General Hygiene and Ecology Lecture I 2024 PDF

General Hygiene and Ecology LECTU RE I SALOME TSARIA 2024 Lecture theme-Week 1 Working conditions, environment and health –introduction. Toxicology: toxicology as a basic of science. Features of chemical substances and information sources of hazardous chemicals. Toxicity...

General Hygiene and Ecology LECTU RE I SALOME TSARIA 2024 Lecture theme-Week 1 Working conditions, environment and health –introduction. Toxicology: toxicology as a basic of science. Features of chemical substances and information sources of hazardous chemicals. Toxicity and its modifying factors, Biological Poisons; Environmental pollutants and their norms; Epidemiology; work space. Reading Materials:  Principles And Practice Of Toxicology In Public Health 2nd Edition Ira, Richards page: 3-115  Environmental health4th  ed. Moeller, Dade W. page: 1-71  What is Ecology?  What Is Environmental Health?  Ecology is a branch of science, including human science, population, community, ecosystem and biosphere. Ecology is the study of organisms, the environment and how the organisms interact with each other and their environment.  An ecologist’s primary goal is to improve their understanding of life processes, adaptations and habitats, interactions and biodiversity of organisms.  Environment meaning  Environment can be defined as a sum total of all the living and non-living elements and their effects that influence human life. While all living or biotic elements are animals, plants, forests, fisheries, and birds, non-living or abiotic elements include water, land, sunlight, rocks, and air.  Environment functions  (1) Provides the supply of resources  The environment offers resources for production.  It includes both renewable and non-renewable resources.  Examples: Wood for furniture, soil, land, etc.  (2) Sustains life  The environment includes the sun, soil, water, and air, which are essential for human life.  It sustains life by providing genetic and biodiversity.  (3) Assimilates waste  Production and consumption activities generate waste.  This occurs mostly in the form of garbage.  The environment helps in getting rid of the garbage.  (4) Enhances the quality of life  The environment enhances the quality of life.  Human beings enjoy the beauty of nature that includes rivers, mountains, deserts, etc.  These add to the quality of life. THE ENVIRONMENT IS…  The air we breathe,  The water we drink,  The food we eat, and  The places where we live, work. There is a connection between the environment and the health of individuals and communities. Likewise, people can affect the health of the environment. ENVIRONMENTAL HEALTH IS THE DISCIPLINE THAT…  Focuses on the inter-relationships between people and their environment,  Promotes human health and well-being, and  Fosters a safe and healthful environment. According to the World Health Organization, “environmental health comprises those aspects of human health, including quality of life, that are determined by physical, chemical, biological, social, and psychosocial processes in the environment. It also refers to the theory and practice of assessing, correcting, controlling, and preventing those factors in the environment that can potentially adversely affect the health of present and future generations Many aspects of human well-being are influenced by the environment, and many diseases can be initiated, promoted, sustained, or stimulated by environmental factors. For this reason, the interactions of people with their environment are an important component of public health.  this field is defined more by the problems it faces than by the approaches it uses. These Environmental problems include the treatment and disposal of liquid and airborne wastes, the elimination or reduction of stresses in the workplace, the purification of drinking-water supplies, the provision of food supplies that are adequate and safe, and the development and application of measures to protect hospital and medical workers from being infected with diseases such as acquired immune deficiency syndrome (AIDS) and severe acute respiratory syndrome (SARS). As this list implies, the basic source of our environmental problems is, in essence, the impact of an ever-increasing population.  Environmental health professionals also face long-range problems that include the effects of toxic chemicals and radioactive wastes, acidic deposition, depletion of the ozone layer, global warming, resource depletion, and the loss of forests and topsoil.  Team that is coping with a major environmental health problem may include:  Scientists  Physicians  Epidemiologists  Engineers  Economists  Lawyers  Mathematicians  Managers  Just as A field of public health involves more than disease (for example, health-care Management, maternal and child health, epidemiology) the field of environmental health encompasses the effects of the environment on animals other than humans, as well as on tress and vegetation and on natural and historic landmarks. While many aspects of public health deal with the “here and now:, many of the topics addressed within the subspecialty of environmental health are concerned with the previously citied impacts of a long-range nature.  