CWEA Grade 2 Lab Analyst Practice Test

These questions are part of the practice quiz. Start practicing

• Which parameter has a regulatory storage time of 14 days?
• Which fire extinguisher class is used for kitchen fires?
• What is the preservation approach for COD samples?
• What is the required preservation and storage time for Alkalinity samples?
• What should be documented during calibration of a DO probe?
• How is flow data used when reporting parameter results for composite samples?
• What are recommended practices for labeling and documenting samples to ensure integrity?
• The alkalinity result is expressed as which unit?
• What is the purpose of a field blank in QA/QC and how is it used?
• What is the role of a quality system in a wastewater laboratory?
• How is total suspended solids (TSS) measured and what controls quality?
• Sludge Volume Index (SVI) is the weight of activated sludge solids in grams per liter of settled sludge.
• In Winkler iodometric analysis, which substances interfere?
• Typical qualifiers used in reporting wastewater lab results and what they indicate?
• Why must the COD digestion be performed in sealed vessels?
• Which statement about E. coli O157:H7 detection in Colilert testing is true?
• Which tubing material is appropriate for delivering acetylene to an atomic absorption spectrometer to avoid copper-related reactions?
• What is the preservation for Nitrate + Nitrite?
• What is the difference between a matrix spike (MS) and a matrix spike duplicate (MSD) in QA/QC data interpretation?
• Copper tubing may be used to connect acetylene to an AA spectrometer when copper is not among the elements to be tested.
• In the hardness calculation, what does A represent?
• In the alkalinity calculation Alk = [A*B*50000]/(mL sample), what do A and B denote?
• At the onset of a digester upset, the pH will drop before the volatile acids concentration begins to increase.
• Oil and grease interference in analysis is typically addressed by what lab step?
• If a label is washed clean, what should you do?
• Which factor may interfere with acidity titration as noted in the material?
• Odor interference is evaluated by what method and unit?
• How would you respond to a QC failure indicating a high blank value?
• In the Presumptive Phase, what observation indicates bacterial presence?
• In QA reporting, how are results below the MDL handled?
• What is the preservation method for Phosphorus, Total samples?
• An analyst may use any method given in Standard Methods for a particular constituent when the results are reported to determine compliance with NPDES limits.
• What is the purpose of a chain-of-custody document in wastewater laboratory analysis?
• Proper labeling of reagents (made in the lab) includes which information?
• Which parameter has a short regulatory storage time of 1-2 days with acidification and cooling?
• Which hazard statement is associated with using copper tubing in systems with acetylene?
• Which statement about E. coli O157:H7 testing is correct in Colilert testing?
• What is the difference between filtered and unfiltered samples for metal analysis, and why does it matter?
• What is the recommended storage/handling time for the Temperature parameter before analysis?
• Chlorine Demand is exerted by which substances?
• Which preservation is required for Chloride samples?
• How are accuracy and precision defined in QA/QC, and how are they evaluated in the lab?
• Which analyte requires acidification to pH < 2 and has a 28-day maximum storage time?
• What is the purpose of method validation in QA/QC?
• N1V1 = N2V2 is used for reactions where components neutralize each other, and N stands for normality.
• Which substance is listed as a toxic solid?
• What is the correct temperature and time to sterilize media in an autoclave/steam oven?
• An oxidizing agent is any substance that accepts electrons.
• Which labeling practice is recommended?
• Which of the following best describes the purpose of a matrix spike test in QA/QC?
• Which liquid is listed as an explosive material?
• How are MDL and LOQ treated in reporting results?
• The mean and STD deviation of a series of analytical results is a way of stating the accuracy of the procedure.
• Formazin NTU standards are used to calibrate turbidity meters to ensure what?
• Outline the principal steps of the COD (dichromate) method.
• How do regulatory requirements such as NPDES influence lab QA/QC and reporting?
• In COD analysis, which reagent fixes interference from halides?
• Why are Formazin NTU standards used when calibrating a turbidity meter?
• Which broth is used in the MPn Confirmed Phase?
• What methods are commonly used to determine nitrate and nitrite in wastewater, and what interferences must be considered?
• Why is equipment maintenance logging essential in a wastewater lab?
• What is a Levey-Jennings chart and how is it used in laboratory QA?
• When should Total Chlorine Residual be analyzed?
