HomeMy WebLinkAbout2020-04-21; Municipal Water District; Resolution 1638RESOLUTION NO. 1638
A RESOLUTION OF THE BOARD OF DIRECTORS OF THE CARLSBAD
MUNICIPAL WATER DISTRICT (BOARD) APPROVING THE CARLSBAD
MUNICIPAL WATER DISTRICT (CMWD) 2019 TRIENNIAL REPORT ON WATER
QUALITY RELATIVE TO PUBLIC HEALTH GOALS
EXHIBIT I
WHEREAS, CMWD is required to prepare a report comparing CMWD's drinking water quality
and source water quality with Public Health Goals (PHGs) adopted by California EPA's Office of
Environmental Health Hazard Assessment and with maximum contaminant level goals (MCLGs)
adopted by the United States Environmental Protection Agency (USEPA); and
WHEREAS, PHGs and MCLGs are not enforceable standards and no action to meet them is
mandated; and
WHEREAS, CMWD's drinking water is supplied from the Metropolitan Water District's (MWD)
Skinner Treatment Plant, the San Diego County Water Authority's (SDCWA) Twin Oaks Valley Treatment
Plant and the Claude "Bud" Lewis Carlsbad Desalination Plant via the SDCWA aqueduct system; and
WHEREAS, California Health and Safety Code Sections 116470(b) and 116470(c) require that,
every three years, a public water system provider with more than 10,000 service connections prepare
a Public Health Goal Report and conduct a public hearing to accept and respond to public comment on
the report; and
WHEREAS, the last CMWD PHG Report was published in 2013 for years 2010, 2011, and 2012.
A report due for 2016 for the years 2013, 2014, and 2015 was inadvertently missed, therefore this
current report for 2019 includes six years (2013 through 2018); and
WHEREAS, on July 1, 2019 the CMWD 2019 Triennial Report on Water Quality Relative to Public
Health Goals was published on the City of Carlsbad's website; and
WHEREAS, a Public Hearing was held on April 21, 2020 to accept and respond to public comment
regarding the report; and
NOW, THEREFORE, BE IT RESOLVED by the Carlsbad Municipal Water District Board of the City
of Carlsbad, California, as follows:
1. That the above recitations are true and correct.
2. That the Board approves the CMWD 2019 Triennial Report on Water Quality Relative to
Public Health Goals, attached as Attachment A.
April 21, 2020 Item #6 Page 5 of 36
EXHIBIT I
3. That the Board authorizes the General Manager to submit the report to the State Water
Resources Control Board.
PASSED, APPROVED AND ADOPTED at a Special Meeting of the Board of Directors of the
Carlsbad Municipal Water District of the City of Carlsbad, California on the 21st day of April, 2020, by
the following vote, to wit:
AYES:
NAYS:
ABSENT:
Blackburn, Bhat-Patel, Schumacher.
None.
Hall.
MATT HALL, PRESIDENT
. u~Jbrbrt~
r"'L-BARBARA ENGLESON, SECRETARY
(SEAL)
April 21, 2020 Item #6 Page 6 of 36
For more information contact Carlsbad Municipal Water District, 5950 El Camino Real, Carlsbad 92008;
phone: 760-438-2722; email: water@carlsbadca.gov
Page 1 of 8
Introduction
Carlsbad Municipal Water District (CMWD) publishes Annual Water Quality Reports every year. These
are published on the City of Carlsbad/ CMWD’s website1 and provided to customers upon request. Once
every three years, the California Health and Safety Code2 specifies that water utilities with more than
10,000 service connections prepare a special report by July 1st if their water quality measurements have
exceeded any Public Health Goals (PHGs) in the previous three years.
The last CMWD PHG Report was published in 2013 for years 2010, 2011, and 2012. A report was due for
2016 for the years 2013, 2014, and 2015. This was inadvertently missed. Hence, this current report for
2019 covers six years (2013 through 2018).
The drinking water quality of the CMWD meets all State of California, Department of Public Health
and USEPA drinking water health-based maximum contaminant level (MCL)3 regulatory standards set
to protect public health.
Guidelines Followed:
The Association of California Water Agencies (ACWA)4 formed a workgroup which prepared guidelines
for water utilities to use in preparing these required reports. The ACWA guidelines were used in the
preparation of our report. No guidance was available from state regulatory agencies.
