A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Accuracy - The closeness of agreement between an observed value and an accepted reference value. When applied to a set of observed values, accuracy will be a combination of a random component and of a common systematic error (or bias) component. back to top
Arsenic – an odorless and tasteless element; it can enter drinking water supplies via natural deposits in the earth or from agricultural and industrial practices; the EPA standard for arsenic is .010 parts per million (10 parts per billion); significant health effects are associated with long-term arsenic consumption. back to top
BNA - Base, neutral and acid extractable compound. The term base, neutral and acid refer to the pH conditions of the sample undergoing extraction. Certain compounds extract more efficiently from water under acidic conditions. Such compounds are often referred to as “acid extractables”. back to top
Chloride – Chlorides are not usually harmful to people. Chlorides are salts resulting from the combination of the gas chlorine with a metal. Some common chlorides include sodium chloride (NaCl) and magnesium chloride (MgCl2). The maximum contaminant level (MCL) for chloride in drinking water is 250 mg/L. back to top
Conductivity - Conductivity is a measurement of the ability of an aqueous solution to carry an electrical current. In the chemical analysis of water, the “specific conductance” is used as an indicator of how salt-free, ion-free, or impurity-free the sample is. The purer the water, the lower the conductivity. back to top
Copper – copper enters into drinking water due to highly corrosive water that eats away at brass plumbing and copper plumbing fixtures; copper causes greenish or bluish staining on porcelain sinks; causes a blue-green tint to water. back to top
Data Qualifiers –
Qualifiers for Reporting Metals Analysis
Q (Quality control) Qualifiers
E - The reported value is estimated because of the presence of interference. An explanatory note is included in the SDG narrative.
M - Duplicate injection precision not met.
N - Matrix spike sample recovery not within control limits.
S - The reported value was determined by the Method of Standard Additions (MSA).
+ - Correlation coefficient for the MSA is less than 0.995.
W - Post digestion spike for Furnace AA analysis is out of control limits (85-115%), while sample absorbance is less than 50% of spike absorbance.
* - Duplicate analysis is not within control limits.
C (Concentration) Qualifiers
B - Entered if the reported value is less than the Contract Required Detection Limit (CRDL) but greater than the Instrument Detection Limit (IDL).
U - Entered if the analyte was analyzed for but not detected, i.e., less than the IDL.
M (Method) Qualifiers
P - Analyzed by ICP.
A.- Analyzed by Flame AA.
F - Analyzed by Furnace AA.
CV - Analyzed by Manual Cold Vapor techniques.
AV - Analyzed by Automated Cold Vapor techniques.
C - Analyzed by Manual Spectrophotometric Method
CA - Analyzed by Midi-distillation Spectrophotometric Method.
NR - Analyte not Required.
Qualifiers for Reporting Organics Data
Value - If the result is a value greater than or equal to the quantification limit, report the value.
U - Indicates compound was analyzed for but not detected. The sample quantitation limit must be corrected for dilution and for percent moisture. For example, 10 U for phenol in water if the sample final volume is the protocol-specified final volume. If a 1 to 10 dilution of extract is necessary, the reported limit is 100 U. For a soil sample, the value must also be adjusted for percent moisture. For example, if the sample had 24% moisture and a 1 to 10 dilution factor, the sample quantitation limit for phenol (330U) would be corrected to:
For semivolatile soil samples, the extract must be concentrated to 0.5 mL, and the sensitivity of the analysis is not compromised by the cleanup procedures. Similarly, pesticide samples subjected to GPC are concentrated to 5.0 mL. Therefore, the CRQL values in Exhibit C will apply to all samples, regardless of cleanup. However, if a sample extract cannot be concentrated to the protocol-specified volume (see Exhibit C), this fact must be accounted for in reporting the sample quantitation limit.
J -Indicates an estimated value. This flag is used either when estimating a concentration for tentatively identified compounds where a 1:1 response is assumed or when the mass spectral data indicates the presence of a compound that meets the identification criteria but the result is less than the specified quantification limit but greater than zero. (e.g.: If limit of quantification is 10 ug/l and a concentration of 3 ug/l is calculated, report as 3J.) The sample quantitation limit must be adjusted for dilution as discussed for the U flag.
N -Indicates presumptive evidence of a compound. This flag is only used for tentatively identified compounds, where the identification is based on a mass spectral library search. It is applied to all TIC results. For generic characterization of a TIC, such as chlorinated hydrocarbon, the N code is not used.
P - This flag is used for a pesticide/Aroclor target analyte when there is greater than 25% difference for detected concentrations between the two GC columns (see Form X). The lower of the two values is reported on Form I and flagged with a “P”.
