Environmental Pollution.GeneralPathology.pptx

General Pathology 02
4th Semester
MLT

1. Environmental Pollution AimaL bashir Bs-mlt (kmu-ipms) Lecturer: tpihs mardan

2. Introduction Any visible or invisible particle or gas found in the air that is not part of the original, normal composition. Natural : F orest fires, pollen, dust storm Unnatural (Man-made): C oal , wood and other fuels used in cars, homes, and factories for energy

3. Air Pollution Air pollution is a significant cause of morbidity and mortality worldwide, particularly among at-risk individuals with preexisting pulmonary or cardiac disease. Airborne microorganisms have long been major causes of morbidity and death, and the causes of two of the moderns world`s great pandemics, Influenza in 1918 to 1919 and COVID-19 beginning in 2019. More widespread are the chemical and particulate pollutants found in the air, both in so-called “developed” and “under developed” countries. Specific hazards have been recognized for both outdoor and indoor air.

4. 1. Outdoor Air Pollution The ambient air is contaminated with a mixture of gaseous and particulate pollutants, more so in cities and in proximity to heavy industry. Exposure to air pollutants is disproportionately greater among marginalized populations of lower socioeconomic status. Lungs bear the brunt of the adverse consequences of air pollution, but air pollutants like other environmental toxins (e.g. lead, mercury ), affect many organ. Here we consider the effects of ozone, nitrogen dioxide,sulfur dioxide, particulates and CO.

5. 1. Ozone ( Ground Level Ozone ) At upper level, Ozone shields Earth from sun’s harmful UV rays, while at ground level ozone is harmful pollutant. Ozone is one of the most pervasive air pollutants; levels in many cities exceed EPA (Environmental Protection Agency) standards. It is a gas formed by sunlight driven reactions involving the nitrogen oxides, which are released mostly by automobile and chemical plant exhausts. It's toxicity stems from its Participation in chemical reactions that generate free radicals, which injure the lining cells of the respiratory track and the alveoli (irritate respiratory system and reduces lung function).

6. … Low levels of ozone may be tolerated by the healthy individuals but are detrimental to lung function, specially in those with asthma or emphysema, or present along with the particular pollution. Children are particularly susceptible to the effects of ozone.

7. 2. Sulfur dioxide Sulfur dioxide, particles, and acid aerosols are emitted by coal- and oil-fired power plants and industrial processes burning these fuels. Of these, particles appear to be the main cause of morbidity and death. Particles less than 10 µm in diameter are particularly harmful, because when inhaled they are carried by the airstream all the way to the alveoli. Here , they are phagocytosed by macrophages and neutrophils, causing the release of mediators and inciting an inflammatory reaction (narrows the airway, causing wheezing and shortness of breath). By contrast, larger particles are removed in the nose or are trapped by the mucociliary “escalator” and as a result are less dangerous.

8. 3. Carbon monoxide Carbon monoxide (CO) is a nonirritating, colorless, taste less, odorless gas. It is produced by the incomplete combustion and oxidation of carbonaceous materials. Its sources include automotive engine exhaust, industries using fossil fuels, home oil burners, and cigarette smoke. The low levels often found in ambient air may contribute to impaired respiratory function but usually are not life threatening.

9. … CO is a systemic asphyxiant (asphyxia- reduced level of oxygen), that kills by binding to hemoglobin and preventing oxygen transport. Hemoglobin has a 200-fold greater affinity for CO than for O2. The carboxyhemoglobin, that is formed by binding of CO is incapable of carrying oxygen. Hypoxia leads to central nervous system (CNS) depression, which develops so insidiously that victims often are unaware of their plight and are unable to help themselves .

10. … Systemic hypoxia appears when the hemoglobin is 20% to 30% saturated with CO, and unconsciousness and death are probable with 60% to 70% saturation. The diagnosis of CO poisoning is based on detection of high levels of carboxyhemoglobin in the blood.

11. 4. Nitrogen Dioxide Reddish , brown gas Produced when nitric oxide combines with oxygen in the atmosphere Present in car exhaust and power plants Affects lungs and causes wheezing, increases chance of respiratory infection

12. 5. Particulate Matter Particles of different sizes and structures that are released into the atmosphere. Present in many sources including fossil fuels, dust, smoke, fog, etc. Can build up in respiratory system. Aggravates heart and lung disease, increases risk of respiratory infection.

13. smog These 5 together form SMOG Combination of gases with water vapor and dust Combination of words smoke and fog Forms when heat and sunlight react gases (photochemical smog) Occurs often with heavy traffic, high temperatures, and calm winds. ( The main difference between fog, smoke, and smog is that fog is made of water droplets, smoke is a byproduct of burning, and smog is a combination of smoke and other pollutants , such as sulfur dioxide, carbon oxide, dust, and soot. Smog is usually darker than fog and can be smelly).

14. effects: 1st smog related deaths were in London in 1873, death toll 500 people, imagine how much worse the atmosphere is now ? Limits visibility Decreases UV radiation Yellow/black color over cities Causes respiratory problems and bronchial related deaths

15. green house gasses Gases that stay in the air for a long time and warm up the planet by trapping the sunlight, that is called green house effect, because gases act like glass in green house. Some of the important green house gases are Co2 , methane and nitrous oxide. Co2 is the most important green house gas. It comes from the burning of fossil fuel in cars, power plants, house and industry. Methane is released during the processing of fossil fuels and also come from the natural source like cows. Nitrous oxide comes from the industry source.

