What do I need to know about water?
- China’s water sources are amongst the most polluted in the world. A World Bank study found that 13 of the 15 major cities (including Shanghai) along the 7 main water source rivers in China are affected by severely polluted water.
- The most common pollutants in Shanghai drinking water are high levels of chlorine, bacteria, and lead and toxic heavy metals. Shanghai’s water authorities have publicly acknowledged that tap water potability is compromised largely by secondary contamination from old piping. The heavy use of chlorine is necessary for disinfection, but is also unhealthy and can create carcinogenic byproducts
- Most Shanghai residents buy bottled drinking water but do not filter their showers. However, studies by the EPA and the Univ of Pittsburgh have shown that people absorb more toxic byproducts of chlorine through skin absorbtion or inhalation than through ingestion
- There are at least many different water purification technologies – what is right for you depends on the type of contaminant you want to remove, your desired water use, and your budget
What’s in the water?
About 80% of the water we get in Shanghai is from the Huangpu River. The remaining 20% comes from the Yangtze River. Unfortunately, both are among the most polluted rivers in the world.
- A weekly report released by the Environmental Monitoring of China agency on Aug 17, 2010 revealed that just two of the 18 monitoring stations along the Yangtze River graded the water quality as good.
- According to Shanghai’s environmental protection bureau, the upstream area of the Huangpu River should be rated at class II, but is at class IV (suitable for industrial use only)
- The total volume of sewage discharged into the Yangtze river reached nearly 30 billion tons, including at least 9 billion tons of domestic sewage in 2005, according to an annual report by the Yangtze River Water Resources Commission.
On a bright note, there is a project underway to source water from the Qingcaosha Reservoir, near Chongming Island, but as of now, the project is not yet complete.
There are a number of potential pollutants and contaminants that may be present in local tap water:
- General sediment and rust
- Bacterial and viruses (Giardia and Cryptosporidium)
- Chlorine and chlorine byproducts like Trihalomethanes (THM)
- Nitrites and nitrates (pesticides, herbicides, etc.)
- Heavy metals (Lead, Mercury, Aluminum, Cadmium, Chromium, Copper)
Source: “How To Filter Your Drinking Water Very Efficiently,” Metaefficient.com. 2/18/08
What’s unusual about the water in China?
Due to the high levels of bacteria caused by improper dumping of sewage and other biological contamination, Chinese departments of water works simply use more chlorine. In turn, Chlorine present in the water will undergo a variety of reactions with organic matter. Some of those reactions will lead to the formation of undesirable by products, some of which have been proven by epidemiological studies to increase the risk of cancer. A Chinese Academy of Sciences study done in conjunction with the University of Hamburg found contamination in the tap water supplied to the southern section of Shanghai and warned, “Caution about the possibility of elevated cancer risks in the population that consumes heavily chlorinated water should be kept in mind.”
In addition, even if tap water is safe to drink when it leaves the treatment facilities, it picks up secondary contamination from the pipes on the way to your faucet. 20 percent of the water pipes in Shanghai were built before 1968. The Shanghai water administration has cited this as the primary reason that water is still not safe to drink from the tap. Contaminants include: rust and heavy metals, among these, lead being the most hazardous. If at home, your water runs yellow or brown when first used in the morning, the water is likely being contaminated by corrosion.
As recently as May 2010, a Chongming company was fined for dumping its sewage directly into a municipal pipeline, sickening 300 residents
Will the water make me sick?
Chlorine, the same disinfectant which eliminates biological and microbial threats, unfortunately, also is not good for the human body. The American Journal of Public Health links chlorine to “significant increases in certain types of cancer, asthma and skin irritations…” and determined that “up to two-thirds of the harmful exposure was due to skin absorption and inhalation of chlorine in shower water”. Inhalation of chlorine and chemical vapors is a suspected cause of asthma and bronchitis. When chemicals are inhaled into our lungs they enter directly into our bloodstream and can have magnified effects compared with ingested chemicals that are partially filtered by digestion. A recent study showed that over one-fourth of the United States Olympic swim team members suffer from some degree of asthma due to prolonged chlorine inhalation. Chlorine also strips natural protective oils from hair and skin, causing excess drying and premature aging.
When combined with organic matter, chlorine can undergo a process called mutagenicity, where chlorine-based products are formed such as trihalomethanes (THMs) and haloacetic acids. These byproducts are actually worse than chlorine and are known carcinogens.