• In salinity measurements, which condition can cause sluggish readings?
• When is a method considered validated, and what evidence supports validation?
• Combined chlorine residual refers to the presence of which species?
• Which steps are essential for calibrating a DO probe in wastewater analysis?
• How should you combine acid and water according to safety guidelines?
• Which gas is listed as a toxic gas?
• Color interference occurs when turbidity exceeds 1 and the pH is within which range?
• When are reference standards used, and what makes them valid?
• Why might standard addition or matrix-matched calibration be used?
• What is a blank correction, and when should you apply it?
• What is the preservation and storage for Color samples?
• Which of the following is required for good quality assurance in bacteriology?
• What does a flow-weighted average concentration represent in composite samples?
• What is the preservation and storage duration for Sulfate samples?
• Which parameter's storage time is 24 hours or 48 hours, requiring cooling?
• Why is it important to retain reference materials and calibration certificates, and how should they be managed?
• Which statement correctly defines MDL and LOQ?
• The COD test is based on a back titration of organic matter using ferrous ammonium sulfate (FAS) as the titrant. This statement is:
• What are the preservation conditions for Solids samples?
• What is the preservation for Ammonia samples?
• How would you calculate a result that requires dilution due to high analyte concentration?
• What is the standard formula for pH?
• What best describes data integrity expectations in wastewater laboratory reporting?
• Volatile solvents over one liter must be stored in the laboratory in explosion-proof containers.
• In the colorimetric determination of orthophosphate, what is the purpose of forming the molybdenum blue complex?
• Which analyte has preservation that requires acidification to pH < 2 and can be stored up to 28 days?
• What safety measures are required when handling concentrated acids and bases in the lab?
• What is the preservation requirement for the pH samples before analysis?
• Which characteristics are typically included in a method validation?
• What is the preservation for Conductivity samples?
• Which parameter has no preservation required and a 28-day regulatory storage time?
• Which reagents produce the blue molybdenum complex used in the colorimetric determination of orthophosphate?
• Which interference can affect nitrate/nitrite measurements in wastewater using colorimetric methods?
• Bacteriological methods for freshwater samples are not suitable for saline water samples.
• What is the preservation/analysis timing for Nitrate?
• Which gas is listed as a toxic gas?
• Which statement correctly differentiates a grab sample from a flow-weighted composite sample and indicates when each is appropriate?
• How does temperature affect pH readings according to the material?
• Why should sample vials be kept closed with minimal headspace during ammonia analysis?
• For ammonia analysis, what preservation and storage conditions are required to minimize volatilization and microbial alteration?
• In the hardness calculation Hardness = [A*B*1000]/(mL of sample), what does B represent?
• Alkalinity can be determined by the sum of which ions?
• During the MPn Presumptive Phase, what is the incubation temperature used when inoculating Lauryl Tryptose Broth?
• Which analyte’s preservation instruction allows an 8-hour delay after acidification for a Winkler titration?
• Which ions are responsible for water hardness and potential scaling?
• Sulfide interference is caused by which factor due to spectrometer readings?
• In QA/QC, which item is used to detect contamination arising during sampling and handling, not during laboratory reagents?
• Define a matrix spike (MS) and explain its use in QA/QC.
• Which action is appropriate when instrument drift is detected between calibration checks?
• Which analyte requires filtration immediately and cooling, with 48 hours storage in glass rinsed with nitric acid?
• Which factor is cited as interference in BOD measurements due to biological variability?
• Which substances interfere with hardness measurements?
• What is the purpose of flow-based sampling in wastewater monitoring?
• Which ferric salt is listed as a miscellaneous corrosive chemical?
• Which preservation guideline applies to Odor samples before analysis?
• Hot sterilizing ovens are held at what temperature range?
• Briefly describe the BOD5 method and the critical steps that influence accuracy.
• In COD back titration, which chemical is used to titrate the excess oxidant after digestion?
• What is the holding time concept and why must it be observed for wastewater samples?
• What is the preservation instruction and potential delay for Dissolved Oxygen (DO) samples?
• Which statement correctly distinguishes Apparent Color from True Color?
• In COD analysis, which reagent fixes interference from volatile organics?
• What is the preservation and storage time for BOD samples?
• Which parameter requires analysis within 15 minutes (0.25 hours)?
