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TN = Total Nitrogen
TP = Total Phosphorus
SS = Suspended Sediment

Sample Collection & Analysis

Samples are collected to measure nutrient and SS concentrations during various flows. For Group A sites, two samples are collected per month: one near the twelfth of the month and one during monthly base flow conditions. Additionally, at least four high flow events are sampled, targeting one per season. When possible, a second high flow event is sampled in accordance with spring planting in the basin. During high flow sampling events, samples are collected daily during the rise and fall of the hydrograph. The goal is to gather a minimum of three samples on the rise and three samples on the fall, with one sample as close to peak flow as possible. Sampling continues until flows returned to pre-storm levels.

For Group B sites, fixed date monthly samples are collected during the middle of each month. All samples are collected by hand with USGS depth integrating samplers. Samples are collected using the same protocol as Group A sites. At each site between 3- and 10-depth integrated verticals are collected across the water column and then composited to obtain a representative sample of the entire waterbody.

Whole water samples are collected to be analyzed for TN species, TP species, TOC, and SS. For Group B sites, SS samples are only collected during storm events. Additionally, filtered samples are collected to analyze for dissolved nitrogen (DN) and dissolved phosphorus (DP) species. All Pennsylvania samples are delivered to the PADEP Laboratory in Harrisburg to be analyzed the following workday. New York samples are sent to ALS Environmental in Rochester, N.Y., for analysis the following workday. SS concentrations for Group A sites are completed at SRBC and for Group B sites at the USGS sediment laboratory in Kentucky. The parameters and laboratory methods used are listed in the Quality Assurance Project Plan (QAPP).

Water Quality Parameters, Laboratory Methods, and Detection Limits

Parameter

Storet

Laboratory

Methodology

Detection Limit (mg/l)

References

Total Ammonia (TNH3)

610

PADEP

Colorimetry

0.020

USEPA 350.1

ALS*

Colorimetry

0.010

USEPA 350.1R

Dissolved Ammonia (DNH3)

608

PADEP

Block Digest, Colorimetry

0.020

USEPA 350.1

ALS*

Block Digest, Colorimetry

0.010

USEPA 350.1R

Total Nitrogen (TN)

600

PADEP

Persulfate Digestion for TN

0.040

Standard Methods
#4500-Norg-D

Dissolved Nitrogen (DN)

602

PADEP

Persulfate Digestion

0.040

Standard Methods
#4500-Norg-D

Total Organic Nitrogen (TON)

605

N/A

TN minus TNH3 and TNOx

N/A

N/A

Dissolved Organic Nitrogen (DON)

607

N/A

DN minus DNH3 and DNOx

N/A

N/A

Total Kjeldahl Nitrogen (TKN)

625

ALS*

Block Digest, Flow Injection

0.050

USEPA 351.2

Dissolved Kjeldahl Nitrogen (DKN)

623

ALS*

Block Digest, Flow Injection

0.050

USEPA 351.2

Total Nitrite plus Nitrate (TNOx)

630

PADEP

Cd-reduction, Colorimetry

0.010

USEPA 353.2

ALS*

Colorimetric by LACHAT

0.002

USEPA 353.2

Dissolved Nitrite plus Nitrate (DNOx)

631

PADEP

Cd-reduction, Colorimetry

0.010

USEPA 353.2

ALS*

Colorimetric by LACHAT

0.002

USEPA 353.2

Dissolved Orthophosphate (DOP)

671

PADEP

Colorimetry

0.010

USEPA 365.1

ALS*

Colorimetric Determination

0.002

USEPA 365.1

Dissolved Phosphorus (DP)

666

PADEP

Block Digest, Colorimetry

0.010

USEPA 365.1

ALS*

Colorimetric Determination

0.002

USEPA 365.1

Total Phosphorus (TP)

665

PADEP

Persulfate Digest, Colorimetry

0.010

USEPA 365.1

ALS*

Colorimetric Determination

0.002

USEPA 365.1

Total Organic Carbon (TOC)

680

PADEP

Combustion/Oxidation

0.50

SM 5310D

ALS*

Chemical Oxidation

0.05

GEN 415.1/9060

Total Suspended Solids (TSS)

530

PADEP

Gravimetric

5.0

USGS I-3765

ALS*

Residue, non-filterable

1.1

SM2540D

Suspended Sediment Fines

70331

USGS

**

 

 

Suspended Sediment (SS)

80154

SRBC

**

 

 

USGS

**

 

 

* ALS Environmental, Rochester, N.Y. (New York sites only)
** TWRI Book 3, Chapter C2 and Book 5, Chapter C1, Laboratory Theory and Methods for Sediment Analysis (Guy and others, 1969)