40537044_SOWv3_0001.pdf

STATEMENT OF WORK

1. Background

The study investigates wildfire-associated contaminants in wildfire ash, in burned soil and stream sediment from the Santa Cruz Mountains, and downstream in estuarine/intertidal organisms in Monterey Bay, California, USA. Lab analyses will identify and quantify concentrations of parent and alkylated polycyclic aromatic hydrocarbons (PAHs) in ash, soil, ash/soil mixtures, sediment, and organism tissue.

A high degree of discrimination of target analytes and low sample detection/reporting limits are required for successful fulfillment of the scope of work because of the high organic and mud contents of the samples, potential dilution of wildfire constituents during storm runoff and in aqueous environments, and the need to quantify background PAH levels and characteristic ratios.

2. Scope of Work

A. Sample matrices and numbers Parent and alkylated PAHs will be quantified in up to 50 samples of ash, soil, ash/soil mixtures, sediment, and organism tissue. The expected breakdown is:

34 solid phase analyses (ash/soil/sediment)

16 tissue analyses (including Homogenization, Moisture content, and Lipid content)

All samples will be stored and shipped frozen (-20C) to the analytical lab.

B. Timeline

- Sample collection has already begun. Sample will be submitted in batches over the Period of Performance.

- Results will be delivered in an electronic format no later than 60 days (or the next business day) after receipt of samples by the analytical lab.

- The Period of Performance is 2 years from the Contract Award Date with a 1-year renewal option by mutual consent of the USGS and the analytical lab.

C. Methods for parent and alkylated PAH identification and quantification Unknown and quality control samples are first spiked with deuterated surrogate standards then Soxhlent-extracted, cleaned up, and quantified by isotope dilution low resolution gas chromatography mass spectrometry (GC/MS) in multiple ion detection mode (MID) acquiring data for a target analyte and its paired surrogate to minimize false positive identifications. The list of the required parent and alkylated PAHs is provided in Table 1.

Extraction and clean up Sediment and tissues will be spiked with deuterated surrogate standards and then undergo Soxhlet extraction with an appropriate solvent such as toluene, dichloromethane, or another with equal or better performance.

Extracts will be cleaned up with routine, matrix-appropriate procedures such as column chromatography (e.g., silica, gel permeation, alumina, biobeads) and treatment with activated copper.

Calibration The GC/MS will be initially calibrated with at least five calibrations standards with a linear range.

Within-run calibrations will be done at least every 12 hours using a mid-range calibration verification standard.

Quantification Target PAH analyte concentrations will be quantified using the method of isotope dilution or isotope dilution/recovery correction quantification as warranted. Response factors between target analytes and paired surrogate standards will be determined with ongoing precision and recovery (OPR) and calibration verification standards. If surrogate standards are not commercially available for certain PAHs, quantification will be by an internal standard.

Quality Assurance and Quality Control (QA/QC) The analytical laboratory must be accredited by the American Association of Laboratory Accreditation (Standard ISO/IEC 17025:2017) for the quantification of parent and alkylated PAHs by isotope dilution GC/MS in solids and tissues.

A procedural blank and a spiked matrix sample (OPR) for Percent Recovery will be processed with every batch of 20 samples.

One duplicate will be run on an unknown sample with each batch when sufficient mass is available.

Analytical performance will meet or exceed the criteria for Sample (Estimated) Detection Limits, Procedural Blanks and Matrix Spike Recovery shown in Table 1.

Reporting, Deliverables, and Timeliness Parent and alkylated PAH concentrations in Solid samples will be reported on a dry weight basis (e.g. ng/g) and in Tissue samples on a wet weight basis with corresponding Moisture and Lipid content values to allow comparisons to other studies. Samples are not required to be returned to the USGS point of contact after analysis.

Results will be delivered in an electronic spreadsheet-readable format and will include parent and alkylated PAH concentrations (if greater than the sample detection limit), reporting limits, and surrogate recoveries in samples, blanks, duplicates, and matrix spikes; moisture content, and, if applicable, lipid content.

Results will be delivered no later than 60 days (or the next business day) after receipt of samples at the analytical lab.