Best Available Treatment Technology and Cost Estimates:
Both the United States Environmental Protection Agency (USEPA5) and California Department of Public
Health (CDPH)6 adopt what are known as Best Available Technologies (BATs), which are the best known
methods of reducing contaminant levels to the MCL. Costs can be estimated for such technologies.
However, since many PHGs and all maximum contaminant level goals (MCLGs) are set much lower than
the MCL, it is not always possible, nor feasible to determine what treatment is needed to further reduce
1 https://www.carlsbadca.gov/services/depts/pw/utils/water/quality.asp
2 https://leginfo.legislature.ca.gov/faces/codesTOCSelected.xhtml?tocCode=HSC
3 MCLs are adopted as regulations. They are health protective drinking water standards to be met by public water
systems. MCLs take into account not only chemicals' health risks but also factors such as their detectability and
treatability, as well as costs of treatment. For more information, please refer to this site:
https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/MCLsandPHGs.html
4 https://www.acwa.com/
5 https://www.epa.gov/
6 https://www.cdph.ca.gov/
CARLSBAD MUNICIPAL WATER DISTRICT
2019 TRIENNIAL REPORT ON WATER QUALITY RELATIVE TO PUBLIC
HEALTH GOALS
April 21, 2020 Item #6 Page 7 of 36
For more information contact Carlsbad Municipal Water District, 5950 El Camino Real, Carlsbad 92008;
phone: 760-438-2722; email: water@carlsbadca.gov
Page 2 of 8
a constituent downward to or near the PHG or MCLG, many of which are set at zero. Estimating the
costs to reduce a constituent to zero is difficult, if not impossible because it is not possible to verify by
analytical means that the level has been lowered to zero. In some cases, installing treatment to try and
further reduce very low levels of one constituent may have adverse effects on other aspects of water
quality.
What are PHGs?
PHGs are non-enforceable goals established by the Cal-EPA's Office of Environmental Health Hazard
Assessment (OEHHA)7. A PHG is the level of a chemical contaminant in drinking water that does not pose
a significant risk to health. PHGs are not regulatory standards. However, state law requires State Water
Resources Control Board (SWRCB) to set drinking water standards for chemical contaminants as close to
the corresponding PHG as is economically and technologically feasible. In some cases, it may not be
feasible for the SWRCB to set the drinking water standard for a contaminant at the same level as the
PHG. The technology to treat the chemicals may not be available, or the cost of treatment may be very
high. There are currently 91 chemicals on the PHG list.
The process for establishing a PHG for a chemical contaminant in drinking water is very rigorous. OEHHA
scientists first compile all relevant scientific information available, which includes studies of the
chemical's effects on laboratory animals and studies of humans who have been exposed to the chemical.
The scientists use data from these studies to perform a health risk assessment, in which they determine
the levels of the contaminant in drinking water that could be associated with various adverse health
effects. When calculating a PHG, OEHHA uses all the information it has compiled to identify the level of
the chemical in drinking water that would not cause significant adverse health effects in people who
drink that water every day for 70 years. OEHHA must also consider any evidence of immediate and
severe health effects when setting the PHG.
For cancer-causing chemicals, OEHHA typically establishes the PHG at the “one-in-one million” risk level.
At that level, not more than one person in a population of one million people drinking the water daily
for 70 years would be expected to develop cancer as a result of exposure to that chemical. The law also
requires that, where OEHHA has not adopted a PHG for a constituent, the water suppliers are to use the
maximum contaminant level goals (MCLGs).
The MCLG is the maximum level of a contaminant in drinking water at which no known or anticipated
adverse effect on the health of persons would occur, allowing an adequate margin of safety. MCLGs are
non-enforceable public health goals. MCLGs consider only public health and not the limits of detection
and treatment technology effectiveness. Therefore, they sometimes are set at levels which water
systems cannot meet because of technological limitations.
7 https://oehha.ca.gov/water/public-health-goals-phgs
April 21, 2020 Item #6 Page 8 of 36
For more information contact Carlsbad Municipal Water District, 5950 El Camino Real, Carlsbad 92008;
phone: 760-438-2722; email: water@carlsbadca.gov
Page 3 of 8
There are a few constituents that are routinely detected in water systems at levels usually well below
the drinking water standards for which no PHG nor has MCLG yet been adopted by OEHHA or USEPA.
The PHGs and MCLGs are not enforceable and are not required to be met by any public water system.
