Predicting Microcystin Levels in Source Water and Beneficial

Reuse of Spent Lime

Daryl Dwyer Ph.D. Ryan Jackwood M.S.

University of ToledoDepartment of Environmental

Sciences

Predicting Contaminant Levels in Source Waters and Recreational Waters

• Need for Early Warning System– Quantification of dangerous

fecal coliforms and algal toxins may require 24 – 48 hrs

– Public advisories are often posted hours or days after contaminants are present

Early Warning System for E. coli since 2006• Predictive models use

environmental variables as surrogates (i.e. turbidity, precipitation, and wind direction)

• Probability of exceeding the E. coli standard (235 CFUs/100 mL)

– Traditional Model (24 hr delay): ~50% accurate

– Predictive Model: ~75% accurate

• Provides real-time swimming advisories to the public

• Use same approach to predict microcystin toxins?

Ohio Nowcasthttp://ny.water.usgs.gov/maps/ohnowcast/

Model Development for MicrocystinPredictions

• Identified factors related to microcystin in recreational sites and source waters from drinking-water plants– Preliminary results indicate phycocyanin,

nitrates, phosphorus and pH as potential factors

• Collected multi-year dataset with samples collected before, during, and after the HAB season to develop robust models.

– Preliminary samples collected 2013-2014

– Targeted samples collected 2016-2017

• Initial model developed for Maumee Bay beach and tested during 2017 recreational season (ongoing)

• Additional models will be developed for other sites in subsequent years.

Predictive Model Concept• Input: Site-specific

factors– Water physico-chemical

characteristics– Algal Characteristics– Molecular Markers– Wet Chemistry

• Output– Prediction of Microcystin

Concentration (validated with cyanotoxin analysis)

Multilinear Regression Model

Factors used to Develop ModelPhysico-chemical• Water Quality

• Temp• pH• ORP• Sp Cond• Turbidity• Dis Oxygen• TOC• DOC• NO3-N

• Weather

Algal Characteristics• Fluorescence

• Chlorophyll• Phycocyanin

(cyanobacteria)• Microscopic

enumeration

Cyanotoxin Analysis• ELISA

• MC-ADDA• LC-MSMS

• MC congeners

• Cylindrospermopsin

• Anatoxin-a• MMPB

Molecular Markers• Next Gen Sequencing

• 16S rRNA gene• 18S rRNA gene• Cytochrome

oxidase• Metagenome• Metatranscriptome

• qPCR and RT-qPCR• Toxin specific gene

assays• 16S rRNA gene

group and genus specific assays

• 18S rRNA gene group specific assays

Wet Chemistry• Total Nitrogen• NO2-NO3• Total NH4• Total Phosphorous• Total Reactive

Phosphorous

Model Benefits

• Real-time predictions• Provide real-time swimming advisories to the public

(similar to E. coli model)

• Additionally,• Provide information to trigger sample collection

• Provide data to optimize water treatment and intake options for current conditions

Maumee Bay State Park 2016: Example

• Combination of correlated factors are used to predict microcystin concentration

Correlation of Selected Factors to Microcystin

Maumee Bay State Park 2016(n=35)

Total phosphorus 0.52Nitrate + nitrite -0.40Total nitrogen 0.44N to P ratio, total 0.28

Phycocyanin, RFU 0.84

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MicrocystinPhycocyaninTotal phosphorusNitrite+nitrate

Maumee Bay State Park 2016: Example

• Correlated factors are used to develop predictive model

• Ohio Public Health Advisory: 6 μg/L microcystin-LR (regulatory threshold)

• Exceedance probability threshold is adjusted to improve model accuracy

Observed values (x-axis) are log transformed microcystin concentrations (μg/L). Probability of prediction exceedance (y-axis) represents the likelihood that model results (calculated from combination of nitrates, total phosphorus, and phycocyanin) indicate an exceedance of the regulatory threshold.

Additional study sites include: WTP intakes and recreational areas (2016 – 2017)

7 water treatment plants and 4 recreational sites.

Science Team• USGS Michigan-Ohio Water Science Center

– Donna Francy

– Amie Brady

– Erin Steltzer

– Jessica Cicale

• University of Toledo– Daryl Dwyer

– Pam Struffolino

– Ryan Jackwood

Collaborators• Justin Chaffin―The Ohio State University Ohio Sea Grant, Stone Laboratory, Put-in-Bay, Ohio

• Joel Allen and Chris Nietch―U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, Ohio

• Paul DePasquale and Michael Hessen―Stark County Health Department, Canton, Ohio

• Shelly Tomlinson―National Oceanic and Atmospheric Administration (NOAA), Annapolis, Maryland

• Doug Wagner―City of Oregon

• Ron Wetzel, Mike Jividen, Kelly Frey―Ottawa County

• Henry Biggert—Carroll Township

• Matt Berry―Village of Marblehead

• Tom Carter, Dave Barr, Roy Moore―Village of Cadiz

• Amy Elliott—City of Alliance

• Tim Neyer—Clermont County

Beneficial Reuse of Spent Lime

• Problem: Excess loadings of dissolved phosphorus from Lake Erie tributaries (specifically the Maumee River) contribute to harmful algal bloom (HAB) occurrence and severity.

• Our Approach: Strategically place nutrient interceptors that contain material with an affinity to sorb dissolved phosphorus in the Maumee River watershed.

Phosphorus Sorbing Materials (PSMs)

• Growing interest in using PSMs to reduce dissolved phosphorus in urban and agricultural drainage

• PSMs are generally composed of Ca, Fe, or Al

Chad Penn USDA-ARS

Nutrient Interceptor

• Incorporate viable PSM into filtration unit to remove phosphorus from drainage waters

Identify Cost-Effective PSM

• We chose 4 different PSMs that were locally and cost-effectively acquired.– Zebra Mussel Shells– Toledo Water Treatment Plant

Residuals– Sand (control)– Limestone

Sorption Characteristics of PSMs

-Water Treatment Residuals sorb the most phosphorus per unit mass and achieve saturation within 1 min of contact with water containing phosphorus.

Potential Applications for Nutrient Interceptor

In-stream/reservoir filtration units

Treatment system for urban runoffTreatment system for agricultural drainage

http://articles.extension.org/pages/67669/designing-structures-to-remove-phosphorus-from-drainage-waters

http://www.sciencedirect.com/science/article/pii/S0043135416304602

http://articles.extension.org/pages/67669/designing-structures-to-remove-phosphorus-from-drainage-waters

Pellets

Pellets created from spent lime to improve filtration versatility

Questions?

• EPA Office of Water Resource Center• University of Toledo• U.S. Geological Survey• Ohio State University• NOAA• Stark County Health Department

Contact Hour Information

• Title: Predicting Microcystin Levels in Source Water and Beneficial Reuse of Spent Lime

• Course Number: OEPA-D88171998-OM

• Contact Hours: 0.5 hours