C - This flag applied to pesticide results where the identification has been confirmed by GC/MS. If GC/MS confirmation was attempted but was unsuccessful, do not apply this flag, instead use a Laboratory defined flag, discussed below:
B - This flag is used when the analyte is found in the associated blank as well as in the sample. It indicates possible/probable blank contamination and warns the data user to take appropriate action.. This flag must be used for a TIC as well for a positively identified target compound.
E - This flag identified compounds whose concentrations exceed the calibration range of the GC/MS instrument for that specific analysis. If one or more compounds have a response greater than full scale, except as noted in Exhibit D, the sample or extract must be diluted and re-analyzed according to the specifications in Exhibit D. All such compounds with a response greater than full scale should have the concentration flagged with an “E” on the Form I for the original analysis. If the dilution of the extract causes any compounds identified in the first analysis to be below the calibration range in the second analysis, then the results of both analyses shall be reported on separate copies of Form I. The Form I for the diluted sample shall have the “DL” suffix appended to the sample number. NOTE: For total xylenes, where three isomers are quantified as two peaks, the calibration range of each peak should be considered separately, e.g., a diluted analysis is not required for total xylenes unless the concentration of the peak representing the single isomer exceeds 200 ug/l or the peak representing the two coeluting isomers on the GC column exceeds 400 ug/l. Similarly, if the two 1,2-Dichloroethene isomers coelute, a diluted analysis is not required unless the concentration exceeds 400 ug/l.
D - This flag identifies all compounds identified in an analysis at a secondary dilution factor. If a sample or extract is re-analyzed at a higher dilution factor, as in the “E” flag above, the “DL” suffix is appended to the sample number on the Form I for the diluted sample, and all concentration values reported on the Form I are flagged with the “D” flag. This flag alerts data users that any discrepancies between he concentrations reported may be due to dilution of the sample or extract.
A - This flag indicates that a TIC is suspected aldol-condensation product.
X - Other specific flags may be required to properly define the results. If used, they must be fully described, and such description attached to the Sample Data Summary Package and the SDG narrative. Begin by using “X”. If more than one flag is required, use “Y” and “Z” as needed. If more than five qualifiers are required for a sample result, use the “X” flag to combine several flags as needed. For instance, the “X” flag might combine “A”, “B”, and “D” flags for some samples. The Laboratory defined flags limited to the letters “X”, “Y” and “Z”.
The combination of flags “BU” or “UB” is expressly prohibited. Blank contaminants are flagged “B” only when they are detected in the sample. back to top
Equipment Rinsate - A sample of analyte-free media which has been used to rinse the sampling equipment. It is collected after completion of decontamination, and prior to sampling. This blank is useful in documenting adequate decontamination of sampling equipment. back to top
Field Duplicates - Independent samples which are collected as close as possible to the same point in space and time. They are two separate samples taken from the same source, stored in separate containers, and analyzed independently. These duplicates are useful in documenting the precision of the sampling process. back to top
Hardness – is a measure of the amount of calcium and magnesium in the water and is usually reported as calcium carbonate (CaCO3); hardness must be taken into consideration when corrosion control techniques are being considered. back to top
Inorganic Chemicals – Chemical substances of mineral origin, unlike organic chemicals, which rely on carbon atoms for there structure. back to top
Instrument Detection Limit (IDL) - For inorganics it is determined by multiplying by the Students t-Test value the standard deviation obtained for the analysis of a standard solution (each analyte in reagent water) at a concentration of three to five times the estimated IDL on three days, with a minimum of seven measurements per day. back to top
Internal Standards - Compounds added to every standard, blank, matrix spike, matrix spike duplicate, matrix spike blank sample (for VOA), and sample extract (for semivolatiles) at a known concentration, prior to analysis. Internal standards are used as a basis for quantitation of the target compounds. back to top
Iron – is one of the most abundant naturally occurring elements on earth; enters water as it is dissolved from the earth’s crust or as iron or steel pipes corrode; causes red/brown staining on sinks and clothes. back to top
Iron bacteria – this harmless bacteria uses iron in its metabolic processes; can form gelatinous deposits that may clog pipes or cause dirty, iron-laden water with unpleasant tastes and odors. back to top
Laboratory Control Sample (LCS) - A known matrix spiked with compound(s) representative of the target analytes. This is used to document laboratory performance. back to top
