GE15 Week 6-7 Module PDF

College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 1...

College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 THE UNIVERSITY OF MINDANAO College of Arts and Sciences Education Physically Distanced but Academically Engaged Self-Instructional Manual (SIM) for Self-Directed Learning (SDL) Course/Subject: GE 15: Environmental Science Name of Teacher: THIS SIM/SDL MANUAL IS A DRAFT VERSION ONLY, NOT FOR REPRODUCTION AND DISTRIBUTION OUTSIDE OF ITS INTENDED USE. THIS IS INTENDED ONLY FOR THE USE OF THE STUDENTS WHO ARE OFFICIALLY ENROLLED IN THE COURSE/SUBJECT. EXPECT REVISIONS OF THE MANUAL. Prepared by: Hazel G. Carreon, PhD Christian Dell A. Gentallan Jason Ben R. Paragamac Ronnel P. Senining \1 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 BIG PICTURE WEEK 6-7 Unit Learning Outcome e (ULOe) To identify human-induced and natural sources of toxic elements and identify their implications and tendencies to bioaccumulate and bio-magnify affecting the agriculture sector. METALANGUAGE In this section, the essential terms relevant to the study environmental science ULOe will be operationally defined to establish a standard frame in the field of natural sciences about the global issues of environmental toxicology. Pollution as well occurrence of global diseases affecting human health and the implications of toxic substances to the food and agriculture sector. You will encounter these terms as we go through environmental science studies with how people, and development and intimately connected, and the implications to ecological health and safety. It involves a broader understanding of toxic and hazardous substances and their corresponding disposal and treatment processes. Please refer to the definition in case you will encounter difficulty in the knowledge of environmental science concepts. 1. Toxicology. A scientific discipline that overlaps with biology, chemistry, pharmacology, and medicine involves studying the adverse effects of chemical substances on living organisms and diagnosing and treating exposures to toxins and toxins. 2. Allergens it is an antigen that produces an abnormally potent immune responsewhere the immune system targets and fights a threat or an invader that could potentially harm the body. Allergens are recognized by the immune system to causean allergic reaction. 3. Neurotoxins it is referring to toxins that are destructive to nerve tissue. Neurotoxins are an extensive class of exogenous chemical, neurological insults that can adversely affect function in both developing and mature nervous tissue. 4. Mutagens are a physical or chemical agent that causes an increase in D.N.A. modifications by altering the organism's D.N.A. 5. Teratogens. Any agent that can disrupt embryonic or fetal development causes a child's congenital disability or may completely cease the pregnancy. These agentsinclude radiation, maternal infections, chemicals, or drugs. 6. Carcinogens are any substance or agents that promote cancer development (carcinogenesis), causing genome damage or disruption of cells' metabolic processes. \2 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 7. Persistent Organic Pollutants (P.O.P.s). Organic compounds are resistant to biochemical, photolytic, and other environmental degradation processes. Becauseof this, P.O.P.s are sometimes called "forever chemicals," which can bioaccumulatewith potentially detrimental effects on ecological and human health. 8. Acute effects. A physiological reaction in a human or animal body which cause severe symptoms that could rapidly develop through acute exposure to toxic substances. However, it may lead to chronic health effects if the cause is not removed. 9. Chronic effects. An adverse effect on animals or the human body with symptoms that develop slowly, due to prolonged and continuous exposure to low concentrations of a hazardous substance. 10. Risk assessment. The combined effort of identifying and analyzing potential eventscan negatively affect individuals, assets, and even the environment. It also makesmindful judgments on the tolerability of the risk analysis and examines factors influencing it. 11. Risk Management. The evaluation, prioritization, and identification of risks followed by coordinated and economical application of resources to control, monitor, and minimize the probability or impact of unfortunate events or to maximize the realization of opportunities. 12. Pesticides. Chemical compounds used to eliminate pests, such as insects, rodents, fungi, and weeds. These chemicals are also used in public health to kill disease vectors (e.g., mosquitoes) and pests that damage crops. 13. Herbicides. Pesticides used to kill unwanted plants (weeds). There are selective herbicides that explicitly target a weed/s by interfering with its growth without harming the desired crop. 14. Insecticides it is any substances that formulate to eliminate or mitigate insects,including ovicides, which are used against insects and larvicides to kill insect larvae. 