Impact of Drought on Household Water Quality in Rural ...border.nmsu.edu/documents/Final Report - 2016 Water...for residents of New Mexico’s southern border counties of Don a Ana,

IMPACT OF DROUGHT ON HOUSEHOLD WATER QUALITY IN RURAL SOUTHERN NEW MEXICO: CONTINUATION PROJECT

FINAL REPORT

. . . to test for contaminants known to be present in thfe state’s border aquifers . . .

June 2016

The research team at the New Mexico Water Resources Research Institute wishes to thank the

New Mexico Department of Health and the state Cooperative Extension Service for supporting this

project. A special note of thanks goes to Freida Adams with the NMDOH Office of Border Health;

Jeff Anderson, Mary Ellen Dziak and Karoline Getkin with Don a Ana County Extension; Kristen N.

Fisher, Judy O’Loughlin, Marlee Runyan and Jessica Swapp-Lucas with Grant County Extension;

and Shelly Batts, Jack Blandford and Beatrice Dominguez with Luna County Extension.

Cover Photo

Grant County residents receive a free well water testing kit from their Cooperative Extension Office,

2610 N. Silver St. in Silver City. The free tests were funded by the New Mexico Department of Health

in partnership with the state’s Water Resources Research Institute and Cooperative Extension

Service.

Page i

Project Summary

The border region of southern New Mexico and northern Chihuahua is well into its sixth

consecutive year of drought. The U.S. National Weather Service reports precipitation remaining

below the 12-month annual average and lists the New Mexico border region as suffering from

“abnormally dry” conditions. Previous research finds that concentrations of contaminants in

groundwater may rise during periods of drought. The objective of this two-year effort is to test the

levels of known contaminants in private, domestic wells in the state’s border region. As a

deliverable, the project provides healthcare professionals with “hot spot” maps showing the risk of

finding harmful levels of contaminants in border region aquifers.

APPROACH

The two-year effort (1) measured changes in aquifer elevation in the state’s border region, (2)

analyzed laboratory results from more than 435 private, domestic wells, and (3) mapped the

potential for elevated contaminant levels within each of three border aquifers. Follow up

measures were conducted with well owners whose household water supplies exceeded federal

and state standards for healthy drinking water.

FINDINGS

A series of depth-to-water measurements in wells located within the Mimbres groundwater basin

identified a three-year drop in aquifer elevation of more than 60 feet. The drop exceeded historical

changes in the aquifer and pointed to drawdown of the aquifer during a period of drought.

Lab analysis of water samples from 435 private domestic wells recorded concentrations of arsenic,

uranium, fluoride and nitrates and the presence of total coliform and E. coli in three border region

aquifers. In total, 61 samples or 14.0% of the total samples exceeded the standard for one or more

contaminant. Seven (7) samples exceeded the health standards by two or more contaminants.

Laboratory data was used to develop color-coded maps that highlight the potential for elevated

contaminant levels areas within each of three aquifers. The maps can be found in the Maps section

of this report or online at http://border.nmsu.edu/ under the “Well Water Sampling Project” tab.

The maps identify areas within each aquifer where groundwater likely exceeds the maximum

concentration for healthy drinking water. Of note, elevated concentrations of arsenic and/or

fluoride were identified within each of the three regional aquifers.

http://border.nmsu.edu/

Page ii

CONCLUSION

As drought advances in the border region of southern New Mexico, it may be concluded that

groundwater sampling becomes a more relevant exercise for monitoring private domestic water

supplies. Maps showing the potential for elevated concentrations of harmful contaminants in

groundwater may aid healthcare workers in identifying individuals at risk of exposure to

unhealthy drinking water.

Page iii

Table of Contents

Project Summary ___________________________________________________________________________________________ i

Approach ____________________________________________________________________________________________________________ i

Findings _____________________________________________________________________________________________________________ i

Conclusion __________________________________________________________________________________________________________ ii

Table of Contents _________________________________________________________________________________________ iii

Introduction _______________________________________________________________________________________________ 1

Background ________________________________________________________________________________________________ 2

Scope of Work______________________________________________________________________________________________ 3

Task 1 – Aquifer sampling _________________________________________________________________________________________ 4

Sampling Approach ________________________________________________________________________________________________ 4

Task 2 – Follow Up Activities ______________________________________________________________________________________ 5

Task 3 - Workshops ________________________________________________________________________________________________ 5

Task 4 – Data Analysis & Water Quality Maps ___________________________________________________________________ 6

Findings ____________________________________________________________________________________________________ 7

Exceedances ________________________________________________________________________________________________________ 7

