Development of In-Situ Extraction for Point-of-Use Trace Metal Sensor in New

Jersey SedimentPhilip Sontag1, Katherine Dawson2, Mikayla Byron2, Matthew Esteves2, Azam Gholizadeh3, Malcolm X Shabazz Biogeochemistry Team4, Andrew D. Steen5,

Ali Maher1, Mehdi Javanmard6, and Robert Miskewitz1

1Center for Advanced Infrastructure and Technology, Rutgers University 2Department of Environmental Sciences, Rutgers University 3Virginia Tech University 4Malcolm X Shabazz High School, NJ 5University of Tennessee, Earth and Planetary Sciences 6Department of Electrical Engineering, Rutgers University

Directions for Future Research• Analyze lead (Pb) concentrations using sensor and traditional laboratory

techniques in sediment from NY/NJ harbor• Determine the impact of the microbial community on enzyme-sediment

digestion through 16S (DNA) and response of bacteria through expressionof RNA transcripts

• Determine the need for regional or broad-scale chemical speciationmodels to determine modeled total Pb concentrations in sediment

• Move from point-of-use sensor application to autonomous deploymentfor real-time sediment measurements in estuarine ecosystems

Acknowledgements

Discussion• Iron (Fe)-bound and residual (sulfide)-bound lead (Pb) controls the

majority of the Pb fractions in New Jersey sediment• Addition of β-glucosidase exoenzyme increased Pb signal in most samples

of digested sediment• Bacterial communities and metabolisms may impact enzyme-sediment

digestion at varying salinities in estuarine watersheds• Good agreement between sensor signal and modeled total Pb

concentrations was achieved in Fe-replete New Jersey sediment

We would like to thank: Dr. Reinfelder at Rutgers University, Dr. Steen atUniversity of Tennessee, and the Malcolm X Shabazz High School andPat Murray.

0

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-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Cu

rren

t (µ

A)

Voltage vs Ag/AgCl (V)

Pb measurment without enzyme digestion

Pb measurment with enzyme digestion

ICP-OES Sediment [Pb] (mg/kg)Nitric Acid alone (control): 1.2

+Enzyme Extraction: 2.2

CC7B

Square wave anodic stripping voltammogram (SWASV) of lead (Pb) ion in enzyme digested sediment sample

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-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Cu

rren

t (µ

A)

Voltage vs Ag/AgCl (V)

Pb measurment without enzyme digestion

Pb measurment with enzyme digestion

ICP-OES Sediment [Pb] (mg/kg)Nitric Acid alone (control): 4.4

+Enzyme Extraction: 4.3

CC5A

ICP-OES Sediment [Pb]

(mg/kg)

Nitric Acid alone (control):

1.2

+Enzyme Extraction: 2.2

ICP-OES Sediment [Pb]

(mg/kg)

Nitric Acid alone (control):

4.4

+Enzyme Extraction: 4.3

SedimentOrganic Matter

Extracellular Enzymes, Hydrolysis Reactions

Stimulate Microbial

Metabolism

Liberate Trace

Metals

Breakdown of Sediment Organic Matter (OM)

y = 27.789ln(x) + 143.58R² = 0.8248

y = 26.176ln(x) + 144.23R² = 0.9768

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0.00 0.50 1.00 1.50 2.00

To

tal [P

b]

(pp

m)

Sensor [Pb] (ppm)

Relationship between Sensor [Pb] and Total [Pb]

(Measured and Modeled)

Stacked bar chart of archaeal and bacterial diversity in Raritan River-Bay sediment samples3D Printed Sample

Preparation Cartridge with

ElectrodesLaboratory Setup

% of Lead (Pb) Bound – Four Sediment Fractions –

Cheesequake CreekSample

Name

F1-

Carbonates %

of Total

F2- Fe Oxides

% of Total

F3- OM

% of Total

Residual-

Sulfides % of

Total

SC1A 3.1 34.6 15.9 46.4

CC2B 2.9 27.6 4.4 65.1

CC7B 4.4 40.1 ND 55.5

CC5A 9.6 40.7 4.7 45.0

SC2A 6.1 39.3 4.2 50.4

Results

Contact InformationPhilip Sontag – Postdoctoral Associate – Center for Advanced

Infrastructure and Technology - Email: philip.sontag@rutgers.edu

AbstractCollaborative research efforts between the Center for Advanced Infrastructure and Technology, Electrical Engineering, and Environmental Science Departments at Rutgers University have yielded a graphene oxide sensor capable of measuring lead (Pb) in sediment at part per billion levels. Parallel measurements of total Pb and Pb speciation in various sediment fractions were used to produce modeled total Pb concentration from the sensor’s electrochemical response. Addition of exoenzyme (β-glucosidase) increased sensor’s signal (factor of 2 to 10) and is likely attributed to natural chemical and microbial reduction fueled by the breakdown of complex organic matter. Future project aims include the evaluation of microbial communities in New Jersey and New York sediment and response of microbial metabolisms to exoenzyme additions in enzyme-sediment digestion.

Project Goals• Point-of-use lead (Pb) detection in less than five minutes at part per

billion (ppb) levels• Model total Pb concentrations from sensor signal within 15% of measured

total concentrations in New Jersey and New York sediment• Optimize enzyme-sediment digestion with different exoenzyme additions• Characterize microbial community and activity in response to exoenzyme

additions