Defining the Environment  To accomplish their goals effectively, Environmental Health Professionals must keep in mind that there are many ways to define the environment.  From the standpoint of the human body, there are two environments: the one within the body and the one outside it. Separating them are three principal protective barriers: the skin, which protects the body from contaminants outside the body; the gastrointestinal (GI) tract, which protects the inner body from contaminants that have been ingested; and the membranes within the lungs, which protect the inner body from contaminants that have been inhaled  Although they may provide protection, each of these barriers is vulnerable under certain conditions!!!!  The Personal versus Ambient Environment People’s “personal” environment, the one over which they have control, is contrasted with the working or ambient (outdoor) environment, over which they may have essentially no control. The personal environment, influenced by: Hygiene Diet Exercise Use of tobacco sexual practices, Drugs Alcohol Frequency of medical checkups These various factors to cancer deaths in an industrialized society. The personal environment and the lifestyles followed by individuals account for about 70 percent or more of such deaths. The environment can also be considered as existing in one of three forms—gaseous, liquid, or solid. Each of these is subject to pollution, and people interact with all of them. Particulates and gases are often released into the atmosphere, sewage and liquid wastes are discharged into water , and solid wastes, particularly plastics and toxic chemicals, are disposed of on land. Another perspective considers the environment in terms of the four avenues or mechanisms by which various factors affect people’s health. 1. Chemical constituents and contaminants include toxic wastes and pesticides in the general environment, chemicals used in the home and in industrial operations. 2. Biological contaminants include various disease organisms that may be present in food and water , those that can be transmitted by insects and animals , and those that can be transmitted by person-to-person contact. 3. Physical factors that influence health and well-being range from injuries and deaths caused by accidents to excessive noise, heat, and cold and to the harmful effects of ionizing and nonionizing radiation. 4. Socioeconomic factors, though perhaps more difficult to measure and evaluate, significantly affect people’s lives and health. Statistics demonstrate compelling relationships between morbidity and mortality and socioeconomic status. People who live in economically depressed neighborhoods are less healthy than those who live in more affluent areas.  Urban Environemnt Another environment that is assuming increasing importance is that of large cities, the so-called urban environment. One of the primary reasons is that today about half of the world’s population lives in urban centers. As a result, many urban environments today are noisy, congested, frustrating, and unhealthy. If these Problems are to be mitigated, methods must be found to make urban areas environmentally and socially sustainable.  Cancer and the Personal Environment  Cancer is one of the leading causes of death in both developed and developing countries. It was estimated that approximately 18.1 million new cancer cases occurred and 9.6 million cancer patients died worldwide in 2018 based on the GLOBOCAN 2018 (Bray et al., 2018). Tobacco smoking has been associated with numerous cancer sites, including cancers of the lung, pharynx, esophagus, larynx, stomach, bladder, kidney, ureter, pancreas, colon and rectum, liver as well as acute myeloid leukemia (Doll et al., 2004; Pirie et al., 2013; U.S. Department of Health Education and Welfare, 1964; Patel and Steinberg, 2016; U.S. Department of Health and Human Services, 2004; U.S. Department of Health and Human Services, 2014). Environmental tobacco smoke (ETS), known as secondhand smoke, or passive smoking, is an established risk factor for lung cancer. ETS is a mixture of side-stream smoke and exhaled mainstream smoke, it contains hundreds of chemicals and similar carcinogens as active tobacco smoking (International Agency for Research on Cancer, 2004; California Environmental Protection Agency, 2005). It was estimated that 35% of female non-smokers, 33% male non-smokers, 40% of children were exposed to ETS worldwide (Öberg et al., 2011). The prevalence of ETS exposure is one of major public health concerns. It was estimated that secondhand smoke may contribute to 453,562 cancer cases and 323,284 of cancer deaths annually worldwide (Kristina et al., 2019).  