Maps _______________________________________________________________________________________________________ 19

Discussion _________________________________________________________________________________________________ 21

Property Owner-Supplied Data __________________________________________________________________________________ 33

workship evaluations _____________________________________________________________________________________________ 33

Sampling Errors___________________________________________________________________________________________________ 33

PROJECT Promotion ______________________________________________________________________________________________ 33

Conclusion ________________________________________________________________________________________________ 34

References and Works Cited _____________________________________________________________________________ 35

Page 1

Introduction

In 2014 - ‘16 the New Mexico Department of Health (NMDOH) partnered with the Water

Resources Research Institute (WRRI) to test the quality of groundwater in the state’s border

aquifers. The aquifers are significant in serving as the primary source of domestic water supplies

for residents of New Mexico’s southern border counties of Don a Ana, Grant, Hidalgo and Luna

counties. These transboundary aquifers also supply several Mexican communities, including

Palomas, Chihuahua. Results from the first of two projects identified elevated concentrations of

harmful contaminants in 11.2% of wells sampled in Luna County. More than 9% were measured at

levels that exceed the federal and state health standards. Some samples tested as high as four

times the maximum concentration for healthy drinking water. Much of this information was

previously unknown.

This report constitutes the final report for the second-year of groundwater sampling. The report

combines data from the first year’s project with data from the second year. Completed in June

2016, the second-year effort was designed to extend the reach of well water sampling into Don a

Ana and Grant counties and develop a more detailed description of domestic water quality in the

state’s border aquifers.

The objective of this two-year effort is to test the levels of known contaminants in

private, domestic wells in the state’s border region. As a deliverable, the project

provides healthcare professionals with “hot spot” maps showing the risk of finding

harmful levels of contaminants in border region aquifers.

Page 2

Background


consecutive year of drought. For the current year, the U.S. National Weather Service reports

precipitation remaining below the 12-month average and lists the New Mexico border region as

suffering from “abnormally dry” conditions.1 Many authors cite rising concentrations of

contaminants in groundwater during periods of drought (i.e., Delpla et al., 2008; van Vliet et al.,

2009). Under such circumstances, groundwater quality can degrade.

The 272,383 residents of New Mexico’s Don a Ana, Grant, Hidalgo and Luna counties rely almost

solely on groundwater for their domestic and agricultural supplies. Of those, an estimated 15%2

obtain their household water from private wells. Private wells are unregulated in most U.S. states,

including New Mexico. As such, no requirements are in place for routine testing or assessment of

water quality.3

Due to a combination of extended drought and the high percentage of individuals in New Mexico’s

border counties served by unregulated, private wells, WRRI and NMDOH agreed to conduct a well

testing project to determine if resident well owners were at risk from elevated concentrations of

harmful contaminants in their drinking water.

1 U.S. Drought Monitor, National Weather Service. Accessed Aug. 5, 2016 at http://droughtmonitor.unl.edu/ 2 Domestic water use: self-supplied population 2005, U.S. Geological Survey. Published by the U.S. Census Bureau. Accessed July 18, 2016 at http://censtats.census.gov/ 3 EPA regulates public water systems; it does not have the authority to regulate private drinking water wells. Approximately 15 percent of Americans rely on their own private drinking water supplies, and these supplies are not subject to EPA standards, although some state and local governments do set rules to protect users of these wells. Unlike public drinking water systems serving many people, they do not have experts regularly checking the water’s source and its quality before it is sent to the tap. These households must take special precautions to ensure the protection and maintenance of their drinking water supplies. Accessed July 2, 2016 at www.epa.gov/

http://droughtmonitor.unl.edu/

http://censtats.census.gov/

http://www.epa.gov/

Page 3

Scope of Work

As with the first project, the second-year effort tested for the presence of harmful contaminants in

the state’s border aquifers. Contaminants included arsenic, fluoride, nitrates, uranium, total

coliform and E. coli. In addition, water samples were tested for PH to understand if the border

aquifers are meeting EPA’s secondary drinking water standard for alkalinity. Electrical

conductivity was measured and used as an indicator of salinity.4

New Mexico-Chihuahua Transboundary Aquifers

Source: New Mexico Water Resources Research Institute, NMSU.

4 EPA has established National Secondary Drinking Water standard of 6.5 – 8.5 for PH in drinking water. EPA

does not enforce these "secondary maximum contaminant levels" (SMCLs). They are established only as

guidelines to assist public water systems in managing their drinking water for aesthetic considerations, such as

taste, color, and odor. These contaminants are not considered to present a risk to human health at the SMCL.

