Lake Water Sample Collection, Handling, and Custody

Resolve requirements with the receiving laboratory before mobilization. The project QAPP or sampling and analysis plan states the decision and quality objectives; the cited analytical method and laboratory instructions translate those objectives into bottle-level requirements. Where documents conflict, pause and obtain a documented resolution from the authorized project and laboratory contacts. Field crews should not choose the most convenient instruction.

Treat each distinct matrix, fraction, method, laboratory, or preservation path as a separate row. Record the controlling document and version so a later reviewer can tell which instruction was active on the collection date. Precalculate whether the route, carrier cutoff, weekend schedule, and laboratory receiving hours can satisfy the project-defined holding clock. A sample that cannot reach its destination in time is a planning exception, not a field surprise.

Sources: [7], [1], [9], [10]

Name the target population: for example, an open-water station, an intake depth, an inflow mixing zone, a nearshore exposure area, a bloom patch, a deep basin, or a reference location. Record coordinates and datum, station-selection rule, total depth, the sample depth and its reference, bottom clearance, weather, hydrologic or operational context, and any departure from the intended station. A convenience shoreline sample should not be represented as whole-lake water.

Choose a surface grab, discrete-depth sample, defined depth-integrated sample, or another approved design because it answers the stated question. A depth-integrated sample averages only the specified interval and can conceal sharp gradients. A discrete sample preserves one defined depth but cannot describe the entire water column. A targeted bloom or discharge sample can document a hotspot but does not estimate lake-wide condition unless the design supports that inference.

Define the timing window and event logic as explicitly as the location. Season, turnover, inflow, treatment, reservoir operations, bloom movement, wind, and time of day can change what is sampled. Record the actual start and end times and the as-found conditions so missed timing or changed conditions remain visible.

• Decision and target population are stated in one sentence.
• Station coordinates, datum, total depth, sample depth reference, and intended bottom clearance are defined.
• Grab, discrete-depth, or integration interval is named and justified.
• Timing window, event trigger, revisit rule, and conditions that invalidate substitution are defined.
• Inference boundary, station, zone, interval, event, or broader population, is written before collection.

Sources: [6], [8], [7]

Field measurements such as temperature, dissolved oxygen, pH, specific conductance, and turbidity depend on instrument identity, calibration or verification status, stabilization, deployment geometry, fouling and interference checks, units, time, and raw readings. Laboratory samples depend on collection, container, processing, preservation, custody, receipt, preparation, and analytical evidence. Link them through station, depth, time, event, and sample-set identifiers, but do not collapse one into the other.

Freeze the order of operations in the field procedure. The sequence should minimize disturbance, cross-contamination, aeration, warming, sediment resuspension, and delay while meeting method-specific priorities. Record the actual sequence whenever the crew changes it. A field reading may explain sample context; it does not replace a laboratory result, and a bottle result does not reconstruct an unmeasured vertical profile.

1. 01

   Connect the evidence

   Use the event, station, location, depth, and unambiguous time to associate field readings with the correct sample set.

2. 02

   Preserve separate method records

   Retain calibration, verification, stabilization, and raw meter evidence separately from bottle, processing, preservation, and custody evidence.

3. 03

   State the comparison limit

   Before comparing results, confirm that depth, time, fraction, units, and measured quantity are comparable; otherwise describe the difference rather than forcing agreement.

Sources: [4], [8], [7]

Stage the current plan, laboratory kit and instructions, stable sample IDs, labels, custody record, cleaned and protected equipment, required quality-control materials, field instruments, spare parts, cooler and packing system, temperature-evidence device, shipping materials, carrier details, receiving contacts, and site permissions. Inspect container identity, seals, pre-added material, lot or expiration evidence when required, and equipment-cleaning records without opening protected bottles unnecessarily.

The field lead confirms crew roles, communications, weather and access, boat and personal flotation requirements, lifting and traffic controls, chemical training and protective equipment, decontamination boundaries, emergency contacts, and the decision to proceed. Suspected harmful blooms, sewage, spills, unknown contamination, thin ice, lightning, strong wind, unstable banks, and restricted property require the applicable trained and authorized response, not improvised sampling.

• Current approved documents and laboratory contacts are available offline.
• Every planned sample and QC sample maps to a prepared ID, container set, analysis request, and custody row.
• Clean equipment is protected from transport contamination; dirty and clean zones are physically separated.
• Cooler, packing, temperature evidence, receiving hours, shipment cutoff, and contingency route are confirmed.
• Site permission, launch or vessel requirements, preservative training, PPE, emergency communications, and stop-work authority are confirmed.
• A missed event, broken bottle, delayed route, unsafe site, or document conflict has a named escalation path.