3. Evaluation Criteria

Quotes will be evaluated primarily for technical merit based on compliance with the list of required analytes and Quality Assurance/Quality Control criteria in Table 1. The successful quote will meet or exceed required criteria. Analytical labs will provide documentation of compliance with required criteria if so requested.

Total price will be a secondary consideration providing that the total does not exceed the funds available.

4. Period of Performance

Base Year: Estimated 08/20/2021 – 08/19/2023, estimated 50 samples Option Year: Estimated 08/20/2023 – 08/19/2024, estimated 25 samples

Table 1. List of required parent and alkylated PAHs and Quality Control (QC) acceptance criteria.

Analyte

Sample Detection

Limits, Solids (ng/g)

Procedural Blanks, Solids

(ng, total)

Sample Detection

Limits, Tissue (ng/g)

Procedural Blanks, Tissue

(ng, total)

Acceptable Matrix Spike

Recovery, in % (all types)

Naphthalene 0.5 ≤ 10 0.1 ≤ 50 70-130

Acenaphthylene 0.5 ≤ 5 0.1 ≤ 5 70-140

Acenaphthene 0.5 ≤ 5 0.1 ≤ 5 70-130

Fluorene 0.5 ≤ 5 0.1 ≤ 5 60-140

Phenanthrene 0.5 ≤ 10 0.1 ≤ 10 70-130

Anthracene 0.5 ≤ 5 0.1 ≤ 5 70-130

Fluoranthene 0.5 ≤ 5 0.1 ≤ 5 70-130

Pyrene 0.5 ≤ 5 0.1 ≤ 5 70-130

Benz(a)anthracene 0.5 ≤ 1.9 0.1 ≤ 0.9 70-130

Chrysene 0.5 ≤ 3.0 0.1 ≤ 1.3 70-130

Benzo(b)fluoranthene 0.5 ≤ 4.2 0.1 ≤ 1.6 70-130

Benzo(j/k)fluoranthenes 0.5 ≤ 2.1 0.1 ≤ 1.2 70-130

Benzo(e)pyrene 0.5 ≤ 5 0.1 ≤ 5 70-130

Benzo(a)pyrene 0.5 ≤ 3.6 0.1 ≤ 0.7 70-130

Perylene 1 ≤ 10 0.2 ≤ 10 70-130

Dibenzo(ah)anthracene 1 ≤ 2.8 0.2 ≤ 0.7 70-130

Indeno(1,2,3-cd)pyrene 1 ≤ 2.8 0.2 ≤ 1.5 70-130

Benzo(ghi)perylene 1 ≤ 2.4 0.2 ≤ 0.7 70-130

Biphenyl 1 ≤ 5 0.2 ≤ 5 70-130

Dibenzothiophene 1 ≤ 5 0.2 ≤ 5 60-140

1-Methylnaphthalene 1 ≤ 5 0.2 ≤ 5 70-130

2-Methylnaphthalene 1 ≤ 5 0.2 ≤ 5 70-130

2,6-Dimethylnaphthalene 1 ≤ 10 0.2 ≤ 10 70-130

1,2-Dimethylnaphthalene 1 ≤ 10 0.2 ≤ 10 60-140

2,3,5-Trimethylnaphthalene 1 ≤ 10 0.2 ≤ 10 50-150

2,3,6-Trimethylnaphthalene 1 ≤ 10 0.2 ≤ 10 50-150

1,4,6,7-Tetramethyl-naphthalene 1 ≤ 10 0.2 ≤ 10 50-200

2-Methylanthracene 1 ≤ 5 0.2 ≤ 5 50-150

3-Methylphenanthrene 1 ≤ 10 0.2 ≤ 10 N.A.

2-Methylphenanthrene 1 ≤ 10 0.2 ≤ 10 50-150

9/4-Methylphenanthrenes 1 ≤ 10 0.2 ≤ 10 N.A.

1-Methylphenanthrene 1 ≤ 10 0.2 ≤ 10 50-150

3,6-Dimethylphenanthrene 1 ≤ 10 0.2 ≤ 10 50-150

2,6-Dimethylphenanthrene 1 ≤ 10 0.2 ≤ 10 N.A.