EPA has no federal standard for electro-conductivity in drinking water. However, drinking water is often tested

for electrical conductivity as a benchmark for total dissolved solids. Measures that exceed 1,000 siemens (SI)

units per meter are often associated with high salinity.

Page 4

TASK 1 – AQUIFER SAMPLING

Project staff developed a plan to promote a volunteer well water sampling program targeted to

private well owners in Don a Ana, Grant and Luna counties. Well sampling in Hidalgo County was

found to require a more labor-intensive approach and was postponed for the third year of the

program. As with the first-year effort, residents of incorporated communities, such as Silver City

and Deming, were excluded from participation in the program due to their access to public water

supplies, which are regulated and routinely tested.

To “get the word out” to the mostly rural, private well owners, WRRI partnered with the Don a Ana,

Grant and Luna County Cooperative Extension Offices, each of which maintains a database of 4-H

and FFA members who represent a large number of private property owners. News releases were

prepared by WRRI’s Erin Ward and distributed by the public relations office at New Mexico State

University (NMSU). Notices on Extension Offices’ Facebook pages promoted the program to online

audiences.

Examples of project media coverage from the Las Cruces Sun-News

SAMPLING APPROACH

Well owners in Don a Ana, Grant and Luna counties were invited to visit their Extension Offices in

Las Cruces, Silver City and Deming to obtain free water sampling kits. The kits included sampling

bottles, labels, rubber gloves and written instructions in English and Spanish detailing how to

Page 5

collect well water for laboratory analysis. Property owners were instructed to collect their

samples on Tuesday mornings (Don a Ana) or Thursday mornings (Grant and Luna) and deliver

them to their respective Extension Office by 2 p.m. on the same day. The deadline allowed time for

Extension staff to pack the samples in ice and ship them overnight to the state’s authorized

drinking water laboratory in Albuquerque. The quick turnaround from sample collection to

delivery at the lab ensured that each water sample would arrive within a 24-hour window,

improving the reliability of the lab analysis.

Property owners were guaranteed anonymity for participation in the program. As such, Extension

staff asked well owners to identify themselves by street address or to label their collection bottles

with the latitude and longitude of their wellheads by using a mobile phone app or computer

program. Well locations were later verified by WRRI student employees to assure accuracy in

mapping contaminant concentrations within each aquifer.

TASK 2 – FOLLOW UP ACTIVITIES

Laboratory results were returned to property owners usually within three to four weeks. The

results were provided to well owners either in hardcopy at the Extension Office or communicated

via email or telephone, depending on well owner preference. To help property owners understand

their lab reports, a flyer was developed in English and Spanish that explained how to read the

report. In some cases, WRRI or Extension staff met in person with a property owner to discuss a

lab result or assist the well owner in understanding the probable source of contamination. Staff

also instructed owners of contaminated wells in methods to reduce or eliminate the contaminant.

WRRI and NMDOH worked together to develop brochures in English and Spanish explaining the

health impacts of certain contaminants.

TASK 3 - WORKSHOPS

Workshops were conducted May 25 in Grant County and June 15 Luna County for well owners

who participated in the program. The workshops were scheduled to evaluate the second-year

effort and determine the extent of follow up by property owners in installing or updating water

treatment devices.

Written evaluations were completed by participants attending the Silver City workshop. Overall,

some 86% of participants said they were “very satisfied” with the project. A perfect 100% of

evaluators said the well sampling instructions were clear and easy to follow. More than 92%

reported the “Hot to Read Your Lab Results” instruction sheet as helpful in interpreting the

laboratory data.

Page 6

Six participants reported lab results that exceeded the health standards. Of the six, two reported

installing or treating their household water with an installed device or treatment system. The

remaining four reported exceedances of total coliform only, and were directed to retest their well

water for coliform contamination at a later time.5

At close of the Silver City workshop, several residents requested information on how to construct

a homemade water filter. WRRI staff provided a brochure and performed a demonstration,

showing how to assemble a filter to fit their needs. Variations of the device are currently in use in

Palomas, Chih., where the homemade filters were found to reduce high concentrations of fluoride

and arsenic from local well water supplies.

The Luna County workshop was conducted with the staff of the County Extension Office in

Deming. For this meeting, WRRI provided Powerpoint slides, which were edited so that the

Extension staff could use the slides for meetings with agriculture producers held after the fall

harvest season.

TASK 4 – DATA ANALYSIS & WATER QUALITY MAPS

This report contains the chief deliverables for the project. The report includes a database of

laboratory results from 435 individual well samples and “hot spot” maps showing the risk in each

of three groundwater basins of finding elevated contaminant concentrations. Risk is calculated

using the magnitude of values from laboratory analyses of well water and the distances between

each wellhead to assign a range of values by contaminant (See Maps B through M).

