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Investigating the Lead Content of Drinking Water
Transcript of Investigating the Lead Content of Drinking Water
Jung Kim, Eun. "Effect of pH on the concentrations of lead and trace contaminants in drinking water: A combined batch, pipe loop and sentinel home study." UWO. 10 Jan. 2012. University of Western. 7 Dec. 2012 <http://www.eng.uwo.ca/people/jherrera/journal1.pdf>.
"Lead in Drinking Water." Lead in Drinking Water. Mar. 2011. Water Quality and Waste Management. 15 Dec. 2012 <http://www.bae.ncsu.edu/programs/extension/publicat/wqwm/he395.html>.
Lee, Michelle. "What is pH?" Water Quality, Drinking water, Corrosion and Water pH. 2012. 14 Dec. 2012 <http://www.water-research.net/Watershed/pH.htm>.
Muecker, Cristin. "The Health Canada Maximum Acceptable Concentration (MAC) for lead in drinking water." Central New Brunswick Academy. July 2012. CNBA. 10 Dec. 2012 <http://cnba.nbed.nb.ca/news/health-canada-maximum-acceptable-concentration-mac-lead-drinking-water>.
Stewart, John. "Drinking Water PH Levels." LIVESTRONG.COM. 4 Feb. 2011. Livestrong. 15 Dec. 2012 <http://www.livestrong.com/article/104683-drinking-water-ph-levels/>.
"Water Pollution." Government of Canada, Environment Canada. 2 Jan. 2012. Environmental Canada. 10 Dec. 2012 <http://www.ec.gc.ca/eau-water/default.asp?lang=En>. What is Lead, How Does it Get into our Water, and What Does pH have to do with It? For a prolonged period of time, (often six hours), lead can dissolve into drinking water that is left standing in household piping made from lead. The most common cause is corrosion, a reaction between the water and the lead pipes or solder. Dissolved oxygen within, a low pH (acidity) and a low mineral content in water (distilled properties) are common causes of corrosion. All kinds of water can have high levels of lead, and that is why pH is a common indication of this. The Health Canada Maximum Acceptable Concentration (MAC) for lead in drinking water is 10 micrograms per litre of water (0.01 mg/L) . This guideline is designed to be protective for chronic, long term exposures – drinking water at or below this level over a lifetime Acidic and basic are two extremes that describe a chemical property chemicals.
A ph below 7, or pOH above 7 indicates a solution that is acidic. Solutions that are acidic often have properties such as being sour, corrosive to metals and skin, turns blue litmus paper red, contains hydrogen (H+ ions), and reacts with bases to form water and a salt.
A pH above 7 or having a pOH below 7 indicates a solution that is basic. Solutions that are basic often have properties such as being bitter, slippery/soapy, turns red litmus paper blue, contains hydroxide (OH- ions), and has the ability to react with acids to form water and a salt.
A pH equal to 7 indicates a solution that is distilled water! Distilled water obtains the properties of having no dissolved ions, colourless, no odour or taste, and is essentially the definition of purity! Introduction
to pH Lead is a toxic metal that was used for many years in products found in and around homes. Back in the past, when lead was distinguished as safe, it was used to make water piping in houses. Older homes (that were constructed before the late 1950's) often contain lead water service lines. It was discovered that lead was very toxic, so the construction of homes included a new metal to be made for the water piping. Even at low levels, lead may cause a range of health effects including behavioral problems and learning disabilities. Children six years old and under are most at risk because this is when the brain is developing. The primary source of lead exposure for most children is in drinking water. So how does this lead get into our tap water? Usually lead gets into your water after the water leaves the local treatment plant or if you have a well. Homes constructed prior to the mid to late 1980's may have their plumbing connected with lead base solder. Therefore, the source of lead in your home's water is most likely from pipes or solder in your very own home's plumbing system. MAC of Lead What factors can Affect the pH of Drinking Water? The government of Canada then states the following: “Raising the pH remains the most effective method for reducing lead corrosion and minimizing lead levels in drinking water.” What should We do to Change this? What Can You Do to Reduce the Risk of Exposure to Lead? Always use cold, fresh water for drinking, cooking, making baby formula and preparing beverages.
Do not drink water that has been standing in your household water pipes for more than six hours. To rid your plumbing system of standing water, let the water run for approximately one minute or until it feels cold to the touch. You can also use the flushed water for other purposes such as plant watering or household cleaning.