those people who live in the developed countries must decide what changes in their lifestyles they are willing to make to ensure the “greatest good” for the majority of the world’s population, a vast number of whom live in the less developed countries.  The problems of the environment are enormous. Solutions will require the cooperation of government, industry, and commerce, as well as the concern and dedication of individuals throughout the world.  Toxicology Toxicology is the study of the adverse effects of chemicals in biological systems. We must also recognize that we share our planet with other organisms, both plants and animals ,that are also affected by chemical agents. Terms commonly used to refer to toxic chemicals are as followers: Toxic chemical-toxic chemical as any substance which may be harmful to the environment or health. Toxic substance-A toxic substance is a substance that can be poisonous or cause health effects. Toxic agent- A toxic agent is anything that can produce an adverse biological effect. It may be chemical, physical, or biological in form. For example, toxic agents may be: Chemical (such as cyanide) Poison-poisons are substances that cause death, injury or harm to organisms, usually by chemical reaction. Toxin-must be reserved for those chemicals that are produced by living organisms) Toxicant-may affect specific tissues or organs (target tissues, target organs) Xenobiotic-A xenobiotic is a chemical substance found within an organism that is not naturally produced or expected to be present within the organism(examples as plant constituents, drugs, pesticides, cosmetics, flavorings, fragrances, food additives, industrial chemicals and environmental pollutants.) A hazard is any physical,chemical or biological agent that has the capacity to cause physical damage or harm the health of living organism. A hazardous material is any chemical substance or agent that poses a potential health hazard. Those chemical substances or agent that have the potential to harm the health of living organisms are called toxic substance. Poisons are substances that cause death, injury or harm to organisms  Toxicity  All chemicals have the potential to produce toxicity.  Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism.  Toxicity can damage an organism.  Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant.  The level of toxicity depends on the concentration of the toxicant at the site of action and is influence by such factors as the rate of absortion,access to the target cell, the degree of biotransformation or bioactivation and the rate of elimination.  Chemicals can interact with molecular targets specifically or nonspecificially,through reactions that are either reversible or irreversible.  Botulinum toxin,asbestos, Carbon Monoxide are one most of the dangerous chemical substances.  Factors That Modify Toxicity Age-the body undergoes developmental and metabolic changes.infants and children are more likely to be adversely affected by toxicants than adults. Gender-gender differences in metabolism,body fat composition,body water and hormones may all contribute to susceptibility. Disease-imunne defucuency syndrome ,are possibly more susceptible to carcinogenic agents. Lifestyle and diet-lifestyle considerations factor into how well the body can handle toxicants. Genetics-although the genetic similarity among is remarkable in many ways,individual variations in importans biochemical processes may result in differences in both xenobiotic distribution and sensitivity to toxic insult. Biological poisons:Plant and Animal Toxins A toxin is a poisonous substance produced within living cells or organisms. Toxins fall into several broad categories based on the organism that produces them: Bacteria:endotoxins,exotoxins,enterotoxins] Fungi:mycotoxins Algae:phycotoxins Plants:phytotoxins Animals:zootoxins  Bacterial toxins  Botulinum toxin-refers to a collection of extremely potent neurotoxic proteins that are produced under anaerobic conditions by the gram- negative bacterium clostridium botulinum.three main forms of botulism:infant,foodborne,wound.the symptoms of botulism can be prevented by antitoxin antibodies. The general public is not vaccinated against botulism because it is very rare in developed countries. The muscle weakness of botulism characteristically starts in the muscles supplied by the cranial nerves.  Tetanus toxin-tetanus, from the Greek tetanus (meaning stretched, rigid).the bacterium clostridium tetani is the causal agent it is an anaerobic bacterium with spores germinating under very low oxygen levels. The toxin is referred to as tetanospasmin or spasmogenic toxin. n the most common type, the spasms begin in the jaw and then progress to the rest of the body.  