5 Hall Environmental Analysis Laboratory reports a high sensitivity to false positives for exceedances of total coliforms.

Page 7

Findings

The second-year effort was initiated the second week of December 2015. Samples were collected

each week for 15 weeks through mid-March. Some 329 well samples were collected and tested for

arsenic, fluoride, nitrates, uranium, total coliform, E. coli, PH and electro-conductivity. Data from

the second-year effort were combined with data from 106 wells sampled the first year. In total,

435 individual wells were sampled, tested for contaminants and their locations mapped within

three aquifers. Total samples represented an estimated 5.2% of all private domestic wells in the

three-county border region and exceeded by more than 140 the number of wells targeted by the

project team.

Of the total samples, some 380 qualified for testing of the full range of six contaminants, PH and

electro-conductivity. Some 56 samples were analyzed for the five contaminants of arsenic,

fluoride, uranium and the presence of total coliform and E. coli. This was due to an error by the

testing lab, which shipped collection bottles with an incorrect preservative that curtailed testing

for nitrates. Another 22 samples could not be tested for total coliform or E. coli because of delays

in reaching the laboratory within 24 hours or when water samples exceeded the maximum

temperature for testing. A smaller group of samples were analyzed only for total coliform and E.

coli at the request of the well owners. One sample in the five-contaminant group also exceeded the

24-hour limit for coliform and E. coli testing.

EXCEEDANCES

Of the 435 samples tested, 61 or 14.0% exceeded the drinking water standard for one or more of

the contaminants of arsenic, fluoride, nitrates, uranium or E. coli. Seven (7) of the 61 were found to

exceed the standards for two or more contaminants. Eleven (11) or 2.5% of samples failed to meet

EPA’s secondary standard for PH, demonstrating high alkalinity. Electro-conductivity, which

carries no state or federal health standard, was measured at 1000 or greater in 87 or 20.0% of

total samples, indicating a potential for high salinity.

GILA RIVER BASIN

The Gila River Basin, the smallest of the three regional aquifers, demonstrated high potential for

exceedances of arsenic and fluoride, with isolated potential for exceedances of the uranium

standard. The single nitrate exceedance was associated with poor septic maintenance.

MESILLA BASIN

The Mesilla Basin supplies domestic water to the city of Las Cruces, the largest population center

in the state’s border region. Groundwater south of Las Cruces showed particularly high

Page 8

concentrations of arsenic. Well samples also identified isolated exceedances of uranium and

fluoride.

MIMBRES BASIN

Groundwater supplies in the Mimbres Basin showed regional diversity in water quality with

healthy supplies found in the middle of aquifer near Deming. Portions of the aquifer demonstrated

a high potential for elevated levels of arsenic, uranium and fluoride. Nitrates were measured in

isolated areas and are likely due to septic system failures or livestock operations.

TABLE A

EXCEEDANCES OF DRINKING WATER STANDARD BY AQUIFER

AQUIFER SAMPLES

PRIMARY STANDARD SECONDARY

STANDARD NO STANDARD

Arsenic Uranium Fluoride Nitrates Total Coliform*

E. coli %

Samples PH

% Samples

Electro-Conduct

% Samples

Gila 86 5 3 8 1 29 1 20.9 8 9.3 4 4.7

Mesilla 116 6 1 1 0 15 0 6.9 0 0 58 50.0

Mimbres 233 6 9 7 9 56 4 15.02 3 1.3 25 10.7

TOTALS 435 17 13 16 10 100 5 14.0 11 2.5 87 20.0

* Total Coliform was excluded from data analysis due to high sensitivity to false positives.

Source: Hall Environmental Analysis Laboratory, Albuquerque

TABLE B

GILA AQUIFER - CONTAMINANT CONCENTRATION BY SAMPLE

NO.

COLLECTION DATE COUNTY

EXCEEDANCES (ppm) PRESENCE

PH Electro-Conduct Arsenic

≥ 0.010 Uranium ≥ 0.030

Fluoride ≥ 4.0

Nitrates ≥ 10.0

Total Coliform*

E. coli

1 12/9/2015 Grant 0.01 0.0026 7.8 0.28 Present Absent 8.14 600

2 12/16/2015 Grant 0 0.021 1.1 0 Absent Absent 7.94 1100

3 12/16/2015 Grant 0 0.0048 0.39 4.8 Absent Absent 7.71 600

4 12/16/2015 Grant 0.0046 0.0051 0.51 0.82 Absent Absent 7.82 410

5 12/16/2015 Grant 0 0.033 1.6 0.31 Present Absent 7.71 720

6 12/23/2015 Grant 0.0017 0.0062 2.7 0 n/d n/d 8.13 880

7 12/23/2015 Grant 0.001 0 1.5 0.75 n/d n/d 7.86 360

8 12/23/2015 Grant 0.001 0 1.9 0 n/d n/d 7.79 250

9 12/30/2015 Grant 0 0 1.8 0 n/d n/d 7.37 250






Page 9

NO.




