin, aldrin,
methoxychlor, heptachlor
Resistant to degradation
Persistent in soil, sediments, and fatty
tissues of organisms
Strong biomagnification – DDT levels in
birds are 50 times higher than in small
fish and 625 times higher than in small
insects.
“SILENT SPRING” (1962)
Bald eagles and brown pelicans almost
completely disappeared from eastern U.S. in
1960s due to excess DDT use.
Zoologist Rachel Carson warned that
pesticides were contaminating natural
environment and accumulating in our bodies.
Book linked pesticides to thinning of bird
egg shells and predicted “silent spring” (no
birds) if trend continued.
ATRAZINE
Used for control of broad-leaved annual
and perennial weeds in corn
Very mobile and moderately persistent
in soil
Heavy rain can wash atrazine into
nearby waterbodies.
Found in drinking water wells in U.S.
farming areas in spring and summer
ATRAZINE AND FROGS – 1990s
Exposure of leopard frog larvae and tadpoles
to an environmentally realistic concentration
of atrazine (0.1 part per billion - ppb) resulted
in retarded gonad development and
hermaphroditism.
Male frogs had undeveloped testes and no or
low numbers of sperm-producing cells.
29% had oocytes in testes or produced
vitellogenin, an egg yolk protein that is
normally produced only by female frogs.
ATRAZINE AND FROGS – 1990s
Same effects observed in frogs collected
from atrazine-contaminated areas in U.S.
Testicular oocytes were detected in male
frogs from 7 of the 8 field sites.
Atrazine contamination of waterbodies
coincides with amphibian breeding season
(early spring).
Lab and field data suggest contribution of
atrazine to declining amphibian populations.
PCB USES AND PROPERTIES
Used for heat transfer in electrical
circuitry and electronic equipment due
to their insulating properties and
nonflammability
Increased PCB production in 1960s
Banned in U.S. in 1970s, but persist in
soil, sediments, and fatty tissues
Personal medical testing
PCBs AND BRAIN DEVELOPMENT
IN CHILDREN - 1980s
Impaired intellectual development in
children born to women who had eaten
two or three Great Lakes fish meals
monthly in the six years BEFORE
pregnancy
Children had losses in motor
coordination, short-term memory,
verbal skills and overall intelligence.
PCBs AND BRAIN DEVELOPMENT
IN CHILDREN - 1980s
Correlation between severity
of
。
intellectual impairment in child and
PCB levels in mother’s blood and milk
at time of child’s birth
PCBs impair normal thyroid function
which has an important role in brain
development.
PBDEs ANNUAL WORLDWIDE USE:
150 million metric tons
Furniture foams,
carpet padding
Plastic in electronics
– Computer and TV
casings, kitchen
appliances
Upholstery / textiles
Products can contain up to 30% PBDE by weight
Used to reduce the ignition and spread of fire
PBDEs SAVE LIVES
PBDEs IN HUMAN BREAST MILK:
Sweden 1972-1997
ppb lipid, Total PDBEs
6
5
4
3
2
1
0
(Norén and Meironyté 2000)
PBDEs IN HUMAN BREAST MILK:
Sweden vs. North America
North America
Sweden
PBDE TOXICITY
Closely related to PCB toxicity
Animal studies: PBDEs disrupt thyroid
hormones, therefore harming fetal
brain development and impairing
memory and learning.
Developing fetuses, infants, and young
children are most at risk.
BPA USES AND PROPERTIES
Hard plastic in water bottles and baby
bottles, lining of metal-based cans
Migrates from containers to contents.
Crosses placenta and is found in
human breast milk.
Chronic, low level exposure of almost
all people in developed countries
Binds to estrogen receptors and
mimics estrogen.
EDC EFFECTS OF BPA
Reduced sperm counts, testicle size,
and fertility in male mice exposed
prenatally and as adults to low doses of
BPA are believed to be applicable to
humans.
Evidence for BPA contribution to
human breast cancer
Correlation between BPA urinary levels
in adults and incidence of diabetes
PHTHALATES - PROPERTIES
Used as fragrances and plasticizers,
but not chemically bound to plastics
Dispersed via food, air, water, soil
Continuous exposure of aquatic
organisms and humans, especially
children
Found in children’s toys, as high as
28% – 47% by weight
PHTHALATES AND
AQUATIC ORGANISMS
Discharged in sewage and stormwater
Exposure via water, sediments, food
chain
Impaired reproduction in mussels and
sand fleas in Thea Foss Waterway in
Tacoma, Washington
Can have ripple effects on ecosystem.
PHTHALATES AND
HUMAN HEALTH
Block testosterone production.