Endotoxins are known to cause an inflammatory response in the human respiratory tract. Gram negative bacteria. Its released when bacteria lyses.endotoxins are associated with fever, inflammation and lowering of blood pressure.symptoms:hadache,fecer,tightness of the chest, decreased lung function, nonproductive cough and general malaise  Fungal toxins Common names for poisonous mushrooms are “toadstool” or “death of stool"; these toxins are produced from fungi and cannot be made nontoxic by cooking, freezing or other forms of food processing. Effects: gastrointestinal effects,disulfiram like effects,neurotoxic effects, cytotoxic effects. Mycotoxins- is a toxic secondary metabolite produced by organisms of the fungus kingdom and is capable of causing disease and death in both humans and other animals.mycotoxins are the fumonisis,which have been associated with an increased incidence of human esophageal cancer in some parts of Asia, Africa and central America. Major groups of mycotoxins:aflatoins,trichothecenes,ergolines.  Algal toxins  The cyanobacteria of the plant kingdom monera are known by the common are photosynthetic organisms,wich about a dozen toxic species name blue- green algae. They found on land, in freshwater and in the oceans. Blue-green algae are responsible for the deaths of large populations of wild and domestic animals, including migrating ducks and geese cattle and sheep that have consumed contaminated water. Types of algal toxins:dinoflagellates, diatoms., Cyanobacteria.  Red tides-the term red tide refers to the reddish orange- brown color of coastal water during outbreaks of certain species of dinoflagellates in the gulf of mexico,Caribbean and other coastal areas around the world. Associated with massive fish and bird kills  Higher plant toxins Many higher plants produce harmful substances that can produce injury and sometimes death if ingested. Young children are especially at risk for toxicity from plants.ingestion of toxic plants affects primarily the gastrointestinal,cardiovascular,and central nervous systems. Plant toxins can be classified based on their general chemical structure. Example of the types of toxins contained in plants are as follows:  Alkaloids  Proteins and amino acids  Glycosides  Oxalates  Phenols, resins and volatile oils  Photo toxins  Plant toxins can be present even in fruit and vegetable plants.  Animal toxins The Australian funnel-web spiders are known as the most dangerous type of spider in the world. Widow spider venom is neurotoxic ,and envenomation's result in a syndrome that develops within 1 or 2 hours of being bitten. Referred to as latrodectism,this syndrome is characterized by:  Pain first localized at the lymph nodes  Nausea  Abdominal muscle rigidity  Generalized muscle contractions and cramps  Hypertension  Transient tachycardia  Bradicardia  Profuse sweating  Oliguria Scorpion venom is generally neurotoxic and interferes with neurotransmission. The “death stalker has potent venom that has resulted in fatilities. Hymenopterans these stinging insects can produce envenomation's that can be painful and produce local tissue injury. The amount of venom from single stings is essentially insufficient to produce system toxicity. Cnidaria comprises jellyfish,hydroids,corals and anemones. Their venom apparatus is the nematocyst that contains a coiled thread-like structure with skin-piercing barb on the end. Even they are dead they are capable of discharge upon chemical or mechanical stimulation. Mollusks : there are two species of blue-ringed octopus,hapaloclaena lunulata and hapalochlaena maculosa,differing in size and distribution. They share the ability to painlessly kill human within 5 minutes. They inject paralytic neuromuscular venom that contains both maculotoxin and tetrodotoxin.both block nerve conduction by interfering with sodium channels. They posses two poisn glands, each as large as their brain.one gland contains mild toxin reserved for prey, whereas the other contains a vastly more potent toxin used for defense. Shellfish poisonings are usually classified as: Amnesia shellfish poisoning Diarrheic shellfish poisoning Neurotoxic shellfish poisoning Paralytic shellfish poisoning  Enviromental pollutants Environmental pollutants are chemicals that have ended up in the environment as a result of human activities and that are hazardous to health. Environmental pollutants can relocate from their original source though interface transport processes.as interface in theoretical boundary between air and water, air and soil and soil and water. DDT-Dichlorodiphenyltrichloroethane It was originally developed as an insecticide, then it became infamous for its environmental impacts. DDT was used in the second half of World War II to control malaria and typhus among civilians and troops. Although it was promoted by government and industry for use as an agricultural and household pesticide. Human health effects from DDT at low environmental doses are unknown. Following exposure to high doses, human symptoms can include vomiting, tremors or shakiness, and seizures. Laboratory animal studies showed effects on the liver and reproduction. DDT is considered a possible human carcinogen. Some studies in humans linked DDT levels in the body with breast