| NSF Org: |
CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems |
| Recipient: |
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| Initial Amendment Date: | June 29, 2017 |
| Latest Amendment Date: | July 10, 2019 |
| Award Number: | 1705206 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Mamadou Diallo
CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems ENG Directorate for Engineering |
| Start Date: | July 1, 2017 |
| End Date: | June 30, 2021 (Estimated) |
| Total Intended Award Amount: | $190,000.00 |
| Total Awarded Amount to Date: | $190,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
1600 HAMPTON ST COLUMBIA SC US 29208-3403 (803)777-7093 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
SC US 29208-0001 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
EnvE-Environmental Engineering, GOALI-Grnt Opp Acad Lia wIndus |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.041 |
ABSTRACT
Collaborative Proposal
PIs: Susan D. Richardson/Michael Plewa
Proposal Number: 1705206/1706862
The majority of citizens in the US consume disinfected water. Chemical disinfectants inactivate pathogens in drinking water; however, an unintended consequence is their reaction with natural organic matter (NOM), anthropogenic contaminants, and bromide/iodide to form disinfection by-products (DBPs). For our drinking water supplies, a wide range of pristine and impacted waters are used, where high levels of certain emerging DBPs of concern have been reported. As a result, DBPs represent a ubiquitous chronic chemical exposure, yet the forcing agents for toxicity remain unknown. This research will address this knowledge gap, serve as the basis for a future wider International DBP study, and create a new paradigm for drinking water regulation to enhance drinking water safety and sustainability. The PIs will employ the on-going academic programs at their universities to provide research experiences for undergraduate and high school students, in particular students from underrepresented groups.
An international group of leading scientists participating at the 2015 Gordon Research Conference on Drinking Water Disinfection By-Products met to address these issues and recommended an International DBP study to (1) evaluate DBP levels globally, focusing on key emerging DBPs and surrogate parameters: total organic chlorine (TOCl), total organic bromine (TOBr), total organic iodine (TOI), and (2) determine which subsets of DBPs are the forcing agents of toxicity. The PIs seek to accomplish these goals in an initial assessment in the US. Results from this research will generate data to better understand DBP risks, determine the forcing agents of toxicity, and enable long-term engineering solutions to enhance drinking water safety and sustainability. This research will identify the drivers of in vitro toxicity as a metric of potential human health risk for DBPs in drinking water from the United States and will serve as the basis for a future International DBP study that will globally assess DBP risks. While it is widely recognized that individual bromine- and iodine-containing DBPs are more toxic than their chlorine-containing analogues, the correlation of TOCl, TOBr, and TOI with a wide range of individual DBPs has not been evaluated. These chemical surrogates are recognized as holding great potential (especially TOBr and TOI) for accounting for risk, both from known DBPs (including the 65 priority DBPs to be quantified in this study) and the unknown DBPs, where >50% of the total organic halogen (TOX) content has yet to be identified. The Environmental Protection Agency (EPA) has expressed interest in the potential to use these kinds of surrogates for regulation if they adequately represent the adverse health risk from halogenated DBPs. Thus, this research also has the potential to modify regulations as we know them today and better protect human health and enable global, safe, and sustainable drinking water.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Water disinfection is widely hailed as the greatest public health achievement of the 20th Century. By killing harmful bacteria and viruses, disinfection has significantly reduced waterborne diseases in drinking water. Globally, billions of people have access to quality drinking water from their public water systems. However, chemical disinfection has also raised an important public health issue due to the formation of disinfection byproducts (DBPs) that are linked to adverse health effects, including bladder cancer, miscarriage, and birth defects. It is currently not known which DBPs are responsible for these effects. DBPs are very different from other environmental contaminants, in that they are not already present in water sources (from industrial or other contamination), but are formed during drinking water treatment by the reaction of the disinfectant with organic matter and salts that are present naturally in waters. As a result, they are an unintended consequence of trying to make the water safe to drink. Common disinfectants in the U.S. include chlorine, chloramine, chlorine dioxide, and ozone. DBPs form from each of these disinfectants and are generally present at 100-1000× higher concentrations than other environmental contaminants of concern. In the U.S., 11 DBPs are currently regulated in drinking water. However, most scientists believe the critical DBPs driving the toxicity in disinfected waters are not adequately identified, regulated, or controlled.
This study reveals key DBP toxicity drivers in drinking water across the United States. We report the most comprehensive investigation of drinking water risk to-date, with measurements of drinking water toxicity, 70 regulated and priority unregulated DBPs, and total organic chlorine, bromine, and iodine, revealing a more complete picture of toxicity drivers. A variety of impacted waters were investigated, including those impacted by wastewater, agriculture, and seawater. Results revealed that unregulated haloacetonitriles, particularly dihaloacetonitriles, are important toxicity drivers. In seawater-impacted water treated with chloramine, toxicity was driven by iodinated DBPs, particularly iodoacetic acids. In chlorinated waters, combined total organic chlorine and total organic bromine were highly and significantly correlated with toxicity; in chloraminated waters, total organic iodine was highly and significantly correlated with toxicity. Overall, these results suggest that haloacetonitriles and iodoacetic acids should be considered for regulation. These results have important implications for public health. We also found that advanced water treatment strategies, particularly granular activated carbon (similar to the material used in a Brita filter), can effectively limit DBP formation and resulting toxicity in wastewater- and seawater-impacted drinking waters by removing DBP precursors and other contaminants.
Last Modified: 09/28/2021
Modified by: Susan D Richardson
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