By looking at the source of water contamination, I believe you agree with me that the water quality today is not the same as 20 – 30 years ago.

How safe it is, is depends on the types of contaminants and how much the level is present in our drinking water. However, not all contaminants are harmful and fatal. It may just dirty drinking water.

Generally, the types of harmful contaminants are:

  • natural occuring contaminants such as arsenic, selenium, fluoride, boron and uranium
  • man-made contaminants such as chlorine by-products, pesticides (insecticides & herbicides), nitrate and lead
  • patogen such as Escherichia coli, Cryptosporidium, Salmonella typhimurium, Vibrio cholerae, Vibrio comma, and Giardia lamblia.

Table 1. Examples of Water Pollution Source and Its Possible Contaminants

Source of Water ContaminationPossible Contaminants
Water pipesAsbestos, lead, rust
Sewage treatment plants
– inadequately treated sewage discharges
– leaky sewage collection systems
– overflows during rain storms
Manufacturing Industries
– chemical waste/discharges
– food processing waste
– Sulfur dioxide, volatile organic compounds (VOCs)
– Ammonia
Agricultural fieldPesticides
Surface runoff (storm-water)
– motor vehicles
– construction sites
– logging activities
– heavy metals, petroleum hydrocarbons
– sediments
– sediments

Table 2. Partial Listing of Contaminants and Its Potential Health Effects

ContaminantsPotential Health Effects
ArsenicSkin, nervous system toxicity, cancer
PatogensGastrointestinal disorders (water borne diseases)
ChlorineChlorination by-products (Trihalomethanes)
Chlorination by-products (Trihalomethanes)Cancer
Ethylene DibromideCancer
FluorideSkeletal and dental fluorosis
Heptachlor EpoxideCancer
LeadKidneys, nervous system damage
LindaneLiver, kidney, nerve,immune, circulatory
Herbicide 2,4-D, 2,4,5-TPLiver and kidney damage
MercuryKidney, nervous system disorders
MethoxychlorGrowth, liver, kidney, nerve effects
o-dichlorobenzeneLiver, kidney, blood cell damage
Nitrate & NitriteMethemoglobulinemia (blue baby syndrome)
RadiumBone cancer
SeleniumLiver damage
StyreneLiver nervous system damage
Trichloroethylene (TCE)Cancer
XylenesLiver, kidney, nervous system

Source :