Explain the least potential for cross contamination

Question

Assignment:

Question 1 CH₃-(CH₂)₄-C-O-H is an

A. aldehyde

B. phenol

C. acid

D. alcohol

Question 2 The Contract Laboratory Program (CLP) was created under the program related to:

A. Superfund Act

B. Clean Water Act

C. Clean Air Act

D. Resource Conservation and Recovery Act

Question 3 In which CFR (Code of Federal Regulations), you would be able to find methodologies for drinking water?

A. 21 CFR 189

B. 40 CFR 141

C. 40 CFR 401

D. 29 CFR 1900

Question 4 Which of the following regulation in the U.S. is related to the 129 Priority Pollutant List (PPL)?

A. Resource Conservation and Recovery Act

B. Clean Air Act

C. Clean Water Act

D. Safe Drinking Water Act

Question 5 For analytical results with = 26.17, SEM = 1.74, s = 4.26, n = 6, its Student's t value to calculate confidence interval at 95% confidence level is:

A. 2.571

B. 2.015

C. 1.943

D. 2.447

Question 6- Which of the following is considered as an appropriate unit in reporting pesticide concentration in soil sample?

A. ppm_v

B. mg/m³

C. mg/kg

D. mg/L

Question 7 The measurement of 5 replicates reveals an analyte's concentration at 10.5, 10.2, 9.8, 9.7, and 10.4 mg/L. The standard error of mean (SEM) is _____ mg/L. Use Excel if needed.
 
Question 8 Four analysts were given the same spiked sample containing 5.00 mg/L analyte, which one of the following analyst is the most accurate?

A. Analyst C: mean = 5.10 mg/L; s = 0.10 mg/L

B. Analyst B: mean = 4.95 mg/L; s = 0.20 mg/L

C. Analyst D: mean = 5.15 mg/L; s = 0.20 mg/L

D. Analyst A: mean = 4.90 mg/L; s = 0.10 mg/L

Question 9 The group of chemicals that are solvent extractable and can generally be determined by chromatography such as phenol, phthalates, and PAHs and PCBs are defined as

A. VOC_s

B. SVOC_s

C. NVOC_s

D. B/N

Question 10 The measurement of 5 replicates reveals an analyte's concentration at 10.5, 10.2, 9.8, 9.7, and 10.4 mg/L. The standard error is _____ mg/L. Use Excel if needed.

Question 11 The following absorbance data were obtained for a series standard solutions containing tannin using colorimetirc method: A = 0.014 (0.1 mg/L), A = 0.069 (1 mg/L), A = 0.145 (2 mg/L), A = 0.289 (4 mg/L), A = 0.442 (6 mg/L), A = 0.528 (8 mg/L). The coefficient of determination (R²) of the calibration equation is _____ (Report R² to 4 significant figures after the decimal point). Using Excel if needed.

Question 12 The following set of censored data was obtained in drinking water with a detection limit of 1.0 µg/L for Cr(VI): 1.5 µg/L, 2.0 µg/L, N.D., 2.5 µg/L, 3.0 µg/L. As per U.S. EPA, the average concentration is best determined as:

A. (1.5 + 2.0 + 0 + 2.5 + 3.0)/5 = 1.8 µg/L

B. (1.5 + 2.0 + 2.5)/3 = 2.0 µg/L

C. (1.5 + 2.0 + 0.5 + 2.5 + 3.0)/4 = 1.9 µg/L

D. (1.5 + 2.0 + 2.5 + 3.0)/4 = 2.25 µg/L

Question 13 Using z-test, an outlier is detected if its z-score is greater than:

A. 2

B. 3

C. 4

D. 6

Question 14 Which of the following environmental data set is censored data?

A. 1.5, 1.1, 1.3, 1.2, 1.0

B. 1.5, 1.1, 1.2, 1.3, 1500

C. 1.5, 1.1, 1.2, <0.5, 1.0

D. None of above
 
Question 15 Contaminant concentration data show a normal distribution with mean of 100 mg/L and s = 10 mg/L. The probability of a measured concentration in the range of 80 mg/L and 120 mg/L is _____ (Reporting format: input 0.50 for 50%).
 