CMWD Water Quality Data
All the water quality data collected between 2013 and 2018 for purposes of determining compliance
with drinking water standards was considered for this report. This data is usually available and
summarized in the Annual Water Quality Reports published on the City of Carlsbad/ CMWD’s website8. If
a constituent was detected in the District's water supply between 2013 and 2018 at a level exceeding an
applicable PHG or MCLG, this report provides the information required to understand the risks. Included
is the numerical public health risk associated with the MCL and the PHG or MCLG9, the category or type
of health risk, the best treatment technology available that could be used to reduce the constituent
leve110, and an estimate of the cost to install that treatment, if it is appropriate and feasible.
CMWD imports ALL of its drinking water from three sources:
· The Metropolitan Water District (MWD) Lake Skinner water treatment plant in Southern
Riverside County,
· The San Diego County Water Authority (SDCWA) Twin Oaks Valley water treatment plant in San
Marcos,
· The Claude ”Bud” Lewis Carlsbad Desalination Plant, privately owned and operated, and sourced
by SDCWA,
Water from these treatment plants are received by CMWD via SDCWA’s complex system of aqueducts
and pipelines where the water from all these sources are thoroughly blended before reaching CMWD’s
system connections. At any moment of time, it is very difficult for CMWD to know the exact proportion
of the blend. Where applicable, data from all three treatment plants are included in this report.
Constituents Detected That Exceed a PHG or a MCLG:
The following is a discussion of constituents that were detected at a level above the associated PHG, or
if there is no PHG, above the MCLG. The levels for theses constituents were well below their respective
MCLs (regulatory standards), so this does not constitute a violation of drinking water regulations and is
for advisory purposes only. These results are typical of all the water agencies in the region who receive
their water from the same MWD and SDCWA water treatment plants.
8 https://www.carlsbadca.gov/services/depts/pw/utils/water/quality.asp
9 Health Risk Information for Public Health Goal Exceedance Reports (OEHHA) https://oehha.ca.gov/water/public-
health-goal-report/health-risk-information-public-health-goal-exceedance-reports-2019
10 Cost Estimates for Treatment Technologies (ACWA)
April 21, 2020 Item #6 Page 9 of 36
For more information contact Carlsbad Municipal Water District, 5950 El Camino Real, Carlsbad 92008;
phone: 760-438-2722; email: water@carlsbadca.gov
Page 4 of 8
Arsenic
The contamination of a drinking water source by arsenic can result from either natural or human
activities. Arsenic is an element that occurs naturally in rocks and soil, water, air, plants, and animals.
Volcanic activity, the erosion of rocks and minerals, and forest fires are natural sources that can release
arsenic into the environment. About 90 percent of the arsenic used by industry in the United States is
currently used for wood preservative purposes; arsenic is also used in paints, drugs, dyes, soaps, metals
and semiconductors. Agricultural applications, mining, and smelting also contribute to arsenic releases.
The CADPH and USEPA have determined that arsenic is a health concern at certain levels of exposure.
The category of health risk associated with arsenic, and the reason that a drinking water standard was
adopted for it, is that some people who drink water containing arsenic above the MCL over many years
may experience skin damage and circulatory system problems and are at a higher risk of getting cancer.
The numerical health risk for the PHG of 4 ng/L is one excess cancer case per million people. The
numerical health risk for the MCL of 10 µg/L is 2.5 excess cancer cases per thousand people.
The level of arsenic detected in CMWD's source water supplied by MWD and SDCWA for 2013 and 2018
are listed below.
Constituent Units MCL PHG
(MCLG)
2013 2014 2015 2016 2017 2018
Source: SDCWA Twin Oaks Plant
Arsenic ppb 10 0.004 Average 2 3.4 3.0 2.4 2 3
Source: SDCWA Carlsbad Desal Plant
Arsenic ppb 10 0.004 Average NA NA ND 0.42 0.42 ND
ppb = parts per billion. ND = Non Detect. NA = Not Available
Uranium
Radiological constituents come from decay and erosion of natural deposits of certain minerals that are
radioactive and may emit a form of radiation known as alpha radiation, photons and beta radiation.
Uranium is a naturally occurring radioactive element that is ubiquitous in the earth's crust. Uranium is
found in ground and surface waters due to its natural occurrence in geological formations. The uranium
intake from water is about equal to the total from other dietary components. An additional source of
radiological contamination is from mine tailings in Moab Utah.
