I-22_WaterSampleFiltrationSOP_FINAL_06292021 - signed

Title:
Version
Approvals
Approved by:
Approved by:
CITY OF
DURHAM
City of Durham, North Carolina
Department of Public Works
Stormwater and GIS Services
Water Quality Unit
Standard Operating Procedures for Water Sample Filtration
1.0
Date: Jun 30, 2021
Michelle Woolfolk, Water Quality Manager
lod'eal��1111
Date: Jun 30, 2021
Paul Wiebke, Assistant Director for Stormwater & GIS Services
City of Durham, WQ Unit, Water Sample Filtration Page 1 of 10
06/29/2021

Revision Record
Revision
Date
Updated by
Description of change
1.0
06/29/2021
J. Smith
Minor Edits
Distribution
Current copies of this approved SOP should be provided to the following positions with the City of
Durham Stormwater and GIS Services:
• Water Quality Manager
• Assistant Water Quality Manager
• Environmental Planning and Compliance Senior Analysts
• Environmental Planning and Compliance Analysts
• Environmental Planning and Compliance Coordinators
• Environmental Planning and Compliance Specialists
• Temporary Environmental Planning and Compliance Specialists or other staff assigned to the
project
The current SOP should also be provided to any contractors performing these procedures on behalf of
City of Durham Stormwater & GIS Services.
City of Durham, WQ Unit, Water Sample Filtration Page 2 of 10
06/29/2021

Abbreviations
DI Water
Deionized water
IDDE
Illicit Discharge Detection and Elimination
PPE
Personal Protection Equipment
PFD
Personal Floatation Device
QA/QC
Quality Assurance/Quality Control
QAPP
Quality Assurance Project Plan
SDS
Safety Data Sheet
SOP
Standard Operating Procedure
SW Lab
Stormwater Lab
USEPA
United States Environmental Protection Agency
µm
Micrometer
WQU
Water Quality Unit
Table of Contents
Procedures...............................................................
Purpose and scope ..............................................
Method summary ................................................
Health and safety warnings .................................
General safety considerations for fieldwork...
Personal protective equipment .......................
Chemical safety ...............................................
Cautions and interferences .................................
Personnel qualifications and responsibilities......
Equipment and supplies ......................................
Methods..............................................................
Data and records management ...........................
Quality assurance and quality control (QA/QC).......
References...............................................................
City of Durham, WQ Unit, Water Sample Filtration Page 3 of 10
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Procedures
Purpose and scope
The purpose of this Standard Operating Procedure (SOP) is to establish uniform and consistent
procedures for field filtering of water samples in preparation for analysis by an analytical laboratory.
Filtration is required if the analyte(s) of interest are compounds that are dissolved in the water sample
under ambient conditions. The appropriate size of the filter pores is dependent on the analyte of
interest and generally defined by the associated analytical method. For example, the approved
analytical methods for laboratory analysis of metals (US Environmental Protection Agency (USEPA),
1994) specify the use of a filter with 0.45µm pore size. Measuring the dissolved forms of compounds, as
compared to particulate forms, are important because they are more bioavailable to instream organisms
and can affect aquatic ecosystem health. For example, dissolved metals are commonly of interest.
Method summary
A new disposable filter is attached to a short length of appropriate flexible tubing (usually silicone)
specified by the manufacturer for use with the peristaltic pump. A length of rigid tubing may be inserted
into this flexible tubing if allowed in the quality assurance project plan (QAPP). The use of rigid tubing,
such as polyethylene, is an effective cost saving measure. However, some compounds may bind to the
tubing and affect lab results, so refer to the specific project QAPP for requirements. The flexible tubing is
inserted into the pump head of a peristaltic pump. The other end of the tubing is placed in the water
source to be sampled. The pump is turned on, the tubing and filter are allowed to flush, and the filtered
sample is collected. The filter and tubing are removed from the peristaltic pump and returned to the
Stormwater Lab (SW Lab) for proper disposal.
Health and safety warnings
This procedure requires the use of a peristaltic pump. Personnel operating the peristaltic pump should
refer to the owner's manual and the Standard Operating Procedures for Use of Peristaltic Pumps for
Sample Collection (City of Durham 1a, 2018) for safety and proper handling information. Rechargeable,
sealed, 12-volt batteries are normally used to power the peristaltic pump. Care should be taken to avoid
damage to the battery or exposure of its internal components to the environment.
General safety considerations for fieldwork
The Water Quality Unit (WQU) conducts sampling throughout the City of Durham and surrounding areas
at times and places where medical facilities may not be readily available. It is imperative that all
employees receive instruction and follow safety precautions when using equipment and hazardous
materials to prevent injury. "Safety first" must always be the rule.
