Radiation and Heavy Metal Pollution

Radiation and Heavy Metal Pollution

• Radiation pollution is a type of physical environmental pollution.
• It involves the emission of high-energy particles or radioactive substances into air, water, or land due to human activities, often in the form of radioactive waste.
• Radiations are classified into two types: non-ionizing and ionizing radiations.
• Non-ionizing radiations have short wavelengths and low energy. Examples include radio waves, microwaves, infrared radiation, and visible light.
• Ionizing radiations have high energy and short wavelengths. Examples include X-rays and gamma rays.
• Alpha, beta, gamma, X-rays, and neutron rays are different types of radiation with varying penetration power.
• Paper stops alpha rays, aluminum stops beta rays, and thick lead stops gamma and X-rays; water or concrete stops neutrons.
• Radioactive pollution can be continuous, occasional, or accidental depending on its frequency.
• Natural sources of radiation include cosmic rays, terrestrial radiation (radium-224, uranium-235, uranium-238, thorium-232, radon-222).
• Man-made radiation sources include nuclear accidents (Fukushima Daiichi, Chernobyl, Three Mile Island).
• Alpha particles cannot easily pass through the skin but can damage lungs or bones if the source is internal.
• Beta particles can penetrate the skin but do not damage tissues, however they can damage skin and eyes.
• X-rays penetrate tissues easily but cannot travel through bones.
• Gamma rays penetrate easily, damaging cell structures.
• Solutions to radioactive pollution include proper radioactive waste disposal, alternative energy sources, proper labelling, proper storage, reusing, and precautions at the personal level.
• Nuclear waste is classified into low-level, intermediate-level, and high-level based on its danger and handling requirements.
• Low level waste is often not dangerous, though it sometimes requires shielding.
• Intermediate-level waste is usually chemical sludge; high-level waste consists of fissionable elements from a reactor core.
• Transuranic waste includes transuranic alpha-emitting radionuclides with longer half-lives.
• Waste volume breakdown: low level 7%, intermediate level 3%, high level 90%.
• Radioactive waste management includes pretreatment (collection, segregation, chemical adjustment, and decontamination).
• Treatment methods change waste characteristics, involving volume reduction, radionuclide removal, and composition change.
• Low-level waste disposal often involves incineration.
• Disposal of radioactive waste can be near surface disposal (engineered channels or vaults), deep boreholes, or geological disposal in tunnels, vaults, or silos.
• Vitrification solidifies waste into glass (amorphous solid) using borosilicate glass.
• Other disposal ideas include long-term above-ground storage, disposal in outer space, rock-melting, disposal at subduction zones, sea disposal, sub-seabed disposal, disposal in ice sheets, and deep well injection.

Heavy Metal Poisoning

• Heavy metals are naturally occurring elements with high atomic weight and density.
• Examples include Uranium, Aluminium, Thorium, Arsenic, Barium, Cadmium, Cesium, Copper, Mercury, Nickel, Platinum, Tin, etc.
• They are toxic at low concentrations.
• Heavy metal pollution can be natural or anthropogenic, arising from sources like industrial chemicals, food, water.
• Exposure to heavy metals by accumulation can cause poisoning.
• Heavy metals tend to bioaccumulate (concentrating in organisms over time).
• Routes of exposure include contaminated water, food, air, commercial products, and workplaces.
• Acute effects of heavy metal poisoning include nausea, vomiting, diarrhea, abdominal pain, CNS effects (hyperactivity/lethargy, ataxia, convulsions), hair/skin/nail changes, and CV (volume loss, dysrhythmia, congestive CM) problems.
• Chronic effects include CNS problems, renal problems, various cancers, and skin rashes/colored lines on nails/gums.
• Acute and chronic effects of arsenic are respiratory failure, pulmonary edema, GI problems (nausea, vomiting, colicky abdominal pain, diarrhoea), haematological problems (anaemia, leukopenia), and renal failure, Skin problems like rashes, colored lines on nails/gums.
• Acute and chronic effects of chromium are respiratory tract inflammation, lung cancer, nasal septum ulceration, and perforation, and dermal effects like ulcers.
• Acute and chronic effects of lead include developmental problems, GI problems (constipation/diarrhea, vomiting), CNS problems (hyperactivity/lethargy, ataxia, convulsions, behavioral changes), and skin/hairy changes, and effects on blood pressure.
• Acute and chronic effects of mercury include oral ingestion effects (inorganic salts, gastrointestinal pain, vomiting, diarrhea, hemorrhage), and systemic effects (shock, kidney issues, lethargy), and neurological damage.

Heavy Metal Contamination in Bangladesh

• Arsenic contamination of ground water is a major public health issue in Bangladesh.
• Chronic toxicity occurs from contaminated drinking water.
• In Bangladesh, levels are higher in rice compared to other vegetables or plants.
• Lead contamination is found in rivers and in the market.
• Mercury contamination results from cement factories, paper and pulp mills, dental work, and others. High amounts are released from the energy sector.
• Chromium contamination occurs through feeds, fertilizer production, and tanned skin wastes.
• Contamination from ship breaking is an issue.
• Heavy metal contamination is found in both city and coastal areas of Bangladesh.
• Heavy metal concentrations in water, sediment, and fish exceed permissible limits in rivers like Turag and Buriganga.

Heavy Metal Pollution of River Water

• Heavy metals are a serious concern in various rivers in Bangladesh due to urban/industrial pollution (sewage, waste), and pesticides/industrial waste.
• High levels of heavy metals have been found in rivers like Meghna, contributing to contaminated water, fish and sediments.
• Rivers in Dhaka are contaminated, exhibiting high concentrations of various metals.