Chemistry – Chemistry of the environment - Water | e-Consult

The following statements describe substances that can potentially be harmful:

• Some metal compounds are toxic: Certain metal compounds, such as lead, mercury, and cadmium, are toxic. They can interfere with biological processes in living organisms. For example, lead can damage the nervous system and kidneys. Mercury can cause neurological damage. Cadmium can accumulate in the kidneys and bones, leading to kidney damage and bone disease.
• Some plastics harm aquatic life: Many plastics are not biodegradable and persist in the environment, particularly in aquatic ecosystems. Marine animals can ingest plastic debris, mistaking it for food. This can lead to digestive blockages, starvation, and internal injuries. Larger plastic items can also entangle marine animals, causing injury or drowning. Microplastics can also be ingested by smaller organisms, entering the food chain.
• Sewage contains harmful microbes which cause disease: Sewage contains a variety of microorganisms, including bacteria, viruses, and parasites. These microbes can cause a range of diseases if they enter the human body through contaminated water or food. Examples include cholera, typhoid fever, dysentery, and hepatitis.
• Nitrates and phosphates lead to deoxygenation of water and damage to aquatic life: Nitrates and phosphates are nutrients that can enter water bodies from fertilizers, sewage, and other sources. An excessive amount of these nutrients leads to eutrophication. This is a process where algal blooms occur. When the algae die and decompose, the decomposition process consumes large amounts of oxygen in the water, leading to deoxygenation. This oxygen depletion can suffocate fish and other aquatic organisms, causing mass die-offs and damage to the aquatic ecosystem.