WERF Research Helps Cincinnati Use Innovative Biomarkers To Assess & Monitor Water Quality In National Scenic River
By Ting Lu1*, Vikram Kapoor2, Biju George3, MaryLynn Lodor3, James Parrott3, Deborah Metz4, and David Wendell2*
- Black & Veatch, Cincinnati OH
- University of Cincinnati, Cincinnati OH
- Metropolitan Sewer District of Greater Cincinnati (MSDGC), Cincinnati OH
- Greater Cincinnati Water Works
*1Corresponding authors. Mailing address: 1600 Gest Street, Cincinnati, OH 45204. Phone: (513) 244-5137. Fax: (513) 557-7175. E-mail: Ting.Lu@cincinnati-oh.gov
2Mailing address: 2901 Woodside Dr., 705 Engineering Research Center, Cincinnati, OH 45221
E-mail: wendeldw@uc.edu
In 1986, ambient water quality criteria recommendations from the USEPA were developed for recreational waters using E. coli as an indicator organism. With the benefit of advances in environmental microbiology, molecular tools and quantitative microbial risk assessment (QMRA), USEPA has released the recreational water quality criteria (RWQC) recommendations that reflect the risk to human health from fecal contamination. WERF’s Waterborne Pathogens and Human Health Research Program has provided significant information on understanding the novel tools such as quantitative polymerase chain reaction (qPCR), QMRA and microbial source tracking methods in a variety of regions including Chicago, Hawaii, and Santa Barbara. The outcomes of this research have provided better understanding of the available tools and helped decision-making for utilities to develop water quality improvement programs. In fact, one of the significant findings of the WERF Pathogens research is that molecular methods are site-, source-, and event-specific.
The Metropolitan Sewer District of Greater Cincinnati (MSDGC) operates and maintains a collection system of more than 4828 km (3000 mi) of pipe covering an area of more than 1036 km2 (400 mi2). About 40% of the system was developed as combined sewers. Wet weather flows cause about 53.4 million m3 (14.1 billion gal) of combined wastewater to overflow into local waters each year. MSDGC has begun work on a $3.25 billion combined sewer overflow reduction plan, known as Project Groundwork to improve water quality.
Within these overflows, fecal microorganisms are a major source of surface water pollution. In fact, water quality evaluations from between 1999 and 2004 for Hamilton County — one area served by MSD — show that fecal bacteria are the major pollutant of concern during both dry and wet weather. The fecal sources detected may have mixed origins, including human and animal waste, stormwater runoff, urban runoff, CSO, sanitary sewer overflows (SSO), non-point source contamination, malfunctioning private systems, or upstream boundary flow.
To help solve this problem, MSDGC, in conjunction with the University of Cincinnati, is conducting a watershed-scale biomonitoring assessment project that includes multiple biomarkers to identify the fecal origin in Duck Creek Watershed. Duck Creek was chosen as a study watershed because it has various pollutants leading to the Little Miami River. It also has the largest combined sewer area in Cincinnati area, making up approximately 70% of the total acreage. A recent macroinvertebrate monitoring study in Duck Creek Watershed in 2010 showed that macroinvertebrate species diversity among the monitoring locations are very low, and are predominated by pollution tolerant organisms due to 1) habitat modification, specifically channelization, 2) point source pollution, and 3) non-point source pollution.
The most commonly used bacterial indicators for fecal matter are E. coli and Enterococcus sp.; however, these bacteria can survive and grow in environmental reservoirs making them unreliable for waste source tracking. To overcome this limitation we sought to identify and quantify potential sources of fecal bacteria using a collection of more recent fecal molecular indicators, including human mitochondrial DNA, pathogenic strains of E.coli (O157:H7), and universal, human, bovine, and canine associated bacteroides. These targets were used to identify pollution from CSO, watershed runoff and other sources in Little Miami tributaries.
Although experiment data showed heavy pollutions from E. coli analysis, pathogenic E. coli O157:H7 was not detected in any of the sites tested. It suggests that pathogenic fecal coliforms may not be the most appropriate method for microbial risk assessment, rather, other pathogens such as Norovirus are a better indication for pathogen marker. On the microbial source tracking work, the outcome provided great information on the sources of origin so that utilities can prioritize the engineering work to cost-effectively address water quality issues. As utilities are faced with spending millions of dollars, this study illustrates that solutions to water quality problems cannot be solved in a vacuum – there are issues of land use and associated runoff characteristics that can be assessed through the advancement of better science and technology. Microbial source tracking is very useful to identify the major pollution contributors to the impairment of Little Miami River and further guide the development of CSO strategies for the actual field work and the subsequent data analysis for a baseline bioassessment. It also provides a platform to collaborate between different government agencies and other non-point sources. As demonstrated here, integrating a multidisciplinary and integrated approach is essential to support developing a cost-effective watershed management plan to address existing and emerging contamination issues and improve water quality.
The monitoring results presented here provide helpful information on the predominant bacteriological pollution to watershed and aid in decision-making to assist in the prioritization of engineering projects to improve water quality. In the long term, it fulfills multiple watershed management purposes, and facilitates a multisource, multiagency and regional strategy to lead to assist improving surface waters and their ability to attain their designated uses.
Reference
Ashbolt et al. (2010), Predicting pathogen risks to aid beach management: The real value of quantitative microbial risk assessment (QMRA) Wat Res 44:4692-4703
Stantec (2010), Biological and Water Quality Study of the Little Miami River and Selected Tributaries Hamilton County, Ohio OEPA NPDES Permit No. 1PX00022*BD
Recreational Water Quality Criteria, OFFICE OF WATER 820-F-12-058, USEPA, 2012,
http://water.epa.gov/scitech/swguidance/standards/criteria/health/recreation/upload/RWQC2012.pdf
http://www.cdc.gov/norovirus/about/overview.html