Water Wonk Wednesdays
Weekly water news, tips, and innovations.
by Erik Baard
Sometimes just looking at the water is enough to send you running back inland; witness the Gowanus Canal turdnami above. Snow melt from our recent storm could less dramatically force raw feces releases into our estuary through combined sewer overflows. The National Institute of Environmental Health Sciences warns that global climate change will likely increase the risk of waterborne diseases. The Inuit, who invented kayaking, are already suffering.
Dangerously contaminated waters don’t usually reveal themselves to our eyes, or even noses. Most commonly used detection and measurement methods are slow and require careful laboratory work. Imagine if you could instead scan coastal waters from orbit aboard the starship Enterprise? Already on it, as this paper describes. Or perhaps point a “Star Trek” tricorder at a water body to measure its pathogens. That prospect might too be approaching, but expect bumps and high costs along the way.
The Dutch company BlueLeg Monitor has developed handheld, installed, and backpack devices to detect pigments and other suspended particulates instantly. The company also processes satellite images. The main markets are public agencies and large businesses that need fast, reliable data to close beaches or protect water resources and aquaculture. Small nonprofits like HarborLAB couldn’t afford the installed EcoWatch, for example, at 40,000 Euros ($42,930). Veritide, based in New Zealand, adds first responders and meat packers to the market list.
Researchers Mohammad Haji Gholizadeh, Assefa M. Melesse, and Lakshmi Reddi of Florida State University provide “A Comprehensive Review on Water Quality Parameters Estimation Using Remote Sensing Techniques.” They conclude that while aerial and satellite sensing of water contamination is reliable and less expensive than the in situ sampling now prevalent, “Improvement of the methodology to interpret images from simple linear regression to multivariate statistical analysis approaches like principle components analysis (PCA) and neural networks will help to make the procedures more accurate and easier to manipulate.”This is a prospect the US Geological Survey takes seriously. Irish researchers make a case for cheaper, ubiquitous sensors that can measure turbidity and color.
Danish research, published in NatureResearch’s Scientific Reports, promises to reveal fecal bacteria like e. coli in just ten minutes by comparing microscopic photos of a water samples with a library of images. A 3D image recognition algorithm can sort species from each other and suspended particles.
Perhaps innovations along these lines for the mass market of grocery shoppers and healthcare might attract even more research, lowering costs across the board and speeding solutions to our waterfront.
Why is this a big deal? Determining the most probable number of fecal bacteria per unit of water is a slow process (more than 24 hours) of sampling, incubation, and testing. Enterococcus testing is the preferred method for determining swimming beach safety in the U.S., succeeding the old standard of fecal coliform testing in 2004. If a beach shows a five week mean of 35 colony-forming units or more per 100 milliliters of water, it’s closed. The Virginia Department of Environmental Quality published a great introductory explanation of this process. Improved, faster assays are sold or in development, but most cost too much for groups like HarborLAB.
Each week members of the NYC Water Trail Association, like HarborLAB, sample water for laboratories to test for fecal bacteria indicating sewer overflows. One test involves incubating bacteria cultures and then detecting the presence of enterococcus, a genus found in human intestines, by the contaminated vials’ glow when exposed to ultraviolet light. Above you see the results from a lab operated by Bronx River Alliance. HarborLAB initiated sampling in western Queens and samples the water at Gantry Plaza State Park.
You can count on our Water Quality Monitoring volunteer crew to be out there each week to keep paddling at Gantry Plaza State Park safe, and we welcome you to join us by emailing firstname.lastname@example.org with the subject line “Water quality volunteer.” But forgive us for scanning periodicals for hints of when robots might replace us! 😉