15. Fungicides. Biocidal chemical compounds or biological organisms (plants or animals) used to kill parasitic fungi, or their spores can cause severe damage in agriculture, resulting in decreased yield, crop quality, and profit. ESSENTIAL KNOWLEDGE To perform the aforesaid big picture (unit learning outcomes) for the sixth to seventhweeks of the course, you need to fully understand the following essential knowledge thatwill be laid down in the succeeding pages. Please note that you can refer to other resources; thus, you are expected to utilize other books, research \3 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 articles, and other available resources in the university library (e.g., e-library, search.proquest.com, etc.) ENVIRONMENTAL HEALTH AND TOXICOLOGY The World Health Organization (W.H.O.) defines health as a state of complete physical,mental, and social well-being. A person can be ill to some extent; however, health can beimproved to live a happier, longer, and more productive and satisfying lives. The disease can also be influenced by environmental factors such as the Earth's climate system by impairing physical and psychological functions. Disease is defined as the impairment of an individual's well-being and capacity to function and is mostly attributed to inadequate behavioral and environmental change. The factors that result in morbidity (illness) and mortality (death) are diet and nutrition, infectious agent, hereditary qualities, a poisonous substance, injury, and stress. Environmental health focuses on disease-causing external factors, including elements of the natural, social, cultural, and technological worlds in which we live. GLOBAL BURDEN OF DISEASE (GBD) Global Burden of Disease (GBD) is a comprehensive regional and global research program of disease burden that assesses mortality and disability from major diseases, injuries, and risk factors. It considers the health, social, political, environmental, and economic factors to determine the cost that particular disease and disability exert upon the individual and society. Mortality data is now based on Disability Adjusted Life Years (DALYs) as a measure of disease burden. Smallpox was completely wiped out in 1977. Polio has been eliminated everywhere in the world except for a few remote villages in northern Nigeria. Epidemics of typhoid fever, cholera, and yellow fever are now rarely encountered. AIDS has become a highly treatable disease. According to the WHO, chronic diseases now account for nearly 60% of the 56.5 million total deaths worldwide each year and about half of the global disease burden. \4 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 https://www.google.com/search?q=global+burden+of+disease+&tbm=isch&ved=2ahUKEwia39-oxZX5AhVXz4sBHadgAKYQ2- cCegQIABAA&oq=global+burden+of+disease+&gs_lcp=CgNpbWcQAzIFCAAQgAQyBQgAEIAEMgUIABCABDIFCAAQgAQyBQgAEIAEM gUIABCABDIFCAAQgAQyBQgAEIAEMgUIABCABDIFCAAQgAQ6BAgAEB46BwgAEB4QxwNQnAdY9yRgoy5oAHAAeACAAYgBiAH1EZI BBDUuMTaYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&sclient=img&ei=8FXfYpqnKteer7wPp8GBsAo&bih=597&biw=1226&hl=en#imgrc=2 bvEsQeVXcpGVM \5 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 https://www.google.com/search?q=global+burden+of+disease+world+health+organization2020&tbm=isch&ved=2ahUKEwig5MjKzZX5AhWSxYsBHc99CoAQ2- cCegQIABAA&oq=global+burden+of+disease+world+health+organization2020&gs_lcp=CgNpbWcQAzoECAAQQzoGCAAQHhAIOgkIABAeEMcDEAg6BAgAE BhQiQtYvEVgik1oAHAAeACAAaUDiAHKK5IBCjAuMTYuNy4yLjGYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&sclient=img&ei=m17fYuCqBpKLr7wPz_upgAg&bi h=597&biw=1226&hl=en#imgrc=lskEeHCeAW7iQM Infectious and emergent diseases still kill millions of people. A wide variety of pathogens afflict humans, including viruses, bacteria, protozoans, parasitic worms, and flukes. People rarely die from parasites, but they can be extremely debilitating, and can cause poverty that leads to other deadly diseases. Diarrhea, acute respiratory illnesses, malaria, measles, tetanus, kill about 11 million children under age 5 every year in the developing world. Better nutrition, clean water, improved sanitation, and inexpensive inoculations could eliminate most deaths. EMERGENT DISEASE Emergent diseases are those not previously known or that have been absent for at least 20 years. Rapid international travel makes it possible for these new diseases to spread around the world at jet speed. Epidemiologists warn that the next deadly epidemic is only a plane ride away. \6 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 https://www.google.com/search?q=recent+outbreaks+of+lethal+infectious+dises&tbm=isch&ved=2ahUKEwio6Nr6zpX5AhUBzosBHQgRB7QQ2- cCegQIABAA&oq=recent+outbreaks+of+lethal+infectious+dises&gs_lcp=CgNpbWcQAzoLCAAQgAQQsQMQgwE6CAgAEIAEELEDOgUIABCABDoECAAQQz oHCAAQsQMQQzoICAAQsQMQgwE6BggAEB4QBToGCAAQHhAIOgkIABAeEMcDEAg6BAgAEBhQzhtYtI4BYMWRAWgAcAB4AYABqAOIAek5kgEKMC4zN S42LjEuMZgBAKABAaoBC2d3cy13aXotaW1nwAEB&sclient=img&ei=DGDfYqiyHoGcr7wPiKKcoAs&bih=597&biw=1226&hl=en#imgrc=5p6SnOyb0q1LNM&im gdii=YvDjfoi5zwvHPM Emergent diseases in humans and ecological diseases in natural communities arise due to stresses in biological systems that upsets normal ecological relationships. These growing concerns are adverse synergistic interactions between emerging diseases and other infectious and non-infectious conditions leading to the development of novel syndemic. Many emergent diseases originated from a non-human animal species, such as HIV which originated in chimpanzees, and SARS which came from the Masked Palm Civet native to China. Factors Contributing to Disease Emergence: 1. Microbial adaption - e.g., genetic drift and genetic shift in Influenza A 2. Changing human susceptibility - e.g., mass immunocompromising with HIV/AIDS 3. Climate and weather - e.g., diseases with zoonotic vectors such as West Nile Disease (transmitted by mosquitoes) are moving further from the tropics as the climate warms. 