16. ozone A gas that can be found in two places. Near the ground it is the major part of smog. Second is a protective layer of ozone in the upper atmosphere which screen out harmful ultraviolet rays. Ozone is not created directly, but is found when nitrogen oxide and volatile organic compound mix in sunlight. Mostly found in summer. Nitrogen oxides come from burning coals, fossil fuels.

17. effects: Ozone near the ground level cause a number of health problem. Ozone can lead to more frequent asthma attack in people who have asthma and can cause sore throat, cough and breathing difficulty. Ozone can also damage plants and corps.

18. 2. Indoor Air Pollution As modern homes are increasingly sealed to exclude the environment, the potential for pollution of indoor air increases. The most common pollutant is tobacco smoke but additional offenders are CO, nitrogen dioxide and asbestos. A few comments about some other agents are presented here.

19. 1. Smoke From Burning Of Organic Materials Smoke from burning of organic materials containing various oxides of nitrogen and carbon particulates. It is an irritant that predisposes exposed persons to lung infections and may contain carcinogenic polycyclic hydrocarbons . It is estimated that one-third of the world, mainly in developing areas, burn carbon-containing material such as wood, dung, or charcoal in their homes for cooking, heating, and light.

20. 2. radon Radon a radioactive gas derived from uranium, is widely present in soil and in homes. Although radon exposure can cause lung cancer in uranium miners ( particularly in those who smoke). I t does not appear that low-level chronic exposures in the home increase lung cancer risk, at least for nonsmokers.

21. 3. Bioaerosols Bioaerosols may contain pathogenic microbiologic agents, such as those that can cause Legionnaires’ disease, viral pneumonia , and the common cold, as well as allergens derived from pet dander, dust mites, and fungi and molds , which can cause rhinitis, eye irritation, and even asthma.

22. Metals as Environmental Pollutants Lead, mercury, arsenic, and cadmium, the heavy metals most commonly associated with harmful effects in human populations, are considered here.

23. 1. lead Lead is a readily absorbed metal that binds to sulfhydryl groups in proteins and interferes with calcium metabolism, leading to hematologic, skeletal, neurologic, GI, and renal toxicities . Lead exposure occurs through contaminated air, food and water. For most of the 20th century the major sources of lead in the environment were house paints and gasoline. Children absorb more ingested lead than adults, the main source of exposure for children is lead-containing paint .

24. 2. Mercury Mercury, like lead, binds to sulfhydryl groups in certain proteins with high affinity, leading to damage in the CNS and several other organs such as the GI tract and the kidneys . Humans have used mercury in many ways throughout history, including as a pigment in cave paintings , a cosmetic, a remedy for syphilis, and a component of diuretics. Poisoning from inhalation of mercury vapors has long been recognized and is associated with tremor, gingivitis, and bizarre behavior.

25. … Today, the main sources of exposure to mercury are contaminated fish and dental amalgams, which release mercury vapors . Ingested mercury can injure the gut and cause ulcerations and bloody diarrhea. In the kidneys, mercury can cause acute tubular necrosis and renal failure.

26. 3. arsenic Arsenic salts interfere with several aspects of cellular metabolism, leading to toxicities that are most prominent in the GI tract, nervous system, skin, and heart . Arsenic is found naturally in soil and water and is used in wood preservatives, herbicides, and other agricultural products . Arsenic is present in Chinese and Indian herbal medicine, and arsenic trioxide is a frontline treatment for acute Promyelocyte leukemia.

27. … If ingested in large quantities, arsenic causes acute toxicity manifesting as severe abdominal pain, diarrhea, cardiac arrhythmias, shock and respiratory distress syndrome and acute encephalopathy. GI , cardiovascular and CNS toxicity may be severe enough to cause death. These effects may be attributed to the interference with mitochondrial oxidative phosphorylation.

28. 4. Cadmium Cadmium is preferentially toxic to the kidneys and the lungs through uncertain mechanisms that may involve increased production of ROS. In contrast with the metals already discussed, cadmium is a relatively modern toxic agent . Excessive cadmium intake can lead to obstructive lung disease and renal toxicity, initially as tubular damage that may progress to end-stage renal disease. Cadmium exposure can also cause skeletal abnormalities associated with calcium loss.

29. Industrial & Agricultural Exposures Other important agents that contribute to environmental diseases include the following : Organic solvents (chloroform and carbon tetrachloride ): Acute exposure to high levels of vapors from these agents can cause dizziness and confusion, leading to CNS depression and even coma. Lower levels may cause liver and kidney toxicity . Polycyclic hydrocarbons : Are released during the combustion of coal and gas, particularly at the high temperatures used in steel foundries.

30. … Organochlorine s : Are synthetic products that resist degradation and are lipophilic. Important organochlorines used as pesticides are DDT (dichlorodiphenyltrichloroethane ) and its metabolites. Acute DDT poisoning in humans causes neurologic toxicity . Non-pesticide organochlorines: Include polychlorinated biphenyls (PCBs) and dioxin. Dioxins and PCBs can cause skin disorders such as folliculitis and acneiform dermatosis known as chloracne, which consists of acne, cyst formation , hyperpigmentation, and hyperkeratosis, generally around the face and behind the ears. It can be accompanied by abnormalities in the liver and CNS.

31. … Bisphenol A (BPA ): I s used in the synthesis of polycarbonate food and water containers and of epoxy resins that line almost all food bottles and cans. BPA has long been known as a potential endocrine disruptor. Vinyl chloride: U sed in the synthesis of polyvinyl resins, can cause angiosarcoma of the liver, a rare type of liver tumor. Inhalation of mineral dusts: Causes chronic, non-neoplastic lung diseases called pneumoconioses. This group of disorders includes diseases induced by organic and inorganic particulates.

32. Thank you