Environmental Chemistry Overview

Environmental Chemistry Overview

• Environmental chemistry focuses on the interaction between chemistry and biology, and the environment.
• Previous units focused on matter and chemical changes, illustrating how chemistry explains matter's properties and transformations.

Nutrients

• Nutrients are essential for life, and can be either organic or inorganic.
• Organic nutrients contain carbon and hydrogen. Examples include carbohydrates, lipids, proteins, and vitamins.
• Inorganic nutrients include minerals, such as calcium and iron.

Organic Compounds

• Carbohydrates: Serve as energy sources for metabolism and are found in rice, grains, potatoes, and fruits.
• Proteins: Act as structural molecules supporting body function and aiding chemical reactions. Examples include meat, eggs, dairy, legumes, and nuts.
• Lipids: Store unused chemical energy and are found in vegetable oil, nut oil, and legumes.

Essential Elements for Healthy Bodies: Minerals

• Minerals are categorized as either macrominerals (needed in large quantities) or trace elements (needed in small quantities).
• All living things require 16 naturally occurring elements. Plants require 18 elements, and humans need 22.
• Examples of important minerals include calcium (for strong bones and teeth, nerve conduction, muscle contraction, and blood clotting), phosphorus (for bone formation and energy storage), magnesium (component of bones and teeth, essential for enzyme function, and nerve function), and potassium (regulation of nerve signals, muscle activity, protein formation, and acid/base balance).
• Sulphur is used in some amino acids. Iron is crucial for red blood cells and oxygen transport. Iodine is a key part of thyroid hormones, which regulate metabolism.

Obtaining Minerals

• Plants absorb minerals from the soil and transport them to other parts of the plant, where they are used to create compounds like proteins, lipids, and vitamins.
• Other organisms obtain minerals through absorbing them from a substrate, a material on which an organism moves or lives.

Fertilizers and Impacts

• Fertilizers are used to help plants grow, and they imitate the nitrogen cycle by adding nitrates, ammonia, and urea.
• Phosphorus is provided as phosphate compounds.
• Potash acts as a source, and fertilizers generally contain a blend of these.
• Increased use of artificial fertilizers has added significant amounts of nitrogen to the environment (approx. 140 million tonnes per year).
• Increased plant growth, potential for high yields on previously unsuitable land, and use of fertilizer and water may yield positive results.
• However, single-crop farming practices can increase the likelihood of plant diseases. Fertilizer and water can be expensive for productivity.
• Pesticides are used to reduce crop loss, but they may be expensive and harmful.

Harmful Algal Blooms

• Rapid growth of algae can deplete oxygen in water, harming other organisms and blocking sunlight.

Summary

• Living things need nutrients to survive, which can be organic or inorganic.
• We obtain these nutrients from food, including plants.
• Plants absorb minerals, using them to build proteins, lipids, and vitamins.
• Fertilizers enhance plant growth, but their use can have environmental consequences.

Comparisons and Recent Topics

• Last Class: Focused on nutrients for living things and organic vs. inorganic nutrients.
• This Class: Includes investigating pesticide movement and impact, bioaccumulation, biomagnification of pollutants, and the effects of DDT, a potent insecticide.

Pesticides

• Three types of pesticides:
  • Herbicides: Designed to kill plants. Some are selective (e.g., Killex), while others are not (e.g., Round-up).
  • Insecticides: Designed to kill insects (e.g., Raid, DDT, dieldrin).
  • Fungicides: Designed to kill fungus.

Ingestion vs. Absorption

• Ingestion: Taking in a material (e.g., eating).
• Absorption: Process of taking in a material through different ways, including the digestive tract, respiratory tract, or the skin.

DDT (Dichlorodiphenyltrichloroethane)

• A potent insecticide used to kill mosquitoes, originally believed to solve malaria.
• Its use was later restricted due to harmful consequences like bioaccumulation and biomagnification in the food chain. Bioaccumulation: the process where chemical concentrations increase in organisms; Biomagnification: this process increases the pollutant concentration as you move up the food chain.
• Birds feeding on insects exhibited thinning egg shells, harming their ability for successful chick hatching.

Bioaccumulation vs. Biomagnification

• Bioaccumulation: The build-up of a substance in an organism over time.
• Biomagnification: The increasing concentration of toxins in higher trophic levels of the food chain. This means that top predators are exposed to much larger amounts of a substance than organisms lower on the food chain.
• The pollutant must be long-lived, mobile, soluble in fats, and biologically active for biomagnification to occur.

DDT Restriction

• DDT restriction has faced challenges due to initially effective malaria reduction; later resurgence of malaria after ban; less-effective and/or unsafe replacements; cost of alternatives; and pesticide resistance.

This quiz covers the interaction between chemistry and biology, focusing on essential nutrients and organic compounds vital for life. Various types of nutrients, including organic and inorganic, and their importance to health will be highlighted. Test your knowledge on carbohydrates, proteins, lipids, and essential minerals.