Water Technology - Jan 2012

FEATURE The search for water contamination can create hazards of its own Here is a tested solution for dealers looking to minimize risk 18 Water Technology January 2012 solvent attracts the contaminants The mixture is then allowed to settle with the solvent and contaminants separating from the water and sinking to the bottom of a funnel where they are removed from the sample This is repeated two more times each time using 60 mls of new solvent In the end the solvent evaporates into the atmosphere leaving the contaminants behind for further analytical measurement CLLE operates on a similar principle but uses larger volumes of water and 500 ml of solvent plus the mechanisms are more complex SPE process for testing contaminants By contrast a newer method called solid phase extraction SPE uses significantly lesser amounts of solvent 50 90 percent less and incorporates a filtration process with absorbent disks Its a process that begins with placing these disks in the device which then delivers the necessary solvents to condition each SPE disk Next the water to be tested is passed through Its a paradox Most of the very technologies being used today to test water for contaminants actually return more pollution to the environment than the tested water itself Nevertheless as we all know water testing is crucial to our health Modern industry has unleashed tens of thousands of chemicals into the environment Many of these chemicals are essential but its the control of them thats the issue Without these chemicals we would not enjoy many products that we now take for granted such as computers smart phones plastic baby bottles and disposable diapers Just about every product the consumer can buy or touch depends on these chemicals and processes Emerging threats Bisphenol BPA for example is used by manufacturers to make polycarbonate plastics used in items such as baby bottles and beverage containers The problem is that over time BPA can leach from these containers especially if theyve been reused a lot This and other widely used chemicals have been blamed for causing early puberty in girls as young as seven or eight and a host of other social and medical problems Pharmaceuticals are now a major problem around the world Many common antidepressants are now found in lakes and oceans not enough to affect big fish but enough to affect smaller fish They get there through human urine being flushed down into the sewer system and people wrongly disposing their pills in the toilet as well The biggest problem of all is PCBs polychlorinated biphenyls They once were used to manufacture electrical equipment such as capacitors In fact from 1947 1977 a capacitor plant on the Hudson River poured 13 million pounds of PCBs into the waterway PCBs are long lasting and persistent in the environment They have been shown to cause changes in human DNA and are considered to be potent carcinogens The Environmental Protection Agency EPA reports strong indicators that PCBs cause cancer and that they have also been associated with many other negative health effects such as changes to the immune system reproductive system nervous system and endocrine system in humans Clearly water testing is critical but how good is it if it returns more pollution to the environment The traditional methods of LLE and CLLE Traditional methods used to test for contaminates in water were two processes called liquid liquid extraction LLE and continuous liquid liquid extraction CLLE LLE has been the standard for the last 30 years In brief LLE testers take two liters of a water sample and then blend them with 60 milliliters of solvent Shake well shaken not stirred In the process the added By Marc Hamel For more information on this topic go to www watertechonline com and enter keyword s LLE CLLE SPE PCBs water testing