The CWEA Environmental Compliance Inspector (ECI) exams are designed for people currently working as, or aspiring to become, Environmental Compliance Inspectors in California.
The exams are administered by the California Water Environment Association (CWEA), a professional organization dedicated to wastewater professionals in California.
The CWEA ECI exams are categorized into four grades: Grade 1, Grade 2, Grade 3, and Grade 4:
Grade 1 is the entry-level exam, ideal for beginners
Grade 2 is more challenging and suited for supervisory roles
Grade 3 is even more advanced, targeting middle-management positions
Grade 4 is the most difficult and is intended for upper-management roles.
While CWEA certification isn't mandatory for a job as an Environmental Compliance Inspector, it can help you get a job and can also lead to a pay raise and other benefits.
3) During a titration, 32.20 mL of 0.250 M NaOH neutralizes 26.60 mL of H₂SO₄. What is the molarity of the H₂SO₄ solution?
0.071 M
0.083 M
0.106 M
0.151 M
4) How many mL of a 0.2 M KOH solution will neutralize 15 mL of 0.4 M HCl?
10 mL
20 mL
30 mL
40 mL
5) How many liters of 0.2 M potassium hydroxide are needed to neutralize 25,000 liters of 0.8 M hydrochloric acid?
25,000
50,000
75,000
100,000
6) In the context of gases, what does LEL stand for?
Lead equivalent level
Lower explosive limit
Lowest effective level
Lowest exposure limit
7) During an eight-hour shift, an employee is exposed to zinc oxide fumes at a concentration of 150 ppm for two hours, 75 ppm for another two hours, and 50 ppm for four hours. Calculate the 8-hour time-weighted average.
81.25 ppm
88.515 ppm
91.75 ppm
95 ppm
8) Which of these is written information that must be supplied by manufacturers of chemicals and hazardous materials?
OSHA
OSM
SDS
TOSM
9) Which section of a safety data sheet gives the flammability of a chemical?
Accidental release measures
Handling and storage
Physical and chemical properties
Transport information
10) Who is responsible for preparing safety data sheets?
The customer
The end-user
The government
The manufacturer
11) On the NFPA hazard diamond below, what do the letters SA mean?
Can shock or cause acid damage
Safety assessed
Simple asphyxiant
Substance abuse
12) What is NH₃ more commonly known as?
Ammonia
Benzene
Hydrazine
Nitrogen hydroxide
13) A pH of 9 is how many times more alkaline than a pH of 7?
2
3
10
100
14) Primary treatment of wastewater typically removes what percentage of total suspended solids?
0–10%
20–40%
50–70%
80–100%
15) If the settled sludge volume is 30 mL/L and the mixed liquor suspended solids (MLSS) is 3,000 mg/L, what is the sludge volume index in mL/g?
0.01 mL/g
0.1 mL/g
1 mL/g
10 mL/g
16) What is flocculation?
The biochemical decomposition of organic matter
The process of bringing a liquid into contact with air
The process of particles joining together to form larger particles
The separation of liquids from solids
17) In the context of wastewater treatment, what does the abbreviation IU stand for?
Incoming undercurrent
Industrial user
Intelligent user
Intermediate user
18) Which of these is a physical wastewater treatment method?
Ion exchange
Neutralization
Oxidation
Screening
19) Which chemical is added to raw wastewater to make dirt particles stick together and coagulate?
Alum
Chloramine
Hypochlorite
Ozone
20) What is the final step of SARS-CoV-2 wastewater testing?
RNA extraction
RNA measurement
Sample concentration
Sample preparation
21) UV disinfection happens at what stage of wastewater treatment?
Primary
Secondary
Tertiary
Quaternary
22) What is the sedimentation step of wastewater treatment also known as?
Clarification
Flocculation
Rapid gravity filtration
Slow sand filtration
23) If chlorine is used for water disinfection, then the sewage treatment plant will require a sample measurement of:
chlorinating granules
fecal coliform
total residual chlorine
total suspended solids
24) When testing wastewater samples for viruses, what is used to estimate the amount of virus lost during sample processing?
Matrix recovery control
Phage recovery control
TDS recovery control
Virus recovery control
25) Which of these wastewater treatment methods uses specially modified soil to remove microorganisms and extra nutrients from effluent?
Absorption trenches
Amended soil mounds
Sand mounds
Subsurface irrigation
26) Which emerging technology uses microorganisms to generate electricity from the organic matter in wastewater?
