Endocrine Disrupters: Effects on Wildlife

Endocrine Disrupters: Effects on Wildlife

What Are Endocrine Disrupters?What Are Endocrine Disrupters?

The Endocrine System Regulates Numerous The Endocrine System Regulates Numerous Biological FunctionsBiological Functions

The hormones secreted act like messengers The hormones secreted act like messengers within various cells or organswithin various cells or organs

These messages are extremely vital before These messages are extremely vital before birth for development of sexual birth for development of sexual differentiation and proper brain differentiation and proper brain developmentdevelopment

What are Endocrine Disrupters?What are Endocrine Disrupters?

Cells have specifice receptor sites for Cells have specifice receptor sites for specific hormonesspecific hormones

Endocrine DisruptersEndocrine Disrupters

Endocrine disrupters are chemicals that can Endocrine disrupters are chemicals that can fit into these receptor sitesfit into these receptor sites

They can then interfere with hormone They can then interfere with hormone functionfunction

They can alter hormone synthesis, storage, They can alter hormone synthesis, storage, release, secretion, transport, elimination, or release, secretion, transport, elimination, or binding action.binding action.

Environmental Estrogens (EEs)Environmental Estrogens (EEs)

Some substances in the environment can act Some substances in the environment can act like the hormone estrogenlike the hormone estrogen

Naturally occurring EEs are known as Naturally occurring EEs are known as phytoestrogensphytoestrogens cloverclover soybeans, legumessoybeans, legumes whole grainswhole grains fruits and vegetablesfruits and vegetables

Other EEs are man made:Other EEs are man made: pesticides: DDT, chlordane, methoxychlor, etc..pesticides: DDT, chlordane, methoxychlor, etc.. plastics containing bisphenol Aplastics containing bisphenol A pharmaceuticals:DES, birth control pillspharmaceuticals:DES, birth control pills detergents and surfactantsdetergents and surfactants industrial chemicals:PCBsindustrial chemicals:PCBs

Estrogen: What does it do?Estrogen: What does it do?

Steroid hormone found in male and female Steroid hormone found in male and female sex organssex organs

Females: regulates and sustains female Females: regulates and sustains female sexual development and behavior, regulates sexual development and behavior, regulates reproductive cyclesreproductive cycles

Males: regulates fluid reabsorption in the Males: regulates fluid reabsorption in the tubules that carry sperm from the testis to tubules that carry sperm from the testis to the epididymisthe epididymis

Effects on WildlifeEffects on Wildlife

Various wildlife studies have shown a direct Various wildlife studies have shown a direct relationship between exposure to endocrine relationship between exposure to endocrine disrupters and:disrupters and: abnormal thyroid functionabnormal thyroid function sex alterationsex alteration poor hatching successpoor hatching success decreased fertility and growthdecreased fertility and growth altered behavioraltered behavior

FishFish

England: fish found near a municipal England: fish found near a municipal sewage outlet known to dump several sewage outlet known to dump several different chemicals including alkylphenolsdifferent chemicals including alkylphenols had both male and female sex organshad both male and female sex organs male livers had produced a female egg-yolk male livers had produced a female egg-yolk

protein normally found in females onlyprotein normally found in females only fish closest to the outlet showed more severe fish closest to the outlet showed more severe

abnormalitiesabnormalities

FishFish

Mollusks have been found to exhibit a Mollusks have been found to exhibit a condition known as imposex:condition known as imposex: male characteristics are imposed on genetic male characteristics are imposed on genetic

femalesfemales found in areas where tributyl tin is used as an found in areas where tributyl tin is used as an

“anti-fouling paint on ships”“anti-fouling paint on ships”

FishFish

Great Lakes trout extinction now thought to Great Lakes trout extinction now thought to be due to high levels of dioxin in the fish be due to high levels of dioxin in the fish which caused the developing trout within which caused the developing trout within the egg to die: the egg to die: concentrations could be as low as 5 parts per concentrations could be as low as 5 parts per

trillion (University of Wisconsin)trillion (University of Wisconsin)

FishFish

Female fish downstream from pulp and Female fish downstream from pulp and paper mills:paper mills: developed male sex organsdeveloped male sex organs tried to mate with normal females or each othertried to mate with normal females or each other males were “hypermasculinized”, exhibiting males were “hypermasculinized”, exhibiting

very aggressive mating behaviorvery aggressive mating behavior Salmon in Great Lakes region have been Salmon in Great Lakes region have been

found whit enlarged irregular thyroid glandsfound whit enlarged irregular thyroid glands

AlligatorsAlligators

Lake Apopka in Florida had DDT spill in Lake Apopka in Florida had DDT spill in 1980, alligator population declined severely 1980, alligator population declined severely over next 10 yearsover next 10 years

Mortality among eggs and newborns higher Mortality among eggs and newborns higher than normalthan normal

females had estrogen levels 2X normal levelfemales had estrogen levels 2X normal level males had lower testosterone levels and males had lower testosterone levels and

abnormal sex organsabnormal sex organs

AlligatorsAlligators

Other Florida lakes were found to have Other Florida lakes were found to have alligators with abnormal reproductive and alligators with abnormal reproductive and thyroid hormonesthyroid hormones