4. Change in human demographics and trade - e.g., rapid travel enabled COVID to rapidly propagate around the globe \7 | P a g e  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 5. Economic development - e.g., use of antibiotics to increase meat yield of farmed cows leads to antibiotic resistance 6. Breakdown of public health - e.g., the current situation in Zimbabwe 7. Poverty and social inequality - e.g., tuberculosis is primarily a problem in low- income areas 8. War and famine – e.g., Gulf war, Ukraine war 9. Bioterrorism - e.g., 2001 Anthrax attacks 10. Dam and irrigation system construction - e.g., malaria and other mosquito borne diseases ECOLOGICAL EPIDEMIOLOGY It is the study of the ecology of infectious diseases. It includes population and community level studies of the interactions between hosts and their pathogens and parasites and covers diseases of both humans and wildlife. Examples: ▪ Ebola hemorrhagic fever kills up to 90% of its human victims. A global outbreak killed ¼ of all the gorillas. ▪ Chronic wasting disease (CWD) is caused by a prion. CWD is one of a family of irreversible, degenerative neurological diseases known as transmissible spongiform encephalopathies (TSE) that include mad cow disease in cattle, scrapie in sheep, and Creutzfelt-Jacob disease in humans. ▪ Tropical diseases, such as malaria, cholera, yellow fever, and dengue fever, have been moving into areas from which they were formerly absent as mosquitoes, rodents, and other vectors expand into new habitat. Resistance to Drugs, Antibiotics, and Pesticides The protozoan parasite that causes malaria is now resistant to most drugs, while the mosquitoes that transmit it have developed resistance to many insecticides. The following are the reasons for antibiotic resistance to develop - Antibiotics do not work against certain diseases, e.g., viral infections. They are given when the person could recover fully without them and starting and not finishing a full prescription. Hence, there is also a widespread use of antibiotics in animal agriculture. ECOTOXICOLOGY Ecotoxicology is the study of toxins (poisons) and their effects, particularly on living systems because many substances are known to be poisonous to life (whether plant, animal, or microbial). It is a broad field, drawing from biochemistry, histology, \8 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 pathology, pharmacology, and many other disciplines. Toxin’s damage or kill living organisms because they react with cellular components to disrupt metabolic functions. They are harmful even in extremely dilute concentrations. In some cases, billionths, or even trillionths of a gram can cause irreversible damage. https://www.google.com/search?q=top+20+toxic+and+hazardous+substances&tbm=isch&ved=2ahUKEwil- 6qz8JX5AhVyKaYKHd8NAFoQ2cCegQIABAA&oq=top+20+toxic+and+hazardous+substances&gs_lcp=CgNpbWcQAzoGCAAQHhAIOgQIABAYOgUIABCABDo ICAAQgAQQsQM6CAgAELEDEIMBOgQIABBDOgsIABCABBCxAxCDAVCROFi7hgJgio4CaABwAHgDgAHiAYgBxjKSAQYzLjQ3LjOYAQCgAQGqAQtnd3Mtd2l 6LWltZ7ABAMABAQ &sclient=img&ei=HYPfYuX4JfLSmAXfm4DQBQ&bih=597&biw=1242&hl=en#imgrc=CFF-80aqy_T6_M EFFECTS OF TOXINS Allergens are immune-activating agents. Some allergens act as antigens directly; that is, white blood cells recognize them as foreign and stimulate the production of specific antibodies. Certain allergens function indirectly by linking and modifying the composition of foreign materials and become antigenic and induce an immune system to the response.Formaldehyde is an excellent example of a widely used chemical that is a potent sensitizer of the immune system. It is directly allergenic and can also trigger reactions to other substances. Commonly used in plastics, wood products, insulation, glue, and fabrics, formaldehyde concentrations in indoor air can be thousands of times higher than in healthyoutdoor air. Some people who suffer from sick building syndrome have headaches, allergies, and chronic fatigue. And other symptoms caused by improperly ventilated indoor air contaminate with carbon monoxide, mold spores, nitrogen oxide, formaldehyde, and other pollutants emitted from carpets, furniture, fabrics, and construction materials and other sources \9 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 Immune System Depressants suppress the immune system. Dead animals contained high levels of pesticide residues, polychlorinated biphenyls (PCBs), and other contaminants that are suspected of disrupting the immune system and making it susceptible to a variety of opportunistic infections. Endocrine disruptors are chemicals that disrupt the natural activity of hormones. Hormones are chemicals released by cells into the bloodstreams in one part of the body toregulate the function and development of tissues and organs in the body. We realize now that some of the most gradual, yet harmful effects of persistent chemicals such as dioxinsand P.C.B.s are that they interfere with healthy growth, development, and physiology of avariety of animals—including humans—at shallow doses. https://www.google.com/search?q=suspected+endrine+disruptord&tbm=isch&ved=2ahUKEwj-5JG79pX5AhVOx5QKHZIVAe0Q2- cCegQIABAA&oq=suspected+endrine+disruptord&gs_lcp=CgNpbWcQAzoHCAAQsQMQQzoECAAQQzoICAAQgAQQsQM6CwgAEIAEELEDEIMBOgUIABC ABDoGCAAQHhAIOgQIABAYUNoNWOhHYL5QaABwAHgBgAHyBYgBozCSAQ4wLjE5LjQuMS4xLjAuMpgBAKABAaoBC2d3cy13aXotaW1nwAEB&sclient=i mg&ei=eInfYv7IJM6O0wSSq4ToDg&bih=597&biw=1242&hl=en#imgrc=4ocaqJO1_zaVrM Hormone mimics have similar shapes to natural hormones and amply their effects. BPA (Bisphenol A) is known to be a hormone mimic used for plastic products ranging from water bottles to tooth- protecting sealants. The chemical can cause abnormal chromosome numbers which is the leading cause of miscarriages and several forms of mental retardation. It also is an environmental estrogen and may alter sexual development in both males and females. Bills are considered to ban BPA and certain phthalates in children’s toys and feeding products. \ 10 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 https://www.google.com/search?q=plastic+coding+system&tbm=isch&ved=2ahUKEwj1lcjM-ZX5AhVkE6YKHU9RB1YQ2- cCegQIABAA&oq=plastic+coding&gs_lcp=CgNpbWcQARgCMgUIABCABDIFCAAQgAQyBQgAEIAEMgQIABAYMgYIABAKEBg6CAgAEIAEELEDOgsIABC ABBCxAxCDAVD6DliaKGCDSGgAcAB4AoAByQSIAZQakgELMC45LjQuMC4xLjGYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&sclient=img&ei=wozfYvWsG- SmmAXPop2wBQ&bih=597&biw=1242&hl=en#imgrc=Gbw3ZI298aZTwM Hormone blockers prevent natural hormones from attaching to their target organ. Endocrine disruption is linked to increased risk of breast cancer, develop- mental and reproductive toxicity, allergies, and immuno-toxicity. Neurotoxins are a