Membrane technology
Microalgae
Microbial fuel cells
Restriction fragment length
27) If a vertical cylindrical tank has a diameter of 5 feet and a height of 8 feet, what is the capacity of the tank in cubic feet?
145 ft³
157 ft³
227 ft³
290 ft³
28) During the initial stages of water treatment, water mixes gently to form heavier and larger particles called:
clogs
clusters
flocs
sediments
29) A well has a one-meter diameter and its water is ten meters deep. How much water is in the well?
385 liters
2,730 liters
4,890 liters
7,850 liters
30) A river has a flow rate of 50 cubic feet per second. Calculate its flow rate in gallons per second.
39
92
198
374
31) Which of these is the preferred way to prevent pollution?
Recycling
Source reduction
Waste disposal
Waste treatment
32) What does an orifice plate measure?
Flow rate
Salinity
pH
Temperature
33) An industry discharges 5,000 gallons of wastewater per day. The wastewater contains 10 mg/L of magnesium. What is the industry's mass emission rate of magnesium in pounds per day?
0.31 pounds per day
0.42 pounds per day
0.58 pounds per day
0.64 pounds per day
34) Which industry typically produces runoff high in nitrogen?
Agriculture
Metal plating
Petrochemical
Textiles
35) Which of these water treatment methods is a chemical treatment process?
Activated sludge
Filtration
Neutralization
Trickling filter
36) What is the best method to determine the chemicals that industrial dischargers are placing in the collection system?
Field test kits
Laboratory chemical analyzes
Results of industrial self-monitoring
Visual observations
37) Which of these is a variable the Manning formula requires to calculate the flow rate in a pipe?
BOD of the water
Hydraulic radius
Length of the pipe
Runoff coefficient
38) What is the purpose of an unannounced industrial inspection?
To check effluent quality
To meet with POTW's normal contact person
To review paper work
To test response of industry
39) Which of the following is a recoverable chemical from textile mill waste?
Caustic soda
Soda ash
Sulfur dioxide
Sulfuric acid
40) What does the term buffer capacity mean?
A measure of the ability of a solution or liquid to neutralize acids or bases
A solution that resists change in pH from the addition of acid or base
The amount of liquid a solid material can absorb
The flow or load that a treatment plant is designed to handle
41) A district charges a sewer impact fee of $2,500 per REC (Residential Equivalent Connection) for new developments, where one REC is 150 gallons per day. Calculate the sewer impact fee for a new office building with 15 employees, assuming each employee will use 20 gallons of water per day.
$2,175
$2,875
$3,000
$5,000
42) A developer anticipates that a new site will use 1,100 gallons of water per day. The sewer impact fee is $29.81 per gallon per day. Calculate the total daily sewer impact fee.
$28,198
$29,100
$32,791
$34,814
43) Which of these Acts regulates pollutant discharges into water and the quality standards for surface waters?
Clean Water Act
Comprehensive Environmental Response, Compensation, and Liability Act
National Environmental Policy Act
Safe Drinking Water Act
44) Hydraulic load is the height in inches of the average volume of wastewater introduced into a pond in one:
second
minute
hour
day
45) For protection from effluent splashes and flying debris, workers should use:
fall-detection technology
flame-resistant clothing
respiratory equipment
safety goggles
46) Typically, how often do facilities have to submit discharge monitoring reports (DMRs)?
Weekly
Monthly
Bi-annually
Annually
47) Which of these is a conventional pollutant?
Benzene
Biochemical oxygen demand
Cyanide
Hexavalent chromium
48) Which of these should you never do around a UV system?
Collect samples
Drink bottled water
Look into the lamps without eye protection
Plug a UV system into a grounded electrical outlet
49) What are receiving water standards based on?
Categorical standards
Technology-based standards
The best available technology economically achievable
The tolerance of the stream to pollutants
50) A factory uses 3 cubic feet of copper daily. Assuming the factory operates five days a week, calculate the number of gallons of copper the industry uses every week, to the nearest gallon.
22
73
112
157
51) Which law provides increased protection for groundwater systems susceptible to fecal contamination?
Ground Water Rule
Hydraulic Fracturing Law
Source Water Protection
The Underground Injection Control Program
52) A primary clarifier is 120 feet long, 40 feet wide, and 14 feet deep. The influent flow is 7.5 MGD. Calculate the detention time in hours.