The State of California has a uranium MCL of 20 pCi/L based on earlier studies of toxicity to the kidney in
rabbits. Cancer risk is stated in terms of excess cancer cases per million (or fewer) population exposed
for a lifetime (theoretically 70 years). The numerical health risk at the MCL is 5x10-5. This means five
cancer cases per 100,000 population. The numerical health risk at the PHG is 1x10-6. This means one
cancer case per 1,000,000 population. The health risk category for uranium is carcinogenicity: chronic
toxicity. Carcinogenic risk means capable of producing cancer. Chronic toxicity risk means there may be
April 21, 2020 Item #6 Page 10 of 36
For more information contact Carlsbad Municipal Water District, 5950 El Camino Real, Carlsbad 92008;
phone: 760-438-2722; email: water@carlsbadca.gov
Page 5 of 8
adverse effects that usually develop gradually from low levels of chemical exposure and that persist for
a long time. The primary non-carcinogenic toxic effect is on kidneys.
The level of radionuclide constituents detected in CMWD's source water supplied by MWD and SDCWA
for 2013 and 2018 are listed below.
Constituent Units MCL PHG
(MCLG)
2013 2014 2015 2016 2017 2018
Source: MWD’s Skinner Plant
Uranium pCi/L 20 0.43 Average 1 2 2 2 ND ND
Source: SDCWA Twin Oaks Plant
Constituent Units MCL PHG
(MCLG)
2013 2014 2015 2016 2017 2018
Uranium pCi/L 20 0.43 Average 2.0 2.0 2.0 2.9 2.9 2.2
pCi/L = picoCuries per Liter of water (approximately parts per billion). ND= Non Detect
Bromate
Bromate is a byproduct of water disinfection and occurs when bromide in the water reacts with the
ozone disinfectant. Bromate consumed in drinking water in excess of the MCL over many years may
cause an increased risk of cancer. Bromate is categorized as a haloacetic acid.
The State of California has a bromate MCL of 0.010 mg/L and a PHG of 0.0001 mg/L. Bromate values
ranged from 0.0001 to 0.0005 mg/L. The levels detected were below the MCLs at all times. Bromate can
be found in drinking water as a byproduct of the ozonation disinfection process. The Office of
Environmental Health Hazard Assessment (OEHHA) has developed a Public Health Goal for bromate in
drinking water, based on its carcinogenicity. The numerical health risk at the MCL is 1x10-4. This means
one cancer cases per 10,000 population. The numerical health risk at the PHG is 1x10-6. This means one
cancer case per 1,000,000 population.
The level of bromate detected in CMWD's source water supplied by MWD and SDCWA for 2013 and
2018 are listed below.
Source: MWD Skinner Plant
Constituent Units MCL PHG
(MCLG)
2013 2014 2015 2016 2017 2018
Bromate ppb 10 0.1 Highest RAA 5.9 3.6 4.3 4.2 4.1 3.7
Source: SDCWA Twin Oaks Plant
Constituent Units MCL PHG
(MCLG)
2013 2014 2015 2016 2017 2018
Bromate ppb 10 0.1 Highest RAA 2.6 3.1 4.2 5.9 6.0 5.0
RAA = Running Annual Average. Highest RAA is the highest of all Running Annual Averages calculated as the
average of all samples collected within a 12-month period. ppb = parts per billion.
April 21, 2020 Item #6 Page 11 of 36
For more information contact Carlsbad Municipal Water District, 5950 El Camino Real, Carlsbad 92008;
phone: 760-438-2722; email: water@carlsbadca.gov
Page 6 of 8
Chromium VI
Hexavalent Chromium (chromium VI) occurs in natural waters in the environment and is present in
water from the erosion of chromium deposits found in rocks and soils. It is also produced by industrial
processes and manufacturing activities including discharges from steel and pulp mills, among others. It
can also be released to the environment via improper storage and disposal practices.
Hexavalent chromium consumed in drinking water in excess of the MCL over many years may cause
allergic dermatitis. This chemical has been shown to cause cancer in laboratory animals, such as rats and
mice, and humans when they are exposed at high levels over their lifetimes. The numerical health risk
for the PHG of 0.02µg/L is one excess case of cancer per million people. The numerical health risk for the
MCL of 10 µg/L is one excess of cancer per fifty thousand people.
The level of hexavalent chromium detected in CMWD's source water supplied by MWD and SDCWA for
2013 and 2018 are listed below.