particular class of metabolic poisons that individually attack nerve cells (neurons). The nervous system has an essential function in controlling the body activities,especially to a fast-acting and devastating events. https://www.google.com/search?q=neurotoxins&tbm=isch&ved=2ahUKEwjFm_Hy-pX5AhUJhpQKHWIsA2gQ2- cCegQIABAA&oq=neurotoxins&gs_lcp=CgNpbWcQAzIFCAAQgAQyBQgAEIAEMgUIABCABDIFC AAQgAQyBQgAEIAEMg UIABCABDIFCAAQgAQyBQgAEIAEMgYIABAeEAUyBggAEB4QBToICAAQgAQQsQM6CAgAELEDEIMBOgUIABCxAzoH CAAQsQMQQzoECAAQQzoLCAAQgAQQsQMQgwE6CggAELEDEIMBEENQ3gtY6CFgviRoAHAAeACAAZMCiAHIEJIBBT AuOS4zmAEAoAEBqgELZ3dzLXdpei1pbWfAAQE&sclient=img&ei=H47fYoWQD4mM0g Ti2IzABg&bih=597&biw=1242&hl=e n#imgrc=0RbbH2sNiwPrBM \ 11 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 Neurotoxins have different types, and itacts in different ways. Heavy metals like lead and mercury destroy nerve cells and cause permanent brain damage. Organophosphates (Malathion, Parathion) and carbamates (carbaryl, zineb, maneb) inhibit acetylcholinesterase, the enzymes that control the transfer of signals between nerve cells and the tissues or organs they innervate (e.g., muscle). Anesthetics (ether, chloroform, halothane, etc.) and chlorinated hydrocarbons (D.D.T., Dieldrin, Aldrin) disrupt nerve cell membranes needed for nerve action. Most neurotoxinsare both fast-acting and highly toxic. Mutagens are agents that damage or modify the genetic material (D.N.A.) in cells, such as chemicals and radiation. If the cost happens during embryonic or fetal development, this may contribute to congenital disability. Later in life, genetic damage can contribute to neoplastic (tumor) formation. If reproductive cells undergo injury, the effects may be passed on to future generations. Cells have repair mechanisms to diagnose and repair defective genetic material, but specific changes may be hidden, and the repair cycle itselfcan be flawed. It is widely agreed that there is no “safe” threshold for mutagens exposure. Any contact has the potential to cause harm. Teratogens are chemicals substance or other factors which cause different abnormalities during embryonic growth and development. Some chemicals that are usually not dangerous may cause a severe problem at these vulnerable stages of life. Alcohol is probably the most popular teratogen in the world. Drinking during pregnancy can lead to fetal alcohol syndrome—a cluster of complications that persist throughout a child’s life,including craniofacial abnormalities, developmental disorder, behavioral problems, and mental defects. Even one alcoholic drink a day has been associated with reduced birth weight during pregnancy. Carcinogens are substances that cause cancer, invasive, and out-of-control cell growthresulting in malignant tumors. Cancer rates rose over the twentieth century in most developed nations, and cancer is now the second leading cause of death in the U.S., killingmore than half a million people in 2002. https://www.google.com/search?q=carcinogen+in+the+workplace&tbm=isch&ved=2ahUKEwiy5YCg_ZX5AhVHzIsBHSW8AiQQ2- cCegQIABAA&oq=carcinogen+in+the+workplace&gs_lcp=CgNpbWcQAzoECAAQQzoFCAAQgAQ6CAgAELEDEIMBOggIABCABBCxAzoFCAAQsQM6CwgAEI AEELEDEIMBOgYIABAeEAg6BAgAEBg6BggAEAoQGFC2EljTSmDpT2gAcAB4AIABvQOIAasdkgEIMi4yNS40LTGYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&s client=img&ei=lpDfYrLCLceYr7wPpfiKoAI&bih=597&biw=1242&hl=en#imgrc=UnjIhn6HTEupMM \ 12 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 Bioaccumulation and Biomagnification Bioaccumulation and biomagnification increase concentrations of toxins. The cell performs a selective absorption and storage of variation of molecules called bioaccumulation. It allows them to accumulate nutrients and essential minerals, but at thesame time, they also may absorb and store harmful substances through these same mechanisms. Toxins that are instead dilute in the environment can reach dangerous levels inside cells and tissues through this process of bioaccumulation. The effects of toxins also are magnified in the environment through food webs. When organisms ingest other organisms making toxins accumulated from the base and concentrated in the highest trophic level, it is called biomagnification. PERSISTENT ORGANIC POLLUTANTS (POPs) Some chemical compounds are volatile and degrade rapidly under most environmental conditions so that their concentrations decline quickly after release. Most modern herbicides and pesticides, for instance, promptly lose their toxicity. Other substances aremore persistent and last for years or even centuries in the environment. Metals—such as lead—P.V.C. plastics, chlorinated hydrocarbon pesticides, and asbestos are valuable because they are resistant to degradation. However, this stability causes problems because these materials persist in the environment and have unexpected effects far from their original use sites. Some persistent organic pollutants (P.O.P.s) have become extremely widespread, being found from the tropics to the Arctic. Long-living top predators such asbears, humans, raptors, and sharks are where it frequently accumulates. The following aresome of the most significant concerns: ▪ Polybrominated diphenyl ethers (PBDE). These are known as flame retardants usually used in textiles and plastics found in computers and appliances; these chemicals are now found in humans and other species everywhere globally. Relatively low exposures in the womb or shortly after birth can irreparably harm children’s reproductive and nervous systems. ▪ Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA, also known as C8) are widely used as a nonstick, waterproof stain-resistant product such as Teflon, Gortex, Scotchguard, and Stainmaster. The industry makes use of their slippery, heat-stable properties to manufacture everything from airplanes and computers to cosmetics and household cleaners. This chemical family has been shown to cause