≥ 0.010 Uranium ≥ 0.030

Fluoride ≥ 4.0

Nitrates ≥ 10.0

Total Coliform*

E. coli





19 1/13/2016 Grant 0 0 0.3 0.85 Present Absent 6.99 280

20 1/13/2016 Grant 0 0 2.1 0 Absent Absent 7.07 350


22 1/20/2016 Grant 0.009 0.0042 4 0 Absent Absent 8 540


24 1/20/2016 Grant 0 0 2.1 0.18 Absent Absent 7.26 320


26 1/20/2016 Grant 0.0015 0.0016 0.32 2.1 Present Present 8.06 440

27 1/20/2016 Grant 0.011 0.0012 3.5 0 Absent Absent 9.92 800













40 1/27/2016 Grant 0.025 0.0013 20 0 Absent Absent 8.77 2400


42 2/3/2016 Grant 0.013 0.02 8.3 78 Present Absent 8.01 1700





47 2/10/2016 Grant 0.0078 0 6.7 0 Absent Absent 8.78 350



50 2/10/2016 Grant 0.024 0.0059 16 5.2 Present Absent 8.83 750

51 2/10/2016 Grant 0.0025 0.0027 2 0.23 Absent Absent 7.58 350








59 2/24/2016 Grant 0.0018 0 0.34 1 Absent Absent 8.08 360


Page 10

NO.




≥ 0.010 Uranium ≥ 0.030

Fluoride ≥ 4.0

Nitrates ≥ 10.0

Total Coliform*

E. coli



63 2/24/2016 Grant 0 0.002 0.34 3 Present Absent 8.21 560















78 3/16/2016 Grant 0.0024 0.0031 0.95 0.42 n/d n/d 8.13 350

79 3/16/2016 Grant 0 0 1.6 0.29 Absent Absent 7.55 200








*Total Coliform was excluded from data analysis due to high sensitivity to false positives.

n/d = no data available


TABLE C

MESILLA AQUIFER - CONTAMINANT CONCENTRATION BY SAMPLE

NO.




≥ 0.010 Uranium ≥ 0.030

Fluoride

≥ 0.030

Nitrates ≥ 10.0

Total

Coliform* E. coli

1 2/2/2016 Dona Ana 0.0068 0.0036 0.26 0 Absent Absent 8.11 1200


3 2/9/2016 Dona Ana 0.0028 0.006 0.71 0 Present Absent 7.6 1100

4 2/9/2016 Dona Ana 0.00378 0.0019 0.16 0 Absent Absent 8 1400

5 2/9/2016 Dona Ana 0.0044 0 0.6 0 Absent Absent 7.76 1000


7 2/9/2016 Dona Ana 0 0 0.44 0 Absent Absent 7.7 1200

Page 11

NO.




≥ 0.010 Uranium ≥ 0.030

Fluoride

≥ 0.030

Nitrates ≥ 10.0

Total

Coliform* E. coli






13 2/9/2016 Dona Ana 0.0025 0.021 0.49 0.3 Absent Absent 7.6 1000









22 2/9/2016 Dona Ana 0 0 1.2 1.3 Present Absent 7.11 150




26 2/9/2016 Dona Ana 0 0.0064 1.2 1.9 Absent Absent 7.92 420


28 2/9/2016 Dona Ana 0.0014 0.011 0 0 Present Absent 7.73 1900






34 2/9/2016 Dona Ana 0.007 0 0.27 0 Present Absent 7.72 930












46 2/16/2016 Dona Ana 0 0 1.3 1.4 Absent Absent 7.72 190

47 2/16/2016 Dona Ana 0.0047 0.0099 2 0 Present Absent 7.92 1900







Page 12

NO.




