Environmental chemistry
Introduction
Environmental chemistry is a branch of chemistry that focuses on the chemical processes occurring in the environment which are impacted by humankind's activities. These impacts can be felt on a local scale, like a neighborhood or city, or on a global scale, due to atmospheric circulation and ocean currents.
Chemical Species in the Environment
Chemical species in the environment include both natural substances and contaminants. Natural substances are those that occur naturally in the environment, while contaminants are substances that have been introduced into the environment by human activities.
Natural Substances
Natural substances in the environment include elements such as carbon, nitrogen, and oxygen, as well as compounds such as water, carbon dioxide, and methane. These substances play crucial roles in the biogeochemical cycles that sustain life on Earth.
Contaminants
Contaminants are substances that are not naturally found in the environment or are present at concentrations higher than their natural levels. They can be introduced into the environment through various human activities, such as industrial processes, agriculture, and waste disposal. Examples of contaminants include heavy metals, pesticides, and plastic waste.
Environmental Chemical Processes
Environmental chemical processes involve the transformation and movement of chemical species in the environment. These processes can be broadly categorized into physical, chemical, and biological processes.
Physical Processes
Physical processes in environmental chemistry include processes such as diffusion, advection, and sorption. Diffusion is the process by which molecules spread from areas of high concentration to areas of low concentration. Advection is the transport of substances by the flow of a fluid, such as wind or water. Sorption is the process by which one substance becomes attached to another.
Chemical Processes
Chemical processes involve the transformation of substances through chemical reactions. These reactions can be facilitated by various factors, such as light, heat, and the presence of catalysts. Examples of chemical processes in the environment include oxidation, reduction, hydrolysis, and photolysis.
Biological Processes
Biological processes involve the actions of living organisms. These processes can include biodegradation, where organic substances are broken down by microorganisms, and bioaccumulation, where certain chemicals accumulate in the tissues of organisms.
Environmental Analysis
Environmental analysis involves the measurement of chemical species in the environment. This can be done through various methods, such as chromatography, spectroscopy, and mass spectrometry. These methods allow for the identification and quantification of chemical species in environmental samples.
Environmental Impact
The impact of chemical species on the environment can be assessed through various means, such as toxicity testing and risk assessment. These assessments can help determine the potential harm a chemical species may pose to the environment and human health.