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Human Impact on the Environment Pollution is any environmental change that adversely affects the lives and health of living things. Pollution is directly the third main cause of extinctions and can lead to disease which is the fifth main cause of extinction. 1 – AIR POLLUTION Sulfur introduced into the atmosphere by smokestacks can combine with water vapor to produce sulfuric acid. Engine exhaust also introduces sulfur into the atmosphere. The sulfuric acid is carried back to Earth’s surface in acidified precipitation (rain, sleet, snow, fog) is called acid rain. Research suggests that the acid in precipitation added by human activity is having a dramatic effect. In the United States and Canada, thousands of lakes are “dying” as their pH levels fall below 5.0. Forests in the eastern United States and southern Canada are also being damaged. Starting in 1985, scientists examined satellite images taken over Antarctica & found that the disintegration of the Earth’s ozone (O3) shield was evident as far back as 1978. The major cause of ozone destruction is a class of chemicals called chlorofluorocarbons (CFCs). High in the atmosphere, UV radiation is able to break the bonds in CFCs. The resulting free chlorine atoms then enter into a series of reactions that destroys ozone. Because the decrease in ozone allows more ultraviolet (UV) radiation to reach the Earth’s surface, scientists expect an increased incidence of diseases caused by exposure to ultraviolet radiation. In the United States, the number of cases of malignant melanoma, a potentially lethal form of skin cancer, has almost doubled since 1980. 2 – CHEMICAL POLLUTION Many of the most disastrous incidents of pollution involve industrial chemicals that are toxic or carcinogenic (cancer-causing). In many countries, agriculture introduces large amounts of chemicals into the environment - pesticides, herbicides, and fertilizers. Molecules of chlorinated hydrocarbons a class of compounds that includes pesticides - break down slowly in the environment. As these molecules pass up through the trophic levels of the food chain, they become increasingly concentrated. This is called biological magnification. 3 – WATER POLLUTION 95% of all fresh water is found as ground water, stored within porous rock reservoirs called aquifers. A great deal of ground water is being polluted & once pollution enters the ground water, there is no effective way to remove it. Analysis of tap water in major cities shows they are contaminated with trace amounts of pharmaceuticals including: antibiotics, anti-seizure medications, anti-inflammatory drugs, psychotropic drugs, pain medications, caffeine and even birth control medications. Virtually all water pollutants are hazardous to humans as well as lesser species: • sodium is tied to cardiovascular disease • nitrates in blood disorders • mercury & lead can cause nerve disorders • DDT is toxic to humans and can alter chromosomes • PCBs cause liver and nerve damage, skin eruptions, vomiting, fever, diarrhea, fetal abnormalities and can disrupt hormone function GM-BEDFORD SUPERFUND SITE Historical uses and management of PCBcontaining hydraulic oils (PCB = polychlorinated biphenyl) and PCBimpacted materials has contaminated on-site areas as well as the sediment and floodplain soil within Bailey's Branch and the Pleasant Run Creek watershed. This area includes approximately 5 miles of creek that runs from the GM Bedford Facility Outfall. Deepwater Horizon Oil Spill 2010 The Deepwater Horizon Well/Platform exploded on April 20, 2010, killing 11 people. Roughly 4.9 million barrels of oil blew out of BP's broken well and bled into the water for 86 days, with a portion of that crude making landfall along the coastline. Add in the unknown effect of 1.84 million gallons of chemical dispersants, much of which were applied directly to the well deep below the surface of the ocean - something that had never been done before. As oil bubbled to the ocean’s surface, it swept across the Gulf of Mexico into areas crucial to sea turtles that forage & nest in the basin. But, it’s not just industrial pollution… Laysan Albatross fledgling stomach contents from dead albatross 4 – CLIMATE CHANGE The average global temperature has been steadily increasing for more than a century, particularly since the 1850s. In Earth’s long history there have been many such periods of global warming, often followed by centuries of cold. Many scientists suspect, however, that human activity may be significantly contributing to global warming in modern times. The chemical bonds in carbon dioxide (CO2) molecules absorb solar energy as heat radiates from Earth. This process, called the greenhouse effect, traps heat within the atmosphere in the same way glass traps heat within a greenhouse. THE most abundant greenhouse gas is water vapor! If so, how is human activity to blame? The amount of water vapor in the atmosphere exists in direct relation to the temperature. If you increase the temperature, more water evaporates and becomes vapor. So when something else causes a temperature increase (such as extra CO2 from fossil fuels), more water evaporates. Then, since water vapor is a greenhouse gas, this additional water vapor causes the temperature to go up even further. 5 – SPECIES LOSS Earth is losing many species with 10 percent of well-known species teeter on the brink of extinction. Estimates are that we will lose up to onefifth of the world’s species of plants and animals—about 1 million species— during the next 50 years. Other than climate change, the greatest threat to biodiversity is habitat destruction by deforestation and urbanization. Habitat destruction is a process of land use change in which one habitat is removed and replaced with another type. The Chaco thorn forest is being felled at a rate considered among the highest in the world to give way to soybean cultivation. In the process of land-use change, plants and animals which previously used the site are displaced or destroyed, reducing biodiversity. Urban sprawl is one cause of habitat destruction.