Birds Birds

DDT and softened eggshellsDDT and softened eggshells Gulls and terns in Great Lakes exhibit Gulls and terns in Great Lakes exhibit

abnormal thyroid levelsabnormal thyroid levels supernormal egg clutchessupernormal egg clutches female to female pairingfemale to female pairing excessive chick mortalityexcessive chick mortality birth defectsbirth defects skewed sex ratios (excess of females)skewed sex ratios (excess of females)

BirdsBirds

Also exhibit suppression of immune system:Also exhibit suppression of immune system: T-cell mediated immunity, probably caused by T-cell mediated immunity, probably caused by

PCBsPCBs Nesting Albatross in North Pacific, and Nesting Albatross in North Pacific, and

Gulls in the Puget Sound also show Gulls in the Puget Sound also show contamination of DDTs and PCBscontamination of DDTs and PCBs

MammalsMammals

In the 1980s and 90s, several outbreaks of In the 1980s and 90s, several outbreaks of marine mammal epidemics were marine mammal epidemics were documented:documented: Russia 1987- 10,000 seals died from a virusRussia 1987- 10,000 seals died from a virus United States 1987- 700 bottlenose dolphins United States 1987- 700 bottlenose dolphins

dieddied North Sea 1988- 20,000 harbor seals diedNorth Sea 1988- 20,000 harbor seals died

MammalsMammals

Mediterranean Sea 1990-93-1,000 striped Mediterranean Sea 1990-93-1,000 striped dolphins washed up dead on shoredolphins washed up dead on shore

Diminished reproductive success in seals in the Diminished reproductive success in seals in the Netherlands has also been observedNetherlands has also been observed

Minke whales study shows increasing levels of Minke whales study shows increasing levels of PCBs in bodyPCBs in body

MammalsMammals

Autopsies revealed PCBs present in animal Autopsies revealed PCBs present in animal bodies bodies

PCBs are known to suppress immune PCBs are known to suppress immune systemsystem

MammalsMammals

Studies were prompted to investigate:Studies were prompted to investigate: US and Dutch conducted experiments that US and Dutch conducted experiments that

revealed suppressed immune systems in seals revealed suppressed immune systems in seals fed contaminated fishfed contaminated fish

T-cell responses were significantly below T-cell responses were significantly below normalnormal

MammalsMammals

Reproductive hormones also affected:Reproductive hormones also affected: populations of harbor, ringed and gray seals populations of harbor, ringed and gray seals

declining declining high levels of PCB’s in bodyhigh levels of PCB’s in body beluga whales in St.. Lawrence River showing beluga whales in St.. Lawrence River showing

lower rate of pregnancy and fewer offspring lower rate of pregnancy and fewer offspring producedproduced

AmphibiansAmphibians Frogs especially vulnerable to environmental Frogs especially vulnerable to environmental

contaminants because of permeable skincontaminants because of permeable skin Pesticides and PCBs are stored in frog’s fat and Pesticides and PCBs are stored in frog’s fat and

enter the bloodstream again during enter the bloodstream again during metamorphosismetamorphosis

Many scientists now believe that the commonly Many scientists now believe that the commonly used chemical methoprene degrades in sunlight used chemical methoprene degrades in sunlight into an endocrine disrupterinto an endocrine disrupter

Laboratory ExperimentsLaboratory Experiments

University of Missouri:University of Missouri: female mice exposed to low doses of bisphenol female mice exposed to low doses of bisphenol

A altered the reproductive organs of their male A altered the reproductive organs of their male offspringoffspring

EPA in Research Triangle Park:EPA in Research Triangle Park: Direct link made between thyroid dysfunction Direct link made between thyroid dysfunction

and PCBs in ratsand PCBs in rats

Effects on HumansEffects on Humans

Wayne State University:Wayne State University: children whose mothers had eaten contaminated children whose mothers had eaten contaminated

fish from Lake Michigan in the six years prior fish from Lake Michigan in the six years prior to pregnancy had significant deficits in to pregnancy had significant deficits in intelligence and learning intelligence and learning

mothers themselves however were not mothers themselves however were not contaminatedcontaminated

Effects on HumansEffects on Humans

Similar study in NY State:Similar study in NY State: measurable neurobehavioral deficits in the measurable neurobehavioral deficits in the

newborn children who’s mothers had eaten the newborn children who’s mothers had eaten the equivalent of 40 pounds of Lake Ontario equivalent of 40 pounds of Lake Ontario salmon in a lifetime.salmon in a lifetime.

children tended to have abnormal reflexes, children tended to have abnormal reflexes, shorter attention span and an intolerance to shorter attention span and an intolerance to stressstress

Effects on HumansEffects on Humans

Early exposure of males to endocrine Early exposure of males to endocrine disrupters (DES) causes major problems disrupters (DES) causes major problems such as undescended testes, and increased such as undescended testes, and increased incidence of testicular and prostate cancerincidence of testicular and prostate cancer

Sperm densities in the US are decreasing Sperm densities in the US are decreasing 1.5% every year1.5% every year

ConclusionsConclusions

Thousands of chemicals need to be tested for Thousands of chemicals need to be tested for endocrine disruptionendocrine disruption

October 1998: EPA unveils its strategy to start October 1998: EPA unveils its strategy to start testing chemicalstesting chemicals

No current plan to start testing common No current plan to start testing common household productshousehold products

On the cellular level, we are not very different On the cellular level, we are not very different from animals, if they are being affected by from animals, if they are being affected by endocrine disrupters, so are we.endocrine disrupters, so are we.