Anthropogenic Pollution

 Anthropogenic pollution is defined as the introduction of harmful substances or the creation of harmful impacts in the environment that are directly tied to man’s activities, including: agricul-ture, industry, and energy production and use. It also includes the release and deposition into the environment of waste materials that end up in landfill or are incinerated. Anthropogenic pollution can be described as being intentional or nonintentional, with intentional pollution in many cases being tied to warfare. Our knowledge of the chemistry of the Earth’s environmental systems is based on the studies of these anthropogenic impacts on our air and water resources due to the release of chemicals that are not natural to the environment or are emitted at much higher levels than natural.

The potential impacts on air and water quality from anthropogenic pollution have been recognized for a long time. The intentional pollution of water supplies with poisons or waste was used in ancient times, during long-term sieges of major cities such as the siege of Tortona, Italy in 1155 led by Frederick Barbarossa (Bradbury, 1992). It has been documented as early as 1000 BCE with the ancient Chinese putting arsenic in the water supplies of their enemies (Kroll, 2006). Unintentional pollution was recognized to correlate with higher human popula-tion densities in cities. It was strongly linked to the observation of polluted air and water, which not only impact the environmental systems, but also human health and longevity. As early as the twelfth century, Moses Maimonides (Goodhill, 1971; Finlayson-Pitts and Pitts, 2000), a well-known philosopher and physician, noted in his writings about the city of Cairo that:

        "Comparing the air of cities to the air of deserts and arid lands is like comparing waters that are befouled and turbid to waters that are fine and pure. In the city, because of the height of its buildings, the narrowness of its streets, and all that pours forth from its inhabitants and their superfluities… the air becomes stagnant, turbid, thick, misty, and foggy… If there is no choice in this matter, for we have grown up in the cities and have become accustomed to them, you should… select from the cities one of open horizons…endeavor at least to dwell at the outskirts of the city… If the air is altered ever so slightly, the state of the Psychic Spirit will be altered perceptibly. Therefore you find many men in whom you can notice defects in the actions of the psyche with the spoilage of the air, namely, that they develop dullness of understanding, failure of intelligence and defect of memory…"

This quote from Maimonides predates the Industrial Revolution, when the invention of the steam engine and enhanced farming techniques led to rapidly increasing populations. It clearly notes that, in past as well as present urban settings, anthropogenic pollution is strongly tied to population densities. The increase in population in centralized areas requires increases in energy and water usage, along with the increased transportation necessary to bring the required goods to and from the urban centers. Indeed, the remarks made by Maimonides hit on a number of the present impacts on the chemistry of natural systems, such as the degradation of air and water quality leading to an unpleasant and unhealthy environment.

Another example of the early recognition of health issues caused by exposure to environ-mental contaminants is the linking of cancer in young male chimney sweeps to environmental exposure by Sir Percival Pott, an English surgeon. In 1775 Pott attributed the high incidence of scrotal cancer in young chimney sweeps to the exposure and inhalation of chimney soot (Dobson, 1972). This was the first documented identification of the connection of an environmental occupational exposure to an unintentional health effect. It also led to one of the first child labor laws based on an environmental exposure impact on children’s health called the Chimney Sweepers Act of 1788 (Hayes, 2008).

Occupational exposure to chemicals and the associated health risks are a significant part of the impacts of anthropogenic pollution. The identification of mercury as a toxic metal with adverse health effects, including dementia, originated with the use of mercuric nitrate in the production of felt for hats in the eighteenth and nineteenth centuries. The term “mad as a hat-ter” is now a colloquialism meaning crazy, but its first use referred to hatters who developed a mental disorder called mad hatter syndrome after being exposed to mercury during their work. One particular city that had a thriving hat industry was Danbury, CT, which had so many cases of mercury poisoning that the condition was referred to as the “Danbury Shakes” and led to the banning of mercury compounds in the city in 1941 (New England Historical Society, 2016). Other occupations that are well known for impacts from chemical and environmental expo-sures include: coal miners, asbestos workers, industrial chemists, and refinery workers. These well-known occupational exposure problems led to the establishment of the Occupational and Safety Administration (OSHA) in the United States and similar agencies throughout the world. These agencies have responsibility for establishing regulations detailing occupational exposure limits and monitoring requirements for hazards to workers in the workplace.

One of the major changes in our view of the impacts of anthropogenic pollution on the environment is the recognition that man occupies a planet that is not limitless in its resources, especially as the human population increases and the demands on those resources increases. Originally recognized as local problems, we have come to realize that pollutants can have a wide variety of impacts and that the various chemicals and materials released into the environment can have effects on more than one environmental system, depending on their chemical and physical properties. An understanding of these properties and the chemical lifecycles of pollutant species is an important key to our developing environmentally sustainable practices with minimal environmental impacts. Thus, this text will focus on the connections between the chemical reactions of both natural and anthropogenic species in the different environmental systems.