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 Contamination | Possible Contaminants |
|---|---|
| Water pipes | Asbestos, lead, rust |
| Sewage treatment plants – inadequately treated sewage discharges – leaky sewage collection systems – overflows during rain storms | Patogens |
| Manufacturing Industries – chemical waste/discharges – food processing waste | – Sulfur dioxide, volatile organic compounds (VOCs) – Ammonia |
| Agricultural field | Pesticides |
| 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
| Contaminants | Potential Health Effects |
|---|---|
| Arsenic | Skin, nervous system toxicity, cancer |
| Asbestos | Cancer |
| Patogens | Gastrointestinal disorders (water borne diseases) |
| Chlorine | Chlorination by-products (Trihalomethanes) |
| Chlorination by-products (Trihalomethanes) | Cancer |
| Dibromochloropropane | Cancer |
| Ethylene Dibromide | Cancer |
| Fluoride | Skeletal and dental fluorosis |
| Heptachlor Epoxide | Cancer |
| Lead | Kidneys, nervous system damage |
| Lindane | Liver, kidney, nerve,immune, circulatory |
| Herbicide 2,4-D, 2,4,5-TP | Liver and kidney damage |
| Mercury | Kidney, nervous system disorders |
| Methoxychlor | Growth, liver, kidney, nerve effects |
| o-dichlorobenzene | Liver, kidney, blood cell damage |
| Nitrate & Nitrite | Methemoglobulinemia (blue baby syndrome) |
| PCB | Cancer |
| Radium | Bone cancer |
| Radon | Cancer |
| Selenium | Liver damage |
| Styrene | Liver nervous system damage |
| Toxaphene | Cancer |
| Trichloroethylene (TCE) | Cancer |
| Xylenes | Liver, kidney, nervous system |
Source : www.nsf.org