Environmental Pollution PDF

Environmental Pollution Environmental toxicology designated to study the effects of pollutions on wildlife and how this might affect the ecosystem. The main causes of air pollution: 1- Carbon Monoxide (CO). 2- Sulfur Dioxide (SO2). 3- Hydrocarbons. 4- Particulate Matter. 5- Nitrogen Dioxide....

Environmental Pollution Environmental toxicology designated to study the effects of pollutions on wildlife and how this might affect the ecosystem. The main causes of air pollution: 1- Carbon Monoxide (CO). 2- Sulfur Dioxide (SO2). 3- Hydrocarbons. 4- Particulate Matter. 5- Nitrogen Dioxide. The Major sources of air pollution: 1- Transportation. 2- Industry and Industrial disposal. 3- Electric power generation 4- Space heating. Air Pollutions Types: There are two types of air pollutions with their subtypes: 1- Outdoor pollution: a- Reducing type pollution (London particular). b- Oxidative type pollution (Photochemical air pollution). 2- Indoor pollution: a- Sick-Building Syndromes. b- Building related illnesses. 1- Outdoor pollution: A- Reducing type pollution (London particular). It is characterized by sulfur dioxide (SO2) and smoke resulting from incomplete combustion of coal and by conditions of fog and cool temperatures. 1 1- Sulfur dioxide (SO2) Chronic exposure of animal to sulfur dioxide produces a thickening of mucosa layer in the trachea and hypertrophy of goblet cell and mucous glands. 2- Sulfuric acid Animals were more sensitive at one or two months of age than at 18 months. The cause of death in animals that exposed rapidly appeared to be bronchoconstriction. Ammonium carbonate provides an excess of ammonia protected against the effect of sulfuric acid. 3- Particulate sulphates and particulate matter Zinc ammonium sulfate have an irritant potency, it was found producing a response similar to that produced by histamine. The principal sites of constriction were the alveolar ducts and terminal bronchioles. Effect of partical according to its size (5µm) fiber may cause respiratory disease like asbestosis or silicosis. B- Oxidative type pollution (Photochemical air pollution). It results from the atmospheric reaction products of automobile exhaust and occurs with particular frequency and intensity in areas such as Los Angeles, where intense sunlight cause photochemical reaction in polluted air. The major oxidants found in the atmosphere are: 1- Carbon Monoxide (CO): It would be classed toxicologically as a chemical asphyxiant, and its toxic action due to formation carboxyhemoglobin (CoHb). The normal concentration of carboxyhemoglobin in blood of nonsmokers is about 0.5%. This is attributed to endogenous production of CO from such sources as hemoglobin. No human health effects have been demonstrated for (CoHb) levels below 2%. Above 2% CoHb in nonsmokers (the median value of smoker 5%), it has been possible to demonstrate effect on CNS cause Anoxia (Silent killer). 2- Ozone: The toxic effect include: (a) Mortality and lung pathology: Ozone is capable of causing death from pulmonary edema and high levels of histamine could be produced. 2 (b) Pulmonary function: Shallow and rapid breathing and decreases in pulmonary compliance, increases the sensitivity of the lung to bronchoconstrictive agents (histamine, Acetylcholine). (c) Susceptibility to bacteria: It is result from inhibition clearance mechanism, either mucocilliary streaming or phagocytosis (reduce number and phagocytic ability of macrophages). (d) Biochemical and genital effects: Ozone and X-irradiation are nearly additive in producing Chromosomal aberrations in plants and animals. Antioxidant and radical trapping agents such as quinines, ascorbic acid and α- tochopherol protect against ozone toxicity. Ozone exposure provide evidence of lipidperoxidation. 3- Nitrogen Dioxide: It is deep lung irritant capable of producing pulmonary edema. This a practical problem to farmers, as sufficient amounts can be liberated from ensilage to produce the symptoms of pulmonary damage known as Silo- Fibers disease. Animals and human subjected to nitrogen dioxide can cause alteration in pulmonary function (increase in respiratory frequency and decrease in lung compliance). 4- Aldehydes: Various aldehydes in polluted air are formed as reaction products in photooxidation of hydrocarbons. The two major aldehydes are (1) Formaldehyde: - It is very soluble in water, it irritates mucus membrane of the nose, upper respiratory tract and eyes. Concentration of 0.5 to 1 ppm are detectable by odor. (2) Acrolein: - Because it is an unsaturated aldehyde, acrolein is much more irritant than formaldehyde. Concentration below 1 ppm cause irritation of the eyes and mucous membrane of the respiratory tract. The irritant action of acrolein stimulate the pituitary- adrenal system, leading to hypersecretion of glucocorticoids, which induces or stimulates the synthesis of increased amounts of enzymes by the liver. 3 2- Indoor pollution: The indoor environment has only recently been appreciated in terms of its contribution to total personal exposure. Sources: 1- Unvented space heaters and poorly vented fire spaces and wood stoves. 2- Fuels used for heating and cooking. 3- Secondhand tobacco smoke. 4- Carpets, furnishings. 5- Dry cleaner clothes and household cleaning products (volatile organic compounds VOC). 6- Overcrowded homes and insufficient living space. The largely unique to the indoor pollution are: 1- Sick-Building Syndromes: This collection of ailments, which identified by (Eye, nose and throat irritation; Headaches; Fatigue; Reduced attention span; Irritability; Nasal congestion; Difficulty breathing; Nose bleeds; Dry skin and Nausea). It is unknown specific etiology but is relieved sometime after an affected individual leave building, this syndrome frequently occurs in new, poorly ventilated or recently refurnished buildings, the suspect causes include: combustion products, as well as furnishings and poor ventilation. 