ke he, lee blaney department of chemical, biochemical and...

Ke He, Lee Blaney

Department of Chemical, Biochemical and Environmental Engineering

University of Maryland Baltimore County

2017 National Environmental Monitoring Conference

August 7, 2017 (Washington, DC)

NEMC - August 7, 2017 2

NAE GC – Restore and improve urban infrastructure

Compromised urban wastewater infrastructure highlights the need to consider the fate of contaminants upstream of WWTPs


Sources of CECs – revisiting assumptions


Wastewater leaks are common occurrences

Literature indicates that sewer exfiltration can be as high as 10-20% of dry weather flow; furthermore, larger leaks/spills occur on a regular basis…


“We get what we measure”

Sampling campaigns for CECs focus on expected sites

• Kolpin et al., 2002 – “the selection of sampling sites primarily focused on areas considered susceptible to contamination from human, industrial, and agricultural wastewater.”

• Barnes et al., 2008 – “Site selection focused on areas suspected to be susceptible to contamination from either animal or human wastewaters (i.e. down gradient of a landfill, unsewered residential development, or animal feedlot).”

There have been few efforts conducted in “unimpacted” streams and watersheds.


My objectives for today

1. To examine the ability of fluorescence excitation emission matrices (EEMs) to highlight water quality disturbances in urban streams

2. To quantify concentrations of contaminants of emerging concern (CECs) in an unimpacted, urban watershed

We propose that these parameters can be used as forensics tools to not only locate sewer leaks, but also examine the occurrence, fate, transport, and impacts of CECs in urban streams.


Study site – Gwynns Falls watershed (Baltimore, MD)

The 2004 water quality management plan states, “Sewage discharge into the Gwynns Falls is a major concern…Many sections of the stream…are posted due to contaminated streamflow... Continuous sewer leaks are common occurrences in Baltimore City”.

Source: Baltimore Ecosystem Study

Part 1:

Excitation emission matrices as screening tools for water quality changes in urban

streams


EEMs act as a solution fingerprint (DOM)

Hypothesis: Sewer leaks introduce wastewater DOM to urban streams, and that DOM can be identified by its fluorescence signature

POBR DRKR GRGF1

2

3

4

5

Forested ref. Suburban Urban

Region 1: Tyrosine-like aromatic proteinRegion 2: Tryptophan-like aromatic proteinRegion 3: Fulvic acid-like

Region 4: Soluble microbial product-likeRegion 5: Humic acid-like

(Chen et al., 2003)


Fluorescence signatures correlated to land use

The rural-to-urban flow gradient was captured by plotting a fluorescence index corresponding to fulvic acid-like molecules against an index for soluble microbial products

1.0

1.5

2.0

2.5

3.0

3.5

4.0

-1.0 -0.5 0.0 0.5 1.0 1.5 2.0

FI2

40

/42

5-5

10

FI275/300-345

POBR

BARN

GFGL

GFGB

MCDN

GFVN

DRKR

GRGF

GFCP

EFF

RAW

rural-to-urban gradient

more urban


EEMs showed local disturbances in water quality

baseline disturbance

5750–6050 m upstream of DRKR

dilutionbaseline

4550-5000 m upstream of DRKR2100-3300 m upstream of DRKR

5100-5600 m upstream of DRKR


Regional analysis indicated a location of interest

1.E+03

1.E+04

1.E+05

1.E+06

0 1500 3000 4500 6000

Re

gio

nal

inte

grat

ion

Distance (m)

Region 1Region 2Region 3Region 4Region 5

TunnelFlow direction

Tunnel

DR5DR4DRKR

Part 2:

CECs in unimpacted urban watersheds highlight impacts of wastewater leaks

0

50

100

150

200

250

Co

nce

ntr

atio

n (

ng

/L)


Following up on location of interest in Dead Run

Hypothesis: CECs are present in unimpacted urban streams and can be used in tandem with EEMs to identify sources of contamination

* Average of eight sampling events

[He et al., 2015]

Our earlier work showed the presence of a wide variety of fluoroquinolones in Gwynns Falls


We conducted two 10-week sampling campaigns in 2016

Collected samples from 13 sites in the Gwynns Falls watershed for analysis of 17 fluoroquinolones, 13 sulfonamides, 8 tetracyclines, 5 macrolides, 3 estrogens, and 5 UV-filters.