Source: SDCWA Twin Oaks Plant
Constituent Units MCL PHG
(MCLG)
2013 2014 2015 2016 2017 2018
Chromium VI ppb 10 0.02 Average ND ND 0.04 0.06 ND 0.09
ppb = parts per billion. ND = Non Detect.
NDMA
NDMA is a chemical formed in both industrial and natural processes. It is a byproduct of chlorination at
wastewater treatment plants that use chloramines for disinfection. NDMA was also formerly used in the
production of rocket fuel, antioxidants, and softeners for copolymers.
Although NDMA is listed as a priority toxic pollutant, no federal MCL has been established for drinking
water. It is classified as a probable human carcinogen. The Notification Level (NL) for NDMA is a health-
based advisory level established by the Division of Drinking Water (DDW) for chemicals in drinking water
that do not have MCLs. In 2013, sample results included a value of 11 ppt, which exceeded the NL of 10
ppt.
The level of hexavalent N-Nitrosodimethylamine (NDMA) detected in CMWD's source water supplied by
MWD and SDCWA for 2013 and 2018 are listed below.
Source: MWD Skinner Plant
Constituent Units MCL PHG
(MCLG)
2013 2014 2015 2016 2017 2018
NDMA ppt NL=10 3 Range ND ND-
2.3
ND-
3.1
ND-
3.2
NDMA ppt NL=10 3 D. Wide ND-ND-ND ND-
April 21, 2020 Item #6 Page 12 of 36
For more information contact Carlsbad Municipal Water District, 5950 El Camino Real, Carlsbad 92008;
phone: 760-438-2722; email: water@carlsbadca.gov
Page 7 of 8
Source: MWD Skinner Plant
Constituent Units MCL PHG
(MCLG)
2013 2014 2015 2016 2017 2018
6.0 5.1 3.2
NDMA ppt NL=10 3 Single 6.5 2.0-
2.9
ppt = parts per trillion. NL = Notification Level. D. Wide = District Wide. ND = Non Detect
Cost Estimate for Treatment
The best available technology (BAT) to lower the level of these compounds below the PHG is reverse
osmosis. Since the levels are already below the MCL, reverse osmosis would be required to attempt to
lower the levels to below the PHG. Please note that accurate cost estimates are difficult, if not
impossible, and are highly speculative and theoretical. All costs including annualized capital,
construction, engineering, planning, environmental, contingency, and O&M are included, but only very
general assumptions can be made for most of these items. Costs estimating guides from the Association
of California Water Agencies guidance report were used in determining the estimated cost to implement
the BAT. The cost of implementing RO treatment would start at approximately $1.85 - $4.33 per 1,000
gallons treated. CMWD’s annual water usage is approximately 15,000 to 18,000 acre feet and therefore
will cost approximately $23 million per year to treat, and does not include the capital costs of
installation of such facilities and maintenance thereafter. There would be additional costs for corrosion
control because water treated by reverse osmosis is corrosive and could cause the water to exceed the
lead and copper regulations. Additionally, CMWD does not have a treatment plant of its own where
such a treatment plant is not feasible. Hence, it is logistically not possible for CMWD to implement such
a BAT. As previously stated, it is unclear whether treatment to lower a constituent below the PHG or
MCLG would be feasible, as BATs are designated for treatment to achieve compliance with the
corresponding MCL only, and not the PHG or MCLG.
Recommendations:
The drinking water quality of the Carlsbad Municipal Water District meets all State of California,
Department of Public Health and USEPA drinking water standards set to protect public health.
To further reduce the levels of the constituents identified in this report that are already significantly
below the health-based MCLs established, additional costly treatment processes would be required. The
effectiveness of the treatment processes to provide any significant reductions in constituent levels at
these already low values is uncertain.
NDMA ppt NL=10 3 Sample ND-6.7 ND-
5.0
April 21, 2020 Item #6 Page 13 of 36
For more information contact Carlsbad Municipal Water District, 5950 El Camino Real, Carlsbad 92008;
phone: 760-438-2722; email: water@carlsbadca.gov
Page 8 of 8
The health protection benefits of these further hypothetical reductions are not at all clear and may not
be quantifiable. Therefore, no action is proposed.
CMWD’s drinking water is provided by the MWD and SDCWA water treatment plants and these source
plants treat water prior to being received by CMWD. CMWD continues to work with MWD and SDCWA
to ensure that the drinking water is safe and affordable.
April 21, 2020 Item #6 Page 14 of 36