New technologies for protecting public health at beaches and resolving pollution problems
Southern California is notorious for its chronically polluted water bodies, from the affluent areas of Malibu to the more industrial city of Long Beach. California Assembly Bill 411 requires that city and county health departments regularly monitor impaired water bodies for fecal indicator bacteria (FIB) and that they notify the public of water quality problems.
Inherent flaws with current monitoring schemes, however, undermine the protective intent of such mandates. County officials are only required to sample once a day; moreover, the sample turnaround time is 24 to 96 hours. This delay translates to notifications that may not reflect the actual quality of the water, potentially putting swimmers at-risk or causing unnecessary beach closures.
These ongoing concerns have led to the development of new, rapid technologies that may be more effective at protecting public health at beaches and at resolving pollution problems. In our lab, supervised by Professor Jenny Jay, we are devising a detection method that is both rapid (conducted in < 30 minutes) and field portable. In this technique, antibodies designed to bind to a specific target bacteria, such as E. coli, are sorbed to magnetic particles, enabling the use of a magnetic field to pull targets out of solution and provide separation from other species. Cells are then lysed and treated with enzymes that catalyze a reaction in which ATP [Christine – define ATP] is consumed and light is emitted as a by-product. Ultimately, we can use the intensity of this light emission to determine cell count and microbial water quality.
We have built upon previous work that developed and evaluated this method for use in freshwater by improving on the binding mechanism of IMS/ATP [Christine, explain this too!]. With these improvements, IMS/ATP can also be applied to marine environments and for additional organisms such as E. faecalis and a human-specific marker for pollution, E. bacteroides. We will also be able to use this tool to triangulate on the location of fecal contamination hotspots, enabling the identification and effective characterization of specific inputs of pollution.
Our work includes other important applications – such as quantifying bacterial contamination in water quality sources. This application will be explored in late summer 2009 in Dar es Salaam, Tanzania where water quality is an especially pressing issue. This project is an with Stanford research group in an effort to promote simple water treatments, hygiene behavior, and improved health conditions.