Water Pollutants & Sources - Aqua Invaders
- Biological (Pathogens):
- Bacteria: V. cholerae (cholera), S. typhi (typhoid), Shigella, E. coli.
- Viruses: Hepatitis A/E, Rotavirus, Poliovirus.
- Protozoa: Giardia, Entamoeba, Cryptosporidium.
- Helminths: Ascaris, Hookworm eggs/larvae.
- Chemical:
- Inorganic:
- Heavy Metals: Pb (neurotoxic), Hg (Minamata), As (arsenicosis), Cd (Itai-Itai), Cr.
- Emerging Contaminants: Pharmaceuticals, Microplastics, PFAS (per-/polyfluoroalkyl substances).
- Nitrates: >45 mg/L as $NO_3^-$ (Blue Baby Syndrome) - IS 10500:2012.
- Fluorides: >1.5 mg/L (dental/skeletal fluorosis) - IS 10500:2012. Cyanides.
- Organic:
- Pesticides: Organochlorines (DDT), Organophosphates (Malathion), Carbamates.
- Industrial: PCBs, PAHs (carcinogenic), Phenols, Solvents, Detergents.
- Inorganic:
- Physical:
- Turbidity, Color, Odor, Temperature (thermal pollution), Suspended solids.
- Radioactive: Sr-90, Cs-137.
- Sources:
- Point: Direct discharge (sewage outlets, industrial effluents - tanneries).
- Non-Point: Diffuse (agricultural runoff - fertilizers/pesticides; urban stormwater). 📌 Point = Pipe, Non-point = Pervasive.
⭐ Groundwater Arsenic (As) contamination in West Bengal & Bangladesh causes chronic arsenicosis (skin lesions, cancer risk).
💡 WASH Approach: Coordinated Water, Sanitation, Hygiene provision prevents fecal contamination. Detection Methods: AAS, ICP-MS, ASV for heavy metals in forensic investigations.
Waterborne Diseases Overview - Germy Gulps
Transmitted via fecal-oral route from contaminated water (sewage, poor sanitation). Prevention: Safe water, sanitation, hygiene (WASH). Vulnerable: Infants, children, elderly, immunocompromised.
Common Waterborne Diseases & Features:
| Disease | Causative Agent | Key Clinical Features |
|---|---|---|
| Cholera | Vibrio cholerae | Profuse "rice-water" stools, rapid dehydration, muscle cramps. |
| Typhoid Fever | Salmonella typhi | Step-ladder pyrexia, rose spots, relative bradycardia, blood cultures, PCR, rapid antigen tests. |
| Bacillary Dysentery | Shigella spp. | Bloody mucoid stools, tenesmus, fever, cramps. Highly infectious. |
| Hepatitis A | Hepatitis A Virus (HAV) | Jaundice, fever, anorexia, dark urine. Fecal-oral. |
| Hepatitis E | Hepatitis E Virus (HEV) | Similar to Hep A; endemic. More severe in pregnancy. |
| Amoebiasis | Entamoeba histolytica | Amoebic dysentery (blood/mucus), flask-shaped ulcers, liver abscess. |
| Giardiasis | Giardia lamblia | Chronic diarrhea, malabsorption, steatorrhea (greasy stools). |
| Rotavirus Infection | Rotavirus | Severe dehydrating diarrhea in infants/young children. Vaccine preventable. |
| Leptospirosis | Leptospira interrogans | Weil's disease (jaundice, renal failure, hemorrhage); animal urine in water. |
Chemical Contamination & Health - Poison Puddles
Key chemical water pollutants and their health impacts:
| Pollutant | Key Sources | Major Health Impacts | Associated Disease/Syndrome |
|---|---|---|---|
| Lead (Pb) | Old pipes, paints, batteries, contaminated soil | Neurotoxic (esp. children: ↓IQ, learning disability), anemia, colic, nephropathy, hypertension | Plumbism, Lead encephalopathy, Burton's line |
| Mercury (Hg) | Industrial waste, contaminated fish, dental amalgam, thermometers | Neurotoxic (tremors, ataxia, paresthesia), nephrotoxic, teratogenic, gingivostomatitis | Minamata disease (methyl-Hg), Acrodynia (Pink disease), Erethism |
| Arsenic (As) | Groundwater (natural/industrial), pesticides, smelters | Skin lesions (keratosis, hyperpigmentation), neuropathy, peripheral vascular disease; Carcinogen (skin, lung, bladder) | Arsenicosis, Blackfoot disease, Mees' lines (nails) |
| Cadmium (Cd) | Batteries, pigments, smoking, industrial effluent | Nephrotoxic (proteinuria), bone disease (osteomalacia, osteoporosis), emphysema, lung cancer | Itai-Itai disease |
| Fluoride (F⁻) | Groundwater (excess: >1.5 mg/L WHO limit) | Dental fluorosis (mottling), skeletal fluorosis (crippling), non-skeletal manifestations | Fluorosis |
| Nitrates (NO₃⁻) | Fertilizers, animal waste, sewage contamination | Methemoglobinemia in infants (<6 months) due to bacterial conversion to nitrites ($NO_2^-$) | Blue Baby Syndrome (Infantile Methemoglobinemia) |
⭐ Minamata disease, a neurological syndrome caused by severe mercury poisoning, was first discovered in Minamata city, Japan, due to consumption of fish contaminated with methylmercury from industrial wastewater. Neurological damage from mercury poisoning, particularly in the form of diffuse and widespread neuronal atrophy, is most severe in individuals exposed in utero. Long-term studies suggest that even low concentrations of prenatal exposure can lead to subtle but detectable impairments in motor function, language, and memory.
💡 Public education, especially for children, is crucial in preventing mercury contamination. This includes educating people on how to avoid polluting the environment (water, soil, air) with mercury and how to clean up mercury contamination. Training for workers in industries that use mercury (e.g., fluorescent bulb plants) is also very important.
High‑Yield Points - ⚡ Biggest Takeaways
- Key waterborne bacterial diseases: Cholera, Typhoid, Bacillary Dysentery.
- Viral Hepatitis A & E: Transmitted via faeco-oral route by contaminated water.
- Arsenic contamination: Leads to Arsenicosis (e.g., Blackfoot disease, skin lesions).
- Excess Fluoride: Causes Dental Fluorosis (mottling) and Skeletal Fluorosis.
- Mercury poisoning: Results in Minamata disease (neurological symptoms).
- High Nitrates: Cause Methaemoglobinaemia (Blue Baby Syndrome) in infants.
- E. coli: Most reliable indicator of faecal water pollution.
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