Wastewater-borne markers of neurodegenerative disease: β-methylamino-L-alanine and aminomethylphosphonic acid.

Exposure to toxic organic chemicals such as β-methylamino-L-alanine (BMAA) and glyphosate has been associated with neurodegenerative diseases (NDDs), including amyotrophic lateral sclerosis (ALS), Parkinson's Disease (PD), and Alzheimer's Disease (AD). We explored the utility of BMAA and glyphosate's metabolite aminomethylphosphonic acid (AMPA) for serving as potential markers of NDDs by comparing levels of wastewater-borne BMAA and AMPA with regional U.S. rates of NDD prevalence. Newly developed liquid chromatography tandem mass spectrometry (LC-MS/MS) methods were applied to U.S. wastewater samples (n = 87) and resultant concentrations of putative biomarkers were statistically compared to NDD prevalence rates in conjunction with environmental data on algal blooms and agricultural glyphosate use. Locations of algal blooms were found to be significantly associated (p = 0.01) with ALS prevalence rates per 100,000 people. BMAA levels in wastewater were highly correlated (p < 0.0001) with ALS prevalence rates by region. BMAA in wastewater typically peaked in summer months. We conclude that NDD biomarker detection in wastewater holds potential value, with BMAA outperforming AMPA. Furthermore, prevalence data for NDDs may have to be reported to the Centers for Disease Control and Prevention at a higher geospatial resolution to further enhance the value for the present type of analysis. Further method development is needed for AMPA to be quantified using LC-MS/MS. Future method developments focusing on metabolites (e.g., AMPA) may enable epidemiologists to determine human exposure levels rather than the mere occurrence of toxic organic chemicals in the environment.