Abnormal reproductive system
development in male fetuses
Correlation between exposure of baby
boys to phthalates in breast milk and
decreased testosterone production
Correlation between reduced sperm
quality and high urinary levels of
phthalates in adult men
VITELLOGENIN AND MALE FISH
Male fish exposed to chemicals that act
like estrogens produce vitellogenin
(vtg).
Puget Sound Assessment and
Monitoring Program, spring of 19972001, surveyed adult English sole at 16
sites for exposure to EDCs, using
blood plasma vtg as indicator.
VITELLOGENIN AND MALE FISH
Vtg found in male
fish at 12 sites
Highest levels in
Commencement and
Elliott Bays: 1900 5900 ppb
11.8% - 47% of male
fish affected at sites
in these bays
EDCs AND BREAST CANCER
Incidence of breast cancer has tripled
in industrialized countries since 1960.
Currently 1 in 8 women in U.S.
Genetic predisposition accounts for
<10% of breast cancer cases.
~50% of breast cancer cases are in
women with no known risk factors.
EDCs AND BREAST CANCER
Chronic exposure to EDCs that mimic
estrogen may be a contributing factor.
Significant body of experimental,
epidemiologic, and ecologic studies
support this hypothesis.
Women who move from countries with
low breast cancer rates to developed
countries soon acquire the higher risk
of their new country.
SUPPORTING EVIDENCE
Atrazine causes mammary cancer in
other mammals.
Exposing pregnant mice to extremely
low levels of BPA altered the
development of the mammary gland in
their female offspring at puberty.
Phthalates significantly increase cell
proliferation in human breast cancer
tumors.
SUPPORTING EVIDENCE
Increased breast cancer risk among Long
Island, New York women residing within one
mile of hazardous waste sites containing
pesticides
Correlation between PCB levels in fatty
tissue and risk of breast cancer recurrence in
Long Island women
Exposure to three pesticides was associated
with increased risk of breast cancer in Latina
agricultural workers in California.
SUPPORTING EVIDENCE
Exposure to EDCs (prenatal and in
everyday products) may be
contributing to earlier puberty in girls.
Earlier puberty is risk factor for breast
cancer.
EDCs AND MALE
REPRODUCTIVE HEALTH
Incidence of testicular cancer has
doubled in past 50 years.
Data from 15,000 men and 60 countries
show 42% decrease in average sperm
count and 18% decrease in average
semen volume from 1940 to 1990.
Especially true in urban areas
SUMMARY OF EDC FINDINGS
Many synthetic chemicals released into the
environment can disrupt endocrine systems
of fish, wildlife, and humans.
EDCs have more severe effects on embryos
or newborn organisms than on adults.
One EDC or a mixture of EDCs may impair
functioning of reproductive system, thyroid
gland, and pancreas.
EDCs are a major long-term threat to
biodiversity and sustainability.
BPA RESTRICTIONS
Canada is first country to declare BPA is
toxic (April 18, 2008) and to ban BPA in baby
bottles (October 18, 2008).
Most major retailers have also removed foodrelated BPA products from their stores.
Proposed Washington State ban on BPA in
food or drink containers for children age 3 or
younger (Safe Baby Bottle Act of 2009) would
begin on July 1, 2010.
PHTHALATE RESTRICTIONS
Washington State Children’s Safe Products
Act of 2008 prohibited sale of toys and other
children’s products with phthalates >100
ppb. Took effect this year.
www.HealthyToys.org
DECREASING EXPOSURE TO
EDCs – INDIVIDUAL ACTIONS
Heed government agency advisories
about fish consumption.
Avoid animal fat as much as possible.
Avoid or decrease use of pesticides.
Eat organically grown produce.
Minimize contact between food and
plastics.
Do not give plastic toys to babies.
DECREASING EXPOSURE TO
EDCs – INDIVIDUAL ACTIONS
Ask your state legislators to vote for
BPA ban.
Attend Toxic-Free Legacy Coalition
lobbying day in Olympia – March 5
Get involved in environmental nonprofit
organizations that address EDC issues.
Sign petition to President Obama (see
Breast Cancer Fund website).
FOR FURTHER INFORMATION
Breast Cancer Fund
(www.breastcancerfund.org)
Institute for Children’s Environmental Health
(www.iceh.org)
Puget Soundkeeper Alliance
(www.pugetsoundkeeper.org)
Silent Spring Institute (www.silentspring.org)
Toxic-Free Legacy Coalition
(www.toxicfreelegacy.org)
Washington Toxics Coalition
(www.watoxics.org)
FOR FURTHER INFORMATION
Colburn, Theo, Dianne Dumanoski, and
John Peterson Myers (1997), Our Stolen
Future, Penguin Books, New York, N.Y.
two-credit course at Evergreen Olympia
Extension during spring quarter:
Wednesdays, April 1 – June 3, 6:30 –
8:30 PM