liver damage as well as various cancers and reproductive and developmental problems in rats. Exposure may be especially dangerous to women and girls, who may be 100x more sensitive than men to these chemicals. ▪ Phthalates (pronounced thalates) These are present in products such as deodorants, plastics, and cosmetics. Also present in products used for children's toys, medical equipment, and packaging for food. Some chemicals pose a toxic threat to animals found in laboratories as they damage the kidney and liver and might cause cancer. Many phthalates act as endocrine hormone disruptors, and have been linked to reproductive abnormalities and decreased fertility \ 13 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 ▪ Perchlorate is a waterborne contaminant leftover of fuel utilized by rockets andfrom propellants. It includes the cause of pollution in our waters, especially in waters used for irrigation. Thus, allows it to enter the human food chain. Perchlorate can interfere with iodine uptake in the thyroid gland, disrupting adult metabolism and childhood development. ▪ Bisphenol A (B.P.A.), widely used in various products such as bottled water and tooth-protecting sealants. It is a vital component in the creation of polycarbonate plastics. Furthermore, it is an environmental estrogen and may alter sexual development in both males and females. It has been found in humans with or without known chemical exposure. It has been found out that the presence of such a chemical causes abnormal chromosome numbers called aneuploidy. Having this kind of abnormality will result in several forms of mental retardation and miscarriages during pregnancy. ▪ Atrazine is a substance applied to crops such as corn, cereal grains, sugarcanes,and Christmas trees as herbicide in the United States of America. It is also the cause of damage and disruption to the hormonal functions in mammals of their endocrinesystem, resulting in low birth weights, disorders in the neurological services, and abortions. Chemical Interactions Increasing Toxicity Interactions happen because some substances have antagonistic reactions in which materials will interfere with the effects or will somehow stimulate the breakdown of other chemicals. The reaction occurs in Vitamin E and A, which enables to diminish the responseof some carcinogens. Subsequently, there are also materials which occur together in exposures: this is an additive. In essence, rats exposed to both lead and arsenic show thatthe toxicity level rats are exposed to double compared to being presented with one of them. The most significant concern about this is the synergistic effect. An interaction in which one substance intensifies the impact of another material is called synergism. In essence, exposing to occupational asbestos, it will increase the rate of lung cancer 20-foldtimes. At the same time, smoking will also intensify rates of lung cancer by the same amount. In other cases, workers exposed to asbestos at the same time smoke have a 400- fold increase in cancer rates. The question now is how many substances, when combined, will give intensified results? Synergism is an important concept that considers pollution at the same time. It is the interaction of different materials, which results in a total effect more significant than the added impact of separate substances. Factors Influencing Toxicity There are several origins of poisonous and dangerous chemicals in the environment and various factors related to each compound itself. The sources are toxics and hazardous chemicals in the environment that is related to the release of chemicals itself. The target of these chemicals is both biotic and abiotic community. The dose (amount), route of entry, the timing of exposure, and sensitivity of the \ 14 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 organism all play an essential function in determining toxicity. In this section, we will look at each of these characteristics and how it affects environmental health. A. Factors Related to Toxic agent. 1. Chemical composition and reactivity 2. Physical characteristics (such as solubility, state) 3. Presence of impurities or contaminants 4. Stability and storage characteristics of a toxic agent 5. Availability of vehicle (such as the solvent) to carry agent 6. Movement of the agent through the environment and into cells B. Factors Related to Exposure 1. Dose (concentration and volume of exposure) 2. Route, rate, and site of exposure 3. Duration and frequency of exposure 4. Time of exposure (day, season, year) C. Related Factors to Organism 1. Storage, cell permeability of agent and resistance to ingestion 2. Ability to metabolize, inactivate, sequester, or eliminate the agent 3. The tendency to activate or alter nontoxic substances, so they become toxic. 4. Concurrent infections or physical or chemical stress 5. Species and genetic characteristics of an organism 6. Nutritional status of the subject 7. Sex, body weight, age, maturity, and immunological status Solubility is one of the essential characteristics in determining how, where, and when atoxic material will move through the environment. It also includes the body at its place ofaction. The classification of chemical substances divides into two main groups: 1. those that dissolve more easily in oil. 2. Those that dissolve more easily in water. Since water is everywhere, water-soluble compounds move rapidly and widely in theenvironment. They seem to have easy access to most cells in the body since aqueous solutions bathe all our cells. Molecules that are oil- or fat-soluble (usually organic molecules) generally need a carrier to move through the environment, into, and within, the body. Onceinside the body, however, oil-soluble toxins quickly pass into tissues and cells, since the membranes that enclose the cells are composed of similar oil-soluble chemicals. Once theyget inside