Monday, Oct. 20, 1 p.m. ET

Science: Climate Change and Waterborne Disease

Kari Lydersen
Washington Post Staff Writer
Monday, October 20, 2008; 1:00 PM

Scientists say, it is a near-certainty that global warming will drive significant increases in waterborne diseases around the world, writes Washington Post staff writer Kari Lydersen.

Rainfalls will be heavier, triggering sewage overflows, contaminating drinking water and endangering beachgoers. Higher lake and ocean temperatures will cause bacteria, parasites and algal blooms to flourish. Warmer weather and heavier rains also will mean more mosquitoes, which can carry the West Nile virus, malaria and dengue fever. Fresh produce and shellfish are more likely to become contaminated.

Lydersen was online Monday, Oct. 20 at 1 p.m. ET to discuss this story.

Read more in today's story: Risk of Disease Rises with Water Temperature and look at this graphic to see how your state may be impacted.


South Riding, Va.: I wonder if scientists had started using the phrase like "Global Climate Change" instead of "Global Warming" to describe what they were seeing if more people would have accepted their theory. After all, it seems funny when they blame "Global Warming" on a cooler or wetter than normal summer.

Kari Lydersen: Scientists, policy makers and others have been widely using the term "climate change" for a good while now, since as you say the effects are more complicated than just warming...though the intense rainfall which will be responsible for much of the waterborne disease outbreaks is a direct effect of warming since warmer air holds more water which means more intense rainfall.


South Range Wisc.: Will population shifts, as some areas become less habitable, increase the vulnerability of some to pathogens they have never experienced before or to introduce pathogens to new territories?

Kari Lydersen: I think scientists do consider this a definite danger; you hear much about pathogens or carriers of pathogens moving into areas they weren't in before because of warming climates, and hence exposing people and animals who haven't previously built up immunity to these pathogens. What you describe would likely be a similar outcome as, if I understand your question right, people move into new areas where there are pathogens they do not have immunities to or experience with treating...


Munich, Germany: The West Nile virus has already gotten a foothold in North America. What would it take for malaria to become a problem in the U.S. if rainfall and temperature increase in the future?

Also, do you have any thoughts on Steven Mufson's article about falling oil prices reducing incentives to develop alternative (and cleaner) sources of energy? As Fuel Prices Fall, Will Push for Alternatives Lose Steam (By Steven Mufson, Oct. 20)

Kari Lydersen: Malaria won't necessarily become a problem in the US with warmer and wetter climates; since cities in Latin America and elsewhere with tropical climates have managed to control malaria through mosquito control and other measures. But the danger of malaria will make mosquito control more urgent and create more work (monitoring, administering, environmental impact assessments) for already overburdened local government agencies.

And of course mosquito control raises its own health and environmental concerns when chemicals are used.


Reston, Va.: Are there any plans in place in cities with "combined sewer systems" to separate them? Is it technologically feasible and/or financially possible?

Kari Lydersen: Many cities are in various stages of overhauling their combined sewer systems to "separate" them, including cities like Washington DC who have been sued by the EPA and hence are under a consent decree to upgrade their combined sewer systems. however it is a very expensive undertaking in most cases; in fact revamping combined sewer systems is one of the major costs in the $20 billion that Great Lakes advocates say is needed to rehabilitate and protect the Great Lakes from contamination; and that's just in the Great Lakes region, not to mention the Northeast and other parts of the country that have many combined sewer systems.


Albany, N.Y.: What technologies are researchers saying will be the answer to treating contaminated drinking water sources? Are public water suppliers equipped to begin such treatment? Understandably, the treatment will depend on the contaminants present in the raw water source, but is there a rule of thumb? Is industry (such as the American Water Works Association - AWWA) working on solutions? If so, what does the horizon look like? Any side effects to treatment (such as disinfection byproducts that can be created with organics in raw water and chlorination)?

Kari Lydersen: When everything works according to plan water suppliers are already equipped to deal with many of these pathogens, but the more frequent and intense the sewage overflows or other sources of contamination, the more likely and often things will go wrong...and as Epstein pointed out some pathogens like cryptosporidium can't be killed by chlorine or other usual treatment measures. There is already some concern about the health and environmental effects of chemicals used to treat water, so utilities would not want to increase their level of treatment across the board in anticipation of increased contamination; hence the key is constant monitoring to know when increased treatment is needed, and the ability to get those results and act immediately.

I was told new rapid result water testing technologies are being developed and are possibly the most important way of responding to the waterborne disease risk.


Bowie, Md.: What are the plans for converting the sewer/stormwater systems to modern technology? Are there any plans for Washington D.C., or New York?

Kari Lydersen: Many cities including Washington DC and I think New York are in the process of converting their sewer systems, but it is a very costly process, see previous answer...