1.6 hours
3.2 hours
4.8 hours
6.2 hours
53) Which federal program authorizes the President to take emergency action in the event of the release of hazardous substances into the environment?
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
Environmental Change and Security Program (ECSP)
National Environmental Policy Act (NEPA)
Resource Conservation and Recovery Act (RCRA)
54) What is brownwater?
Water from sinks, showers, bathtubs, and washing machines
Water that contains soil
Water that has been cleaned at a water treatment plant
Water that has come into contact with feces
55) The provisions of 40 CFR part 433 subpart A apply to six metal finishing operations. These are electroplating, electroless plating, anodizing, coating, chemical etching and milling, and:
electrochemical machining
electron beam machining
printed circuit board manufacture
vapor plating
56) Algal bloom is mostly caused by the presence of large amounts of what in water?
Carbon dioxide
Nitrogen and phosphorus
Plastic
Suspended matter
57) In traffic control, which taper requires the longest distance?
Downstream
Merging
Shifting
Shoulder
58) A representative sample is:
collected during minimum flows
obtained when industrial representatives are present
similar to the larger body of wastestream being sampled
transported to a laboratory for analysis
59) Which organization administers the Manual on Uniform Traffic Control Devices (MUTCD)?
Environmental Protection Agency (EPA)
Federal Highway Administration (FHWA)
Federal Motor Carrier Safety Administration (FMCSA)
National Transportation Safety Board (NTSB)
60) A battery manufacturing industry discharges 4,000 kg of wastewater per day carrying 6 g/L of benzene. How many kilograms of benzene does the industry discharge per day?
20 kg
24 kg
28 kg
32 kg
61) A solution of hydrogen peroxide contains 20% hydrogen peroxide and has a density of 2 g/mL. How many grams of hydrogen peroxide are in one liter of the solution?
100 g/L
200 g/L
300 g/L
400 g/L
62) Which of these is a reason for collecting a water sample in a septum vial?
To keep the sample cool
To prevent infection by possible pathogens
To prevent people from tampering with the sample
To prevent water evaporation
63) What is the difference between point-source pollution and non-point-source pollution?
Point-source pollution comes from a single place while non-point-source pollution comes from many places
Point-source pollution is characterized by continuous discharges while non-point-source pollution occurs in sudden, concentrated releases
Point-source pollution is mainly associated with agricultural runoff while non-point-source pollution is linked to industrial discharges
Point-source pollution results from natural processes while non-point-source pollution results from human activities
64) Which method of pollution treatment uses fungi?
Mycoremediation
Phytotransformation
Rhizodegradation
Rhizofiltration
65) Which of these bacteria is an indicator of water pollution?
Azospirillum
Biggiata
E. coli
Lactobacillus
66) What is the main toxic metal in dental amalgam?
Aluminum
Chromium
Lead
Mercury
67) When taking a water sample from a plastic spigot, what is the easiest and most effective way to disinfect the spigot?
Alcohol swab
Flame
Ozone disinfection
Peracetic acid immersion
68) New Sources must submit a baseline report to the Control Authority at least _____ days before starting discharge.
90
180
270
360
69) A tank holds 10,000 gallons of cyanide solution with a cyanide concentration of 20 mg/L. Calculate the number of pounds of cyanide in the tank.
0.84
1.67
2.32
3.84
70) Which formula calculates the response factor in gas chromatography?
Concentration × detector response
Mass / volume
Mass × slope of the plot
Peak area / concentration
71) Which term means the movement of water through porous materials such as soil?
Percolation
Precipitation
Reticulation
Sedimentation
72) What is the primary goal when attending to a spill?
Keep people safe
Minimize damage to machinery
Minimize damage to the environment
Prevent the spill from spreading
73) An industry has three sewer connections with the following discharge rates:
Connection 1: 500 gpd
Connection 2: 150 gpd
Connection 3: 350 gpd
A flow-weighted composite sample of 3 liters is needed. How many milliliters of sample from each connection should be composited?
1,000 mL, 1,000 mL, 1,000 mL
1,200 mL, 800 mL, 1,000 mL
1,500 mL, 450 mL, 1,050 mL
500 mL, 150 mL, 350 mL
74) If a water sample is not properly chilled and sealed, which of these water quality indicators would stay the same?
BOD
COD
Dissolved sulfide
Hardness
75) Which Resource Conservation and Recovery Act (RCRA) waste code applies to wastes from nonspecific sources?
