What are the sources of lead in drinking water?
Lead in drinking water results primarily from corrosion of materials containing lead installed in building plumbing such as lead solder, brass, bronze and other alloys containing lead in contact with the water. The amount of lead attributable to corrosion by-products in the water depends on a number of factors, including the amount and age of lead bearing materials susceptible to corrosion, the way they were manufactured, how long the water is in contact with the lead containing surfaces, and how corrosive the water is toward these materials. The corrosivity of water is influenced by a number of factors, including acidity, alkalinity, dissolved solids and
hardness. In general, soft acidic waters are more corrosive to lead than hard waters.
Health Effects of Lead
Lead is a common, natural, and often useful metal found throughout the environment is lead-based paint, air, soil, household dust, food, certain types of pottery, porcelain, pewter and water. Lead can pose a significant risk to your health if too much of it enters
your body. Lead builds up in the body over many years and can cause damage to the brain, red blood cells, and kidneys. The greatest risk is to young children and pregnant women. Amounts of lead that won’t hurt adults can slow down normal mental and
physical development of growing bodies. In addition, a child at play often comes into contact with sources of lead contamination – like dirt and dust – that rarely affect an adult. It is important to wash children’s hands and toys often, and to try to make sure they only put food in their mouths.
Lead in Drinking Water
Lead in drinking water, although rarely the sole cause of lead poisoning, can significantly increase a person’s total lead exposure, particularly the exposure of infants who drink baby formulas and concentrated juices that are mixed with water. The EPA estimates
that drinking water can make up 20 percent or more of a person’s total exposure to lead.
Lead is unusual among drinking water contaminants in that it seldom occurs naturally in water supplies like rivers and lakes. Lead enters drinking water primarily as a result of the corrosion, or wearing away of materials containing lead in the water distribution system and household plumbing. These materials include lead-based solder used to join copper pipe, brass and chrome plated brass faucets, and in some cases, pipes made of lead that connect your house to the water main (service lines).
In 1986, Congress banned the use of lead solder containing greater than 0.2% lead and restricted the lead content of faucets, pipes; and other plumbing materials to 8.0%.
When water stands in lead pipes or plumbing systems containing lead for several hours or more, the lead may dissolve into your drinking water. This means the first water drawn from the tap in the morning or later in the afternoon after returning from work or school can contain fairly high levels of lead.
Steps You Can Take in the Home to Reduce Exposure to Lead in Drinking Water:
Despite our best efforts mentioned earlier to control water corrosivity and remove lead from the water supply, lead levels in some homes or buildings can be high. To find out whether you need to take action in your own home, have your drinking water tested to determine if it contains excessive concentrations of lead. Testing the water is essential because you cannot see, taste, or smell lead in drinking water. For more information on having your water tested, please call your health department or water department.
If a water test indicates that the drinking water drawn from a tap in your home contain lead above 15 ppb, then you should take the following precautions:
(A) Let the water run from the tap before using it for drinking or cooking anytime the water in a faucet has gone unused for more than six hours. The longer water resides in your home’s plumbing the more lead it may contain. Flushing the tap means running the cold water faucet until the water gets noticeably colder, usually about 15-30 seconds.
If your house has a lead service line to the water main, you may have to flush the water for a longer time, perhaps one minute before drinking. Although toilet flushing or showering flushes water through a portion of your home’s plumbing system, you still need to flush the water in each faucet before using it for drinking or cooking.
Flushing tap water is a simple and inexpensive measure you can take to protect your family’s health. It usually uses less than one or two gallons of water and costs less than .42 cents per month. To conserve water, fill a couple of bottles for drinking water after flushing the tap, and whenever possible use the first-flush water to wash the dishes or water the plants.
(B) Try not to cook with or drink water from the hot water tap. Hot water can dissolve more lead more quickly than cold water. If you need hot water, draw water from the cold tap and heat it on the stove.
(C) Remove loose lead solder and debris from the plumbing materials installed in newly constructed homes or homes in which the plumbing has recently been replaced by removing the faucet strainers from all taps and running the water for 3 to 5 minutes. thereafter, periodically remove the strainers arid flush out any debris that has accumulated over time.
(D) If your copper pipes are joined with lead solder that has been installed
illegally since it was banned in 1986, notify the plumber who did the work and request that he or she replace the lead solder with lead-free solder. Lead solder looks dull gray, and when scratched with a key looks shiny. In addition, notify your health department about the violation,
(E) Determine whether or not the service line that connects your home or
apartment to the water line is made of lead. The best way to determine if your service line is made of lead is by either hiring a licensed plumber, or a private home inspector or building inspector to inspect the line or by contacting the plumbing contractor who installed the line.
What are Nitrates & Nitrites?
Nitrates and nitrites are nitrogen-oxygen chemical units which combines with various organic and inorganic compounds. Once taken into the body, nitrates are converted into nitrites. The greatest use of nitrates is as a fertilizer. The MCLG for nitrates has been set at 10 parts per million (ppm), and for nitrites at 1 ppm, because EPA believes this level of protection would not cause any of the potential health problems described below.
Based on this MCLG, EPA has set an enforceable standard called a Maximum Contaminant Level (MCL). MCLs are set as close to the MCLGs as possible, considering the ability of public water systems to detect and remove contaminants using suitable treatment technologies.
The MCLG for nitrates has been set at 10 parts per million (ppm), and for nitrites at 1 ppm, because EPA believes this level of protection would not cause any of the potential health problems described below. These drinking water standards and the regulations for ensuring these standards are met are called National Primary Drinking Water Regulations. All public water supplies must abide by these regulations.
What are the health effects?
Short-term: Excessive levels of nitrate in drinking water have caused serious illness and sometimes death. The serious illness in infants is due to the conversion of nitrate to nitrite by the body, which can interfere with the oxygen-carrying capacity of the child’s blood. This can be an acute condition in which health deteriorates rapidly over a period of days. Symptoms include shortness of breath and blueness of the skin.
Long-term: Nitrates and nitrites have the potential to cause the following effects from a lifetime exposure at levels above the MCL: dieresis, increased starchy deposits and hemorrhaging of the spleen.
How much Nitrates/Nitrites are produced and released to the environment?
Most nitrogenous materials in natural waters tend to be converted to nitrate, so all sources of combined nitrogen, particularly organic nitrogen and ammonia, should be considered as potential nitrate sources. Primary sources of organic nitrates include human sewage and livestock manure, especially from feedlots.
The primary inorganic nitrates which may contaminate drinking water are potassium nitrate and ammonium nitrate both of which are widely used as fertilizers.
According to the Toxic’s Release Inventory, releases to water and land totaled over 112 million pounds from 1991 through 1993. The largest releases of inorganic nitrates occurred in Georgia and California.
What happens to Nitrates/Nitrites when they are released to the environment?
Since they are very soluble and do not bind to soils, nitrates have a high potential to migrate to ground water. Because they do not evaporate, nitrates/nitrites are likely to remain in water until consumed by plants or other organisms.
How will Nitrates/Nitrites be detected in and removed from my drinking water?
The regulation for nitrates/nitrites became effective in 1992. Between 1993 and 1995, EPA required your water supplier to collect water samples at least once a year and analyze tem to find out if nitrates/nitrites are present above 50 percent of their MCLs. If it is present above this level, the system must continue to monitor this contaminant every 3 months.
If contaminant levels are found to be consistently above their MCLs, your water supplier must take steps to reduce the amount of nitrates/nitrites so that they are consistently below that level.