Drinking water contaminants

Dec 22, 2010

Dr. Lynn Goldman, dean of the GWU School of Public Health and Health Services, will answer questions about the recent news of lead in D.C. drinking water and hexavalent chromium in certain cities.

OK, so there is nasty stuff in the water. Does this shorten the average DC resident's life by 5 years, a year, or 5 minutes? The answer matters a lot and nobody seems to be reporting on it.

I understand!  It would be nice to have this kind of information.  For the lead in drinking water, the levels probably aren't measurably shortening life spans but the there other concerns about effects on developing children -- especially intelligence and behavior -- that are important and the reason for trying to avoid exposure to lead.  For chromium 6, unfortunately at this point in time we don't know enough about the actual levels and the risks to answer your question. 

http://www.washingtonpost.com/wp-dyn/articles/A50459-2004May23.html In 2004 The Post reported on the new WASA water meters leaching lead. WASA is now offering .25 % or less lead meters instead of the 6 to 7 or more lead meters but not publicly telling customers of this option. WASA employees as recently as last month agreed the meters leach lead but argue it is a small amount. WASA (DC Water) as of January 1 now only offers the .25 % or less meters. Should WASA inform customers of this source of lead on the bill each month until all meters are changed out. In light of the fact that no amount of lead is good and that the EPA Maximum Contaminant Level goal for lead is zero why does WASA ignor this source of lead. In addition studies have come out indicating that the HFSA (Hydrofluorsilicic Acid) being added by the Washington Aqueduct not only cause lead, aluminum and other metals to leach out of pipes, fixtures, meters, etc. but that it has lead, arsenic and radionuclides in it.

Honestly I don't know anything about the meters that DC Water is using.   I know that the HFSA issue has been raised however when EPA has evaluated this issue they have not found that the HFSA has raised levels of toxic metals in water.

Why won't the Washington Water Dept consider stopping the use of chloramine, which is the cause of the lead problems? Beth Nord Palo Alto, CA

Good question!  They need to use a disinfectant that leaves a residue in the system.  Rather than stopping chloramine, or switching back to chorine, they have decided to add orthophosphate to the mix.  It is all very complicated but at the end of the day it appears that the orthophosphate "works" pretty well.  However, no matter what they do it also appears that the old lead service connections continue to leach some lead into household drinking water.

Dr Goldman: When I read the reports on the hazards of hexavalent chromium levels and the ratio of 100 parts per billion being too high, it sounds more like just sensationalizing news data. I have worked with hexavalent chrome for 39 years and am 60 yo, I have splashed in it,in my nose,mouth, eyes ears, work 7 days a week for those 39 yrs.,, Have never had 1 person say I am sick because they have been near chrome, not 1 person has contracted cancer or any form of cancer to this point in all of my years of employment there., my boss was in it for 20 yrs. before me,, he is 86 and still runs 3 miles a day, works out at a gym everyday and has time to come to work. You doctors and scientists that work with lab animals, need to get out and check with those of us that actually work everyday with this product and have NO ill effects after years of actual contact environment everyday and all feel healthy. thank you

Thanks for your comment!  My first experience with hexavalent chromium was in working in public health in California, when the state decided to issue an advisory for work related exposures.  What you describe is way too much exposure to chromium 6!  It won't make you immediately ill but it is classed as a human carcinogen.  This is on the basis of studies of workers showing excess cancer rates from chromium 6 exposures.   Not everyone will get cancer from any exposure to any known carcinogen.   You and your boss are healthy but I would recommend that you take reasonable steps to avoid exposure.

Was Chicago's Water system tested, and if so, what were the test results? Also, how can the hexavalent chromium be removed?

I don't know about the test results in Chicago.  First and foremost steps should be taken to try to clean up environmental contamination from hexavalent chromium that would contribute to ongoing exposure.  Once the hexavalent chromium is in the water it can be removed.

Is there a consumer test for hexavalent chromium?

There is not a consumer test on the market at this time.

Will the levels of hexavalent chromium in the water affect us through showering/toothbrushing or only by ingesting it?

In reality most water intake is through ingestion, including cooking and teeth brushing.  However you could have exposure through showering, as well.  EPA's assessments will take all of these into account. 

Can I safely drink tap water filtered by a Brita or something similar? If not, that means I have to buy bottled water. Does DC (and other affected cities) plan to supply safe drinking water to its citizens, or reimburse us for the cost of having to purchase water?

First and foremost we don't yet know that the water is unsafe! We have reports only from one study and we don't yet have a complete set of information about the actual levels, day to day, and over time.  Second we don't yet know if small household filters will remove the hexavalent chromium.  Today both DC Water and WSSC on their websites are stating that their water meets federal standards for total chromium (which is true) and that they are waiting for guidance from EPA before they decide to do anything further on hexavalent chromium. 

We have a one-and-a-half-year-old. Should we have her drink bottled water and then use baby fluoride toothpaste?