≥ 0.010 Uranium ≥ 0.030

Fluoride

≥ 0.030

Nitrates ≥ 10.0

Total

Coliform* E. coli

54 2/16/2016 Dona Ana 0.046 0.0037 2 0 Absent Absent 8.36 1100
















70 2/23/2016 Dona Ana 0.0023 0.01 0 0 Absent Absent 7.77 1900


72 2/23/2016 Dona Ana 0 0.012 1.5 2.4 Absent Absent 7.76 490


74 2/23/2016 Dona Ana 0 0 1 2 Absent Absent 6.92 200


76 2/23/2016 Dona Ana 0.0034 0 0.27 0 Present Absent 7.44 520








84 3/1/2016 Dona Ana 0 0 1.2 1.8 Absent Absent 7.13 170


86 3/1/2016 Dona Ana 0.0044 0 0.52 0.22 Absent Absent 7.82 1300



89 3/1/2016 Dona Ana 0.0046 0 0.28 0.19 Absent Absent 7.84 1300




93 3/8/2016 Dona Ana 0 0.0014 0.18 0.92 Present Absent 7.65 830

94 3/8/2016 Dona Ana 0 0.0059 1.5 0 Present Absent 7.84 550






Page 13

NO.




≥ 0.010 Uranium ≥ 0.030

Fluoride

≥ 0.030

Nitrates ≥ 10.0

Total

Coliform* E. coli




103 3/8/2016 Dona Ana 0 0.0072 0.22 1 Absent Absent 7.89 1300



106 3/15/2016 Dona Ana 0.0021 0.012 0.13 0 n/d 7.83 1700






112 3/22/2016 Dona Ana 0.0015 0.0011 1.9 1.8 Present Absent 7.49 190








TABLE D

MIMBRES AQUIFER - CONTAMINANT CONCENTRATION BY SAMPLE

NO.

COLLECTION

DATE COUNTY


PH Electro-

Conduct Arsenic ≥ 0.010

Uranium ≥ 0.030

Fluoride

≥ 0.030

Nitrates ≥ 10.0

Total Coliform*

E. coli

1 3/11/2015 Luna 0.0031 0.0028 0.86 3 Present Absent n/d n/d

2 3/11/2015 Luna 0.0036 0.003 0.44 0.31 Absent Absent n/d n/d


4 3/11/2015 Luna 0.003 0.0034 0.93 0.27 Present Absent n/d n/d

5 3/11/2015 Luna 0 0 0.41 5.5 Absent Absent n/d n/d




9 3/11/2015 Luna 0.0022 0.0024 0.42 3 Absent Absent n/d n/d



12 3/18/2015 Luna 0 0.014 1.2 3.4 Absent Absent n/d n/d




16 3/25/2015 Luna 0 0.0026 0.46 26 Absent Absent n/d n/d

Page 14

NO.

COLLECTION

DATE COUNTY


PH Electro-


Uranium ≥ 0.030

Fluoride

≥ 0.030

Nitrates ≥ 10.0

Total Coliform*

E. coli



19 4/8/2015 Luna 0.0024 0.0051 1 0.53 Present Absent n/d n/d



22 4/15/2015 Luna 0 0.038 0.51 16 Present Absent n/d n/d




26 4/15/2015 Luna 0.0024 0.0023 0 11 Absent Absent n/d n/d
















42 4/22/2015 Luna 0 0.0081 0.53 0 Absent Absent n/d n/d

43 4/22/2015 Luna 0.002 0 0 0 Absent Absent n/d n/d




47 4/22/2015 Luna 0.003 0.0041 0.81 0 Present Present n/d n/d








55 4/22/2015 Luna 0.0017 0 0 0 Present Absent n/d n/d

56 4/22/2015 Luna 0.0018 0.0096 0 0 Present Absent n/d n/d


58 4/22/2015 Luna 0.0017 0 0 0 Present Absent n/d n/d





Page 15

NO.

COLLECTION

DATE COUNTY


PH Electro-


Uranium ≥ 0.030

Fluoride

≥ 0.030

Nitrates ≥ 10.0

Total Coliform*

E. coli


64 4/22/2015 Luna 0.0027 0.0026 1 1.1 Absent Absent n/d n/d







71 5/6/2015 Luna 0.009 0.025 5 3.3 Absent Absent n/d n/d

72 5/13/2015 Luna 0.0025 0.0045 0 0 Present Absent n/d n/d

















89 5/20/2015 Luna 0.0029 0.004 0 0 Present Present n/d n/d







96 5/27/2015 Luna 0.0026 0 2.5 0.44 Absent Absent n/d n/d













Page 16

NO.

