Cronan McNamara (Creme)
30-04-2008, 12:33 PM
Pharmaceutical contaminants have been found in drinking water at levels which are of concern. Contaminants detected include antibiotics, anti-depressants and birth control drugs. Current water treatment practices do not always remove pharmaceutical residues and the high stability these molecules means they can accumulate in water supplies over time.
There is a large amount of information on the effects that exposure to these chemicals have on humans. The chronic exposure of children, pregnant women and healthy adults over long periods of time to these residues, albeit at low levels is a concern.
In this article we discuss how the long term risk can be assessed for different demographic groups using up-to-date data and methods.
http://www.cremesoftware.com/images2/water.jpg
To assess the exposure of the population to pharmaceutical contaminants in water information on the frequency of presence and concentration levels of the chemicals in the water must be obtained. These can be gathered by performing analytical lab analysis on water samples or from information in published literature. This data gives information on the presence probability of the pharmaceuticals and the concentration of the drugs in the water.
This chemical concentration information is combined with information on the intake of consumers of tap water along with information of the bio-availability of the drugs to consumers from drinking water.
This information is never known to 100% accuracy, so handling the uncertainty in these data inputs is important. For example, the bio-availability of the chemicals of concern may be somewhere between 60% and 80%. In Creme, the bio-availability factor can be inputted as a Uniform(0.6,0.8) distribution to specify this uncertainty. The impact or effect of this uncertainty on the result can then be assessed using sensitivity analysis.
The information on concentrations and bioavailability is then combined with consumer intakes of water from all sources. Information on the consumption habits of people is inputted from food consumption surveys such as the US NHANES, UK NDNS or Irish databases.
Clofibric acid which is the active metabolite of the drugs clofibrate, etofibrate, and etofyllin was found as a contaminant in groundwater at considerable concentrations of 70-7,300 ng per litre.
If these concentrations were to occur in drinking water, the exposure of consumers whose water contained this contaminant can be calculated using the above method. Again a Uniform(70,7300) distribution can be used to represent the concentration of the chemical in water.
Using Creme, we can run an analysis of the consumption levels of tap water for the US, UK and other regions using these databases assessing the intake levels per kg bodyweight for different demographic groups of the population.
Combining this analysis with information on concentrations of pharma contaminants in water products and bioavailability of the chemicals, and converting the results to long term exposures using the Nusser method we can now assess the risk of long term exposures of consumers to these chemicals.
If you would like to discuss this assessment or if you would like more information on how you can use Creme to get these types of results in your organisation, please contact us.
Further Reading:
Pharmaceutical Contaminants in Potable Water: Potential Concerns for Pregnant Women and Children (http://www.ingentaconnect.com/content/klu/10393/2007/00000004/00000002/00000105)
Identifying Future Drinking Water Contaminants (1999) (http://www.nap.edu/openbook.php?record_id=9595&page=114)
There is a large amount of information on the effects that exposure to these chemicals have on humans. The chronic exposure of children, pregnant women and healthy adults over long periods of time to these residues, albeit at low levels is a concern.
In this article we discuss how the long term risk can be assessed for different demographic groups using up-to-date data and methods.
http://www.cremesoftware.com/images2/water.jpg
To assess the exposure of the population to pharmaceutical contaminants in water information on the frequency of presence and concentration levels of the chemicals in the water must be obtained. These can be gathered by performing analytical lab analysis on water samples or from information in published literature. This data gives information on the presence probability of the pharmaceuticals and the concentration of the drugs in the water.
This chemical concentration information is combined with information on the intake of consumers of tap water along with information of the bio-availability of the drugs to consumers from drinking water.
This information is never known to 100% accuracy, so handling the uncertainty in these data inputs is important. For example, the bio-availability of the chemicals of concern may be somewhere between 60% and 80%. In Creme, the bio-availability factor can be inputted as a Uniform(0.6,0.8) distribution to specify this uncertainty. The impact or effect of this uncertainty on the result can then be assessed using sensitivity analysis.
The information on concentrations and bioavailability is then combined with consumer intakes of water from all sources. Information on the consumption habits of people is inputted from food consumption surveys such as the US NHANES, UK NDNS or Irish databases.
Clofibric acid which is the active metabolite of the drugs clofibrate, etofibrate, and etofyllin was found as a contaminant in groundwater at considerable concentrations of 70-7,300 ng per litre.
If these concentrations were to occur in drinking water, the exposure of consumers whose water contained this contaminant can be calculated using the above method. Again a Uniform(70,7300) distribution can be used to represent the concentration of the chemical in water.
Using Creme, we can run an analysis of the consumption levels of tap water for the US, UK and other regions using these databases assessing the intake levels per kg bodyweight for different demographic groups of the population.
Combining this analysis with information on concentrations of pharma contaminants in water products and bioavailability of the chemicals, and converting the results to long term exposures using the Nusser method we can now assess the risk of long term exposures of consumers to these chemicals.
If you would like to discuss this assessment or if you would like more information on how you can use Creme to get these types of results in your organisation, please contact us.
Further Reading:
Pharmaceutical Contaminants in Potable Water: Potential Concerns for Pregnant Women and Children (http://www.ingentaconnect.com/content/klu/10393/2007/00000004/00000002/00000105)
Identifying Future Drinking Water Contaminants (1999) (http://www.nap.edu/openbook.php?record_id=9595&page=114)