Flushing the toilet and washing your hands, or taking a shower is more than sufficient to flush standing water from your pipes each morning.
Do not use ceramic cookware from foreign countries to heat water or store food unless you're sure that they are lead-free!
Do not store beverages in any sort of lead crystal containers.
If your job requires you to work around lead, shower and change clothing and shoes at work, and wash work clothes separately from the rest of your laundry.
Exterior paints SHOULD BE USED OUTDOORS, since they may contain lead. Natural Variation of pH throughout Canada? The Ontario Ministry of Health suggests that the pH level of drinking water should be exist between 6.5 (slightly acidic) and 8.5 (slightly basic). This range suggests that water is safe to drink and that any small amount of pollutants within the water is still safe and drinkable. As stated by the Ministry, all levels of pH in Canada are monitored and vary slightly within the acceptable range depending on the locartion of the surface and where the water is retrieved. In addition, Canada had earned a “B” grade on water quality in the past year and ranks 6th out of 17 countries. Investigating Homes with Lead Containing Pipes Further Some Other Factors - Due to the uprise of global warming, CO2 emissions have been promient in our atmosphere. - The following graph exemplifies the relationship between increased CO2 emissions and pH level of water.
CO2 content increases ----> the lower the pH
CO2 content decreases ---> the higher the pH
- In addition, the pH is affected by the amount of plant growth and organic material within a body of water. When these materials decomposes carbon dioxide is released. The carbon dioxide combines with water to form carbonic acid. Although this is a weak acid, large amounts of it will lower the pH. CO2 Concentration (due to emissions and underwater ecosystems) H2O(l) + CO2(g) ---> H2CO3(aq) Temperature If increased ---> lower pH
If decreased ---> higher pH
- This is scientifically proven as when pure distilled water is raised in temperature by 25 Celsius, the pH had decreased to 0.45. Of course, this would only be effective depending on its atmosphere. Water ionizes further as temperature rises, so hydrogen ion concentration rises, that means that pH decreases. BUT water remains neutral as the number of hydroxyl ions remain equal to the hydrogen ions Dissolved Minerals in water (Bedrock) - Dissolved minerals in water usually contaminated water when coming into contact. For instance, in areas that depend on groundwater, the result is from the limestone bedrock, so the pH is higher in water. Some rock types such as granite, have virtually no effect on pH. Pollution/ Waste Water Contamination - This can raise the pH due to the presence of chemical detergents and cleaning agents that are improperly disposed of.
- The pH of a body of water is affected by the dumping of chemicals into the water by individuals, industries, and communities.
- Many industrial processes require water of exact pH readings and thus add chemicals to change the pH to meet their needs. After use, this altered pH water is discharged either directly into a body of water or through the local sewage treatment plant. Natural Occurrences (Acid Rain/Glacier Water) - Areas affected by acid rain will have a lower pH
- Acid rain is caused by sulfur dioxide (SO2) in the air combining with water vapor. These pollutants are primarily from automobile and coal-fired power plant emissions. Acid rain is responsible for many of our first order streams becoming acidic.
- Glacier water has a general lower pH in comparison to ground water Municipalities Artificial Change in pH - Many municipal processing plants artificially increase the pH of water to prevent acid corrosion of pipes. We will be examining this point further. Water in Northern Canada - It is assumed that water located near glaciers is subjected to a higher pH in comparison to areas with use of groundwater. As it raises the pH, the alkalinity of the water is more prominent. Water Supply Downtown Area - In the hustle and bustle of polluted downtown areas, the pH of nearby water sources will typically have a higher pH (due to air pollutants). This can also be affected by the prominence of acid rain due to fossil fuel emmisions. Water for Suburban Areas that are Far From Sources of Water Small towns or suburban areas that are offset from the large source of water typically use groundwater. As mentioned in the previous section, groundwater, that is a result from the limestone bedrock, typically has a higher pH water. As mentioned in the introduction, majority of the homes that were built before the 1950’s often contain lead plumbing. The lead piping has a high possibility of releasing lead into the water due to corrosion, thus causing lead contaminated water. The amount of lead dissolved in water is dependent on how corrosive the water is. The more acidic the water, the more corrosive the water. The more corrosive the water, the more lead that corrodes and dissolves into the water. -The pH (acidity or alkalinity) of the water affects how easily lead dissolves from pipes, solder, or fixtures into the water. Corrosive water can dissolve lead from the supply pipes, faucets, or solder and flux used to connect copper pipes. Pb (s) + 2H3O+ --> Pb 2+ (aq) + H2 (g) + 2H2O (l) In this following section, we will be examining lead in water in refernce to Le Chatelier’s principle. Le Chatelier’s principle states that if a chemical system at equilibrium experiences a change in concentration, temperature, volume, or partial pressure, then the equilibrium shifts to counteract the imposed change and a new equilibrium is established until settled back to the original. The reaction above shows that lowering the pH will shift the reaction to the right, as it becomes more acidic, making an excess of H3O+, and aqueous Pb will form. - Alkalinity, a higher pH will decrease the amount of (H3O+), therefore shifting the equilibrium reaction to the left, in the reverse direction.
