INTERPRETING YOUR LAB DATA

TYPES OF LABORATORY REPORTS

• ANALYTICAL

• WHOLE EFFLUENT TOXICITY

INFORMATION COMMON TO ALL REPORTS

• Title• Laboratory Name• Address, Phone, Contact• Unique Identifier (Laboratory Control

No.) • Number of Pages• Client Name• Date of Receipt

SAMPLE SPECIFIC INFORMATION

• Unique Sample Identifier

• Sample ID

• Sample Collection Date and Time

ANALYTICAL DATA - SAMPLE

• Parameter

• Analytical Method

• Data

• Units

• Reporting Limit – RL, MDL, PQL

• Date of Analysis

• Workgroup / Batch

• Analyst

QUALITY CONTROL DATA

• Laboratory Control Sample

• Matrix Spike Sample

• Sample Duplicate

• Surrogates

• Laboratory Blank

LABORATORY CONTROL SAMPLE

A sample matrix, free from the analytes of interest, spiked with verified known amounts of analytes or a material containing known and verified amounts of analyte. It is generally, used to establish intra-laboratory or analyst specific precision and bias or to assess the performance of all or a portion of the measurement system.

• Frequency – Minimum 1/batch• Individual LCS is compared to the

acceptance criteria as published in the mandated test method or based upon three standard deviations around the mean

• A LCS that is determined to be within the criteria effectively establishes that the analytical system is in control and validates system performance for the samples in the associated batch.

• If a large number of analytes are in the LCS, it becomes statistically likely that a few will be outside the control limits. This may or may not indicate that the system is out of control.

• Many laboratories have established Marginal Exceedances (ME) Limits. ME limits are between three or four standard deviations around the mean.

• The number of marginal exceedances allowable is dependent upon the number of analytes in the LCS.

• >90 analytes, 5 ME

• 71-90 analytes, 4 ME

• 51-70 analytes, 3 ME

• 31-50 analytes, 2 ME

• 11-30 analytes, 1 ME

• <11 analytes, 0 ME allowed

MATRIX SPIKE

• A sample prepared by adding a known amount of target analyte to a specified amount of matrix sample.

• Matrix spikes are used to determine the effect of the matrix on recovery efficiency.

• Theoretically, matrix spike control limits are typically equal to or greater than laboratory control sample limits.

• If the matrix spike amount is less than four (4) times the result in the unspiked sample, the MS/MSD data may not represent the matrix effect.

SAMPLE DUPLICATE

• Replicate aliquots of the same sample taken through the entire analytical procedure.

• The results from the analysis indicate the precision of the results for the specific sample using the method selected and are expressed as relative percent difference (RPD).

• Typically, RPD limits for sample duplicates > RPD limits established from LSC/MS duplicates.

SURROGATES

• Surrogates are used most often in organic chromatographic test methods and are chosen to reflect the chemistries of the targeted components of the method.

• Added prior to sample preparation /extraction, they provide a measure of recovery for every sample matrix.

METHOD BLANK

• A sample of a matrix similar to the batch of associated samples that is free from the analytes of interest and is processed simultaneously with and under the same conditions as samples through all steps of the analytical procedure, and in which no target analytes or interferences are present at concentrations that impact the analytical results for sample analyses.

• Goal is to have no detectable contaminants.

• Common method blank contaminates are acetone, methylene chloride, copper, iron, and zinc.

GENERAL GUIDANCE - BLANKS

• If the sample contains the contaminant at levels of at least 10 times that in the blank, then the likely contribution to the sample from the contaminant in the laboratory environment is at most 10%. The possible contamination is negligible

• If the sample contains the contaminant at levels of at least 5 times but less than 10 times the blank result, the compound is probably present in the sample, but the numerical result should be considered an upper limit of the true concentration.

• If the sample contains the contaminant at levels below 5 times the level in the blank, there is no adequate means by which to judge whether or not the sample result is attributable to laboratory contamination. The results for that compound in the sample then becomes unacceptable for compliance monitoring.

Parameter RelationshipsCOD>BOD>TOC

BOD> CBODTotal Solids = TSS + TDS

TKN>NH3NTotal Nitrogen = TKN + NO3N+ NO2NTotal Organic Nitrogen = TKN – NH3N

OG > TPHTotal Analyte> Dissolved Analyte

Cr = Cr3 + Cr6

SUPPLEMENT REPORT INFORMATION

• Sample Receipt Documentation

• Case Narrative

• Data Qualifiers

SAMPLE RECEIPT DOCUMENTATION

• Upon receipt, samples are inspected to determine if they meet regulatory compliance. If a sample fails to meet the requirements, the client should be contacted for instructions. If the decision is to proceed with the analysis, any sample failing to meet requirements must be appropriately flagged on the final report.