Lead – Lead (Pb) is a soft, malleable metal considered to be one of the heavy metals. Major sources of lead exposure include lead in paint, water distribution systems, food, and lead used in hobby activities. All U.S. children are exposed to some lead from food, air, dust, and soil, however, lead-based paint is the most widespread and dangerous high-dose source of lead exposure for preschool children. Drinking water can also have dangerously high levels of lead. The water becomes contaminated as it moves through the water distribution system. The lead leaches into the water from lead pipes or connectors; lead solder used to connect pipes and fumes; brass fixtures; and lead lined tanks in water coolers. One should never drink the first water from the tap for this reason. back to top
Manganese – a naturally occurring element dissolved from the earth’s crust, often found in conjunction with iron; acidic waters tend to be higher in this element as they are particularly effective at dissolving it; causes blackish staining on fixtures and laundry. back to top
Matrix Spike (MS) - An aliquot of sample spiked with a known concentration of target analyte(s). The spiking occurs prior to sample preparation and analysis. A matrix spike is used to document the bias of a method in a given sample matrix. back to top
Matrix Spike Duplicate (MSD) - Intralaboratory split samples spiked with identical concentrations of target analyte(s). The spiking occurs prior to sample preparation and analysis. They are used to document the precision and bias of a method in a given sample matrix. back to top
MBAS (surfactants or detergents) – Surfactants enter waters and wastewaters mainly by discharge of aqueous wastes from household and industrial laundering and other cleansing operations. back to top
Method Blank - An analyte-free matrix to which all reagents are added in the same volumes or proportions as used in the sample processing. The method blank should be carried through the complete sample preparation and analytical procedure. The method blank is used to document contamination resulting from the analytical process. back to top
Method Detection Limit (MDL) - The minimum concentration of a substance that can be measured and reported with 99% confidence that the analyte concentration is greater than zero, and is determined from analysis of a sample in a given matrix type containing the MDL levels. back to top
Nitrate – Nitrate (NO3) is a water-soluble molecule made up of nitrogen and oxygen. It is a naturally occurring form of nitrogen found in the soil. Public water supplies are tested regularly for its presence. A nitrate test is recommended for all newly constructed wells. Testing of the water supply is also recommended for pregnant and breastfeeding women, and for infants due to the risk of a condition called methaemoglobinemia (commonly known as “blue baby syndrome”).
Some of the more common ways nitrates enter the water supply are from chemical fertilizers, animal wastes, sewage, septic tanks and industrial wastewaters. Nitrates are also by-products of decomposing vegetation. The EPA has set a Maximum Contaminant Level (MCL) for nitrate at 10 mg/L. back to top
PCBs - Polychlorinated biphenyls are a group of toxic persistent chemicals used in transformers and capacitors for insulating purposes, and in gas pipeline systems as a lubricant. Sale of PCB’s for new uses was banned by law in 1979. back to top
Percent Solids - The proportion of solid in a soil sample determined by drying an aliquot of the sample. back to top
Perchlorate – both naturally occurring and man-made, it is typically found in the form of salts such as ammonium perchlorate, potassium perchlorate, sodium perchlorate and lithium perchlorate; it is extremely soluble in water, making it difficult to remove from water by conventional treatment processes; man-made perchlorate is most commonly used as the primary ingredient in solid rocket fuel; other uses are fireworks, road flares, munitions, air bag inflator charges and matches, and is also an impurity in chemical fertilizers and agricultural chemical compounds; the USEPA is still studying its prevalence, health effects and exposure pathways, so a federal drinking water standard has not been set. back to top
Pesticides – A pesticide is any substance or mixture of substances used for preventing, destroying, repelling or mitigating a pest. The term pesticide refers to insecticides, herbicides, fungicides and various other substances used to control pests. back to top
pH – pH is measured on a scale of 0-14. In general, a water with a pH < 7 is considered acidic and with a pH > 7 is considered basic. Water with a low pH (< 6.5) could be acidic, soft, and corrosive. Water with a pH > 8.5 could indicate that the water is hard. A change of 1 unit on a pH scale represents a 10-fold change in pH. back to top
Practical Quantitation Limit (PQL) - The lowest level that can be reliably achieved within specified limits of precision and accuracy during routine laboratory operating conditions. back to top
Precision - The agreement among a set of replicate measurements without assumption of knowledge of the true value. Precision is estimated by means of duplicate / replicate analyses. back to top
Sample Delivery Group (SDG) - A unit within a sample Case (or sampling event) that is used to identify a group of samples for delivery. An SDG is a group of 20 or fewer samples within a Case, received over a period of up to seven calendar days. Data from all samples in an SDG are due concurrently. A SDG is defined by one of the following, whichever occurs first:
