Branch of Quality Systems


Most Current Cumulative Time Series Charts and Statistical Summaries
for NWQL LS 4440

The Time Series Charts
The charts provide OBSP recovery information for every analyte at different concentrations for every schedule OBSP assesses. The charts exhibit a Locally Weighted Scatterplot Smoothing (LOWESS) line. This line is used to help observe patterns and trends of the data over time. The time series charts also show bias and variability of the OSBP data. The most current time series charts in the table below will be overwritten periodically and will contain data that is currently being reviewed. All data is provisional and may change if the OBSP deems necessary.

There are two tables provided at the bottom of every time series chart that show statistical summaries.

Plotted Points Statistics Table
Description of the OBSP QA recoveries grouped by concentration level. The statistics in the table: mean, median, standard deviation and F-pseudosigma define bias and variability of the OBSP recoveries.

Sample Statistics Table
Counts (N) - The quantity of the variety of items.
Plotted - This number equals the total number in the above table.
Estimated Values - There are a number of reasons the laboratory will estimate (E) a result. If there are 100% of the results estimated the analyte is identified as a permanently estimated compound (analyte name in time series chart will be red).
Deleted Values - The laboratory may delete an entire sample or a single analyte for a number of reasons.
Spiked, Censored - A term for those samples that were spiked and correctly reported as less than a reporting level (possibly a raised reporting level) - the expected concentration was at a lower concentration than the censored result provided by the laboratory.
Spiked - The number of times the OBSP has submitted this analyte to the NWQL.
False Negative - The number of times the laboratory reports this analyte as not present in the sample when it is there.
Not Spiked - The number of times the OBSP has submitted a sample to the appropriate schedule, without this analyte.
False Positive - The number of times the laboratory reports this analyte as present when it is not in the sample.

The charts and data that you might secure from this U.S. Geological Survey (USGS) web page (identified as "OBSP") have not received official USGS approval and as such are provisional and subject to revision. The charts and data are released on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use.

