NYC DEP Bureau of Water Supply, Water Quality

Division of Science and Research

Giardia and Cryptosporidium Monitoring in the New York City Watershed

A Retrospective

Kerri Alderisio

Watershed Science and Technical ConferenceSeptember 17, 2008 West Point, N.Y.

“The Conference will bring scientists, engineers and technical experts together with watershed stakeholders and the public, to technically inform and present leading-edge research findings on information collected to date, with regard to the protection of the nation’s largest unfiltered surface water supply.”

- 2008 WSTC brochure

Outline

Are they out there? Method History

If so, how many? Data Review

Are there any trends? Giardia

Are they harmful to people? Additional Research

Are they out there?

• An accurate, reproducible, validated, approved method is paramount to answering this question…

• Methods for protozoan recovery have undergone many changes over the past 20 years…

DEP Protozoan Method History(16 years; 3 methods; 3 laboratories)

Years Methods Details Laboratory

1992 – 1999(lowest recovery)

ASTM

1000L

Spiral wound nom. Filter, PSF, well

slide

NYS DOH

/ ECWA

1999 – Oct 2001

(20-30% recovery)

ICR

100L

Spiral wound nom. Filter, PSF, Hoef.

man., filter on slides

NYC DEP

Oct 2001-2008(50-75% recovery)

1623HV

50L

Envirochek abs. filter, IMS, spot on

slides

NYC DEP

Method 1623 – Collection & Analysis

IMS Technology

Other Method Improvements:Pressure and NaHex Experimental Results

Data

Type>50psi25psi10psi

Without NaHexNaHexWithout NaHexNaHexWithout NaHexNaHex

80

70

60

50

40

30

20

10

0

Boxplot of 10psi, 25psi, >50psi vs Type

56%

18%

45%

12%

39%

1%

n=8

Stain Experiment

01/01/200201/01/2003

01/01/200412/31/2004

12/31/200512/31/2006

Date

0

1

2

3

4

5

6

7

8

9

10

11

12

Cysts

/50L

Fit = 0.1 LOWESS Smooth

Easy

Stain

Avg. Giardia/ 50L

Merifluor EasyStain

Giardia Detection

2.85 1.06

82% 45%

Stain Differentiation Results• P. Wallis, Hyperion

G. murisSame lot #

G. intestinalis

Colorseed Experiment (FITC & TR)

Damaged cysts

Faded FITC

Subjective Texas Red

Recovery Comparison DEP 1623 and DEP ColorSeed Method

Giardia Recovery Using WI Spike and ColorSeed Spike in DI waterNYC DEP Pathogen Laboratory, Method 1623

0

10

20

30

40

50

60

70

80

1 2 3 4 5 6 7 8 9 10 11 12 13

trial

% re

cove

ry

WI

CS

avg 58%

avg 37%

Giardia Recovery Using Method 1623: Wisconsin spike with 1623 buffer (50L) and ColorSeed with DEP Buffer (40+10L)

NYC DEP Pathogen Laboratory 2004

0

10

20

30

40

50

60

70

80

0 1 2 3 4 5 6 7 8 9 10 11 12 13

trial

% re

cove

ry

CSw/DEP Buffer

WI w/1623 Buffer

How many are there?

Upstate KeypointsKensico StreamsTerminal Keypoints

Sample Year

02 03 04 05 06 07 08

Gia

rdia

cy

sts. 5

0L-1

0

5

10

15

20

25West-of-Hudson Reservoirs (Catskill Watershed)

Giardia at Catskill Sites Combined

Sample Year

02 03 04 05 06 07 08

Gia

rdia

cy

sts

. 50

L-1

0

5

10

15

20

25West-of-Hudson Reservoirs (Delaware Watershed)

Giardia at Delaware Sites Combined

Cryptosporidium at Delaware Sites Combined

Sample Year

02 03 04 05 06 07 08

Cry

pto

sp

ori

diu

m o

oc

ys

ts. 50L-1

0

1

2

3

4

5

6West-of-Hudson Reservoirs (Delaware Watershed)

Sample Year

02 03 04 05 06 07 08

Cry

pto

sp

ori

diu

m o

oc

ys

ts. 50

L-1

0

1

2

3

4

5

6West-of-Hudson Reservoirs (Catskill Watershed)

Cryptosporidium at Catskill Sites Combined

Upstate Key Point Mean Values2002-2007

Reservoir Giardia

In

Giardia

Out

Crypto

In

Crypto

Out

Cannonsville 29.9 7.1 1.0 0.2

Pepacton 21 2.4 1.2 0.1

Neversink 48.6 6 0.4 0.2

Rondout 5.1 3.4 0.5 0.1

Schoharie 42.6 9.4 0.9 0.2

Ashokan 11.8 1.2 0.3 0.2

Sample Year

02 03 04 05 06 07 08

Gia

rdia

cy

sts. 5

0L-1

0

100

200

300

400

5001623 HV DEP1623 HV ECWA

3 values > 500 and < 1200 cysts.50L-1

Sample Year

93 94 95 96 97 98 99 00 01 02 03

Gia

rdia c

ys

ts.5

0L-1

0

2

4

6

8

10ASTM DOH ASTM ECWA

Giardia at Eight Kensico Perennial Streams 1993 - 2008

Sample Year

93 94 95 96 97 98 99 00 01 02 03

Cry

pto

sp

ori

diu

m o

ocysts. 5

0L-1

0

2

4

6

8

10ASTM DOH ASTM ECWA

Sample Year

02 03 04 05 06 07 08

Cry

pto

sp

ori

diu

m oo

cysts.

50L-1

0

20

40

60

80

1001623 HV DEP1623 HV ECWA

3 values > 100 and 250 oocysts.50L-1

Cryptosporidium at Eight Kensico Perennial Streams 1993 - 2008

Sample Year

99 00 01 02 03 04 05 06 07 08

Gia

rdia

cysts.

50L-1

0

3

6

9

12

15

Easy- Stain

ICR DEP 1623 HV DEP

Sample Year

92 93 94 95 96 97 98 99

Gia

rdia cysts.

50L-1

0

3

6

9

12

15 ASTM DOH ASTM ECWA

DEL18 Giardia 1992 - 2008

Sample Year

99 00 01 02 03 04 05 06 07 08

Gia

rdia c

ysts

. 50

L-1

0

3

6

9

12

15

Easy- Stain

ICR DEP 1623 HV DEP

Sample Year

92 93 94 95 96 97 98 99

Gia

rdia c

ysts.50L-1

0

3

6

9

12

15 ASTM DOH ASTM ECWA

CATLEFF Giardia 1992 - 2008

Sample Year

99 00 01 02 03 04 05 06 07 08

Cryp

tosp

orid

ium

ooc

ysts

. 50L

-1

0

2

4

6ICR DEP 1623 HV DEP

Cryptosporidium 1992 - 2008

Sample Year

92 93 94 95 96 97 98 99

Cry

ptos

porid

ium

ooc

ysts

. 50L

-1

0

2

4

6ASTM DOH ASTM ECWA

Sample Year

92 93 94 95 96 97 98 99

Cry

ptos

porid

ium

ooc

ysts

. 50L

-1

0

2

4

6ASTM DOH ASTM ECWA

Sample Year

99 00 01 02 03 04 05 06 07 08

Cryp

tosp

orid

ium

ooc

ysts

. 50L

-1

0

2

4

6ICR DEP 1623 HV DEP

DEL18 CATLEFF

Down the Pipe!

Giardia Crypto Giardia Crypto

RDRRCM 3.4 0.1 CATEARCM 1.2 0.2

DEL17 2.2 0.2 CATALUM 1.2 0.1

DEL18 1.9 0.2 CATLEFF 2.1 0.2

Results are per 50L, US EPA Method 1623 Data from October 2001 – August 2008

Arrows indicate flow

Sample Year

99 00 01 02 03 04 05 06 07 08

Gia

rdia cysts.

50L-1

0

3

6

9

12

15

Easy- Stain

ICR DEP 1623 HV DEP

Sample Year

93 94 95 96 97 98 99

Gia

rdia cys

ts.50L-1

0

3

6

9

12

15 ASTM DOH ASTM ECWA

CLGH Giardia 1993 - 2008

NYC Source Water Cryptosporidium LT2 values

Cry

pto

sp

ori

diu

m oo

cys

ts L-1

0.000

0.005

0.010

0.015Croton Catskill Delaware

LT2ESWTR Treatment Threshold

Are there any trends?

Temperaturerelationship

1623 stain studyMerifluorEasystain

Sample Year

02 03 04 05 06 07 08

Gia

rdia

cys

ts. 5

0L-1

0

5

10

15

20

Tem

pera

ture

(oC

)

0

5

10

15

20

25

30Giardia cysts.50L-1 Temperature (oC)

Giardia and Temperature DEL182002 - 2008

Easy Stain Year

Mean Giardia at CATLEFF by season 2002-2007

Mean

cysts

/ 5

0 L

0

2

4

6

8200220032004200520062007

YEAR

W

Sp

SuF

W

W

W

W

W

Sp

Sp

SpSp

Sp

2002 2003 2004 2005 2006 2007

Su

Su

Su

SuSu

F F

F

F

W Avg.

= 3.04

=0.54

Easy Stain year

Are they harmful to humans?

Storm Samples Wildlife Feces • Storm Sites

– 3 streams

– ~121 samples (1999-2004)

• Genotypes– 22 Cryptosporidium

genotypes found

• Significance – 98%+ not significant human

pathogens

– Most prevalent = deer, rodent, muskrat, skunk

• Animals– 38 different species

– 541 specimens (2005-2007)

• Prevalence– 111/541 (20%) positive

– 21 genotypes were found (11/ 21 previously seen in DEP storm water)

– 6/11 previously unknown

– 4 novel genotypes!

– 4 expanded hosts!

DEP data up to April 2004 indicate wildlife contribute to Cryptosporidium contamination

in stream storm water, but have no major public health significance in cryptosporidiosis

Conclusions

• Are they out there?– Yes, and we have a good, improved method

• How many are there?– Not a lot, source water is:

• ~ 2.0 Giardia / 50L• ~ 0.2 Crypto / 50L

• Are there any trends?– Yes, Giardia low summer/ higher winter; not

enough Crypto detected to be certain

• Are they harmful to humans?– Not significant human pathogens (1999-2004)

Thank You!

Acknowledgements:S. DiLonardoC. PaceWQ Pathogen Laboratory staffWQ Field staff