Question 16 If a cut-off p-value of 0.01 is used, a significant linear regression can be stated if:

A. F < F_critical

B. p = 0.045

C. R² = 0.99

D. None of above

Question 17 For analytical results with = 26.17, SEM = 1.74, s = 4.26, n = 6, its confidence interval at 95% confidence level is:

A. 26.17 ± 4.47 = 21.70 ~ 30.64

B. 26.17 ± 3.51 = 22.66 ~ 29.68

C. 26.17 ± 4.26 = 21.91 ~ 30.43

D. 26.17 ± 3.38 = 22.79 ~ 29.55

Question 18 Four labs were undergone performance evaluation by the state environmental agency with the results of % recovery as follows: Lab A - 93%; Lab B - 95%; Lab C - 102%; Lab D - 105%. The true concentration of the test standard given by the third party was 10.0 mg/L. Which lab is the most accurate?

A. Lab A

B. Lab B

C. Lab C

D. Lab D

Question 19 Which one of the following is the least favorable in treating the data point if it deviates from the rest of the data set?

A. Remove the data point simply because it is much larger (or smaller) than the other data points

B. Replace the data point with a new one after the error source has been identified

C. Retain the data point but using a more robust statistical tool to analyze the data

D. Exclude the data point using the outlier detection software

Question 20 The probability of obtaining a sample with a concentration in the range of 8.5 to 9.5 ppm from a normally distributed population (μ = 8.5 ppm; σ² = 0.25 ppm²) is:

A. 0.3133

B. 0.2881

C. 0.5000

D. 0.4772
 
Question 21 The U.S. EPA defines MDL as "the minimum concentration measurable with _____ confidence that analyte's concentration is greater than zero".

A. 95%

B. 98%

C. 99%

D. 100%
 
Question 22 Volatile organic compounds (VOCs) generally have boiling point of less than roughly:

A. 50 ⁰C

B. 100 ⁰C

C. 200 ⁰C

D. 300 ⁰C
 
Question 23 The confidence interval of a normally distributed data with a mean ), standard deviation (s), and sample size (n) is:

A. ± t ×s/n

B. ± t ×s

C. ± t ×s/

D. ± s
 
Question 24 The Ekman dredge sampler can be used for

A. Soft sediment

B. Compacted or vegetation-covered sediment

C. Rocky sediment

D. All of above
 
Question 25 The stainless steel pump and casing might contribute trace amount of:

A. Chromium (Cr)

B. Iron (Fe)

C. Nickel (Ni)

D. All of above
 
Question 26 Explain which one of the following has the least potential for cross contamination:

A. PVC

B. Teflon

C. FRE

D. Aluminum
 
Question 27 nWhich of the following sampling device/media is based on absorption (not adsorption) and/or chemical reaction:

A. Tedlar bag

B. Canister

C. Impinger

D. XRD sorbent
 
Question 28 In general and for practical purpose, how much water sample you would collect for metal analysis (assuming the amount would be sufficient at least for dupliacte analysis):

A. 100 mL

B. 1 L

C. 5 L

D. 10 L
 
Question 29 Which one of the following should be monitored in the field if possible:

A. acidity

B. dissolved oxygen (DO)

C. pesticides

D. hardness
 
Question 30 Which one of the following analyte in water has the maximum holding time (MHTs) of "days" rather than "hours" or "months"?

A. Dissolved oxygen

B. Metals

C. Pesticides

D. Salinity
 
Question 31 Which of the following sample container material may leach boron (B) and silicon (Si):

A. PVC

B. plastics

C. stainless steel

D. glass
 
Question 32 Which one of the following generally requires the least volume of sample (in liter) needed for subsequent analysis:

A. TPH in liquid wastes

B. Total metals in water

C. Trace pesticide in water

D. Water to perform acute toxicity test
 
Question 33 Which of the following is an effective way to preserve water sample containing cyanide (CN-) as a result of potential volatilization loss:

A. Add HNO₃ to pH < 2

B. Add H2SO₄ to pH < 2

C. Add NaOH to pH > 12

D. Add Na₂S₂O₃
 
Question 34 Coliwasa is generally used for collecting:

A. solid samples from a pile of solid wastes

B. liquid samples from a drum of hazardous materials

C. solid samples from a drum of solid hazardous materials

D. none of above
 
Question 35 For practical purpose, the minimum amount of water sample sufficient for the single analysis of trace organics is approximately:

A. 10 mL

B. 100 mL

C. 1 L

D. 10 L
 
Question 36 Which one of the following is NOT true regarding sample container?