• Temperature

• Preservation

• Holding Time

• Container Information

• Documentation (COC)

CASE NARRATIVE

• Provides a correlation between field sample and laboratory sample numbers

• Identifies any issues with sample receipt

• Identifies extractions or analyses that are performed out of holding times

• Deviations from the method

• Identification of any QC failures and associated corrective actions taken by the laboratory

• Any other factors that could affect the sample results (e.g., air bubbles in VOC sample vials, excess headspace, multi-phasic samples, container type or volume)

DATA QUALIFIERS• Data Qualifers are added by the laboratory

during the review process• Data Qualifers are applied when

measurement quality objects are not met and corrective action is not successful or when corrective action is not performed

• They may also be applied to provided additional information concerning the reported data

• B = Analytes are detected in the blank above the reporting limit

• J = The analyte was positive; the associated numerical value is the approximate concentration of the analyte in the sample

• Q = Data requires usability review due to the exceedance of method-specific holding time, calibration, or batch QC data associated with the sample does not meet measurement quality objectives

• H = Holding time was exceeded• W = Data is presented on an as-received-

basis

WHOLE EFFLUENT TOXICITY

INTRODUCTION

• Permit Number

• Toxicity Testing Requirement of Permit

• Plant Location

• Name of Receiving water body

• Contract Laboratory

• Objective of Test

PLANT OPERATONS

• Products• Raw Materials• Operating Schedule• Description of waste treatment• Schematic of waste treatment• Retention time (if applicable)• Volume of waste flow• Design flow of treatment facility at time

of sampling

Source of Effluent, Receiving Water and Dilution Water

Effluent Samples• Sampling Point• Collection dates and times• Sample Collection method• Physical and chemical data• Mean daily discharge on sample collection date• Lapsed time from sample collection to delivery• Sample temperature when received at laboratory

Receiving Water Samples

• Sampling point

• Collection date and time

• Sample collection method

• Physical and chemical data

• Streamflow

• Sample temperature when received at lab

• Lapsed time from sample collection to delivery

Dilution Water Samples

• Source

• Collection dates and times

• Pretreatment

• Physical and chemical characteristics

TEST METHOD

• Toxicity test method used

• Endpoints of test

• Deviation from reference method

• Date and time test started

• Date and time test terminated

• Type and volume of test chambers

• Number of organisms per test• Number of replicate test chambers per

treatment• Acclimation of test organisms• Test temperature• Specify if aeration was needed• Feeding Frequency, and amount and type of

food• Specify if pH control measures were

implemented

TEST ORGANISMS

• Scientific name

• Age

• Life stage

• Source

QUALITY CONTROL• Reference toxicant used routinely• Date and time of most recent reference toxicant

test, test results, and current control chart• Dilution water used in reference toxicant test• Results (NOEC or where applicable, LOEC,

LC50, EC50, IC25 and/or IC50)• Report Percent Minimum Significant Difference

(PMSD) calculated for sublethal endpoints determined by hypothesis testing in reference toxicant test

• Physical and chemical methods used.

RESULTS

• Provide raw toxicity data in tabular form, including daily records of affected organisms in each concentration (including controls) and replicate, and in graphical form (plots of toxicity data)

• Provide table of LC50s, NOECs, IC25, IC50, etc (as required in applicable NPDES permit)

• Indicate statistical methods used to calculate endpoints

• Provide summary table of physical and chemical data

• Tabulate QA data

• Provide percent minimum significant differences (PMSD) calculated for sublethal endpoints.

• Relationship between test endpoints and permit limits

• Actions to be taken (if any)

GLOSSARY

• Effect Concentration (EC) is a point estimate of the toxicant concentration that would cause an observable adverse effect in a given percent of the test organisms. EC25 is a point estimate of the toxicant concentration that would cause an observable adverse effect in 25 percent of the test organism

• Inhibition Concentration (IC) is a point estimate of the toxicant concentration that causes a percent reduction in a non-lethal biological measurement (reproduction and growth), calculated from a continuous model. IC25 is a point estimate of the toxicant that would cause a 25% reduction in a non-lethal biological measurement.

• LC50 (lethal concentration, 50%) is the toxicant or effluent concentration that would cause death in 50 percent of organisms.

• Lowest Observed Effect Concentration (LOEC) is the lowest concentration of an effluent or toxicant that results in adverse effects on the test organisms.

• No Observed Effect Concentration (NOEC) is the highest test concentration of an effluent or toxicant that causes no observable adverse effect on the organism

• Percent Minimum Significant Difference (PMSD) allows comparison of different tests and represents the smallest significant difference from the control as a percentage of the control mean that can be measured.

GUIDANCE FOR REVIEWING BIOMONITORING REPORTS

• Were all samples chilled to 4oC during and/or immediately after collection and maintained at just above freezing.

• When reviewing the holding times – the maximum holding time of effluents is 36 hours and samples should not be used for renewals if older than 72 hours.

• Was the dilution series used in the test as specified in the permit?

• Does the laboratory have your latest permit?

• Fathead Minnows tests use to be a series of 10 minnows /4 concentrations. New permits now have 8 minnows / 5 concentrations.

• Was the DO acceptable for the test >4 but <9?

• Was chlorine present in the receiving water ?

• Was the sample brought to the correct temperature prior to starting the analysis?

• Was the control and sample handled in exactly the same manner. (Example – Treated for the same interferences (UV / antibiotic)?

• Was the critical dilution reported the same as that listed in the permit?

• Was the Coefficient of Variation (CV) in the control and the critical dilution <40%.

• Fathead – Survival in control must be at least 80%. The average dry weight per surviving control larvae at the end of the test must equal or exceed of 0.25 mg.

• Ceriodaphnia dubia – Test result acceptable, at least 80% of all control organisms must survive, and 60% of surviving control females must produce at least three broods, with an average of 15 or more young per surviving female.

VARIABILITY CRITERIA FOR SUBLETHAL HYPOTHESIS (Upper and Lower PMSD)

• Fathead Minnow 12-30

• Ceriodaphnia dubia 13-47

CONTROL (CV) RANGECOEFFICIENTS OF VARIATION

• Fathead 3.5 to 20 Minnow (0.035-0.2)

• Ceriodaphnia 8.9 to 42

dubia (0.089 to 0.42)