COLLECTION

DATE COUNTY


PH Electro-


Uranium ≥ 0.030

Fluoride

≥ 0.030

Nitrates ≥ 10.0

Total Coliform*

E. coli





113 No record Grant 0.0015 0.0011 0.25 0.52 n/d n/d 7.98 290

114 No record Grant 0 0.0085 1.3 2.9 n/d n/d 7.89 470

115 No record Grant 0.002 0.0026 2.5 0 Absent Absent 8.96 250

116 No record Grant 0 0.025 2.3 2.3 Absent Absent 8.11 470

117 No record Grant 0 0.012 1.9 2.4 Absent Absent 7.91 400

118 No record Grant 0 0 0.25 1.9 n/d n/d 7.77 450





123 1/13/2016 Grant 0.0017 0.0011 1.1 0 Present Absent 7.95 760








131 1/13/2016 Grant 0 0.0026 0.37 0 Present Present 7.46 1200






137 1/20/2016 Grant 0.0018 0 0.4 12 Present Absent 7.8 580












149 1/27/2016 Grant 0.0013 0 0.17 0.63 Absent Absent 7.86 290



152 2/3/2016 Grant 0 0.046 1 0 Absent Absent 7.64 630

153 2/3/2016 Grant 0 0.12 2 1.2 Absent Absent 7.84 490


Page 17

NO.

COLLECTION

DATE COUNTY


PH Electro-


Uranium ≥ 0.030

Fluoride

≥ 0.030

Nitrates ≥ 10.0

Total Coliform*

E. coli







161 2/10/2016 Luna 0 0.0011 3.9 0 Absent Absent 8.41 850









170 2/17/2016 Luna 0.008 0.0036 2.4 0.28 Absent Absent 8.39 380


172 2/17/2016 Grant 0 0.011 0.31 10 Present Present 7.63 1000




176 2/17/2016 Grant 0 0.0072 0.75 2.7 Absent Absent 8 610


178 2/17/2016 Grant 0.0016 0 0.28 0.66 Present Absent 7.94 300



181 2/17/2016 Grant 0 0.0077 0.6 9.6 n/d n/d 7.97 800

182 2/24/2016 Luna 0.0028 0.0026 0.46 0.77 Present Absent 8.21 330









191 3/2/2016 Luna 0.0021 0.0022 0.47 4.2 Present Absent 7.89 370




195 3/2/2016 Grant 0.003 0.029 4.6 n/d n/d 8.02 1700






Page 18

NO.

COLLECTION

DATE COUNTY


PH Electro-


Uranium ≥ 0.030

Fluoride

≥ 0.030

Nitrates ≥ 10.0

Total Coliform*

E. coli











211 3/9/2016 Grant 0 0.0011 1.3 0 n/d n/d 8.16 650













224 3/16/2016 Grant 0.0013 0 0.26 0.79 Present Absent 7.99 340





229 3/16/2016 Grant 0.0039 0.002 1 1.3 Absent Absent 8.07 420

230 3/16/2016 Grant 0.0041 0.0021 1.5 0.84 n/d n/d 8.15 480

231 3/16/2016 Grant 0 0.038 2.8 0 n/d n/d 7.93 490

232 9/18/2014 Ascensión 0.017 n/d 5.95 2.54 n/d n/d 7.49 1541

233 9/18/2014 Ascensión 0.042 n/d 4.63 10.38 n/d n/d 7.61 1179




Page 19

Maps

This section contains maps that show data collected from laboratory analyses of 435 well water

samples collected by rural property owners in the Gila, Mesilla and Mimbres groundwater basins.

Map A shows changes in depth-to-water measurements from drought years 2012-2015. Of

significance, the map identifies a three-year decline of more than 60 feet in groundwater elevation

at the southern and eastern portions of the basin. The map also identifies a large increase in

aquifer elevation at the northeastern end of the basin. However, this change in elevation is based

on a one-time depth reading and is a likely anomaly of the data. Much of this data was collected

during the first year of the project.

The remaining maps (Maps B through M) highlight the potential for concentrations of arsenic,

uranium, fluoride and nitrates in each of the three regional aquifers. On each map, locations with

the highest potential for contaminant concentrations that exceed the health standards are marked

in dark red. The maps are scalable and easily printed. Online versions can be found at

http://border.nmsu.edu/ under the “Well Water Sampling Project” tab.

http://border.nmsu.edu/

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MAP A

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http://border.nmsu.edu/Well-Water-Sampling-Project.html/

MAP B


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MAP C



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MAP D


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MAP E


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MAP F



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MAP G



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MAP H


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MAP I


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MAP J


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MAP K


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MAP L


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MAP M


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Discussion

PROPERTY OWNER-SUPPLIED DATA

Most participants (74%) identified the location of their wellheads using measurements for

latitude and longitude obtained from a mobile phone app. To verify the accuracy of this

information, WRRI staff confirmed the location of each well. In some cases, staff members phoned

the property owner to verify the information. If a well’s location could not be confirmed, the data

from that well was eliminated from the mapping profile. This process assured the overall accuracy

of data provided by property owners and improved the level of confidence in developing the “hot

spot” maps.