cells, oil-soluble materials are likely to be accumulated and stored in lipid deposits. They are protected from metabolic breakdown and will continue for several years. \ 15 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 Exposure Just as there are many sources of toxins in our environment, there are many routes for entry of dangerous substances into our bodies. Airborne toxins generally cause moreill-health compared to other sources. Our lungs are programmed to efficiently exchange gases and, at the same time, absorb toxins. The complication in measuring toxicity is thatsignificant differences in sensitivity exist between species. MEASURING TOXICITY In controlled conditions, it is the most used and widely accepted toxicitytest to expose a population of laboratory animals to measured doses of specific substances.This procedure takes so much time, painful, expensive, and debilitating to the animals usedas specimens in tests. Dose/response curves are not always symmetrical, making it challenging to compare the toxicity of unlike chemicals or different species of organisms. A convenient way to describe the toxicity of a chemical is to determine the dose to whichfifty percent (50%) of the test population is sensitive. In the case of a lethal dose (L.D.), thisis called the LD50. Acute and Chronic Doses Acute effects have been the effects of most toxics we have discussed. They are caused by a single exposure to the toxin and result in an immediate health crisis of some sort. An individual survives an urgent crisis due to an acute reaction, most likely because the effectsare reversible. If the effects have resulted in becoming permanent, it is a Chronic effect.A constant effect can result from a single dose of a very toxic substance, resulting from a continuous or repeated sublethal exposure. We also describe long-lasting vulnerabilitiesas chronic, although their effects may or may not persist after the toxin is removed. It usually is challenging to assess the specific health risks of chronic exposures because other factors,such as aging or joint diseases, act simultaneously with the consideration under study. RISK ASSESSMENT Risk is the possibility or results of suffering harm or loss by hazard and an indicationof the severe damage. Risk assessment (R.A.) is the scientific process of estimating the threat that hazards pose to human health. It is the overall process of hazard identification, risk analysis, and risk evaluation. Risk assessment for identified toxicity hazards (for example, lead) includes collection and analysis of site data, development of exposure and risk calculations, and preparation of human health and ecological impact reports. Exposure assessment is the process of estimating, measuring, characterizing, andmodeling the following: \ 16 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 1. magnitude 2. frequency 3. duration, and 4. route of exposure to a possible toxin. Toxicity assessment weighs all available evidence and estimates the potential for adverse health effects to occur. Risk assessment can also define as the process of determining potential adverse health effects of exposure to pollutants and potentially toxicmaterials. Exposure to toxic air pollutants can intensify your health risks. For example, if you live near a factory that discharges cancer-causing chemicals and inhale contaminated air,your chance of getting cancer can increase. https://images.app.goo.gl/zskX5jcF9wZmJKFo7 1. Identification of the hazard. It is using to evaluate if any situation may have the potential to cause harm and consists of testing materials to determine whether exposure is likely to cause health problems. One method used is to investigate populations of people who are exposed previously. For example, to understand the toxicityof radiation produced from Radon (Rn) gas, researchers studied workers in uranium (U) mines. Another method is to conduct experiments to test effects on animals, such as monkeys, rats, or mice.This method has drawn augmenting criticism from groups who believesuch experiments are unethical. Another approach is to try tounderstand how a particular chemical works at the molecular level ofcells. \ 17 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 2. Dose-response assessment. This next step involves identifying relationships between the dose of a chemical (therapeutic drug, pollutant, or toxin) and the health effects on people. Some studies include administering reasonably high doses of a compound toanimals. The results of exposures will be different illnesses, or symptoms, such as tumor or rashes development, are recorded for varying doses. 3. Exposure appraisal. This step evaluates the duration, frequency, andintensity of human exposure to a particular chemical pollutant or toxinin the environment. It includes some discussion of the size, nature, andtypes of human populations exposed to the agent. The total population exposed to the agent is directly proportional to the hazardin the society. 4. The risk to an individual is generally more significant closer to the source of exposure. Like dose-response assessment, exposure assessment is difficult. The results are often controversial because of difficulties in measuring the concentration (conc.) of a toxin in doses since it is as small as parts per million, billion, or even trillion. 