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109. Health effects of microbiological and chemical water pollutants, water quality testing
- Natural ingredients of water
- Iodine, fluoride, calcium, magnesium, sodium, etc.
- The calcium and magnesium content of water determines its hardness
- Hardness should be around 5 – 35 degrees
- High sodium intake increases risk for hypertension
- Fluoride in water
- Protects against dental caries
- Too high level gives dental fluorosis, fragile bones
- Level should be 0,7 – 1,2 mg/L
- Fluoridation of drinking water may be necessary to reach optimal level
- Chemical water pollutants
- Toxins from algae
- Pesticides (mercury or chloroorganic)
- Minamata disease – due to organic mercury
- Causes neurological symptoms
- Fertilizers (nitrate)
- Nitrate toxicity can lead to methaemoglobinaemia / blue baby syndrome
- Especially in infants and those with methaemoglobin reductase deficiency
- Nitrate inhibits iodide uptake -> endemic goiter
- Prevention: addition of methylene blue to the water
- Arsenic
- Oil
- PAHs
- Detergents
- Microbiological water pollutants
- Bacterial
- Campylobacter jejuni, campylobacter coli
- Pathogenic e. coli
- Salmonella typhi
- Shigella spp, yersinia enterocolitica
- Pseudomonas aeruginosa
- Legionella pneumophila
- Viruses
- Adenovirus
- Enterovirus
- Hepatitis A
- Norovirus
- Rotavirus
- Protozoa
- Entamoeba histolytica
- Giardia lamblia
- Worms
- Water-born outbreaks
- Legionella is the major cause of water-born outbreaks
- Criteria
- Many cases at the same time in one distribution area
- Pathogens detectable in water or biological sample
- No new cases after closing the distribution system
- No new cases after disinfection
- Water quality testing
- Dissolved oxygen
- pH
- Nitrates
- Total dissolved solids
- Hardness
- Faecal coliform bacteria
- These are not pathogens, but they indicate the presence of other pathogens
- They are so-called indicator organisms
- Phosphorous
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