Ofloxacin

Roxithromycin

Doxycycline

Sulfamethoxazole

Estrone

Oxybenzone


All analytes were measured using SPE with LC-MS/MS

For the sake of brevity, full analytical methodologies are not included here…

0

20

40

60

80

100

120

0 2 4 6 8 10 12 14

Re

lati

ve r

esp

on

se (

%)

Retention time (min)

Clarithromycin

Fleroxacin

Gatifloxacin

Nadifloxacin

Orbifloxacin

Sulfadimethoxine & Sulfadoxine

Sulfamethoxazole

Sulfapyridine

Sulfisomidine & Sulfadimidine


A wide variety of antibiotics were detected

CompoundDetection

frequency (%)Maximum

concentration (ng/L)

Ciprofloxacin 1.6 49

Ofloxacin 2.9 200

Azithromycin 4.5 13

Clarithromycin 5.7 280

Erythromycin 40.2 54

Roxithromycin 2.5 327

Tylosin 2.5 4.9

Sulfadimethoxine 3.3 7.1

Sulfadimidine 4.1 6.7

Sulfamethoxazole 37.3 71

Doxycycline 9.4 365

Meclocycline * 42.2 17,700

Methacycline 2.5 215

SMX

ERY

0

20

40

60

80

100

GRGF_4 GRGF_3 GRGF_2 GRGF_1 GFCP DRKR GFVN MCDN GFGB GFGL BARN POBR

Me

dia

n c

on

c. (

ng/

L)

Clarithromycin Erythromycin Roxithromycin Sulfadimethoxine Sulfadimidine Sulfamethoxazole

0

20

40

60

80

100

GRGF_4 GRGF_3 GRGF_2 GRGF_1 GFCP DRKR GFVN MCDN GFGB GFGL BARN POBR

Me

dia

n c

on

c. (

ng/

L)


Spatiotemporal trends in antibiotic concentrations

Summer 2016

Winter 2016

280 ng/L 327 ng/L

Most urban Least urban


Hydrological profiles in Gwynns Falls watershedD

isch

arge

(ft

3/s

)

DRKR

POBR

GFVN

Source: USGS NWIS

GFCP

Summer sampling6/15/16 – 08/26/16

Winter sampling11/8/16 – 01/12/17


Antibiotic time series for rural (low) → urban (high) sites

POBR GFGL

DRKR GRGF-4


Mapping antibiotics in Gwynns Falls watershed (mean)

Winter meanSummer mean

99 ng/L


Mapping antibiotics in Gwynns Falls watershed (max)

Winter maximumSummer maximum

674 ng/L


UV-filters are widely present in the Gwynns Falls

CompoundDetection

frequency (%)Maximum

concentration (ng/L)

17α-ethinylestradiol - -

Estradiol - -

Estrone 41.4 6.4

Oxybenzone 100 251

4-Methylbenzylcathinone 1.2 31

Octocrylene 100 168

Ethylhexyl methoxycinnamate 68 161

Homosalate 98 314

BP3 OC HMS


UV-filters ubiquitously present, but urban effect observed

POBR GFGL

DRKR GRGF-4


Mapping UV-filters in Gwynns Falls watershed (mean)

Winter meanSummer mean

274 ng/L


Mapping UV-filters in Gwynns Falls watershed (max)

Winter maximumSummer maximum

609 ng/L


The consistent [UV-filter] suggested a continuous source

[He et al., 2017]

BP3: 23.7±0.3 ng/g

4-MBC: 112 ± 12 ng/g

OC: 113±6 ng/g HMS: 260 ± 16 ng/g

EE2: 17.1 ± 1.6 ng/g

Conclusions


Concluding thoughts

1. Fluorescence EEMs represent a quick and easy approach to identify locations of interest in urban streams for follow-up study with other metrics

2. CECs are present in unimpacted urban streams, and we posit that the source of these contaminants is leaking wastewater infrastructure

3. Antibiotics, estrogens, and UV-filters were detected throughout the watershed; antibiotic concentrations varied with space and time, but UV-filters were fairly consistent

4. Synthetic estrogens and UV-filters accumulate in aquatic organisms and may disrupt urban ecosystems

A special thanks

Sample collectionBaltimore Ecosystem Study LTERCenter for Urban Environmental Research and Education

Funding sourcesUMBC Office of Undergraduate EducationNSF Environmental Engineering (1510420)NSF Career Award (1653726)USDA Forest Service

Student SupportMeyerhoff Scholars Program; MARC U*STAR Program

Thanks for your attention

Any questions?

ke he, lee blaney department of chemical, biochemical and...

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