F
K
P
U
76) What do composite samples measure?
Pollutants of specific concern
The average concentration of pollutants
The maximum concentration of pollutants
The pollutant discharge at a specific time
77) How is the flow depth measured in a Palmer-Bowlus flume?
Channel bottom to water surface at measure point
Channel bottom to water surface at throat
Floor of flume to water surface at measuring point
Floor of flume to water surface at throat
78) How many gallons of water can a 200 cubic-foot tank hold?
1,017
1,496
1,938
2,432
79) An industry has a wastewater discharge of 40,000 gallons per day containing 15 mg/L of cyanide. What is the industry’s mass emission rate of cyanide in pounds per day?
5 lb/day
8 lb/day
10 lb/day
12 lb/day
80) A wastewater treatment plant exceeds its daily nitrogen discharge limit on 3 days in January, 1 day in March, 2 days in September, and 5 days in December. The penalty is $2,000 for every day the discharge limit was exceeded. Calculate the plant's total penalty for the year.
$18,000
$20,000
$22,000
$24,000
81) How should an inspector respond when an unknown material that is neither flammable nor asphyxiating is found in a collection system?
Assume the unknown material was an accidental spill
Disregard the unknown material until next time
Try to trace the unknown material back to the industrial source
Wait for the unknown material to arrive at the treatment plant
82) Which type of safety system involves a team leader calling their staff periodically (every hour, for example) to make sure they are safe?
Check-call
Checklist
Contact-tracing
Dispatch
83) What is dangerous about gasoline in sewers?
It can cause sewage to expand
It can explode
It can rust pipes
It can thicken sewage and cause blockages
84) In wastewater systems, what does the term "peaking factor" mean?
A value indicating the smoothness of the interior of a pipe
The maximum momentary load placed on a water treatment plant, pumping station, or distribution system
The ratio of a maximum flow to the average flow
The ratio of true power to apparent power in an electrical circuit
85) What is the purpose of ultraviolet light in wastewater treatment?
To improve water taste
To kill pathogens
To reduce water hardness
To remove suspended particles
86) If the residual chlorine is 2.0 mg/L and the chlorine dosage is 8.0 mg/L, what is the chlorine demand?
4.0 mg/L
6.0 mg/L
10.0 mg/L
16.0 mg/L
87) For new developments, a district charges a sewer impact fee of $3,200 per REC (Residential Equivalent Connection), where one REC is 240 gallons per day. If a new build will have 20 employees and each employee will use 15 gallons of water per day, then what is the sewer impact fee?
$1,000
$2,000
$3,000
$4,000
88) The CWA makes it unlawful to discharge any pollutant from a point source into navigable waters unless a(n) ___________ is obtained.
amendment
demineralization certificate
discrete conveyance
permit
89) What is the maximum residual chlorine dioxide level allowed by the EPA for drinking water?
0.004 ppm
0.02 ppm
0.8 ppm
5 ppm
90) Which of these is always required when working in a confined space?
Breathing apparatus
Continuous air monitoring
Fall arrest tripod
Radio
91) Which of these gases is odorless?
Arsine
Bromine gas
Carbon monoxide
Hydrogen sulfide
92) Animal slurries are usually treated by:
anaerobic lagoons
brine treatment
electrochemical coagulation
reverse osmosis membrane filtration
93) What is the normal sampling frequency for water companies carrying out operator self-monitoring (OSM)?
1 or 2 samples per year
4 or 8 samples per year
12 or 24 samples per year
16 or 28 samples per year
94) What association is devoted to eliminating death and injury due to fire hazards?
CWEA
NFPA
NSC
OSHA
95) Before entering an industrial facility for an inspection, why should an environmental compliance officer first visit the sampling points and collect wastewater samples?
To collect an unbiased wastewater sample
To ensure following proper chain of custody procedures
To minimize the time required of the industrial contact
To present the industrial contact with the results of the analysis of sample
96) What are the sources of pollutants in stormwater runoff?
Drag out dripping on the floor
Products which have spilled on the grounds
Rinse waters
Scrubber wastewater
97) Physicochemical wastewater treatment methods, such as coagulation and reverse osmosis, are examples of which level of treatment?
Primary
Quarternary
Secondary
Tertiary
98) What is the purpose of the buffer area in traffic control?
To redirect traffic out of its normal path
To separate traffic from the work area
To store tools and machinery
To warn drivers of work or danger
99) Which of these causes concrete to crack when it reacts with calcium?