cancer, but other studies have not made this link. There are three major factors that determine the severity of environmental contaminants:  Their chemical nature  their concentration  Their persistence  Toxicity in a population The toxicity of chemicals to a population depends on many factors. Ecosystems are complex and made up of a multitude of animals and plant. The level of effects of any chemical, or any particular population of species, may be different from another in that community. Toxicity depends on many factors:  Species  Age  Gender  Exposure route  Duration of exposure  Form and activity of the chemical  Concentration or dose bioavailability  Primary route of exposure  Ability to be absorbed  Metabolism  Distribution within the body  Excretion  Presence of other chemicals Depending on these characteristics, some people will experience the toxic effects of a chemical at a lower (or higher) dose than other people.  Epidemiology  Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants of health and disease conditions in defined populations. The founder of epidemiology is often considered to be John Snow.  Environmental epidemiology is the study of the distribution and environmental determinants of disease. This observational science relies upon events occurring within human populations, so-called natural experiments, from which inference is drawn to identify causes of disease  Environmental epidemiology is one of the most important tools used in environmental management decision making owing to its capacity to assess and monitor environmental hazards in different settings and quantify their health impact on the population at risk.  Epidemiology is the study of how often diseases occur in different groups of people and why. Epidemiological information is used to plan and evaluate strategies to prevent illness and as a guide to the management of patients in whom disease has already developed.  The basic epidemiological study designs are cross-sectional, case-control, and cohort studies  Cross-sectional studies provide a snapshot of a population by determining both exposures and outcomes at one time point  Cohort studies identify the study groups based on the exposure and, then, the researchers follow up study participants to measure outcomes (  Case-control studies identify the study groups based on the outcome, and the researchers retrospectively collect the exposure of interest. Another key distinction in longitudinal research is between prospective and retrospective studies:  In prospective studies, individuals are followed over time and data about them is collected as their characteristics or circumstances change. Birth cohort studies are a good example of prospective studies.  In retrospective studies, individuals are sampled and information is collected about their past. This might be through interviews in which participants are asked to recall important events, or by identifying relevant administrative data to fill in information on past events and circumstances. In the case of historical cohort studies, people are linked to existing historical information.  Workplace Hygine  Today the profession that has primary responsibility for recognizing, evaluating, and controlling hazards in the workplace is known in most countries of the world as occupational hygiene.  Through science and engineering, occupational hygienists identify, evaluate and control exposure to workplace hazards that may include chemicals, dust, fumes, noise, radiation, vibration and extreme temperatures, to name a few.  The aim is to understand workplace health risks and communicate advice on what needs to be done to prevent serious illnesses like cancer, asthma, skin diseases and deafness.  In either case, the primary responsibility of those working in this field is to address the full range of chemical, biological, and physical hazards.  Occupational Hygiene  musculoskeletal problems that are becoming increasingly common in the modern technological world.  The effects of occupational exposures range from lung diseases, cancer, hearing loss, and dermatitis to more subtle psychological effects, many of which are only now being recognized.  Workplace exposures include those to airborne contaminants, ionizing radiation, ultraviolet and visible light, electric and magnetic fields, infrared radiation, microwaves, heat, cold, noise, extremes of barometric pressure, and stress. Each of these may also interact with other chemical, physical, or biological agents. For example, cardiovascular diseases may be related to a combination of physical, chemical, and psychological job stresses. The workplace can also be the source of a wide range of infectious diseases.  