Lead is very poisonous to human beings, even in tiny amounts measured in millionths of grams (micrograms). Lead poisoning leads to elevated blood pressure, kidney dysfunction, anemia, and colon cancer in adults. The greatest danger is to young children under the age of six and fetuses. Lead poisoning at trace amounts has been conclusively linked to irreversible neurological damage, retardation of cognitive and physical development, and even violent behavior in children. For more on the health impact on lead, click here. The US EPA has estimated that 10-20 percent of lead exposure comes through drinking water
Nitrates enters water through fertilizer and other organic runoff, and interferes with the blood’s ability to carry oxygen. At very high levels, it can be fatal to infants under six months because at that age their stomachs are not acidic enough to prevent the chemical reaction that changes nitrates to nitrites. Symptoms include shortness of breath and blue-baby syndrome.
Bacteria and microorganisms, though largely reduced during the water treatment process, can reappear either through secondary contamination from biofilm in the piping, or through parasitic cysts or virii that are so small they pass through municipal filtration systems. They can cause gastrointestinal illness (e.g. diarrhea, vomiting, cramps) which can be fatal for individuals with compromised immune systems.
Why do I need to test my water?
- Lack of available information about tap water quality. Many foreigners are used to having easy access to public water test results, so they know what contaminants tend to affect their local source. In China, this information is closely guarded (we have gotten test information through personal sources but no “official” documentation).
- The water at your tap may be different than what leaves the treatment plant. Secondary contamination from old piping, reservoir tanks, pollution into pipelines, bacteria from biofilm, and chemical reactions along the way explain why water quality degrades by the time it arrives at your faucet.
- You need to validate your purification source. If you already use bottled water or a purification technology you should verify that it actually is doing what it claims to do. Common reasons that “purified” water may not be is due to dirty filters, misleading advertising claims, inadequate technology, or unclean water due to low regulatory oversight (bottled water). Testing is the only way to know the quality of your water in your home.
Why not just buy bottled water?
An unofficial poll of residents in Shanghai shows that the overwhelming response to bad water is to purchase bottled water. This is one response and for many people, it is the easy and safe option. However, surprisingly, tap water is sometimes actually safer and is a more regulated industry than than bottled water!
In late 2008, Master Kong, a Taiwanese multinational brand, was forced to apologize that its popular bottled mineral water, advertised in China as coming from “high quality water sources,” was actually just regular urban tap water. Even in the United States, the National Resources Defence Council (NRDC) published a landmark study in 1999 that revealed that one-third of the 103 brands tested contained levels of contamination — including synthetic organic chemicals, bacteria, and arsenic — in at least one sample that exceeded allowable limits under either state or bottled water industry standards.
If families choose to stick with bottled water for drinking, most overlook that they are still inhaling, ingesting, or absorbing contaminated water through water with which they are cooking, washing food, or showering. Most people don’t realize that tap water typically contains at or above the level of chlorine recommended for swimming pools, 1 to 1.5 ppm. A warm shower opens up the pores of the skin and allows a high rate of absorption of chlorine and other chemicals. The steam we inhale while showering can also contain up to 20 times the concentration of chlorine and other synthetic chemicals as tap water. While over 98% of the water coming from the showerhead goes down the drain, 70% to 90% of the chemicals in the water vaporize before the water hits the shower floor. Researchers at Rutgers University found that during a 10-minute shower, we take in the same levels of chloroform (a toxic byproduct of chlorine) as we get from drinking 2 liters of tap water. Attaching a filter with granulated activated carbon (GAC) to your shower is an inexpensive way to protect yourself.
Filters can also offer significant savings in money and hassle. An average 5 gallon (19L) jug of water costs about 25rmb, which works out to be 5rmb/G or about 1.3rmb/L. An appropriate water filtration system can provide safe, pure drinking water for you and your family at a fraction of the cost – less than 1rmb/G or .25rmb/L!
How do I remediate for clean water?
No single purification system will solve everything. There are three basic questions you must answer before selecting a purification system:
- What contaminants do I need to remove?
- What am I using the water for?