Chloride
Chlorine
Nitrate
Sulfate
100) A containment tank has dimensions of 15×15×2 feet. There is also a cylindrical metal column in the middle of the tank with a diameter of 2 feet and a height of 10 feet. Calculate the number of gallons of water the containment tank can hold.
3,131 gallons
3,266 gallons
3,389 gallons
3,419 gallons
101) When collecting samples to be analyzed for volatile organic compounds, to which point should you fill the vial?
Completely full
Filled with about one inch of space at the top
Four-fifths full
Half full
102) For how long is the BOD₅ test run?
5 minutes
5 hours
5 days
5 weeks
103) What is "direct runoff"?
A discharge from the end of a pipe, often containing pollutants
A pipe that carries stormwater but not domestic and industrial wastewater
Wastewater that flows out of a sanitary sewer as a result of an overflow
Water that flows over the ground surface directly into streams, rivers, or lakes
104) What is the minimum number of years a POTW must retain Industrial User records?
2 years
3 years
4 years
5 years
105) Bubbler systems:
break down foam on the water surface
measure the flow rate of streams
measure the water level
mix water in stilling wells
106) If a wastewater treatment plant can treat 150,000 gallons of sewage in 1 hour, then how many gallons of sewage can it treat in 8 hours?
150,000
400,000
800,000
1,200,000
107) Which of these is most likely to be a source of catastrophic discharges?
Canneries
Chemical plants
Construction sites
Dairies
108) An industry has a discharge of 16,000 gpd. A composite sample of 1 liter is needed. The sampler takes 125 ml each time it is activated. For a flow proportional sample, at what gallon interval should the sampler activate to take a sample?
1,000 gallons
2,000 gallons
3,000 gallons
4,000 gallons
109) The following magnesium results, in mg/L, were taken throughout the day:
0.38, 0.71, 0.47, 0.60, 0.12, 0.11, 0.10, 0.71
Calculate the mean of these results.
0.25
0.27
0.37
0.40
110) In the rapid infiltration method of land treatment:
collected water is discharged into the stream
effluent is applied on the land by ridge-and-furrow spreading
purification is achieved through biological, physical, and chemical means
wastewater is stored in large ponds
111) Domestic water generated by small communities can be treated by:
barren land
coastal lands
constructed wetlands
range land
112) Which of these test papers detects the presence of hydrogen sulfide?
Flame retardant paper
Lead acetate paper
M-9 CAD paper
Peracetic acid test strips
113) COD tests are reported in what units?
mL/mol
mg/L
mol/L
mol/g
114) Which containers are designed exclusively to separate non-polar liquids at oil refineries?
API separator
PE separator
Plastic separator
Polyethylene separator
115) Which term means a conveyance, such as a pipe, ditch, or channel, from which pollutants are discharged?
Effluent
Emergent outflow
Overflow
Point source
116) Which of these tests is reported in mg/L?
Temperature
Total toxic organics
Turbidity
pH
117) What is the flashpoint of car gasoline?
32°C
52°C
82°C
−43°C
118) Facilities do not need to file a Spill Prevention, Control, and Countermeasure (SPCC) plan with the EPA if the oil storage capacity on the facility is less than how many gallons in total?
10,000
20,000
30.000
40.000
119) What is the most used toxic pollutant in leather tanning?
Chromium
Copper
Cyanide
Phenol
120) A rectangular containment tank has a length of 15 feet and a width of 10 feet. To the nearest foot, how tall does the tank need to be to hold 10,000 gallons of water?
6 feet
7 feet
8 feet
9 feet
121) The Environment Protection Agency provides which web-based tool that calculates and reports facility pollutant discharges based on NPDES permit limit and DMR data?
NPDES E-Reporting Tool
Pollutant Head Tool
Toxics Follow-up Tool
Water Pollutant Loading Tool
122) Why are septum vials used for samples to be tested for total toxic organics?
To comply with hazardous waste regulations
To prevent cross-contamination with grab samples
To prevent sample contact with air
To prevent skin contact with toxic organic compounds
123) Most wastewater is treated through the separation of solids and liquids, typically by:
crystallization
distillation
sedimentation
stripping
124) Which method of measuring water level uses high-frequency pulses that hit the surface of the liquid and return to the sensor?
Bubbler
Pressure transducer
Sounder
Ultrasound
125) Which instrument measures water turbidity?
