Maui Water Quality, a Comparative Study for Lahaina and Kihei
Our previous published scientific paper is available online: The influence of wastewater discharge on water quality in Hawai’i: A comparative study for Lahaina and Kihei, Maui by Mailea Miller-Pierce and Neil A. Rhoads. A companion website provides a community resource with a summary of the findings written for a non-scientific audience. The website provides background and supplementary information in addition to interactive access to the data, photos, an interactive map, and easy access to the appendices and all references.
Hawaiian coastal waters testing for non-point source sewage contamination
Our recently published scientific paper is available online: Clostridium perfringens testing improves the reliability of detecting non-point source sewage contamination in Hawaiian coastal waters compared to using Enterococci alone
Abstract: Non-point sources of sewage-related pollution in tropical marine waters are difficult to ascertain. Enterococci(ENT) are widely used as indicators of human waste but their efficacy in tropical waters is highly debated due to natural presence in tropical soils. Clostridium perfringens(CP) is often used as a secondary indicator of fecal contamination because its presence indicates sewage, and in tropical waters environmental sources are unlikely. We analyzed a 27-year dataset containing over 29,000 samples collected by the State of Hawaii, to determine a proposed CP standard for detecting human sewage, which has applicability throughout tropical marine waters globally. Measured ENT concentrations were highly correlated with turbidity. In three instances, sewage contamination was not detected by ENT samples alone, and impairments from non-point pollution may be highly misinformed in Hawaii. The EPA should examine relationships between CP and human health and implement CP as the primary FIB in tropical marine waters.
Microbial indicators of marine recreational water quality in Maui, Hawai`i: Assessing waterbody impairment in relation to known pollution sources
In a proposed paper: The Hawai`i Department of Health uses the fecal indicator bacteria (FIB) enterococcus (ENT) to evaluate recreational water quality and risks to human health. ENT can originate from non-human sources requiring the informal use of Clostridium perfringens (CP) as a secondary microbial indicator; however, no official state standards exist for CP. The distribution of values from ~16,000 ENT samples collected between 1989-2016, were used to establish a new and corresponding set of standards for ~14,000 CP samples. At 73 coastal sites on Maui, FIB concentrations were compared to water quality standards to investigate whether exceedances were more frequent near wastewater reclamation facilities (WWRF) and on-site disposal systems (OSDS, i.e. cesspools and septic systems). Sites of concern were identified based on FIB impairment and degradation of water quality over time; at many sites, concentrations have steadily increased over the last 27 years. Significant bivariate relationships between FIB occurred at 62% of sites.
Maui Water Quality, a Comparative Study of Two Five-year Periods
In a proposed paper, we plan to use similar techniques as in our paper above to provide a summary of ALL available data for ALL Maui sites and for extended time periods. In particular we will compare two 5-year time periods 1993-1997 and 2011-2015, looking for trends and considering possible influencing factors. Look for it later this spring.