If you live in an area where you suspect there is lead, you might want to use an inexpensive water filtering device that removes most contaminants that might be in tap water.  (See the NSF international website:  www.nsf.org)  Also of course if you have any suspicion that there is lead in the environment or you live in an older home built before 1955 a lead test is a good idea.  DC recommends lead tests for all children at 12 and 24 months of age.

Is the proposed California hexavalent chromium standard of 0.06 parts per billion in drinking water a science-based standard?

Yes, the state of California did use a science-based process to develop their standard.  That being said there is still much more to learn about the potential health effects of hexavalent chromium and uncertainties about whether it has the same toxicity when taken by mouth (in drinking water) as when inhaled (in dust).  Most of the human studies are in workers who breathed dust.

With all the insistence of weight conscious folks that we drink at least 8 glasses of water a day, will all this water harm me? I routinely down at least 6 glasses a day and didn't want to have to go cold turkey dry.

I actually think it is a myth that it is necessary to drinking 8 glasses of water a day.  Most adults require about 2 pints of water a day but includes the water that is in drinks, in foods have been prepared and so forth.  You can drink too much water!  (There is such a thing as water toxicity.)  Moderation in all things is a good idea.

How can people out here in the country with well water find out if they have lead or hexavalent chromium in their water?

Actually at this point we don't really know what the levels of hexavalent chromium are, over time, in most drinking water supplies!  Certainly this report is raising the issue and I think it will cause the government to examine this issue more carefully.  However, they probably won't get around to sampling private wells!  You can go to an EPA certified lab and ask for analysis.  A list of such labs can be found at:  http://www.epa.gov/safewater/labs/index.html .  I have no idea what this would cost nor how many of these labs can perform this very specialized test.

I live in Norman Oklahoma and we're all very concerned... Can reverse osmosis remove hexavalent chromium from drinking water? What can the City of Norman do make sure our drinking water is potable?

The levels in Norman seemed to be higher than other areas however I would think that before the City considers adding new treatment processes it may want to first confirm that these high levels are persistent and find out if they are occurring throughout the City.  If they are confirmed then could be a good idea to find out if there is a source or if the hexavalent chromium is naturally occurring there, because removal of a source might be the best treatment.

My understanding is that the actual animal research only correlated with cancer when the animals were given water at a concentration of 57000 parts per billion for a two year period. So why is a radical group claiming a .06 ppb standard, and trying to start a panic over water not meeting that standard.

Good question!  Animal toxicology studies use very high doses on very small numbers of animals, by design.  Usually the results have been found to be predictive of human risk but sometimes they are not!  In this case we know that workers who inhale hexavalent chromium are at risk for lung cancer.  The studies of humans drinking hexavalent chromium have been more uncertain but seem to point to the possibility that drinking hexavalent chromium also isn't good for you.   Meanwhile it probably makes sense to avoid it when we can.

Do we know what the current levels of hexavalent Chromium in Bethesda water [0.19 parts per billion] would cause? Has there been studies that reflecct these levels?

First we aren't really sure that the levels in the report are the exact levels that occur in Bethesda water on a day to day basis, and over time.  In other words in my opiinion this report is very preliminary.  It points to a potential problem but this issue needs more careful evaluation before we can understand the health consequences. 

Is this a new problem in the water, or is it just that they are now able to test for this and other chemicals?

Good question!  Certainly the extent to which hexavalent chromium is in our water today, it probably has been there a long time.  We have been able to test it for a long time, but the routine testing for drinking water contaminants does not specifically identify hexavalent chromium.  Instead it quantifies total chromium,  to see if the water meets EPA standards for total chromium. 

The article that appeared a couple of days ago in the Post says that the DC Department of Health recommends first testing children for lead in blood between the ages of 6 and 14 months. By this time, however, many children have stopped drinking reconstituted infant formula (often mixed with tap water), or are drinking much less of it. Doesn't this mean that waiting to test around 12 months (which is what many pediatricians recommend) might miss potential health harm from exposure to lead at the tap during the first and highly vulnerable months of life? Do you consider the existing blood lead level guidelines adequate?

I think that a first lead test around 12 months makes sense even though, as you note, some exposure can occur prior to that. 

I think that existing blood lead guidelines are adequate and appropriate for clinical treatment.  However, there are demonstrable health effects at lower lead levels and those need to be considered in establishing standards.   One piece of good news is that just this month Congress lowered the allowable amount of lead in plumbing fixtures so that the entire country will now meet the "California standard". 

How does hexavalent chromium impact the health of children, and how do we remove it from the water?

The concern about hexavalent chromium is that it is known to cause cancer.  This has firmly been established in workers who breathe dust containing this substance.  On the basis of animal tests and weaker studies it is suspected that it also causes stomach cancer when taken by mouth (in drinking water).  The effects on children would theoretically be the same as adults but children may breathe more air and drink more water by body weight than adults. 

Doesn't EPA conduct a periodic science-based review of health risk based on health effects and data from its National Occurence Database as required by section 1412 of the Safe Drinking Water Act that was completed recently and determined that a drinking water standard was not necessary for chromium in order to rotect human health ?

EPA currently is conducting just such a review for hexavalent chromium.