1,7-Dimethylphenanthrene 1 ≤ 10 0.2 ≤ 10 50-150, if present

1,8-Dimethylphenanthrene 1 ≤ 10 0.2 ≤ 10 N.A.

1,2,6-Trimethylphenanthrene 1 ≤ 10 0.2 ≤ 10 50-150

Retene 1 ≤ 5 0.2 ≤ 5 50-150

2-Methylfluorene 1 ≤ 5 0.2 ≤ 5 50-150

Analyte

Sample Detection

Limits, Solids (ng/g)

Procedural Blanks, Solids

(ng, total)

Sample Detection

Limits, Tissue (ng/g)

Procedural Blanks, Tissue

(ng, total)

Acceptable Matrix Spike

Recovery, in % (all types)

1,7-Dimethylfluorene 1 ≤ 5 0.2 ≤ 5 50-150

2/3-Methyldibenzo-thiophenes 1 ≤ 10 0.2 ≤ 10 50-150

2,4-Dimethyldibenzothiophene 1 ≤ 5 0.2 ≤ 5 50-150

4,6-Dimethyldibenzothiophene 1 ≤ 5 0.2 ≤ 5 50-150 3-Methylfluoranthene / Benzo(a)fluorene 1 ≤ 5 0.2 ≤ 5

50-150, if present

5/6-Methylchrysenes 1 ≤ 5 0.2 ≤ 5 50-150

1-Methylchrysene 1 ≤ 5 0.2 ≤ 5 50-150

5,9-Dimethylchrysene 1 ≤ 5 0.2 ≤ 5 50-150, if present

7-Methylbenzo(a)pyrene 1 ≤ 5 0.2 ≤ 5 50-150

C1-Biphenyls 1 ≤ 50 0.2 ≤ 50 C2-Biphenyls 1 ≤ 250 0.2 ≤ 250 C1-Naphthalenes 1 ≤ 10 0.2 ≤ 10 C2-Naphthalenes 1 ≤ 50 0.2 ≤ 50 C3-Naphthalenes 1 ≤ 15 0.2 ≤ 15 C4-Naphthalenes 1 ≤ 25 0.2 ≤ 25 C1-Acenaphthenes 0.5 ≤ 10 0.1 ≤ 10 C1-Fluorenes 1 ≤ 25 0.2 ≤ 25 C2-Fluorenes 1 ≤ 50 0.2 ≤ 50 C3-Fluorenes 1 ≤ 20 0.2 ≤ 20 C1-Dibenzothiophenes 1 ≤ 5 0.2 ≤ 5 C2-Dibenzothiophenes 1 ≤ 10 0.2 ≤ 10 C3-Dibenzothiophenes 1 ≤ 15 0.2 ≤ 15 C4-Dibenzothiophenes 1 ≤ 25 0.2 ≤ 25 C1-Phenanthrenes/ Anthracenes 1 ≤ 15 0.2 ≤ 15 C2-Phenanthrenes/ Anthracenes 1 ≤ 15 0.2 ≤ 15 C3-Phenanthrenes/ Anthracenes 1 ≤ 25 0.2 ≤ 25 C4-Phenanthrenes/ Anthracenes 1 ≤ 25 0.2 ≤ 25 C1-Fluoranthenes/ Pyrenes 1 ≤ 15 0.2 ≤ 15 C2-Fluoranthenes/ Pyrenes 1 ≤ 15 0.2 ≤ 15 C3-Fluoranthenes/ Pyrenes 1 ≤ 5 0.2 ≤ 5 C4-Fluoranthenes/ Pyrenes 1 ≤ 5 0.2 ≤ 5 C1-Benz(a)anthracenes/ Chrysenes 1 ≤ 5 0.2 ≤ 5 C2-Benz(a)anthracenes/ Chrysenes 1 ≤ 10 0.2 ≤ 10 C3-Benz(a)anthracenes/ Chrysenes 1 ≤ 10 0.2 ≤ 10 C4-Benz(a)anthracenes/ Chrysenes 1 ≤ 15 0.2 ≤ 15 C1-Benzofluoranthenes/ Benzopyrenes 1 ≤ 15 0.2 ≤ 15 C2-Benzofluoranthenes/ Benzopyrenes 1 ≤ 15 0.2 ≤ 15