Chicago, Ill.: Here in Chicago we get our drinking water out of Lake Michigan, which is vulnerable to many of the problems listed in your article. During heavy storms, of which we have seen record numbers this year, Chicago and surrounding cities discharge sewage overflow into the lake. Furthermore, "exurban" developments along the lake shore may rely on septic systems, and there is agricultural and industrial runoff as well.

How do the EPA and other government agencies currently regulate such pollution? What power do regulators have to fine, punish, or otherwise coerce municipalities or private landowners into compliance with existing standards? Do existing standards take into account the cumulative effect of multiple possible polluters in an area of high population density?

Kari Lydersen: Pollutants discharged into water are generally regulated under the Clean Water Act by the EPA; and the EPA has sued cities or otherwise worked with municipalities to address their sewer overflows and other sources of contamination.

Likewise for industries.

However agriculture isn't covered the same way under the Clean Water Act, so contamination from manure and fertilizer run-off is a huge issue which will become more critical with increased rainfall.

A National Research Council report outlines ways the EPA, it says, needs to change its policies to deal with increased rainfall and exurban sprawl. However this would mean changes to the Clean Water Act and Congressional action -- a long process -- according to EPA water administrator Ben Grumbles.


Bethesda, Md.: What are the main things citizens can do to bring water pollution to the political forefront?

Kari Lydersen: Probably letting local politicians know about their concern is one avenue. Chicago politicians have often expressed outrage at sewer overflows from Milwaukee which contaminate Chicago beaches...though Chicago has its own problems with sewer systems as well...

Fixing combined sewer systems takes a lot of money so building political will for allocating this money on various governmental levels would be one way citizens can get involved.


Washington, D.C.: My understanding is that parts of the Nile river basin and Sahel will actually see less rainfall (or maybe just more infrequent) as a result of climate change. Might this be a good thing for preventing waterborne diseases, even if it's a bad thing for food security?

Kari Lydersen: Interesting point, I suppose that's possible, though at the same time water shortages may in some ways increase problems with the areas you mention combined sewer systems and ag run-off are not the issues; basic infrastructure and social problems that prevent people from accessing clean water may if anything be exacerbated by water shortages...


Dallas, Texas: Your article reminds me of recent movies where we create some kind of disease by accident, that sends the U.S. into a danger zone. Do you foresee anything like this in our forecast?

Kari Lydersen: I don't see us "creating" a disease but there are plenty of pathogens already out there which will become more problematic with climate change. I don't think any of the waterborne diseases currently being discussed are massive hysteria type situations, but localized outbreaks of any of these diseases could have big impacts on local economies not to mention people's quality of life. And as seen in the past some level of fatalities would be expected.


Albany, N.Y.: Kari, thanks for the response to my previous question. As noted in your article, the recent National Research Council report concluded that the EPA's storm water program needs major overhauls to deal with increasing runoff, and EPA's Benjamin H. Grumbles said that upgrading combined sewer systems is among the agency's top priorities. What's the environment for this action to actually take place and is there hope that potential regulatory changes will keep pace with climate change impacts to water sources?

Kari Lydersen: It sounds like the awareness and political will are there; but while the EPA can essentially tell municipalities what to do it with their sewer systems it doesn't give them the money to do it. Hence especially with so many state and local governments hurting financially now, even with the best intentions the outlook seems kind of with all the other aspects of climate change, we were so slow out of the starting blocks that "keeping pace" may be a big challenge...


Detroit, Mich.: What is the EPA doing to protect Americans against these water borne diseases?

Kari Lydersen: The EPA regulates water contamination under the Clean Water Act...the Centers for Disease Control and Prevention (CDC) is also responsible for monitoring and preparing for these outbreaks...see previous answers as far as the EPA's efforts and abilities to demand sewer system overhauls...


Houston, Texas: Being from the Lone Star State, I am surprised to see in the chart so few outbreaks. I figured since we are next to the Gulf we would have a bigger problem

Kari Lydersen: My guess would be that most Texas cities have newer infrastructure and hence are less likely to have combined sewer systems, plus Texas I assume has fewer intense rainfall events than the northeast and Great Lakes regions. These two factors are the main causes of waterborne disease outbreaks...the Gulf of course has the massive dead zone from nutrient pollution but that wouldn't impact drinking water directly...I imagine Texas does have some issues with seafood contamination...


Seafood lover: So should consumers be prepared to take fresh shellfish out of our diets?

Kari Lydersen: As the menus usually say fresh shellfish presents a bit of a risk even now, that risk would likely increase with climate change, I guess the risk-benefit analysis is up to you! As far as the safety of shellfish, at least as far as climate-change-related pathogens are concerned, shellfish from colder northern waters would probably tend to be safer...