hospital workers in particular must be concerned with protection against hepatitis B, tuberculosis, influenza, and other viral infections, including acquired immune deficiency syndrome (AIDS) and severe acute respiratory syndrome (SARS). One of the most common in manufacturing is the presence of contaminants in the air that result from various industrial processes. Other problems include noise, vibration, and ionizing radiation. need to protect workers from potential exposures to biological agents and to provide them with safe (nonslip) floors and stairs and comfortable, employee-friendly workstation environments. toxic chemicals As would be anticipated, toxic chemicals play a major role in occupationally related diseases. Their two primary portals of entry are the skin and the respiratory tract. Once inside the body, such agents can affect other organs, such as the liver and kidneys. biological agents The presence of biological agents (bioaerosols) in the air of the workplace is increasingly recognized as a common problem. This is especially true in the health-care industry, where respirable aerosols that contain blood are routinely produced in the operating room during surgical procedures. physical factors Many health and safety problems in the workplace are caused by inadequate attention to the complex relationships among people, machines, job demands, and work methods, a specialty area that is designated by the term ergonomics. Such relationships include repetitive motions, forceful motions, static or awkward postures, mechanical stresses, and local vibration. tunnel syndrome. (Carpal tunnel syndrome is a common condition that causes pain, numbness, and tingling in the hand and arm. The condition occurs when one of the major nerves to the hand — the median nerve — is squeezed or compressed as it travels through the wrist.)  Occupational Exposure Standards  Occupational exposure limits (OELs) are essential regulatory instruments for health professionals to identify toxic substances and their risk in case of human exposure. The level of an OEL depends on the outcome of the risk assessment and the risk management processes for a substance. The American Conference of Governmental Industrial Hygienists (ACGIH), established in 1938, has played a major role in reviewing and assessing the literature and recommending limits for the control of workplace exposures in the United States. One of its early contributions was the development of what are called threshold limit values (TLVs), which provide guidance on permissible concentrations of airborne contaminants. Through its efforts, TLVs now exist for more than 600 chemical substances. The American Industrial Hygiene Association (AIHA) (established in 1939), OSHA, and NIOSH have subsequently also been involved in developing related standards.  common workplace hazards  Biological hazards  Physical hazards  chemical hazards  Types of things you may be exposed to for biological hazards:  Blood and other body fluids  Fungi/mold  Bacteria and viruses  Plants  Insect bites  Animal and bird droppings  ical hazards  Physical hazards include:  Radiation: including ionizing and non-ionizing (EMF’s, microwaves, radio waves, etc.) materials  High exposure to sunlight/ultraviolet rays  Gases under pressure  Temperature extremes – hot and cold  Constant loud noise  Chemical hazards can be present in the following:  Liquids like cleaning products, paints, acids, solvents – particularly if hazardous products are in an unlabeled container  Vapors and fumes that come from welding or exposure to solvents  Gases like acetylene, propane, carbon monoxide,  Hazardous products and flammable materials like gasoline, solvents, and explosive chemicals  Pesticides  Special Groups Teenagers-this group is at a particularly high risk for injuries. the most common sources of injuries are burns due to exposures to hot oil and grease, hot water and steam, and hot cooking surfaces. The largest sources of deaths are in jobs that involve deliveries and driving; another important source is the construction industry. Outdoor workers-Many people work outdoors. These include those involved in abrasive blasting to remove surface coatings, scale, and rust in preparing large metal structures for finishing operations, such as in the repair of bridges, buildings, and ships; those employed at hazardous waste sites, who maybe exposed to toxic chemicals; airport workers, who may exposed to air pollution and noise. Health-care workers-he rates of injuries and illnesses in this industry doubled. The same was true for the number of lost work days for nursing-home workers. Nurses and nurses’ aides, for example, had the highest claims rate of any occupation because of back injuries.  Integrated Safety Management (ISM) To ensure the adequacy and effectiveness of their efforts to protect workers, many industrial leaders are taking steps to ensure that safety management is an important component of their occupational health programs. The foundation of this approach is the development of procedures for the identification and control of worker risks and hazards. These procedures, in turn, are strongly supported by the adoption of a corporate policy designed to protect workers, the public, and the environment.