5. Risk characterization. This final step aims to delineate health risk in terms of the magnitude of the health issues and concerns that might result from exposure to a particular pollutant or toxin. It is necessary to identify the hazard or danger, complete the dose- response assessment, and evaluate the exposure assessment, as outlined. This method involves all the uncertainties of the previous actions and results are again likely to be controversial TOLERANCE It is the ability to resist or withstand stress from exposure to a pollutant or harmfulcondition. It can develop for some contaminants in some populations, but not for all pollutants in all communities. Tolerance may result from behavioral, physiological, or genetic adaptation. Behavioral tolerance results from changes in the behavior; for example, mice learnto avoid traps. Physiological tolerance as a result when the body of an individual adjusts to tolerate a higher level of pollutant. \ 18 | P age  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 SUSTAINABLE AGRICULTURE Agriculture is a science and art of growing plants and other crops, and the raising of animals for food, other human needs, or economic gain. When they are sustainable managed, they can help preserve and restore critical habitats, protect watersheds, and improve soil health, and water quality. However, when practiced without care, it presents the greatest threat to species and ecosystems. Negative Impacts of Agriculture on Environment ▪ Land Transformation due to the use of land to yield goods and services. Examples for this are deforestation to create gardens/park; drainage of wetlands to grow crops like rice; and landscape degradation through activities like road construction for transport of agricultural produce. ▪ Land Degradation which is the long-term decline in ecosystem function and productivity such as soil erosion, soil exhaustion, soil salinization, overgrazing, frequent burning, and loss of soil biodiversity due to use of agrochemicals like pesticides. The pesticide is a general term for a chemical that kills pests, usually a toxic chemical, but sometimes we also consider chemicals that drive pests away from pesticides. Some pest control compounds kill a wide range of living things and are called biocides. Herbicides are chemicals that kill plants; insecticides kill insects, and fungicides kill fungi. https://www.google.com/search?q=pesticide+cycle&bih=597&biw=1242&hl=en&source=lnms&tb m=isch&sa=X&ved=2ahUKEwiAg4OsmZb5AhXvplYBHUVKCv8Q_AUoAXoECAEQAw#imgrc=R 3cQELFOyDMvGM 19 | P a g e  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 Types of Pesticides One way to classify pesticides is by their chemical structure and main components.Some are organic (carbon-based) compounds. Others are toxic metals (such as arsenic) or halogens (such as bromine). Organophosphates are among the most abundantly used synthetic pesticides. Glyphosate, the single most heavily used herbicide in the United States, is also known by the trade name Roundup. Glyphosate is applied to 90 percent (90%) of U.S. soybeans and other crops. "Roundup-ready" soybeans and corn— varieties genetically modified to tolerate glyphosate while other plants in the field are destroyed—are the most planted genetically modified crops. Chlorinated hydrocarbons, also known as organochlorines, are highly toxic andpersistent to sensitive organisms. In the U.S., atrazine was a heavily used herbicideuntil overtaken by the usage of glyphosate. Corn crops in the U.S., around 96 percent, are applied with atrazine to control weeds in the cornfields. Fumigants are generally small molecular compounds, like ethylene dibromide, methylene bromide, and carbon tetrachloride. These compounds can be deliveredin the form of gas for easy penetration into the soil and other materials. Fumigants are used to control fungus in strawberry fields and other low-growing crops and prevent decay, rodent, and insect infestations in stored grain. Inorganic pesticides are compounds made from toxic elements, like sulfur, copper, arsenic, and mercury. These elements are considered a broad- spectrum poison because they are highly poisonous and indestructible, which means they stay in theenvironment forever. They usually act nerve toxins. Historically, the primary pesticide applied to apples, and other orchard crops were arsenic powder, but traces of the dust remain in groundwater or soil in many agricultural areas. Natural organic pesticides, also known as botanicals, are extracts from plants. Anexample before was nicotine and nicotinoid alkaloids extracted from tobacco, and pyrethrum, extracted from Chrysanthemum cinerariaefolium. These compounds also include turpentine, phenols, and other aromatic oils from conifers. These extracts are toxic to insects and may even prevent wood decay. Microbial agents and biological controls use living organisms or toxins extracted from them that are used instead of pesticides. A natural soil bacterium, Bacillus thuringiensis, is one of the chief pest control agents allowed in organic farming. When eaten, this bacterium targets caterpillars and beetles and eliminates them by producing a toxin that destroys their digestive tract lining. 20 | P a g e  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 Impacts of Environment on Agriculture 1. Global warming 2. Heavy rainfall 3. Flood 4. Acid rain 5. Wind erosion 6. Landslide To satisfy human food and fiber needs, it is very important to make the most efficient use on non-renewable resources and on-farm resources, to sustain economic viability of farm operations at the same time enhances the quality of life for farmers and society. Sustainable agriculture is the practice of farming using principles of ecology to produce healthful food without compromising the future generation’s ability to do the same. Advantages of Sustainable Agriculture 1. Contributes to environmental conservation 2. Prevents pollution 3. Reduces costs 4. Keeps biodiversity 5. Respects the environment 6. Profits farmers economically 7. Preserves social equity Drawbacks of Sustainable Agriculture 1. Limited use of land which makes it difficult to produce large quantities of food. Therefore, mass production is not possible. 2. It takes more work since the use of machines is minimal or eliminated, it takes more time and people to successfully produce plants, which slows down the production. 