• Conductivity measurements must be temperature compensated at a standard reference temperature of what?
• How do you handle instrument drift between calibration checks?
• What practices ensure linearity in spectrophotometric analyses used for colorimetric methods?
• What buffers are used for pH meter calibration?
• What is the standard settling time used when calculating Sludge Volume Index (SVI)?
• Alkalinity is defined as what?
• In the MPn Presumptive Phase, which statement about Lauryl Tryptose Broth is correct?
• Which statement correctly describes what the mean and standard deviation indicate in analytical results?
• What are the preservation steps for dissolved phosphate samples?
• What are common matrix interferences in colorimetric analyses and how can they be mitigated?
• An equivalent of any substance is equal in weight to its formula weight.
• A supervisor must define the limits of authority when delegating responsibility to an employee.
• The statement 'If the conductivity of a sample exceeds the reference standard, the sample should be diluted and the resulting conductivity reading multiplied by the dilution factor' is:
• In COD analysis, which chemical is the primary oxidizing agent used to oxidize organic matter?
• What documentation should be retained for QA/QC records and for how long?
• Define a matrix spike duplicate (MSD) and how it differs from MS.
• According to Standard Methods, water samples suspected to be high in heavy metals should be collected in a sample containing a chelating agent to reduce metal toxicity.
• Fire Extinguisher Class for electrical fires?
• For fluoride interference, which substance is listed as an interferent that should be removed by distillation?
• What is the purpose of a spike recovery test, and how is it interpreted?
• During a digester upset, pH is typically a lagging indicator.
• How is a field duplicate used in QA/QC and what does it indicate?
• What does holding time refer to in regulatory sampling?
• For preserving a sulfide sample, which method is recommended?
• What does a field duplicate indicate?
• What is a key outcome of documenting corrective actions after a QC failure?
• What are typical components of a lab safety program and SDS considerations?
• When reporting a diluted sample, which criteria must the result meet?
• Which organism is listed as an indicator bacterium in this context?
• To remove chlorine interference in an acidity measurement, which reagent is used?
• What preservation method and storage time are specified for TKN (Organic Kjeldahl) samples?
• Explain the indophenol blue method for ammonia determination and what factors influence accuracy.
• Describe the typical workflow from sampling to reporting for a single analyte.
• Which parameter requires storage in the dark up to 24 hours?
• What corrective actions are appropriate for a QC failure in a BOD or COD test?
• Calibration verification is used to determine which of the following?
• What is the purpose of standard addition or matrix-matched calibration, and when is it used?
• Which parameter indicates how close a measured value is to the true value?
• What is the recommended preservation and maximum storage time for Nitrite samples before analysis?
• What is the final phase in the MPN procedure?
• What are the three phases in the MPN test?
• What pH and storage condition are specified for hardness preservation?
• Which category do sodium hydroxide and sodium carbonate belong to?
• What is flow-weighted composite sampling, and how is it computed?
• What is the significance of the method detection limit (MDL) in reporting and QA?
• Which item is not listed as contributing to chlorine demand?
• Which factor is listed as interference with chlorine measurement?
• What is the preservation requirement for Oil and Grease samples?
• What is the purpose of the seed in BOD5 testing?
• Which gas is listed as an explosive gas?
• Dissolved oxygen measurement interference involves which instrument/conditions?
• What should be coordinated with the Safety Data Sheet (SDS)?
• How is the equivalent weight of a substance calculated?
• What strategies reduce data entry errors in a microbiology or chemistry lab?
• How should hardness samples be preserved?
• What are the specified storage conditions for turbidity samples?
• Why might a laboratory perform a grab sample instead of a composite sample?
• A spike recovery test yields 130% recovery. What does this indicate?
• For dissolved metals analysis by atomic absorption spectroscopy, filtration through a 0.45 μm membrane before acidifying is recommended because:
• How does sample temperature affect the stability of wastewater analytes?
• What is a method blank and why is it included in analytical runs?
• Which analyte requires filtration immediately?
• For reagents formulated for internal lab use, what information should be included?
• Which liquid is listed under toxic materials as a toxic liquid?
• Which information should be included on a chemical label?
• Which substances interfere with alkalinity measurements?
• Indicator bacteria characteristics include which of the following?
• Before calculating standard deviation or plotting a control chart, SM recommends making at least how many determinations on a sample?