All employees should receive a copy of the Department of Public Work's Safety Operating Procedures
(Department of Public Works, 2017) and current Safety Policies (City of Durham 1b, 2021) upon hire. Any
injuries or incidents should be documented and recorded in accordance with City and Department
policies. The first priority should be to provide appropriate care (First Aid or emergency treatment) to
the injured employee; the second priority is to notify the appropriate supervisor.
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While the remainder of this section summarizes some of the more common hazards encountered during
fieldwork, all employees are expected to review and comply with all City procedures and policies.
One of the most prevalent situations encountered by field staff is walking over uneven and often wet or
muddy terrain while carrying heavy or bulky equipment. Streams in Durham are also often deeply
incised, with steep banks and soils that are clay -based and slick when wet. These conditions increase
risks for slips, trips, and falls. Many sites require working in urban areas where hazards such as roadway
traffic, domestic animals, and possibly wild animals can make access dangerous. In -stream hazards such
as glass shards, construction debris, medical waste, and miscellaneous trash are commonly present.
Staff must be vigilant to take proper precautions in order to decrease the chance of injury. Working in
streams also exposes staff to uneven, slick, or unstable substrates and potentially high flows, all of which
can challenge balance and lead to falls and even potential risk of drowning. Water depth and velocity
should always be considered during site reconnaissance and fieldwork.
Weather forecasts should be consulted prior to field sampling activities. Weather (such as heavy rain,
thunderstorms, lightning, high winds, and excessive heat or cold) can create unsafe conditions. In
certain cases, such as heavy rain or excessive heat or cold, fieldwork may be modified to minimize
increased risks, such as falls, heat stress, or hypothermia due to weather conditions. Staff should
immediately seek shelter or reschedule fieldwork if there are active thunderstorms with lightning or
other severe weather. Weather conditions are particularly critical if staff will be accessing sampling sites
by boat, when high winds or water levels can make boating unsafe.
Personal protective equipment
The following personal protective equipment (PPE) are required for field staff under most conditions
encountered during sampling, though they may be modified based on current weather conditions,
project requirements, and site -specific conditions.
• Appropriate footwear - chest waders, hip boots, knee boots, or steel toe work boots. The
primary purpose of protective footwear is to protect feet from abrasions and crushing injuries.
Field staff should not sample in shoes that do not cover the entire foot (such as sandals) or
shorts, neither of which offer full coverage of feet and lower legs. If monitoring activities require
wading in a stream or other waterbody then waders, hip boots, or rubber knee boots should be
worn to keep staff dry to reduce risks of cold -related stress and to reduce the potential
exposure of staff to pathogenic organisms and other contaminants that are commonly found in
urban waterbodies. During the winter and spring, neoprene waders can provide additional
protection from cold temperatures and reduce risks associated with hypothermia. However,
during warmer periods, waders can increase the risk of heat -related illnesses. These additional
risks can be reduced by staff by minimizing the time spent in direct sunlight, ensuring they stay
hydrated, and taking frequent breaks (including removing waders) as needed to ensure their
safety.
• Long pants provide protection to the lower legs from abrasions and reduce potential for bites
from ticks, insects, and snakes.
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• Long gloves/gauntlets may be helpful under certain situations, such as during cold weather
work to reduce cold -related stress, when sampling below a known discharge to minimize
exposure to pathogens, or to reduce the risk of cuts in the presence of hazards (glass shards,
etc.) within the stream.
• A hat, such as a baseball cap or wide -brimmed hat, helps to shade the head and face, which
helps reduce the potential for sunburn and heat -related illnesses.
• Sunblock/sunscreen reduces the risk for sunburn.
• Insect repellent is important for preventing vector -borne diseases and reactions (including
allergic reactions). Mosquitoes and ticks are very prevalent in Durham and can be active at any
time of the year, and therefore insect repellents containing DEET or other proven chemical
repellent should be worn during all field activities. Staff should check themselves for ticks at the
end of each field day and document any embedded ticks found.
• Poison ivy pre- or post -exposure treatment is necessary for staff that are prone to allergic
reactions to poison ivy or other plants. Affected employees should minimize exposure whenever
possible and take steps to remove irritating plant oils from their skin and clothes as soon as
possible after exposure to reduce the risk of allergic reactions. Soap -and -water is often effective
for removal, though may not feasible under field conditions. There are commercial products
(such as Tecnu) that are more easily used under field conditions. All staff should be mindful of
transferring oils from their clothing to vehicle seats, etc., which can be a potential source of
exposure for other staff.
• First aid kits should be carried by all field staff during all fieldwork.
• High visibility vests or other clothing must be worn when working alongside roads, bridges, and
in the right-of-way.
• Orange safety cones should be used behind vehicles that are parked on the road or in the right-
of-way and the flashing warning lights on the City vehicle should be on to alert other traffic.
• Rain gear (jacket and pants) should be worn to keep staff dry and reduce risks of cold -related
illness.