2- Building related illnesses: Several of biologically related illness e.g.: 1) Legionnaires disease. 2) Hypersensitivity pneumonitis. 3) Humidifier fever. 4) Allergic to animal dander, dust mites, and cockroaches. 5) Some toxic inhalants might be classified in this group, such as carbon monoxide, nitrogen dioxide and most volatile organic compounds result in less definable conditions. 4 6) Some inhalants, such as nitrogen dioxide and trichloroethylene (arising from chlorinated water or dry- cleaned clothes) have been showed to suppress host defenses and allow opportunistic pathogen to proliferate in the lung. 7) Cat allergy. Water and soil pollution The ultimate sink for most chemicals produced and used by human are water and soil. Organism Air Water Soil Diagram overlapping relationships of environmental compartments The interface between soil and water is an intimate one. Virtually all water system contain suspended soil particles and all soil contains at least small amount of water. Soil compositions: 1- Inorganic constituents (slit, sand and clay). 2- Organic constituents (living, dead). Sources of chemical in the Environment: 1- Industrial e.g. phosphate of detergents used in clothes laundry is nutrient source of algae and other organisms. 2- Agricultural e.g. pesticides applied directly to soil to control insects, wood and plant diseases. Some of these chemicals can persist for many years, and 5 their potential movement from soil into water and from both water and soil into organism in and on water and soil. These effects of pesticides in food chain are now generally familiar. Water Plant Human Soil Animal Diagram of food chain 3- Domestic and urban e.g. lead contamination of soil and occasionally water near highways result from the use of tetraethylead as an antiknock component of gasoline for automobile. E.g. Water fluoridation to prevent tooth decay, but excessive concentration of fluorine can result mottling and discoloration of teeth. E.g. purification water results chlorination of certain hydrocarbons that are potentially carcinogenic. 4- Naturally occurring e.g. naturally occurring Arsenic in copper ores, frequently find its way to soil and water. Classification the sources of chemicals In the environment: 1- Point source a- Easily to identified. 6 b- Remedies are attainable. 2- Nonpoint source a- Less dramatic in its effect. b- More difficult to correct. Bioaccumulation ratio: It concentrates rather than diffuse the chemical in question. This concentration effect is expressed as the ratio of the concentration of chemical in the organism to that in the medium. Conc. of chemical in organism Bioaccumulation ratio = Conc. of chemical in medium (Environment) The two properties of chemical that are responsible for high bioaccumulation ratio value are: 1- High partion coefficient (lipophilic). 2- Recalcitrance toward of all types of degradation Biological effects: Transformation of chemicals in soil and water due to the action of microorganism occur by a- chemical, photochemical and biochemical reactions. b- Degradation results in true disappearance of chemical molecule. c- Transport processes which merely move chemicals from one environment compartment to another. 7 d- Vaporization: e.g. DDT. The most Common Sources of Pollutants in Environmental: 1- Pesticides:- Firstly we most Know that the persistence time reflect the time required for 75-100% disappearance of pesticides residues from the site of application. a- persistence pesticides: like chlorinated hydrocarbon insecticide {DDT, aldrine, hexachlorohexan}. These chemicals have persistent time (2-5) years. They are highly soluble in lipid and most organic solvents, but have low water solubility. Their adsorption depend on presence of soil organic matter. b- moderately persistence pesticides: like triazine herbicides. They have persistent time (1-18) months. Adsorption of triazine to organic matter and clay minerals is depend on the pH of the solution and the acidity of the adsorbent surface (more soluble at low pH). c- nonpersistence pesticides: like organophosphorous compounds, carbamate, synthetic parathyroid have persistent time (1-12) weeks. The organophosphorous and carbamate insecticides are relatively nonpersistent in the environment. They are typically applied to crops, directly to soil as insecticides for the control of phytophorgous crop. 2- Nopesticidal organic chemicals:- a- Low-molecular weight Halogenated Hydrocarbons: they are produced through the use of chlorination for water purification. E.g. chloroform and bromoform result from chlorination. b- Aromatic Halogenated Hydrocarbons: The polychlorinated biphenyl (PCB) have been ubiquitous contaminants of soil and water. Tetrachloride benzo-p-dioxin (TCCD) has contaminated large area of both water and soil through industrial accidents. c- polychlorinated Biphenyls (PCBs): are very stable materials of low flammability, which contain 12-68% chlorine. They are expectinally pesticides in environment. They have been used as insulating materials in electrical capacitors, plasticizers in waxes, in paper manufacturing. 8 d- chlorophenols: pentachlorophenol as antibacterial in number of consuming products (soap, deodorants). It has been detected in surface water. Hexachlorophene is resistant to biotransformation tends to persist in the environment and bioaccumulates in feed chain. e- phthalate Ester plasticizers: They are used in constriction, automotive, household product, apparel, toys, packaging and medical products. They have been found complex with the fulvic acid compounds. e.g. diethyl-hexyphthalate (DEHP) and di-butyphthalate (DBP). DEHP is carcinogenic in rat. Both DEHP and DPB are affect reproductive of some aquatic organism at low concentration. 9