Has any one ever done any studies to look at the summational effects of being exposed to multiple contaminants and whether that affects levels that are harmful? For example, if a person is exposed to 3 different contaminants that are all below their individual harmful levels, can that be just as bad as being exposed to to only a single one of them at a harmful level?

Theoretically this can happen but we have very little research on the impacts of multiple contaminants.

What exactly does it mean that New York City is the largest city without a water filtration plant? What potential dangerous exposures face drinking water in New York City and what is done to minimize risks?

The New York City water is from a very clean source that is far from the city and has not required filtration because of lack of impact by industrial and agricultural pollutants.  Hopefully it will continue to receive a clean bill of health as more work is done to understand what is going on with hexavalent chromium.

What are the dangers of fracking fluids possibly entering into the water systems?

"Fracking" is a new way of mining fuel from oil shales.  Obviously society is doing all it can to find more sources of energy.. I don't think that we know very much yet about the effects of fracking fluids. 

As a physical chemist by training, I'm very concerned about the lack of scientifically supported facts relating to the findings cited by the Environmental Working Group. I simply don't know what to believe. Among other things, is the California standard reasonable in terms of health? How good is detection capability at such low concentrations? Does hexavalent chromium immediately change its valence when exposed to stomach acid? (I remember freshmen experiments with both chromium and molybdenum where colors of these metals in solution changed in response to pH changes). I have to also wonder if releasing information on two different days was intended to get the Environmental Working Group more publicity and possibly additional donations. Another organization recently took a similar tack putting out a press release about money being contaminated with BPA. After downloading their original report, my reading was that the problem was with thermally printed receipts. The low concentrations of BPA on money were not significant when compared to the possible contamination from the receipts themselves. This much more significant danger (to cashiers) wasn't mentioned in press releases but was in the actual report, if one dug hard enough. Generalizing, I believe there are two very significant problems. First, newspapers have no staff trained to analyze press releases of this nature. If they tap the academic community, its would be difficult in time to get a well thought out response in time for a deadline. Also, can the reporter be reasonably sure the academic they are calling has no personal agenda with the topic? I have no constructive suggestions as to how an unbiased "stable" of scientific talent can be readily available for a reporter's call. The second problem is correctable. The articles printed must be exceptionally cautionary regarding issues of this type until there has been a reasonable level of validation. In the case of the BPA on receipts, its possible there is a very significant risk to cashiers, but that got lost completely in the hype over very small amounts of BPA on money. If thermal receipts need to be replaced for the benefit of cashiers health, it won't happen because of press releases like that one. In the case of hexavalent chromium, we don't know risks at various concentrations, nor do we know that it remains in a hexavalent state for more than a moment after entering the stomach. Resources are finite. Do we want water departments reducing efforts at perhaps minimizing lead because of public demand for expensive technologies to deal with hexavalent chromium unless we are very sure about the hazard level? I don't. This is the second danger. If we know something is clearly hazardous then it's appropriate to ignite public opinion to facilitate getting the resources required to deal with it. But the cost of crying fire when one is unsure one is even smelling smoke is immense. Public receptivity to alarms will diminish quickly. Sorry for being so lengthy but I'm becoming very concerned about issues such as these and our inability to know the magnitude of the possible risks.

This is a long question!  I can't address all of it in this time but the California standard is indeed "health based".  At the same time there are many scientific questions around chromium 6 that need to be addressed.  We do not yet have the kinds of national studies -- and data -- to know what the what the levels actually are nationally.   We also don't know if one sample gives an accurate snapshot of chromium 6 levels over time.  So it isn't easy to interpret the Environmental Working Group findings.  However they are raising a serious issue that does need to be addressed with drinking water surveys.  Also today the EPA has stated that they will evaluate the science with respect to developing a possible drinking water standard for chromium 6.  That assessment should address many of the questions you are asking!

Is there any increased safety by filtering tap water ( Montgomery county) in using a filter on a pitcher (for example, a Brita pitcher)?

Generally filtering pitchers do remove many undesirable contaminants.  Check the NSF International website for object testing information (see above). 

What are the health risks of drinking water purified through reverse osmosis, and bottled in PET plastic? Are the lack of fluoridation and minerals a problem?

You are making a good point.  Water treated with reverse osmosis will not contain fluoride.  For young children you can use fluoride drops.  Consult your child's health care provider about this.

I live in DC in a house built in the 1920s and I am concerned about the recent reports about lead and other contaminants in the drinking water. Since apparently the city is unable to fix this problem is there something I can buy to filter the water in my home. The brita filters don't list lead as one of the contaminants it filters out. I have a young child and we could be trying to have another soon.

You also can work with DC Water to address  whether your home has a lead service connection.  They have a lead service hotline at (202) 787-2732.

Dr Goldman - If I have confirmed with DC Water that the supply lines to my home are NOT lead (they are copper), do I need to worry about lead in the water that comes from the main DC supply?

No, you should not. 

In This Chat
Dr. Lynn Goldman
Dean of the George Washington University School of Public Health and Health Services
Recent Chats
  • Next: