preliminary water quality assessment: environmental · five overlap with iron 46. well yields...

UNH Environmental

PRELIMINARY WATER QUALITY ASSESSMENT: Environmental

Engineering

Senior Project Group

QUALITY ASSESSMENT:

SEAWATER INTRUSION Group

Meta Bergwall

Tyler Colvin

SEAWATER INTRUSION AND SEPTIC

Tyler Colvin

Julia Cooke

Meg King

Li d W

CONTAMINATION GEORGETOWN ME Lindsay WarnerGEORGETOWN, ME

May 7th, 2012

ACKNOWLEDGEMENTS

Si th k t

ACKNOWLEDGEMENTS

Sincere thanks to

Georgetown Conservation gCommission

Georgetown Historical SocietyGeorgetown Historical Society

Participating Residents

Connie Donovan and Kate MacKay

2

OUTLINE

Study objectives

OUTLINE

Study objectives

Previous aquifer study

Seawater intrusionSeawater intrusion

Septic contamination

MethodsMethods

Maine drinking water standards

ResultsResults

Conclusions

Recommendations for future researchRecommendations for future research

3

STUDY OBJECTIVES

Identify locations of seawater intrusion or septic

STUDY OBJECTIVES

Identify locations of seawater intrusion or septic contamination in Georgetown

Compare current conditions to results found by Compare current conditions to results found by Dr. Steve Mabee in 1989

Compare our results to Maine drinking water standards (US EPA standards)

Create GIS maps using data collected Give to town for future use

4

PREVIOUS GEORGETOWN

1989 Steve Mabee

AQUIFER STUDY1989- Steve MabeeDissertation at University of Massachusetts at

AmherstAmherst

Geologist’s perspectiveTrace fractures in bedrockTrace fractures in bedrock

82 water samples taken in Georgetown, ME Analyzed for water qualityAnalyzed for water quality

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PREVIOUS GEORGETOWN

Well productivity dependent upon localized

AQUIFER STUDY RESULTS Well productivity dependent upon localized

geology

Wells with high concentrations of chloride and Wells with high concentrations of chloride and sodium were found Indicators of seawater intrusionIndicators of seawater intrusion

Wells with high nitrate concentrations found Indicator of septic contaminationIndicator of septic contamination

6

MABEE SEAWATER INTRUSION RESULTS

Methods

Ratio of sodium to chloride in seawater ~0.56 ± 20%

Wells within 300ft of Wells within 300ft of shoreline

Locations in red indicate Locations in red indicate seawater intrusion

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MABEE SEAWATER INTRUSION RESULTS

Methods

Ratio of sodium to chloride in seawater ~0.56 ± 20%

Wells within 300ft of Wells within 300ft of shoreline

Locations in red indicate Locations in red indicate seawater intrusion

Purple line indicates separation by fracture

8

THEORY OF SEAWATER Meta Bergwall

THEORY OF SEAWATER INTRUSION AND SEPTIC BergwallUS O S C

CONTAMINATION

9

BEDROCK WELLS

75% of wells in

BEDROCK WELLS

75% of wells in Georgetown are bedrockbedrock

18 of 19 sampled are drilled bedrock wells

10

www.maine.gov

SEAWATER INTRUSIONSEAWATER INTRUSION

11(pubs.usgs.gov)


Less Dense

12(pubs.usgs.gov)


Freshwater flows downhilltowards the ocean

13(pubs.usgs.gov)


Pressure from freshwaterdoes not allow seawaterdoes not allow seawaterto enter aquifer

14(pubs.usgs.gov)


15(pubs.usgs.gov)


Pumping fasterthan freshwater is replenished

16(pubs.usgs.gov)


Pumping rate exceedsPumping rate exceedsfreshwater well yield

17(pubs.usgs.gov)

SEAWATER INTRUSION INDICATORS

Sodium

SEAWATER INTRUSION INDICATORS

Sodium

Chloride

S lf tSulfatesNaturally occur in

seawaterseawater

18

(USGS, Paul Barlow)

SEPTIC CONTAMINATIONSEPTIC CONTAMINATION

19

(www.ec.gc.ca)


Solids settle,grease floats

20

(www.ec.gc.ca)


Soil adsorption removes suspended solids by filtration and microbial degradation

21

(www.ec.gc.ca)


100 ft

22

(www.ec.gc.ca)

SEPTIC CONTAMINATION INDICATORS

Nitrates


NitratesNitrate (measured as Nitrogen) has a maximum

contaminant level (MCL) of 10 mg/LHas higher affinity for hemoglobin than oxygenBlue-baby syndrome or shortness of breathNH3 + O2 NO3

Nitrifying bacteria convertOther Sources:Other Sources:FertilizerErosion of natural deposits

23


Total Coliform


Total ColiformMCL: No more than 5% of samples positive in one

month Naturally present in the environmentTwo types of coliformsNon-fecal – found in soil and vegetationFecal coliform – found in guts of warm-blooded

animals (e.g., bird and mammal)( g , )

E. coliMCL: Positive sample triggers repeat, if repeat is

i i h MCL i l ipositive, system has an acute MCL violationSpecific type of fecal coliform 24

Lindsay WarnerMETHODS WarnerO S

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OUR STUDY METHODS

Sampled 19 wells

OUR STUDY METHODS

Sampled 19 wells Sampled across island

Samples taken directly from faucetfaucet

Six well yields Pumped well for 10 minutesMeasured water levelsMeasured water levels Aim was to attempt to

determine recharge and flow rate of wellsate o e s

Samples analyzed for seawater intrusion and septic contamination indicators

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LABORATORY ANALYSIS METHODS

Hach


HachPhotospectrometerNitrate

Sulfate

Phosphate

Addition of reagent produces color

ti l t proportional to concentration in samplep

27(UC Davis)


Chloride


ChlorideConcentration determined

by manual titrationy

Color change from yellow to orange indicates concentrationconcentration

(Hach)

28


ICP AES


ICP-AES Inductively Coupled

Plasma- Atomic Emission Based upon principle that

each element emits a Spectroscopy

Analyzed elements with a positive charge

unique, specific wavelength

positive charge Sodium

Iron(USGS)

Manganese

Arsenic

Aluminum

Calcium 29


Total Organic Carbon


Total Organic Carbon

Analyzed by high temperature temperature combustion

All organic carbon present is converted to carbon dioxide

M hi d t t b Machine detects carbon dioxide

(Hawaii)

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COLIFORM BACTERIA

100 mL of sample

COLIFORM BACTERIA

100 mL of sample incubated for 16-48 hours according to

difi d lit g

Standard

modified colitagpresence/absence procedure

Total coliform bacteria determined using color comparatorcomparator

E. coli analyzed using UV light Bottle fluorescing

31(Hach)

QUALITY CONTROL

Trip blanks

QUALITY CONTROL

Trip blanksDistilled water to ensure no contamination occurs

during travelg

Lab blanksDistilled water to ensure lab cleanliness

StandardsProper calibration of machine

SpikesAccuracy and precision of machine

32

STANDARDSSTANDARDS

33

PRIMARY VS. SECONDARY

Primary maximum contaminant level (MCL) are

MAXIMUM CONTAMINANT LEVEL

Primary maximum contaminant level (MCL) are implemented to protect public healthRegulations federally enforceable for municipalitiesg y p

Nitrate, E. coli and total coliform bacteria

Private wells not regulated

Secondary MCL are reasonable goals to protect aesthetic water qualityChloride, sulfate, iron and manganese

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MAINE DRINKING WATER CONTAMINANTS TESTED

Contaminant Regulatory LimitContaminant Regulatory Limit

Nitrate (MCL) 10 mg/L as Nitrogen

Chloride 250 mg/L as Chloride

Sulfate 250 mg/L as Sulfate

Iron 0.3 mg/L as Total Fe

Manganese 0.05 mg/L as Total MgT l lif b i P i i b l h 5% Total coliform bacteria (MCL)

Positives must be less than 5% of total groundwater samples

E. coli (MCL) Positive result requires

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( ) qcorrective action

Julia CookeRESULTS CookeRESULTS

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CREATING GIS MAPSCREATING GIS MAPS

GPS coordinates GPS coordinates obtained at each site

Quantum GIS

Compiled & formatted dataObtained Maine

base map from www.maine.gov/megis/catalog

Imported data to Quantum GIS

F ft

37

Free software available to town

CHLORIDE CHLORIDE Seawater intrusion

indicator

Secondary MCL = 250mg/L

Typical seawater concentration 19,000 mg/L

Basis for seawater ratioBasis for seawater ratio

One well exceeded secondary MCLsecondary MCL

Three wells approached secondary MCL

38

y

All within 300 ft of shoreline

SODIUM

Seawater intrusion

SODIUM

Seawater intrusion indicator

Non-regulated

Recommended <80mg/L for heart conditions

T i l Typical seawater concentration 10,500 mg/L

Two wells were high

Additional three wells exceed 80 mg/L

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SULFATESULFATE

Seawater intrusion Seawater intrusion indicator

Secondary MCL = 250mg/LSecondary MCL 250mg/L

Typical seawater concentration 2,700 mg/L

Possible product of rock weathering

No wells exceed secondary MCL

40

SEAWATER INTRUSION

Ratio = 0 56 +/- 20% Ratio = 0 1395 +/- 10%

RESULTSRatio = 0.56 +/- 20% Ratio = 0.1395 +/- 10%

41

SEAWATER INTRUSION

Ratio = 0 56 +/- 20%

RESULTSRatio = 0.56 +/- 20%

However, this and one other well may be due other well may be due

to road salt

42

TOTAL COLIFORM BACTERIA


TOTAL COLIFORM BACTERIA

Septic contamination indicator

MCL No more than 5% positive No more than 5% positive

over a monthMany sources naturally

occur in environment Soil Animal waste

Six positiveSix positive Total coliform may indicate

E. coli Further analysis needed Further analysis needed Two of the six tested positive

43

NITRATE


NITRATE

Septic contamination indicator

MCL = 10mg/L as NitrogenMCL 10mg/L as Nitrogen

May be due to fertilizers

44

IRON

Secondary MCL = 0 3mg/L

IRON

Secondary MCL = 0.3mg/L

May cause orange/red stainingstaining

May damage plumbing

Bad taste

Six locations exceed secondary MCL

45

MANGANESE

Secondary MCL = 0 05mg/L

MANGANESE

Secondary MCL = 0.05mg/L

May cause black staining

Eight locations exceed Eight locations exceed secondary MCL

Five overlap with ironp

46

WELL YIELDS

Ranged from 1 5

WELL YIELDS

Ranged from ~ 1.5 to 6.5 gallons per minuteminuteTypical of bedrock

wells

Well yield dependent on localized geology

Field photo

47

Tyler Colvin

STATISTICS & CONCLUSION ColvinCONCLUSION

48

STUDY OBJECTIVES

Identify locations of seawater intrusion or septic

STUDY OBJECTIVES

Identify locations of seawater intrusion or septic contamination in Georgetown

Compare current conditions to results found by Compare current conditions to results found by Dr. Steve Mabee in 1989

Compare our results to Maine drinking water standards (US EPA standards)

Create GIS maps using data collected Give to town for future use

49

SEAWATER INTRUSION

Two wells indicated possible

SEAWATER INTRUSION

Two wells indicated possible seawater intrusion

Road salt shown to Reid State Park

Road salt shown to contribute to chloride levelsTwo wells found possible

chloride increase due to road salt

(Wunderground)

50

SEPTIC CONTAMINATION

No wells exceeded MCL for

SEPTIC CONTAMINATION

No wells exceeded MCL for nitrate of 10 mg/L as N

Wells that contained Wells that contained bacteria should be tested by state laboratory, as UNH laboratory is not certified

DNA testing for E. coli would determine source would determine source, either human or animal

(PNWwaterweb)

51

STATISTICAL ANALYSIS

Student’s T test used

STATISTICAL ANALYSIS

Student s T-test used

Compared 5 wells Same well at two different points in timeSame well at two different points in time

Using a 95% confidence intervalChloride was found to increase over timeChloride was found to increase over time Not necessarily seawater intrusion

Sulfate was found to decrease over time

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RECOMMENDATIONS FOR

Follow up research conducted by future UNH

FURTHER RESEARCHFollow up research conducted by future UNH

senior project classPump tests of individual wells only provide

localized informationCannot extrapolate to entire aquifer

To better identify septic contamination source of To better identify septic contamination, source of E. coli should be determined

Analysis for ammonia should also be conductedMore well overlap should occur in futureSampling should occur in multiple seasons over a

l g di t ib ti f i l dlarger distribution of islandMake GIS available to town 53

54

www.trekearth.com

SLIDESHOW AVAILABLESLIDESHOW AVAILABLE

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preliminary water quality assessment: environmental · five overlap with iron 46. well yields...

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