Environmental Contaminants and Human Health

Environmental Contaminants and Human Health

• Environmental contaminants are harmful chemicals found in soil, air, and water.
• Accumulation of these contaminants over time can harm human health.
• Contaminants can originate from human sources, such as industrial manufacturing, agricultural run-off, and wastewater discharge.
• Contaminants can also originate from natural sources, like chemicals produced by algae and bacteria.

Key Contaminants

• Nitrosamines: A large group of compounds formed from various combinations of amines and nitrogen compounds. Almost all are carcinogenic to animals.
• Volatile Organic Compounds (VOCs): Organic solvents used in industry for producing rubber, plastics, and cleaning agents. Examples include benzene, toluene, and xylene. VOCs can be found in household products like adhesives, air fresheners, and paints.
• Endocrine disrupting chemicals (EDCs): Chemicals that interfere with the endocrine system, often mimicking natural hormones. Associated health problems include endocrine disorders, sperm decline, and certain cancers.
• Toxic metals and elements: Include lead and cadmium, which can cause various health problems when absorbed by humans.
• Pesticides: Major chemical classes include organochlorines, organophosphates, and carbamates. Exposure can lead to health risks like nausea, vomiting, headaches, and even more serious consequences.
• Pharmaceuticals and personal care products (PPCPs): Various chemicals found in medications and personal care products.
• Fuels and fuel additives: A broad category, and various components can pose risks.

Persistent Organic Pollutants (POPs)

• Polychlorinated biphenyls (PCBs): Persistent organic pollutants resistant to environmental degradation. They accumulate in animal feeds and enter the food chain. Milk is a useful indicator of environmental PCB pollution.
• Dioxins: Persistent organic pollutants introduced into the environment as by-products of industrial processes or from natural events. Dioxins accumulate in animal feeds and in fat tissue, leading to potential health risks like reproductive and developmental problems, immune system damage, hormonal disruption, and cancer.

Other Contaminants

• Polycyclic Aromatic Hydrocarbons (PAHs): Carcinogenic compounds formed from the combustion of organic matter, commonly found in certain foods (grilled food, smoked fish) or areas with high air pollution.
• Phthalates: Used as plasticisers in various household goods. While decreasing use in plastics packaging, they are widespread in the environment and can cause endocrine disruption and decrease in sperm count.
• Nitrates and Nitrites: Used to preserve meat products but can be converted to nitrosamines, which are potent liver carcinogens.

Specific Metal Contaminants

• Lead: Sources include paints, industrial processes and products. Lead was removed from gasoline in many areas, reducing its release into the environment. Lead can cause harm to the nervous system, impede gene function, and affect the composition and function of the blood and kidneys, as well as the endocrine system affecting Vitamin D synthesis.
• Cadmium: A metal found in shellfish, molluscs, and leafy vegetables. Exposure can lead to renal dysfunction, osteoporosis, bone pain, vomiting, diarrhea, anemia, and cancer. The Itai-Itai disease, a significant example of cadmium poisoning, originated from contaminated rice.
• Mercury: Mercury increases in concentration up the food chain, with fish and other seafood having higher concentrations. Exposure can cause neurological and kidney problems, affecting bone marrow’s effect on blood cells, the immune system and bone formation, and even result in Minamata disease, a consequence of methylmercury poisoning.

Itai-itai Disease

• A significant example of cadmium poisoning.
• Characterized by weak and brittle bones, leading to severe pain and fractures due to the accumulated exposure.

Minamata Disease

• A mercury poisoning disaster that occurred in Japan.
• Bioaccumulation of methylmercury contaminated fish and shellfish caused a major health crisis.
• A harmful form of mercury poisoning characterized by neurological issues.

Summary and Overall Impacts

• Long-term exposure to environmental contaminants can lead to organ damage, endocrine problems, immunosuppression, reproductive problems, birth defects, negative effects on children's mental and physical development, and certain types of cancers.
• Children and fetuses are more vulnerable to potential harm than adults from environmental contamination.

Question 1: Itai-itai Disease

• Symptom of Itai-itai disease: Soft and brittle bones leading to fractures
• Cause of Itai-itai disease: Cadmium poisoning