Water Pollution and Health

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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.
  • 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:

DiseaseCausative AgentKey Clinical Features
CholeraVibrio choleraeProfuse "rice-water" stools, rapid dehydration, muscle cramps.
Typhoid FeverSalmonella typhiStep-ladder pyrexia, rose spots, relative bradycardia, blood cultures, PCR, rapid antigen tests.
Bacillary DysenteryShigella spp.Bloody mucoid stools, tenesmus, fever, cramps. Highly infectious.
Hepatitis AHepatitis A Virus (HAV)Jaundice, fever, anorexia, dark urine. Fecal-oral.
Hepatitis EHepatitis E Virus (HEV)Similar to Hep A; endemic. More severe in pregnancy.
AmoebiasisEntamoeba histolyticaAmoebic dysentery (blood/mucus), flask-shaped ulcers, liver abscess.
GiardiasisGiardia lambliaChronic diarrhea, malabsorption, steatorrhea (greasy stools).
Rotavirus InfectionRotavirusSevere dehydrating diarrhea in infants/young children. Vaccine preventable.
LeptospirosisLeptospira interrogansWeil's disease (jaundice, renal failure, hemorrhage); animal urine in water.

Chemical Contamination & Health - Poison Puddles

Key chemical water pollutants and their health impacts:

PollutantKey SourcesMajor Health ImpactsAssociated Disease/Syndrome
Lead (Pb)Old pipes, paints, batteries, contaminated soilNeurotoxic (esp. children: ↓IQ, learning disability), anemia, colic, nephropathy, hypertensionPlumbism, Lead encephalopathy, Burton's line
Mercury (Hg)Industrial waste, contaminated fish, dental amalgam, thermometersNeurotoxic (tremors, ataxia, paresthesia), nephrotoxic, teratogenic, gingivostomatitisMinamata disease (methyl-Hg), Acrodynia (Pink disease), Erethism
Arsenic (As)Groundwater (natural/industrial), pesticides, smeltersSkin lesions (keratosis, hyperpigmentation), neuropathy, peripheral vascular disease; Carcinogen (skin, lung, bladder)Arsenicosis, Blackfoot disease, Mees' lines (nails)
Cadmium (Cd)Batteries, pigments, smoking, industrial effluentNephrotoxic (proteinuria), bone disease (osteomalacia, osteoporosis), emphysema, lung cancerItai-Itai disease
Fluoride (F⁻)Groundwater (excess: >1.5 mg/L WHO limit)Dental fluorosis (mottling), skeletal fluorosis (crippling), non-skeletal manifestationsFluorosis
Nitrates (NO₃⁻)Fertilizers, animal waste, sewage contaminationMethemoglobinemia 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.

Practice Questions: Water Pollution and Health

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Flashcards: Water Pollution and Health

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Which snakes have a neurotoxic venom?_____

Cobra and Krait (2)

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