Like anything with climate change, we won't see a catastrophic huge change over night; it's not like people will be dropping left and right from eating shellfish, but if predictions hold true there will be a maybe not debilitating but steady increase in problems like contaminated shellfish...


Washington, D.C.: Looks like the Northeast has been hit pretty heavily with outbreaks of Waterborne diseases. Do you think this is related to the recent tummy aches over in Georgetown?

Kari Lydersen: You never know, in Georgetown - could be a lot of other reasons these days too!


Harrisburg, Pa.: A friend of mine died and the cause of death was contaminated water, here in Pennsylvania. Is there any data on how many deaths there are here in the US due to contaminated water?

Kari Lydersen: Sorry to hear that. Not sure about official national statistics, if anything the CDC would have them...

Kari Lydersen: though many waterborne disease impacts are indirect -- through contaminated produce or seafood for example...and people with already compromised immune systems would be most susceptible...So it would be hard to calculate comprehensive statistics on fatalities from waterborne disease.


Fairfax, Va.: I am wondering, are other parts of the world experience this problem with sewage?

Kari Lydersen: Many parts of the developing world of course have much more rudimentary sewage systems or lack sewage systems altogether...and increased rainfall would logically exacerbate existing sewage-related public health problems in these areas since more rainfall means more water and contaminants in motion.

I'm not aware of European cities having problems with combined sewer overflows but I'm not sure about that.


Rockville, Md.: How do you propose to save us from the next ice age?

Kari Lydersen: An additional answer to Munich re the prospect of interest in alternative fuels falling as gas prices fall -- I suppose that is a possibility, though I'm sure people are still uncertain about fuel prices and looking for alternatives in the long run. I would hope all the effects of climate change - including waterborne diseases -- will help people realize that there are critical reasons other than their pocketbook to work to mitigate climate change...


Washington, D.C.: I'm an undergraduate student at Georgetown University majoring in International Health/premed. I am currently writing a paper evaluating on the demographic effects of clean water in both the United States and developing countries, as well as the policy implications that are effecting climate change and water quality. I really appreciated that your article made the A section of the post, as this public health threat is much more eminent than most believe. I was wondering if knew anyone I could speak to regarding this topic in the health field. But also, I was wondering what your thoughts are on what countries that have the highest risk for water related illnesses? Having just witnessed a local water related epidemic at Georgetown of Norovirus, I think this issue is of great significance to the general public. Thank you and I look forward to hearing from you!

Kari Lydersen: Yes Noroviruses are among the viruses mentioned by scientists that can be transmitted through sewer overflows...different countries will be impacted in different ways (see previous answer); many other countries already have serious problems with waterborne disease because of the lack of solid sewer systems...


Kari Lydersen: As far as people to talk to, the Harvard Center for Health and the Global Environment, the University of Wisconsin, and the University of Michigan among others, seem to be taking the lead on this issue....


Albany, N.Y.: Thanks again, Kari. Another question: Would the EPA's consideration to update its Total Coliform Rule have anything to do with the fact that utilities may now more and more find indicator bacteria upon routine sampling?

Kari Lydersen: That would make sense...and given the intense rainfall/sewer overflow issues it makes sense the new rule increases frequency of testing...but if I understand right it doesn't have to take effect until 2015; there could be many disease outbreaks in that time frame that perhaps could have been curbed by quicker testing and response...


Manassas, Va.: So, if Bottled water isn't that much better than tap. AND, if bottled water gets leaching from Plastics. What's a person to do?

Drink Juices and sodas all the time?

Kari Lydersen: Good question...ideally people would use whatever power they have to demand that the quality of municipal tap water be protected by, among other things, addressing the sewer overflow risk. Some critics of bottled water point out that one of the pitfalls of everyone drinking bottled water is that we may become less demanding of clean tap water...


Encinitas, Ca.: Since Cryptosporidium is not inactivated by chlorine treatment, can its presence in drinking water be detected?

Kari Lydersen: Good question -- yes I think it can, but that goes back to the ongoing issue of how frequently testing is done and how rapidly the results are returned, and how well the local utility is prepared to notify the public of problems. I've been told that currently, it can take a significant amount of time for utilities to get test results and hence take action to prevent a disease outbreak. In cases like this, more frequent testing and the use of rapid results technology may be the most important thing.


Washington, D.C.: In one of my classes my professor said that more rainfall and clouds will lead us to another ice age, is there any merit in this statement?

Kari Lydersen: The risk of a "little ice age" linked to climate change has been discussed, though it is not as simple as being directly caused by more rainfall and clouds. Some scientists think another 'ice age' could be triggered by various effects of our greenhouse gas emissions...but this does not in any way negate the risk of global warming as some might is all the more reason to address climate change and reduce emissions...


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