3. Shorter shelf life since decomposing occurs faster in food that is produced sustainably, causing it to have a shorter shelf life. If a shipment gets delayed, there is a big chance that it will never get to the supermarket because it will already be spoiled. 4. Less fertile lands since it is quite hard to increase the fertility of land just by rotating crops and without the use of fertilizers and other chemicals. 5. Lower income because the land is used sparingly, the income that is generated from farming is very limited. 21 | P a g e  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 FOOD AND NUTRITION Despite dire predictions that runaway population growth would soon lead to terriblefamines, world food supplies have more than kept up with increasing human numbers over the past two centuries. The past 40 years have seen especially encouraging strides in reducing world hunger. More than 850 million people today are considered chronically hungry: their diets don’t provide the 2,200 kcal per day, which is deemed necessary for a healthy and productive life. Poverty is the greatest threat to food security or the ability to obtain sufficient food on a day-to-day basis. Food security occurs at multiple scales. In thepoorest countries, hunger may affect nearly everyone. SELF-HELP You can refer to the sources below to help you further understand the lesson. Dalezios, N., 2017. Environmental Hazards Methodologies for Risk Assessment and Management. IWA Publishing, Canada. Frumkin, H., 2017. Environmental Health: From Global to Local. 3 rd edition. Wiley & Sons Publishing, USA. Knowlton, K., Sorensen, C., & Lemery, J., 2017. Global Climate Change and Human Health: From Science to Practice. 2nd ed. Wiley & Sons Publishing, USA Lippmann, M., Leikauf, G., 2017. Environmental Toxicants: Human Exposures and Their Health Effects. 4th ed. Wiley & sons Publishing, USA. LET’S CHECK Activity No. 5. Now that you have known the most essential terms in the study of environmental science. Let us try to check your understanding of these terms. In the space provided, write the terms, being asked in the following statements: 1. It is the state of complete physical, mental, and social well- being, and not merely the absence of disease or infirmity. 2. It refers to the impairment of an individual’s well-being and ability to function often due to poor adjustments between theindividual and the environment. 3. It refers to the unwanted change in the environment caused by the introduction of harmful materials or the production ofharmful conditions. 4. It is a toxin that increases the risks of cancer. 5. It refers to substances that activate the immune systems. 22 | P a g e  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 6. It refers to chemicals that disrupt normal hormone functions. 7. It is an agent which damage or alter genetic materials in cells. 8. It occurs when toxic burden of many organisms at a lower trophic level is accumulated and concentrated by apredator in a higher trophic level. 9. It is considered a natural bacterium and one of the chief pest control agents allowed in organic farming. 10. It is the ability to resist or withstand stress from exposure to a pollutant or harmful condition. LET’S ANALYZE Activity No. 5. Getting acquainted with the essential terms in studying environmental health and toxicology will not be sufficient. What matters is that you should be able to identify and discuss different toxic elements present in the environment, whether naturally occurring or human induced. It is also important to determine the route and persistence of these pollutants to develop measures and mechanisms to reduce the risk of potential food contamination and other agricultural resources. Now, I will require you to explain your answers thoroughly. 1. What is biomagnification? Why is it essential in toxicology? 2. Differentiate acute effects from chronic effects. 3. Identify and discuss comprehensively the components of risk management. 23 | P a g e  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 4. How are toxic elements being deposited in the environment? Can these toxicelements/ chemicals contaminate the food chain? IN A NUTSHELL Activity No. 5. Studying the environment and its components requires a deeper understanding of the core areas of environmental science. This involves understanding the influence of human dimensions as well as the natural phenomena that resulted in different alterations of the natural ecosystems, which eventually creates threats and danger both the biological, physical, and chemical components of an ecosystem. Also, this includes the analysis and understanding of how humanmade and natural components react with one another. Based on the definitions and the essential elements in the study of environmental and the learning exercises that you have done, please feel free to indicate your arguments or lessons learned below. 1. Different types of elements, whether naturally present or human-induced, have implications for biological safety as these elements tend to persist in the environment due to its non-biodegradable nature. Since it continues, it poses threats to human health as well as security and food safety. 2. The disease is considered an environmental response or an imbalance within an ecosystem. This signifies that the carrying capacity of the environment has been reached which makes a particular ecosystem unable to function very well that resulted in the or reduce the ability to assimilate pollutants and recover. YOUR TURN 3. 4. 24 | P a g e  College of Arts and Sciences Education 2nd Floor, DPT Building Matina Campus, Davao City Phone No.: (082)300-5456/305-0647 Local 118 5. 6. 7. 8. Q&A LIST Do you have any questions for clarification? Questions/ Issues Answers 1. 2. 3. 4. 5. KEYWORS INDEX Carcinogens Mortality Exposure Antigens Morbidity Persistence Risk assessment Mutagens Lethal Dose Toxicology Solubility Tolerance 25 | P a g e