- What is my budget and what is the cost per gallon/liter?
|Boiled water||Kills bacteria (non-cysts) and reduces chlorine||Tap water in Shanghai is generally already sterilized; flat-tasting; actually concentrates chemical and metal contaminants as “healthy” water boils off|
|Bottled (barrel) water||Generally safe when from a reputable source; good taste||Expensive; bad for environment; doesn’t address chlorine absorbtion from showering; can grow bacteria if not rotated in 3-4 days; bottled water is not well regulated|
|Sediment filters||Inexpensive way to physically trap particles and grit, including parasitic cysts. To remove cryptosporidium and Giardia spores, look for “absolute” filter size of 1 micron or smaller||Does not remove chemical contaminants|
|Activated carbon filters||Fairly inexpensive; processes most physical contaminants out; removes hardness and chlorine without stripping beneficial minerals; EPA approved. Also removes pesticides, pharma drugs, and improves taste||Quality ranges widely – cheaper filters may not remove all pollutants; nitrates not removed. Carbon by itself also does not remove heavy metals|
|Kinetic degradation fluxion (KDF)||Copper-zinc granular media that chemically converts chlorine into harmless chloride. Good for shower filters or areas with high chlorine (particularly in China!) Also removes heavy metals and kills microorganisms||Does not remove VOCs|
|Silver impregnation||Anti-bacterial coating prevents formation of biofilm from water that stays in a carbon filter (ie. If you do not run water through the filter for period of time)||Prevents contamination of filter media and is not a purification method by itself|
|Ultraviolet (UV) radiation||Kills microorganisms through irradiation. Extremely useful for untreated water or areas with high bacteria||Difficult to know whether it is working without laboratory analysis – do not use as only source of treatment and look for units with time counters for UV bulb replacement; expensive|
|Distillation||Produces pure water from recondensed steam; removes heavy metals and kills any organisms||Will not remove VOCs; not very practical due to slow production rate (2-5 hrs/gal) and high electricity costs|
|Ionization (“Cation exchange”)||Makes water alkaline (acidic body is said to be associated with cancer & illness); softens water; some like the taste||Ionization process removes no contaminants besides calcium and magnesium; expensive; research on ionization benefits is incomplete and controversial|
|Reverse osmosis (RO)||Provides the purest water; one of only ways to remove nitrates||Up to 80% of water is wasted in purification process; “pure” also means beneficial minerals have been stripped, so requires remineralization; high acidity|
|Whole house systems||Treats all water coming into the house; highest level of safety||Expensive initial and installation cost; overkill for most residents not on well water|
You should first know the facts about your own water and then carefully consider your needs to pick the combination of solutions that works for you. While a whole-house filter offers the most protection, it is probably overkill for those on a budget. We have found that an ideal and cost-efficient solution for most urban dwellers in Chinese cities is to pair a multi-stage kitchen sink filter with inline shower filters. Regardless of filter system, one of the most important rules to remember is that you change your filter regularly as suggested by the manufacturer. A dirty filter can actually harm you as it releases built-up pollutants that can leach back into the water once it is oversaturated.
As with any remediation, it is important to follow-up with independent testing following corrective work to ensure that the problem has been resolved. We can work with you to recommend a strategy to fit your circumstances and recommend a certified purification solution that fits your budget and comfort level.
 Interview with Chen Guogang, Senior Engineer (Shanghai Water Supply Administration) on ICS. http://www.icshanghai.com/html/2010/08/02/2856.html
 Andelman, Julian, 1986. Univ of Pittsburgh Graduate School of Public Health (inhalation); H.S. Brown, Ph.D.; D.R. Bishop, MPH, and C.A. Rowan, MSPH (skin penetration)
 Interview with Mr Gu Jin Shan, Vice President of Shanghai Chengtou Corporation, parent company of the Qingcaosha Project. “Shanghai Tap Water,” Urbanatomy.com 2/5/09
“The mutagenic potentials of tap water samples in Shanghai,” Chemosphere, Shen, Wu, Lin, Westendorf. 9/03
 “Improving Shanghai’s Drinking Quality,” ICS.
 “Shanghai: Pipes carrying dirty tap water to be switched,” Shanghai Daily. 5/19/10
 Liu, W.; Wu, H.; Wang, Z.; Ong, S.L.; Hu, J.Y.; Ng, W.J. “Investigation of assimilable organic carbon (AOC) and bacterial regrowth in drinking water distribution system.” Water Res. 2002, 36, 891–898.
 “Master Kong apologizes for misleading advertisement,” Danwei.org. 9/4/08
 “Summary Findings of NRDC’s 1999 Bottled Water Report,” http://www.nrdc.org/water/drinking/nbw.asp
 Rutgers study