GEN1030 Introduction to Environmental Studies Aliya Nurtaeva, Ph.D.

GEN1030 Introduction to Environmental Studies Aliya Nurtaeva, Ph.D. KIMEP University, Dept of GE Office # 507 [email protected] Lecture 6: Environment & Human Health

2 Environmental Health Emerging Diseases Toxic substances: movement, distribution Toxic Effects: how to minimize them Measuring Toxicity Risk Assessment & Public Policy Lecture 6 Outline

3 What is Health? World Health Organization (WHO) defines health as a state of complete physical, mental, and social well-being. Disease - a deleterious change in the body's condition in response to an environmental factor Diet and nutrition, infectious agents, toxic chemicals, physical factors, and psychological stress all play roles in morbidity (illness) and mortality (death). Morbidity - incidence of illness in a population Mortality – occurrence of death within a population (estimated by death rate)

4 Environmental Health Planet supplies us with: food, water, air, and everything that sustains our life. Historically environmental health focused on preventing infectious diseases spread by water, waste, food, rodents, and insects. Expansion of the modern day definition: Environmental health addresses all the external factors that cause disease, including natural, social, cultural & technological factors. Encompasses all the interactions of humans with the environment and the health consequences of these interactions.

5 Leading Causes of Mortality

6 At any given time, ~2 bln people suffer from worms, protozoa, other internal parasites: elephantiasis, guinea worm, etc.

7 Insect and Rodent Control Great number of illnesses are associated with animal and insect contact. Encephalitis (virus transmitted by ticks) Lyme Disease (bacteria transmitted by ticks) Bubonic plague (bacteria transmitted by fleas from rodents) West Nile virus (virus transmitted by mosquitoes)

8 Factors Contributing to the Spread of Contagious Diseases High population densities Human-caused environmental change Speed and frequency of modern travel Contact with water or food contaminated with human waste

9 Emerging Diseases An emerging disease is one never known before, or has been absent for at least 20 yrs. Important factor in spread of many diseases are speed and frequency of modern travel. EXAMPLES of Emerging Diseases AIDS = Acquired Immune Deficiency Syndrome SARS = Severe Acute Respiratory Syndrome Avian flu (bird flu) West Nile virus TSE (see next slides)

10 Hong Kong residents concerned about SARS -2003 SARS - a potential pandemic

11 SARS briefly: Nov 2002-July 2003 8,098 cases, 774 deaths Southern Asia: China, Hong Kong,... In 2002 – no info on new virus July 2003 – disease was contained: success of international medicine - WHO

12 Avian or bird flu 3 prerequisites for pandemic new virus must be transmitted to humans spread from human to human must replicate in humans causing disease since 1997 became disease of humans: 1997 Hong Kong (H5N1), 2003 Hong Kong (H5N1), 2003 Netherlands (H7N7), 2004 Vietnam and Thailand (H5N1) Swine flu - 2009 worldwide (H1N1)

13 Emergent Environmental Diseases Animals also experience widespread epidemics /pandemics: TSE: Transmissible Spongiform Encephalopathies Creutzfelt-Jacob (human) Mad Cow Disease (cattle) Chronic Wasting Disease (deer, elk) Prions (not virus, not bacteria) are agents causing this disease Agent  Vector  Disease

West Nile Virus in 21 century 2010-2013 Outbreaks in Russia: Volgograd, Astrahan’ cases in Kazakhstan USA: 2001-2002

15 Infectious Disease Outbreaks

16 Microbial adaptation & change Human demographics & behaviour Technology & industry (animal practice, food production) International travel & commerce Breakdown of public health measures Climate and weather Poverty & famines Wars Main Causes of Emerging Diseases

17 TOXINS: Dangerous chemicals, divided into two broad categories: Hazardous means dangerous: flammables, explosives, acids, caustics, etc. Toxic means poisonous: may be general or very specific (able to damage /kill cells). 2: Toxins

18 5 Classes of Toxic Chemicals Neurotoxins - class of poisons that attack nerve cells: Heavy Metals kill nerve cells (lead, cadmium). Chlorinated Hydrocarbons disrupt nerve cell membranes (DDT). Organophosphates inhibit signal transmission between nerve cells. Mutagens - agents that damage or alter genetic material. Radiation Teratogens - cause abnormalities during embryonic growth and development. Alcohol - Fetal Alcohol Syndrome (FAS)

19 5 Classes of Toxic Chemicals Carcinogens - substances that cause cancer. Cigarette smoke, asbestos. Allergens - substances that activate the immune system. Dust, paints, chemicals:, formaldehide, pesticides,..

20 Pesticides in Produce Rank 12 most contaminated foods Strawberries Beets…! Bell peppers Spinach Cherries Peaches Cantaloupe Celery Apples Apricotes Green beans Grapes Cucumbers

21 Radiation Nuclear Weapons, Nuclear Energy Medical Uses of Radiation Radiation in the Home and Workplace Radon Construction materials, buildings Most dangerous types of radiation

22 Noise Pollution Measured in Decibels Noise pollution - > 80-85 decibels Pain threshold = 120 decibels Two sources of excessive noise Workplace Large gatherings of people (concerts, sports events)

23 Toxins in our Life

24 Bioaccumulation & Biomagnification Bioaccumulation: organisms take up and accumulate toxins in their cells and tissues Biomagnification– increase in concentration of toxins through food webs to the higher trophic levels

25 Every material can be poisonous under some conditions: depends on dose. Taken in small doses, toxins break down before they do much harm. Liver - primary site of detoxification Toxins that aren't broken down can affect tissues and organs – they disrupt their growth and possibly cause Minimizing Toxic Effects

26 A Typical Dose/Response Curve

27 LD50 - the dose of a toxin that is lethal to half of the tested population LD50 examples: Alcohol: 10 g/kg Caffeine (rats):~0.2 g/kg Nicotine: ~1 mg/kg Lethal Dose 50 (LD50)

28 Acute vs Chronic Doses & Effects Acute effect - immediate health effect caused by a single exposure to a toxin (can be reversible) Chronic effect - long lasting or permanent health effect caused by (1) a single exposure to a very toxic substance or (2) continuous or repeated sub lethal exposure to a toxin

29 Regulatory Decisions