. AND ENVIRONMENTAL TOXINS!

 The release of an egg (ova).  14 days after the onset of menses.  Production of progesterone tells her body that she is “pregnant.”

 LH (Luteinizing hormone) ◦ Stimulates ovulation, progesterone secretion, mammary glands, and male testosterone secretion.  FSH (Follicle stimulating hormone) ◦ Stimulates follicle development, and other sex hormones.  Estrogen ◦ Class of hormones secreted from the ovarian follicle. ◦ Considered the main “female” hormones.  Progesterone ◦ Maintains endometrium during pregnancy.

 Are you pregnant? ◦ What is “pregnant?”  If you had sex on Friday February 14 th … ◦ Fertilized on Wednesday February 23 rd ? ◦ Implantation on Saturday March 1 st ? ◦ When did you “become” pregnant? ◦ When do you find out you are pregnant?

 How does the egg get fertilized?  Where does fertilization take place?  How long does it take?

 Sperm approaches egg.  Sperm releases enzymes.  Sperm bonds with ova.  Ova membrane changes.

 “The condition of carrying a developing baby within the uterus.”  How long is a pregnancy? ◦ 266 days (38 weeks) ◦ Mice (29 days) ◦ Elephants (22 months)  What is the average size of a baby? ◦ 50 cm (20 inches) and 2.7 – 4.5 kg (6-10 lbs).

 The zygote splits every 20 minutes.  In three hours, a single ball of cells forms.  This continues to divide for three more days.

 Formation of a hollow ball of cells.  This is completed by day 5.

 The tissues migrate, becoming quite different. ◦ Ectoderm  NS and skin ◦ Mesoderm  Heart, kidney ◦ Endoderm  Digestive tract

 Fully formed at 31 days.  Movement of nutrients and waste products.  Some things can pass the placenta. ◦ German measles ◦ HIV ◦ Tetracycline  There is no contact between the mother and fetal blood.

 Fertilization until about 11 weeks.  At nine weeks: ◦ Embryo is now called a fetus. ◦ 5.5 cm long.  All organs are present. ◦ Limb buds have tiny arms and legs, fingers/toes.  At the end, sex is usually apparent.

 The major initial developmental steps have been completed.  Embryo’s still have pharyngeal gill slits, webbing on toes and fingers.

 12 to 24 weeks  Size and overall features develop. ◦ 14 wks (6 cm) ◦ 20 wks (19 cm 500 g)  Mothers abdomen becomes enlarged.

 24 weeks to birth.  Features: ◦ Fetus grows and gains strength. ◦ Internal temperature regulation. ◦ Systems get ready for oxygen. ◦ Bones harden, muscles thicken. ◦ Loss of fetal fur. ◦ Head changes proportions.

Objective Assess our understanding of how chemicals affect child health.

Overview Protect children from neurotoxic exposures from environmental toxins….a Goal!

Too much of a thing makes you blue But not having it can kill you too Too much or too little Let's not be so fickle We'll go Dutch and divide it by two.

 Exposure starts early – pre- conception, breast milk  For their body weight, children eat and breathe more than adults, thus a small exposure translates into a big dose.  Brain developing, cells dividing  Behavior – hand to mouth increases exposure to chemicals Children are not little adults

Timing of exposure A child’s developing nervous system is more sensitive to chemical exposures than the adult nervous system.

Other environmental factors  Pharmaceuticals  Genetic factors  Environmental justice: socioeconomics, nutrition and stress

Environmental agents that we are confident cause learning and developmental disabilities in humans Environmental Agents Alcohol Lead Mercury PCBs PBDEs Manganese Arsenic Solvents PAHs Pesticides Nicotine & ETS

 We will focus on environmental toxins and DEVELOPING humans ( infants and children) as this is when the most profound effects can be seen.  The ramifications are that that these toxins also effect adults as well, but to a lesser degree  Toxins can accumulate in the body, especially the fatty tissue.

 Fetal Alcohol Spectrum Disorder (FASD), is the most preventable form of behavioral and learning disabilities. Alcohol  In the US, FASD is estimated to affect 9.1 per 1000 infants with even higher rates in other parts of the world.  Do not consume alcohol during pregnancy.

 There is no safe level of lead exposure for children  Even the lowliest of lead exposure cause impairs overall intelligence as measured by IQ, learning and memory Lead  The CDC should lower the blood lead action level Rationale for Lowering the Blood Lead Action Level From 10 to 2 µg/dl. Steven G. Gilbert and Bernard Weiss. Neurotoxicology Vol 27/5, September 2006, pp

 Mercury bioaccumulates in fish  Mercury is distributed in the environment by coal burning electric utility plants Mercury  Mercury advisories limit fish consumption for women and children  US EPA RfD 0.1 ug/dL

 Highly persistent and bioaccumulative.  Stored in fat and excreted in women’s breast milk.  Exposure can adversely affect motor skills, learning and memory as shown in lower full-scale and verbal IQ scores and reading ability PCBs - Polychlorinated biphenyls

 Commonly used as flame-retardant  PBDEs, structurally similar to PCBs  Bioaccumulates in animals and humans, and are excreted in human breast milk.  Developmental neurotoxicants PBDEs - Polybrominated diphenyl ethers O Br x Br y

 Commonly found in drinking water around the world, sometimes in concentrations high enough to cause cancer Arsenic  Dose-response relationship between exposure to arsenic and intellectual impairment

 Broad array of different compounds including toluene, benzene, alcohol, turpentine, acetone and tetrachloroethylene (TCE) Solvents  More than 50 million metric tons used in the US and more than 10 million people exposed in the workplace.

 Widely distributed air pollutants and well- recognized human mutagens and carcinogens. PAHs - Polycyclic aromatic hydrocarbons  PAHs are generated during combustion of fuels from motor vehicles, coal-fired power plants, residential heating, cooking, and tobacco smoke  PAHs results in lower birth weight and affects cognitive development

 Designed to kill insects, plants, fungi or animals  Agricultural and residential application of pesticides in the US totals more than one billion pounds per year Pesticides  Childhood exposure enhances the risk for developmental disorders including deficits in memory poorer motor performance

 Maternal smoking or exposure to ETS during pregnancy leads to behavioral disorders in children  CDC reported in 2002 that 11.4 percent of all women giving birth in the United States smoked during pregnancy Nicotine and ETS  Childhood exposure to ETS also results in developmental disorders

Endocrine disruptors  Phthalates, PCBs and polychlorinated dibenzodioxins, brominated flame retardants, dioxins, DDT, perfluorinated compounds (PFCs), organochlorine pesticides, bisphenol A, and some metals

Fluoride  Commonly added to municipal drinking water across the US based on data that it reduces dental decay.  Multiple routes of exposure, from drinking water, food and dental care products  Emerging science suggests we need to further study the dose at which fluoridation may increase risks of neurodevelopment disorders, cancer and skeletal or dental fluorosis, particularly for sensitive individuals.

Food additives  Artificial or synthetic food colors and additives are ubiquitous in the food supply  Artificial food colorings such as sunset yellow, tartrazine, carmoisine and ponceau, as well as the preservative sodium benzoate, can cause conduct and hyperactivity disorders

A free toxicology encyclopedia and resource center that anyone can edit. Toxipedia provides comprehensive, accurate, and scientifically based information on the hazards and risks of chemical and physical agents, with the goal of advancing human and environmental health. ToxipediaToxipedia

 Environmental toxins are just one aspect of environmental health.  Can you think of other factors in the environment that affect your family's health?  The End.