Toxicology Toxicology TOXICOLOGY Toxicology the study of the

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Toxicology

Toxicology

Toxicology

Toxicology

TOXICOLOGY � Toxicology= the study of the adverse effects of toxins on living organisms

TOXICOLOGY � Toxicology= the study of the adverse effects of toxins on living organisms Toxins= chemicals that adversely affect living organisms by disrupting normal metabolic function. � Environmental toxicology = toxic substances that come from or are discharged into the environment Includes study of health effects on humans, other animals & ecosystems

Synthetic chemicals = man-made Chemical Risks Pesticides Detergents Drugs Disinfectants Solvents Our society has

Synthetic chemicals = man-made Chemical Risks Pesticides Detergents Drugs Disinfectants Solvents Our society has developed an incredible amount of chemicals to improve human life…pharmaceuticals, insecticides, pesticides, herbicides, fungicides. Improved human health & food production But the large number of chemicals released into the environment naturally raises questions about potential effects these chemicals have on humans & other organisms…

Toxins… • • • May concentrate in water (hydrophilic) Can travel widely through the

Toxins… • • • May concentrate in water (hydrophilic) Can travel widely through the atmosphere Can persist for a long time May accumulate & move up the food chain (lipophilic) Are not all synthetic (man-made)

Some chemicals of major concern Chemical Sources Type Lead Paint; gasoline Neurotoxin Mercury Coal

Some chemicals of major concern Chemical Sources Type Lead Paint; gasoline Neurotoxin Mercury Coal burning, fish consumption Neurotoxin Arsenic Mining, groundwater Neurotoxin Carcinogen Asbestos Building material Carcinogen Polychlorinated biphenyls (PCBs) Industry Carcinogen Radon Soil, water Carcinogen Vinyl chloride Industry, water from vinyl chloride pipes Carcinogen Alcoholic beverages Teratogen Atrazine Herbicide Endocrine disruptor DDT Insecticide Endocrine disruptor Phthalates Plastics, cosmetics Endocrine disruptor

Toxins can be grouped into 5 categories Neurotoxins, carcinogens, teratogens, allergens & endocrine disruptors

Toxins can be grouped into 5 categories Neurotoxins, carcinogens, teratogens, allergens & endocrine disruptors

Allergens �Allergens= chemicals that causes allergic reaction Cause an abnormally high response from the

Allergens �Allergens= chemicals that causes allergic reaction Cause an abnormally high response from the immune system Given allergens usually cause allergic reactions in a small fraction of people �Peanuts, milk, penicillin, codeine, formaldehyde

Allergens Formaldehyde ▪ Commonly used in the manufacture of furniture, carpeting, and particleboard ▪

Allergens Formaldehyde ▪ Commonly used in the manufacture of furniture, carpeting, and particleboard ▪ Because these items are frequently found in buildings, a building may be labeled as inducing sick building syndrome (SBS) � Symptoms: headache, sneezing, dry cough, itchy skin, nausea, dizziness, and fatigue

Carcinogens �Carcinogens= chemicals that causes cancer Carcinogens can either damage DNA or it can

Carcinogens �Carcinogens= chemicals that causes cancer Carcinogens can either damage DNA or it can interfere with the normal metabolic process of the cell ▪ Mutagen= anything that mutates DNA; carcinogens are a type of mutagen �Asbestos, Radon, Formaldehyde, and chemicals found in tobacco

Teratogens �Teratogens= chemicals that cause birth defects Thalidomide, a drug prescribed to pregnant women

Teratogens �Teratogens= chemicals that cause birth defects Thalidomide, a drug prescribed to pregnant women during the late 1950’s/early 1960’s to combat morning sickness ▪ Taken off the market in 1961 �Alcohol Excess alcohol consumption reduces growth of the fetus & damages the brain & nervous system ▪ Fetal alcohol syndrome

Endocrine disruptors �Endocrine disruptors= chemicals that interfere with the normal functioning of hormones Estrogen

Endocrine disruptors �Endocrine disruptors= chemicals that interfere with the normal functioning of hormones Estrogen & Testosterone are Hormones are normally produced in the endocrine well known system & released into the bloodstream in very hormones low concentrations. As the hormones move through the body, they bind to specific cells Binding stimulates the cell to respond in a way that regulates the functioning of the body

Endocrine disruptors �Water pollution in wastewater: hormones from animal-rearing facilities, hormones from birth control

Endocrine disruptors �Water pollution in wastewater: hormones from animal-rearing facilities, hormones from birth control pills, and pesticides that mimic animal hormones Male fish, reptiles & amphibians found in this wastewater are becoming feminized ▪ Males having low sperm count ▪ Males that can produce both eggs & sperm �Males usually convert estrogen into testosterone- endocrine disruptors interfere with this process

Endocrine disruptors �Effect on humans: Low sperm count in males Increased risk of breast

Endocrine disruptors �Effect on humans: Low sperm count in males Increased risk of breast cancer in women Atrazine (herbicide), DDT (pesticide), phthalates (plastics, cosmetics), Dioxins & PCBs

Neurotoxins �Neurotoxins= chemicals that disrupts the nervous system Ex. Insecticide interferes w/nerve transmissions; insect

Neurotoxins �Neurotoxins= chemicals that disrupts the nervous system Ex. Insecticide interferes w/nerve transmissions; insect becomes paralyzed, cannot obtain oxygen & quickly die �Mercury, Lead, Arsenic & Cadmium Damages a person’s kidneys, brain & nervous system ▪ Kill nerve cells Irreparable Lead in gasoline & paint phased out starting in the 1970 s so lead exposure in US has decreased dramatically, but is still an issue in low-income areas that contain leaded paint

Flint, Michigan 2014 �To save money the city changed where they were getting their

Flint, Michigan 2014 �To save money the city changed where they were getting their water from �The new water was more corrosive and it ate away the lead in the older pipes, which dissolved into their drinking water

Other common neurotoxins DDT, Dieldren (insecticide), PCBs, industrial solvents, and dioxins ▪ Damage neurons

Other common neurotoxins DDT, Dieldren (insecticide), PCBs, industrial solvents, and dioxins ▪ Damage neurons

Mad Hatter Disease �“Mad as a hatter”

Mad Hatter Disease �“Mad as a hatter”

Minimata Disease “Minimata Disease” �Minimata Bay, Japan Birds lost their coordination & fell into

Minimata Disease “Minimata Disease” �Minimata Bay, Japan Birds lost their coordination & fell into ground or flew into buildings Cats running in circles & foaming at the mouth Families of fishermen: fatigue, irritability, headaches, numbness in arms/legs, difficulty swallowing, blurred vision, hearing loss, metalliic taste in mouth

Methyl mercury � Vinyl chloride factory used mercury in production process mercury released as

Methyl mercury � Vinyl chloride factory used mercury in production process mercury released as waste into Minimata Bay ▪ Mercury forms few organic compounds, so safe, not get into food chains � Inorganic mercury converted by bacteria into methyl mercury (CH 3 Hg+), an organic compound ▪ Readily passes through cell membranes, transported by red blood cells throughout the body & damages brain cells � Methyl mercury bioaccummulates up the food web

Minimata Disease What we can learn from this story: � 1. Individuals vary in

Minimata Disease What we can learn from this story: � 1. Individuals vary in their response to exposure to the same dose, or amount, of a pollutant � 2. Pollutants may have a threshold A level below which effects are not observable & above which effects are apparent � 3. Some effects are reversible � 4. The chemical form of a pollutant, its activity, & its potential to cause health problems may be changed markedly by ecological & biological processes