WORKSHIP EVALUATIONS

It is unusual for participants in water research projects to express thanks to researchers for their

efforts. This project has proved different. During each year of well sampling, it was not unusual for

property owners contacted by the project staff to express gratitude for access to water laboratory

testing. Currently, the southern half of the state is without an authorized drinking water lab, and

property owners must drive their samples the 300 plus miles to Albuquerque. In addition, a

typical lab analysis is costly.

SAMPLING ERRORS

The project relied on well owners to fill their sample bottles to the brim, label the bottles with the

exact time and date, identify the latitude and longitude of the wellhead, and return the sample

bottlers to their county extension offices prior to 2 p.m. on the same day of collection. While most

were collected correctly and shipped to the laboratory within the recommended time period,

some well owners were unable to collect samples properly or return their samples in time to allow

for the full set of contaminant analyses. As such, the project recorded a 4% collection error rate.

PROJECT PROMOTION

During the first-year effort, water sampling increased notably after the project was highlighted in

newspaper articles or broadcast over radio. During the second year, the project team found that

word of mouth among rural property owners increased participation. At the beginning of the

second-year effort, some property owners expressed suspicion about state government and its

intentions in obtaining private well water data. Where possible, project staff addressed these

concerns by guaranteeing privacy of the water quality data and confirming the project’s objective

of understanding potential changes occurring in regional aquifers.

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Conclusion

Due to the combination of extended drought and the high percentage of individuals in the state

border region served by unregulated, private wells, WRRI and NMDOH conducted a well water

testing project to determine if well owners were unknowingly at risk from elevated concentrations

of harmful contaminants in their drinking water. Some 435 individual well samples were collected

over a two-year period and shipped for testing to the state-authorized drinking water laboratory

in Albuquerque. Samples were tested for known contaminants of arsenic, uranium, fluoride,

nitrates, total coliform and E. coli. Of the samples tested, 61 or 14.0% were measured at

concentrations that exceeded one or more of the standards for healthy drinking water. Seven (7)

samples exceeded the standards for two or more contaminants, some as high as four times the

maximum concentration level.

The project sampled well water from three regional aquifers: the Gila, Mesilla and Mimbres. The

data were used to map the likelihood of finding elevated contaminate levels within each aquifer.

The Gila River Basin, the smallest of the three groundwater basins, demonstrated high potential

for exceedances of arsenic and fluoride. The Mesilla Basin measured particularly high

concentrations of arsenic in portions of the aquifer south of Las Cruces. The Mimbres Basin, which

stretches across Luna and Grant counties, showed wide diversity in water quality data with

healthy drinking water more likely found at the center of the aquifer and the potential for elevated

concentrations of arsenic, uranium and fluoride found along the aquifer’s edges. Of note, the

potential for poor water quality rose significantly at the southern end of the Mimbres, a trend

confirmed with data from well samples taken from the Mexican community of Palomas.


consecutive year of drought. A series of depth-to-water measurements in wells in the Mimbres

Basin conducted by project staff identified a three-year drop in aquifer elevation of more than 60

feet. The drop exceeded historical changes in the aquifer and pointed to drawdown of the aquifer

during a period of drought.

As drought advances in the border region of southern New Mexico, it may be concluded that

groundwater sampling becomes a more relevant exercise for monitoring private domestic water

supplies. Maps showing the potential for elevated concentrations of harmful contaminants in

groundwater may aid healthcare workers in identifying individuals at risk of exposure to

unhealthy drinking water.

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References and Works Cited

Delpla I, A-V Jung, E Baures, M Clement, O Thomas. Impacts of climate change on surface water quality in

relation to drinking water production. Environmental International 2009; 35(8):1225-33.

van Vliet MTH, JJG Zwolsman. Impact of summer droughts on the water quality of the Meuse river 2008;

353(1-2):1-17.

Drought Summary, National Weather Service Weather. Released Aug. 4, 2016. Accessed Aug. 5, 2016 at

http://www.srh.noaa.gov/abq/?n=drought#Wateryear

Census 2010, U.S. Census Bureau. Department of Commerce. Accessed July 23, 2016 at

http://www.census.gov

http://www.srh.noaa.gov/abq/?n=drought#Wateryear

http://www.census.gov/

Documents

Impact of Drought on Household Water Quality in Rural ...border.nmsu.edu/documents/Final Report - 2016 Water...for residents of New Mexico’s southern border counties of Don a Ana,