Lab Schedule 4440 - VOC Ambient Purge and Trap by GC/MS Preliminary Data (Unapproved)
Choose an analyte below or click here for all analytes sorted by NWQL parameter code Parameter CAS#
1,1,1,2-Tetrachloroethane 77562GCM66 630-20-6
1,1,1-Trichloroethane 34506GCM66 71-55-6
1,1,2,2-Tetrachloroethane 34516GCM66 79-34-5
1,1,2-Trichloroethane 34511GCM66 79-00-5
1,1,2-Trichlorotrifluoroethane 77652GCM66 76-13-1
1,1-Dichloroethane 34496GCM66 75-34-3
1,1-Dichloroethylene 34501GCM66 75-35-4
1,1-Dichloropropene 77168GCM66 563-58-6
1,1-Difluoroethane 49538GCM66 75-37-6
1,2,3,4-Tetrahydronapthalene 77323GCM66 119-64-2
1,2,3,4-Tetramethylbenzene 49999GCM66 488-23-3
1,2,3,5-Tetramethylbenzene 50000GCM66 527-53-7
1,2,3-Trichlorobenzene 77613GCM66 87-61-6
1,2,3-Trichloropropane 77443GCM66 96-18-4
1,2,3-Trimethylbenzene 77221GCM66 526-73-8
1,2,4-Trichlorobenzene 34551GCM66 120-82-1
1,2,4-Trimethylbenzene 77222GCM66 95-63-6
1,2-Dibromo-3-chloropropane 82625GCM66 96-12-8
1,2-Dibromoethane 77651GCM66 106-93-4
1,2-Dichloro-1,1,2,2-tetrafluoroethane 50985GCM66 76-14-2
1,2-Dichlorobenzene 34536GCM66 95-50-1
1,2-Dichloroethane 32103GCM66 107-06-2
1,2-Dichloropropane 34541GCM66 78-87-5
1,3,5-Trimethylbenzene 77226GCM66 108-67-8
1,3-Butadiene 68726GCM66 106-99-0
1,3-Dichlorobenzene 34566GCM66 541-73-1
1,3-Dichloropropane 77173GCM66 142-28-9
1,4-Dichlorobenzene 34571GCM66 106-46-7
1-Chloro-1,1-difluoroethane 85668GCM66 75-68-3
2,2-Dichloro-1,1,1-trifluoroethane 62174GCM66 306-83-2
2,2-Dichloropropane 77170GCM66 594-20-7
2-Butanone 81595GCM66 78-93-3
2-Chlorotoluene 77275GCM66 95-49-8
2-Hexanone 77103GCM66 591-78-6
3-Chloropropene 78109GCM66 107-05-1
4-Chlorotoluene 77277GCM66 106-43-4
4-Isopropyl-1-methylbenzene 77356GCM66 99-87-6
4-Methyl-2-pentanone 78133GCM66 108-10-1
Acetone 81552GCM66 67-64-1
Acrylonitrile 34215GCM66 107-13-1
Benzene 34030GCM66 71-43-2
Bromobenzene 81555GCM66 108-86-1
Bromochloromethane 77297GCM66 74-97-5
Bromodichloromethane 32101GCM66 75-27-4
Bromoethene 50002GCM66 593-60-2
Bromoform 32104GCM66 75-25-2
Bromomethane 34413GCM66 74-83-9
Butane 81563GCM66 106-97-8
Butylbenzene 77342GCM66 104-51-8
Carbon disulfide 77041GCM66 75-15-0
Chlorobenzene 34301GCM66 108-90-7
Chlorodifluoromethane 45028GCM66 75-45-6
Chloroethane 34311GCM66 75-00-3
Chloroform 32106GCM66 67-66-3
Chloromethane 34418GCM66 74-87-3
cis-1,2-Dichloroethylene 77093GCM66 156-59-2
cis-1,3-Dichloropropene 34704GCM66 10061-01-5
Dibromochloromethane 32105GCM66 124-48-1
Dibromomethane 30217GCM66 74-95-3
Dichlorodifluoromethane 34668GCM66 75-71-8
Dichlorofluoromethane 77119GCM66 75-43-4
Dichloromethane 34423GCM66 75-09-2
Diethyl ether 81576GCM66 60-29-7
Diisopropyl ether 81577GCM66 108-20-3
Ethyl methacrylate 73570GCM66 97-63-2
Ethyl tert-butyl ether 50004GCM66 637-92-3
Ethylbenzene 34371GCM66 100-41-4
Hexachlorobutadiene 39702GCM66 87-68-3
Hexachloroethane 34396GCM66 67-72-1
Hexane 81590GCM66 110-54-3
Isopropylbenzene 77223GCM66 98-82-8
m- and p-Xylene 85795GCM66 179601-23-1
Methyl acrylate 49991GCM66 96-33-3
Methyl acrylonitrile 81593GCM66 126-98-7
Methyl iodide 77424GCM66 74-88-4
Methyl methacrylate 81597GCM66 80-62-6
Naphthalene 34696GCM66 91-20-3
n-Pentane 81604GCM66 109-66-0
n-Propylbenzene 77224GCM66 103-65-1
o-Ethyl toluene 77220GCM66 611-14-3
o-Xylene 77135GCM66 95-47-6
sec-Butylbenzene 77350GCM66 135-98-8
Styrene 77128GCM66 100-42-5
tert-Butyl methyl ether 78032GCM66 1634-04-4
tert-Butylbenzene 77353GCM66 98-06-6
tert-Pentyl methyl ether 50005GCM66 994-05-8
Tetrachloroethylene 34475GCM66 127-18-4
Tetrachloromethane 32102GCM66 56-23-5
Tetrahydrofuran 81607GCM66 109-99-9
Toluene 34010GCM66 108-88-3
trans-1,2-Dichloroethylene 34546GCM66 156-60-5
trans-1,3-Dichloropropene 34699GCM66 10061-02-6
trans-1,4-Dichloro-2-butene 73547GCM66 110-57-6
Trichloroethylene 39180GCM66 79-01-6
Trichlorofluoromethane 34488GCM66 75-69-4
Vinyl chloride 39175GCM66 75-01-4

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