A. Plastic container is preferred over glass one for inorganic analytes

B. Containers should have Teflon-lined caps for extractable organic analytes

C. If both plastic and glass containers can be used, then glass container is preferred

D. Certain glass containers may leach significant amount of boron (B) and silicon (Si)

Question 37 Which one of the following is used in the sampling of hazardous waste in 50-gallon drums:

A. Ponar

B. Coliwasa

C. Ekman dredge

D. Kemmerer
 
Question 38 Well purging is used primarily to:

A. remove stagnant water

B. clean sampling pump and tubing

C. minimize cross-contamination

D. none of above
 
Question 39 For which of the following allocation method of stratified random sampling design, its cost is considered through either the optimal precision for a fixed study cost or the optimal cost for a fixed level of precision:

A. equal allocation

B. optimal allocation

C. proportional allocation

D. Neyman allocation
 
Question 40 A stratified sampling plan was adopted for a contaminated site as a result of a recent oil spill in an open agricultural land. Three strata were chosen: 1) the heavily contaminated surface soil (0-2 ft); 2) the unsaturated soil (2 ft to the groundwater level at 7ft deep); and 3) the saturated zone (7 ft-27 ft). Results for benzene concentrations (mg/kg) are surface soil ( = 25, s = 4.0, n = 15), unsaturated soil ( = 17, s = 2.0, n = 6), and saturated soil ( = 10, s = 1.0, n = 5). If the proportional allocation method is based on the depth or volume ratio, then the weight of surface soil, unsaturated soil, and saturated soil are, respectively:

A. 0.58, 0.23, 0.19

B. 0.07, 0.19, 0.74

C. 15, 6, 5

D. 2, 5, 20
 
Question 41 Which one of the following is likely the most appropriate if you have an adequate budget and you are interesting in knowing the information of a spatial or temporal pattern of contamination

A. Simple random sampling

B. Stratified random sampling

C. Systematic grid sampling

D. Search sampling
 
Question 42 A stratified sampling plan was adopted for a contaminated site as a result of a recent oil spill in an open agricultural land. Three strata were chosen: 1) the heavily contaminated surface soil (0-2 ft); 2) the unsaturated soil (2 ft to the groundwater level at 7ft deep); and 3) the saturated zone (7 ft-27 ft). Results for benzene concentrations (mg/kg) are surface soil ( = 25, s = 4.0, n = 15), unsaturated soil ( = 17, s = 2.0, n = 6), and saturated soil ( = 10, s = 1.0, n = 5). If the proportional allocation method is based on the depth or volume ratio, then the overall mean concentration is:

A. 12.4

B. 17.3

C. 20.3

D. none of above
 
Question 43 If you are estimating a population mean and you have budget constraints. The analytical costs are much higher compared to sampling costs. Your goal is to produce an equally precise or a more precise estimate of the mean with fewer analyses and lower cost.

A. Simple random sampling

B. Systematic random sampling

C. Stratified random sampling

D. Composite sampling
 
Question 44 Which of the following may represent the challenge of collecting the "representative" (e.g., due to heterogeneity) biological samples (e.g., fish) for bioaccumulative contaminant concentrations?

A. types of fish species

B. all of above

C. various fish tissues

D. fish size
 
Question 45 Preliminary data show a pile of solid waste from a solvent recovery facility has trichloroethene concentration of 7.0 mg/kg (average of 4 samples) and standard deviation of 1.2 mg/kg. The regulatory soil screening level for trichloroethene is 6 mg/kg. The required minimum number of sample for an estimation at the 80% confidence is _____.
 
Question 46 Which of the following statement is generally NOT true:

A. Quality of data is primarily determined by the nature of analytical methods (instrumentations).

B. Analytical data can be reported to the 3rd decimal points , if sampling error are known to dominate.

C. Errors in the analytical results often are influenced much more by the measurement steps than sampling and sample preparation techniques.

D. All of above
 
Question 47 Which of the following is likely the least preferable sampling approach if the objective is to delineate the extent of contamination:

A. Search sampling

B. Simple random sampling

C. Judgmental sampling

D. Systematic sampling
 
Question 48 Which one of the following may represent cost saving if the "average" concentration is of the primary concern

A. Simple random sampling

B. Stratified random sampling

C. Systematic random sampling

D. Composite sampling
 
Question 49 The issue of collecting "representative" solid samples may be the result of:

A. concentration variations along with different soil depths

B. contaminants present in the "nugget" form

C. contaminants present in two immiscible phases

D. all of above