-If the concentration of the reactant (lead) is also increased, then it will shift equilibrium to the right and make more products.
- Increased amount of reactants- soft water (fewer dissolved minerals) tend to increase corrosively, increasing acidity shifting to the products.
- copper fixings (ex. faucets) can be corroded by water.
- Most older homes use lead solder to seal the joints of copper pipes. Lead solder is 50% lead, which adds a lot more lead into the water, speeding up and increasing the amount dissolved.
- Brass fixtures can contain up to 8% lead and are also a significant source os lead in drinking water
- Heated pipes will increase the temperature of water. Since a temperature increase results in a more acidic pH, more lead will be dissolved into the water. - Therefore, if you were to raise the pH to a higher concentration such as 7.5 and 9.5 it would be an effective method to reduce and lower the amount of dissolving lead in water. Chemistry analysis Increasing the pH of drinking water is a slightly effective way to reduce the amount of lead that will dissolve in water caused from corrosive water (acidic), but not in the long run. In further detail, the pH of the water would be chemically increased by municipality water plants, making the water slightly basic, thus reducing the amount of lead that will eventually dissolve into the water. Less lead will be corroded into the water, therefore a reduced amount of lead. If this were to be done for a long period of time, the equilibrium will be shifted and the reaction will occur in reverse. As long as the pH remains within 7.5 - 8.5 safe range. However, if there is already an excessive amount of lead present in the water, this will not help very much. You must use over methods to reduce the concentration of lead. Some Effective Methods Household water filters are available at major retailers, that are claimed to be effective in removing the amount of lead ions that are present in the water. Another way of reducing lead concentration is to run the tap, causing it to remove the water that was sitting in the pipes for a prolonged period of time. Importance of Water to Our System Effects of Lead on us and the Environment Effects of Altering pH on Us and the Environment Consuming excessively acidic or alkaline water is varingly effective. Drinking water must have a pH value of 6.5-8.5 to fall within EPA standards. If it is not within the acceptable pH range, slightly high or low-pH water can be unappealing for several reasons. High-pH water has a slippery feel, tastes a bit like baking soda, and may leave deposits on fixtures.
In addition, our bodies have the natural ability to neutralize and moderate the pH in our systems, as we consume foods n a daily basis with varying pH's. As the measures taken are only varying the pH a little bit, the effects on us are unheard of, and the change in lead content is beneficial. A varying pH is wanted for soil as it uses it to gather varying nutrients that it would be unable to attain.
Lead is a toxic metal that is present in water, and if not controlled, can have many disastrous effects on human health and the environment. Controlling and maintaining that safe concentration of lead (known as the MAC) is a recommended safety precaution. Human Health Effects Environmental Effects Intake of a high concentration of lead can cause:
- A rise in blood pressure
- Kidney damage
- Miscarriages and subtle abortions
- Disruption of nervous systems
- Brain damage
- Declined fertility of men through sperm damage
- Diminished learning abilities of children
- Behavioral disruptions of children, such as aggression, impulsive behavior and hyperactivity High lead concentrations that breach the MAC can cause:
- the following health risks stated above to animals
- accumulates in the bodies of water organisms and soil organisms. These will experience health effects from lead poisoning.
- Body functions of phytoplankton can be disturbed when lead interferes. Phytoplankton is an important source of oxygen production in seas and many larger sea-animals eat it.
- Soil organisms than suffer from lead poisoning, affecting crop production.
- accumulate in individual organisms, affecting the entire food chains.