Straight pipes and household wastewater discharges into the rural Alabama and impact on watershed water quality with wetland land-uses

In rural areas, untreated wastewater discharged from homes (commonly called “straight pipes”) can cause harmful effects on the region’s rivers, streams and lead to negative impacts on water quality and potentially ecological and human health. Determining and addressing the water quality and health of these aquatic ecosystems requires identification of the source of contamination. Surface water quality in Hale County was evaluated at least once a month at twenty sites in wet and dry seasons. Samples were analyzed for physical (turbidity), chemical (pH, conductivity, chloride, sulfate, calcium, iron, magnesium, potassium, sodium, ammonium, ortho-phosphorus, nitrite, nitrate, dissolved organic carbon, optical indices), and microbiological (E. coli) water quality parameters. Excitation-emission matrixes (EEMs) Parallel Factor Analysis (PARAFAC) was used to identify and classify fluorescence emitting organic substances based on fluorescence peak location. Three fluorescence components, terrestrial humic-like, microbial humic-like, and protein-like fluorophores were identified using the EEM-PARAFAC model. Principal component analysis (PCA) was used to identify analyte signatures associated with sewage contamination. The PCA (varimax rotation) identified three primary components (Eigenvalue >1), accounting for 40.4%, 19.0% and 8.7% of total variance respectively. In order to detect straight pipe wastewater impacts on water quality, three main sites were sampled upstream, midstream and downstream of the town of Newbern, Alabama over the three months of the drought period (i.e., from September to November 28th, 2016). Over 20 water quality parameters were analyzed and compared with the WHO, EPA, and ADEM standards. The results showed that E. coli values highly exceed water quality standards, particularly after the drought when peak E. coli concentrations downstream exceeded 100,000 per 100 mL. This study also investigated the impacts of wetland land use on stream water quality response at eight main sites. The results showed that potassium (R square 0.78), C3 (R square 0.58) and optical brighteners (R square 0.53) correlated positively with percent wetland in the draining watersheds. This study is one of the first to document the adverse impacts of straight pipe discharges on water quality in the United States.