• Personal flotation device (PFD) is required to be worn and fastened during boating activities or
when appropriate such as sampling from a bridge or top of culvert in stormflow conditions.
• Additional safety equipment (flares, fire extinguisher, horn, etc.) may be required for boat or
field work and will be described in the project QAPP or study plan.
Chemical safety
City staff must follow any applicable City guidance and/or policies for activities such as chemical storage
and handling and the storage of preserved specimens. Chemical handling, storage, and disposal should
comply with requirements in associated Safety Data Sheets (SDS). When sampling unknown substances
in the field, staff should assume they are hazardous and wear appropriate PPE, such as disposable nitrile
gloves. The SW Lab is located in the Annex Building in City Hall and is equipped with safety equipment
such as eyewash stations and fully stocked first aid kits in case of emergency. Staff should be familiar
with the location of all SW Lab eye wash stations and first aid kit locations.
City of Durham, WQ Unit, Water Sample Filtration Page 6 of 10
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Currently, laboratory sample processing and analyses (including chemical and biological samples) are
not performed by WQU staff. Laboratories responsible for the analysis and processing of samples are
responsible for following all appropriate laws and regulations as well as any internal safety procedures.
Cautions and interferences
Care should be taken to prevent contamination of the tubing and filter during preparation and active
filtration. Dust, particles, and other materials coming into contact with the end of the tubing or filter
may cause contamination of the filtered sample and subsequent data accuracy issues. In order to
prevent this, tubing and filters should be stored in covered boxes or containers and should not be
removed from their packaging before their use. Clean plastic should be placed on any surface that the
filter is placed on during preparation. Filters and tubing should be handled with gloved hands. Tubing
should be cut using ceramic scissors to prevent metal contamination. Tubing and filters should be
considered single use and replaced between samples.
Consult the Standard Operating Procedures for Use of Peristaltic Pumps for Sample Collection (City of
Durham 1a, 2018) for further cautions and interferences associated with the use of the peristaltic pump.
In the field, if a sample bottle contains a chemical preservative, do not rinse the bottles with native
water. Be aware of possible cross contamination issues. For example, nitric acid is used to preserve
metals, but can cause contamination of nutrient samples that are analyzed for nitrate, so samples for
analysis of metals should be collected after nutrient samples. WQU field staff must be diligent to collect
representative samples that are free of contaminants. To accomplish this, take care to prevent floating
materials and other debris from entering the sample bottles or intake tubing. In the event of a clogged
filter, an appropriate filter from the same lot may be used to complete sampling, after following the
appropriate preparation procedures outlined in the Methods section below. Additionally, WQU staff
must use a new pair of gloves at each sample site. If field staff observe anything that may influence
water chemistry results, the conditions must be documented in the field notes. This includes
environmental contamination such as passing vehicles, precipitation, upstream construction, etc.
During QC sample collection, only unopened bottles of deionized water (DI water) are to be used for
field blanks. DI water is typically purchased in plastic containers. However, when collecting field blanks
for organic carbon analysis (Total Organic Carbon/Dissolved Organic Carbon) DI water is purchased in 1-
liter amber glass bottles. DI water decanted from plastic containers has been shown to be a cause of
contamination for organic carbon samples.
Personnel qualifications and responsibilities
All City of Durham (COD) WQU personnel conducting sample filtration in the field should be familiar with
this SOP as well as the SOP for Use of Peristaltic Pumps for Sample Collection (City of Durham 1a, 2018),
and any project -specific documentation (for example, the project QAPP). All personnel should be trained
on field procedures by an experienced field technician.
Water chemistry sampling should be performed by experienced staff members who are fully trained on
WQU procedures outlined in this SOP. New staff members, at minimum, will be required to
City of Durham, WQ Unit, Water Sample Filtration Page 7 of 10
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independently be capable of reading and interpreting all procedures and accompanying literature
associated with this SOP. New staff members will perform sampling procedures only under the
supervision of trained full-time staff until they are deemed competent. At times staff members will be
required to use and implement field protocols that may be outside of the scope of this SOP, as such new
staff should be capable of process -based thinking and interpretation to conduct sampling to meet
project goals. Water chemistry sampling is limited to WQU staff and others assigned to water chemistry
sample collections.
Equipment and supplies
• peristaltic pump
• 12V battery for pump
• Pump power cable
• Ceramic scissors
• Disposable gloves
• New trash bag or plastic sheet
• High capacity capsule filter (1/sample) (filter size dependent on the analyte of interest)
• Flexible pump tubing (-12 inches long; 1/sample)
• Rigid tubing (variable length; 1/sample) (optional)
• Chemically inert tubing weight (optional)
• Sample bottles
Methods
Filters and tubing are normally prepared in a clean lab setting prior to sampling. Methods outlined
below reflect this. Methods may be modified if preparing filters and tubing in the field.
