Water Resources Research Act Program

Details for Project ID 2016HI463B

Microbial communities and sources of bacteria in Honolulu’s water supply

Institute: Hawaii
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $18,869 Total Non-Federal Funds: $39,980

Principal Investigators: Marek Kirs

Abstract: Groundwater constitutes the largest freshwater biome, yet is the least explored habitat on Earth. Groundwater systems provide essential ecosystem services by storing and providing water and geothermal energy as well as by balancing hydrological extremes, providing active biodegradation of anthropogenic contaminants, and nutrient recycling. While critical for human existence, groundwater is vulnerable to various chemical and microbiological contaminants such as pesticides, petroleum hydrocarbons, human pathogens and others. This is of highest concern on islands where freshwater supply is limited and already partially compromised by saltwater intrusion due to ever increasing demand. Therefore island communities are most vulnerable to any change (i.e. climate, biological or chemical sabotage, fuel spill, etc.) which can alter water quality and limit the supply. Currently we are unable to identify impacts to nor recovery of the compromised systems based on microbiological data, as no information on ambient microbial communities in our drinking water supply exist. The overarching goal of the project is to characterize microbial communities and sources of microbes in Honolulu’s water supply. This is the first in depth analysis of microbes in our water supply which combines cultivation based and molecular approaches and sets following objectives: 1) identification microbial community structure in our drinking water system, 2) identifications of wells which are under direct surface water influence, and 3) risk identification; we will determine whether the source of microbial indicators in compromised groundwater wells or water distribution system is from soil or human sewage. The project is expected to last for two years, with the first year focusing on analyses of water samples collected from source waters (spring and tunnel water) and from the distribution system at sites selected by the Board of Water Supply (BWS). At the end of the first year we will evaluate the approach (i.e. ultrafiltration vs. grab sample) and select study areas (hot spots) for more focused and intensive sampling. Priority will be given to sites that address the most urgent needs of the BWS (e.g. Navy’s fuel spill site in Aiea and others). Water samples will be analyzed for HPC, total coliforms, E. coli, enterococci, C. perfringens, F+ specific coliphages by cultivation based techniques, while concentrations of sewage specific markers (human-associated Bacteroides and human polyomaviruses) will be determined by qPCR. Microbial community composition will be determined using high-throughput sequencing. The project will enhance assessment of water resources and related management decisions in Hawaii which will increase the reliability of our water supply. The project will establish baseline data to evaluate long-term change in water supply (e.g. climate change related, slow leak of contaminants, salinization, etc.) and increase disaster readiness as impact and recovery of the drinking water system can be studied when the water supply has been compromised (e.g. sewage, biological, or other contamination). The project will also enhance water resource management and improve our understanding of sources and dynamics of microbial contaminants in our drinking water supply. The project will also strengthen partnership between the WRRC and Honolulu BWS. Although this project is focused on Oahu, the problems faced and targeted by this proposal are applicable to wider region of the Pacific and beyond.