Flowmeter
Nephelometer
Spectrometer
Venturimeter
126) Which of these is a source of dilute solutions that may be discharged to the pretreatment system or POTWs?
Reject products
Spent plating baths
Static drag out solutions
Stormwater runoff
127) Which of these is found on Self-Monitoring Report (SMR) forms?
Air quality index
Child-resistant closures
Hazard pictograms
Laboratory test results
128) What is the main goal of sample storage procedures?
To accumulate a large enough sample for analysis
To allow samples to accumulate before analysis
To efficiently use the analyst's time
To maintain the integrity of the sample until analysis
129) In which temporary traffic control zone does the work take place?
Activity area
Advance warning area
Termination area
Transition area
130) Chemical oxygen demand is reported in what unit?
kg/meq
meq/mole
mg/L
moles/mL
131) A sulfuric acid solution contains 12% sulfuric acid and has a density of 1.4 g/mL. How many grams of sulfuric acid are in one liter of the solution?
117 g/L
168 g/L
857 g/L
1167 g/L
132) A wastewater sample is to be analyzed for volatile organic compounds but the water contains chlorine. What can be used to preserve the sample?
1 mol of nitric acid
1:2 ratio of 50% ethanol
2 drops of a 25% ascorbic acid solution
5 mL of a 10% mercuric chloride solution
133) In which stage of sewage treatment do microorganisms consume the organic components of the sewage?
Primary
Secondary
Tertiary
Quarternary
134) Temporary traffic control zones generally have five sections: the advanced warning area, the transition area, the buffer area, the work area, and the ___________ area.
controlled
final warning
late warning
termination
135) What does the C in COD stand for?
Carbon
Chemical
Chlorine
Combined
136) In water pipes, what is a "springline"?
A line that represents the elevation of energy head of water flowing in a pipe
An outlet for overload conditions during peak flows
The horizontal centerline of a pipe
The lowest point of the channel inside a pipe
137) For what purpose do metal plating industries use dragout tanks?
Metal recovery
Volume reduction
Wastewater equalization
Wastewater segregation
138) Which of these is a method commonly used to thicken activated sludge before treatment?
Aeration
Dissolved air flotation
Sand filtering beds
Vacuum filtration
139) Wastewater from toilets is known as:
blackwater
brownwater
graywater
whitewater
140) What is the "scouring velocity" of a river?
The average velocity of the river during flooding
The minimum velocity required for zero turbulence
The velocity that prevents particles from settling on the river bottom
The velocity which pulls plants out of the riverbed
141) Lime reacts with carbon dioxide in wastewater to produce which chemical?
Activated carbon
Calcium carbonate
Sodium carbonate
Sodium hydroxide
142) Fees imposed by a local government on a new development project that pay for all or a portion of the costs of providing public services to the new development are called:
buy-in fees
growth-related improvement fees
impact fees
reimbursement fees
143) Bacteria used in water treatment plants function optimally at which temperature?
5–15°C
15–25°C
25–35°C
35–40°C
144) What is a Bronsted-Lowry acid?
A chemical compound with the structural formula HNCO
A salt that produces an acidic solution after being dissolved in a solvent
A substance that donates hydrogen ions during a chemical reaction
An organic compound that reacts with alcohols to form uric arid
145) Water samples to be analyzed for bacteria should be kept at what temperature?
21°C
37°C
4°C
−6°C
146) Water samples to be analyzed for cyanide should be kept at what temperature?
−6°C
4°C
21°C
37°C
147) What container and preservative are needed for samples to be analyzed for total or dissolved metals?
Cubitainer, H₂SO₄ to pH < 2
Glass, HCL to pH > 9
Glass, zinc acetate + NaOH to pH > 9
Plastic, HNO₃ to pH < 2
148) What container and preservative are needed for samples to be analyzed for bromide?
Plastic, no preservative
Plastic, NaOH
Glass, HNO₃
Glass, zinc acetate + NaOH
149) Which container and preservative are needed when collecting a sample to be analyzed for sulfides?
Glass, HNO₃ to pH > 9
Glass, H₂SO₄ to pH < 2
Plastic, HCl to pH < 2
Plastic, zinc acetate + NaOH to pH > 9
150) What container and preservative are needed for samples to be analyzed for oil and grease?
Glass, HCl to pH < 2
Glass, zinc acetate + NaOH to pH > 9
Plastic, HNO₃ to pH < 2
Plastic, NaOH to pH > 9
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