1. Put on a clean pair of disposable gloves.
2. Prepare a clean work surface for assembly of filters and tubing, such as placing a clean trash bag
on the work surface.
3. Cut a 1 foot (approximately) length of flexible tubing using ceramic scissors.
4. Using ceramic scissors, cut a sufficient length of rigid tubing, if specified in the QAPP, to reach
from the end of the flexible tubing to the location of the water source to be sampled.
5. Insert the rigid tubing into one end of the flexible tubing.
6. Remove a new filter from its packaging. Record the lot number. Attach the open end of the
flexible tubing to the filter's inlet barb. The filtered sample will be dispensed to the sample
bottle directly from the outlet of the filter (opposite the tubing). Most filters will indicate the
correct flow direction through the filter with an arrow printed on the outside of the filter. An
example of assembled filter and tubing is shown in Figure 1.
7. If not being used immediately, place the filter and tubing into a clean resealable plastic bag and
seal the bag.
8. Refer to the Standard Operating Procedures for Use of Peristaltic Pumps for Sample Collection
(City of Durham 1a, 2018) and the manufacturers recommendations for set up and use of the
peristaltic pump.
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9. At the sampling location, place the peristaltic pump on a stable, level surface near the water
source to be sampled. If tubing and filter are stored in a resealable plastic bag, carefully remove
them from the bag. Prevent the end of the disposable filter from touching any surface to
prevent contamination. Place the flexible tubing into the pump head and lock it into place
(Figure 2).
10. Prepare and power on the peristaltic pump, as described in the appropriate SOP (City of Durham
1a, 2018) or peristaltic pump user manual.
11. With the intake end of the tubing submerged, hold the filter vertically with the flow direction
oriented up, turn the pump on, and allow water to begin flowing through the filter. Allow water
to discharge from the filter for 30 seconds to flush the filter and force out any air.
Figure 1 Filter, silicone tubing, and rigid polyethylene tubing
Figure 2 Filter connected to pump
12. Invert the filter so flow direction is oriented down and place the sample bottle under the flow.
Do not touch the bottle to the filter in order to prevent contamination.
13. When sufficient sample has been collected, turn off the peristaltic pump. Remove the tubing
and filter from the pump head, as described in the SOP (City of Durham 1a, 2018). Discard the
filter and tubing.
14. Preserve, store, and handle filtered samples in accordance with requirements of the analytical
laboratory and project/program documentation. See Standard Operating Procedures for Water
Chemistry Sampling (City of Durham 1c, 2020) for further information.
Data and records management
Filter lot numbers should be recorded on field sheets or other project records for QC tracking purposes.
Depending on the manufacturer, the lot number may be indicated on individual filters, on the shipping
box, or on the certificate of analysis.
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Quality assurance and quality control (QA/QC)
Filter lot numbers should be recorded in field records. This will allow tracking potential contamination
issues to specific filter lot number so they can be removed from use. Staff should try to use filters from a
single lot number on any one day of sampling to minimize recordkeeping requirements and facilitate
easy identification of potentially problematic filter lots. All filter lot numbers used should be recorded on
the field sheet.
Field blank QC samples are recommended to monitor potential contamination from filtration
equipment. The collection of a field blank is identical to collecting environmental water samples, except
the rigid tubing is placed in a bottle of analyte-free deionized (DI) water. Duplicate QC samples can also
be collected. After set up and flushing the filter and tubing, the sampler alternates filling the primary
and duplicate sample bottles until both sample bottles are full.
References
City of Durham 1a. (2018). Standard Operating Procedures for Use of Peristaltic Pumps for Sampling
Collection. Durham: Department of Public Works.
City of Durham 1b. (2021, January 25). 5-201 to 5-209. Retrieved from CON
https:Hcodinet.durhamnc.gov/apps/citypolicy/Approved Policies/
City of Durham 1c. (2020). Standard Operating Procedures for Water Chemistry Sampling. Stormwater &
GIS Services, Water Quality Unit.
Department of Public Works. (2017). Safety Operating Procedures. Durham: City of Durham.
US Environmental Protection Agency (USEPA). (1994). Method 200.7: Determination of Metals and Trace
Elements in Water and Wastes by Inductively Coupled Plasma -Atomic Emission Spectrometry,
Revision 4.4. Cincinnati: USEPA.
City of Durham, WQ Unit, Water Sample Filtration Page 10 of 10
06/29/2021

WaterSampleFiltrationSOP_FI NAL_06292021
Final Audit Report 2021-06-30
Created:
2021-06-30
By:
Joseph Smith ([e-mail])
Status:
Signed
Transaction ID:
CBJCHBCAABAADWgAFxw2pUdjOndhBf1ip9gnb5hn7Ua7
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