Sources: [1], [2], [8]

Identify every wetted surface from ambient water to final container. Use the project-approved sampler, tubing, pump components, filters, splitters, and containers; retain cleaning, blank, lot, and dedicated-equipment status where required. Protect sample-contact surfaces after cleaning and between stations. Single-use or dedicated equipment can reduce some carryover paths but does not remove handling, manufacturing, storage, or ambient contamination risks.

Use clean-hands/dirty-hands roles when the method or project requires them and define what each person may touch. Change gloves at the procedural triggers in the approved method and whenever they are torn or contaminated; gloves do not make a contaminated workflow clean. Keep bottles closed until use, avoid touching interiors, and control likely sources such as fuel and exhaust, metal fittings, sunscreen, insect repellent, dust, deck water, preservatives, ice melt, marker ink, and previously sampled water.

Approach and position the platform to avoid its wake, exhaust, disturbed sediment, shoreline debris, and surface film unless one of those is the stated target. Follow the approved analyte sequence and decontamination boundary. Record unexpected contact, splash, sediment entrainment, dropped equipment, or role breach as an exception rather than silently recollecting or relabeling.

1. 01

   Map contact surfaces

   Trace water through the sampler and processing train and confirm each material, cleaning status, and protection step against the matrix.

2. 02

   Assign clean and dirty tasks

   Separate bottle and sample-contact handling from anchors, ropes, coolers, paperwork, vehicle surfaces, and other contamination sources as the method requires.

3. 03

   Protect the collection zone

   Collect away from avoidable platform effects and resuspended bottom material unless those conditions are part of the target population.

4. 04

   Document a breach

   Quarantine the affected item or sample, preserve the original ID and facts, notify the authorized lead, and follow the approved recollection or qualification path.

Sources: [2], [3], [4], [11]

At the station, record arrival time and as-found conditions; verify coordinates, total depth, intended sample depth or integration interval, and any avoidance distance. Confirm the sampler and sample IDs before opening containers. Collect using the exact deployment, descent, triggering, retrieval, transfer, and between-sample procedure in the project method. If the sampler closes at an uncertain depth or contacts the bottom, preserve the facts and follow the exception rule.

For a grab, record the actual depth and collection geometry rather than calling it simply "surface." For a discrete-depth sample, document the depth reference and how the sampler was triggered or verified. For a depth-integrated sample, document the top and bottom of the interval, transit pattern, number or duration of passes when controlled, and the approved compositing and subsampling procedure. Do not create a composite, mix discrete depths, or homogenize a container unless the method authorizes it.

Follow method-specific rules for bottle rinsing, direct filling, transfer, fill line, headspace, agitation, and prepreserved containers. Do not rinse a bottle that contains laboratory-added material unless the laboratory explicitly instructs it. Close and protect each container promptly; record start and end times using the project convention and keep the raw field observation even if a replacement sample is later collected.

• Station, coordinates, total depth, target depth or interval, sample ID, and container set agree before collection.
• The actual collection device, depth reference, deployment, retrieval, and transfer route are recorded.
• Surface film, bottom disturbance, vegetation, bloom material, or another non-target condition is avoided or explicitly identified as the target.
• Rinsing, compositing, mixing, splitting, fill, and headspace follow the row-specific instruction.
• Collection start and end, crew, conditions, and any aborted or replacement attempt remain in the raw record.

Sources: [4], [6], [8]

Define the purpose, analytes, preparation, timing, frequency, labeling, custody, laboratory treatment, acceptance criteria, and response for every QC sample in the QAPP. A field blank can assess contamination introduced across a defined field exposure and handling path. An equipment or rinsate blank can assess a defined cleaned equipment train. A trip blank can assess specified transport and storage exposure for applicable analyses. A field duplicate or co-located duplicate estimates variability across the defined collection and handling sequence; a split addresses a different portion of variability.

Do not assume one blank evaluates every sampler, preservative, filter, container, station, or transport route. Do not prepare a nominal equipment blank without passing the approved blank water through the same relevant contact path. Handle QC samples with the same applicable identification, processing, preservation, cooling, custody, and holding-time controls as the samples they evaluate.

Keep any blind-QC crosswalk controlled but recoverable by authorized quality staff. QC findings trigger the preplanned review, qualification, investigation, corrective action, or recollection decision. They do not justify silently deleting a field sample or changing its identity.

Sources: [11], [7], [4], [5]

Assign the sample and bottle-set identifiers before collection and never reuse them after an aborted event. The label, field record, analysis request, custody record, cooler inventory, and laboratory submission must agree. Capture the station, water matrix and fraction, sample depth and reference, collection start and end convention, sampler, analyses, processing and preservation status, container count, and crew in the project system even when the physical label carries a smaller approved subset.

Record date and local time with an explicit UTC offset or other project-approved unambiguous time-zone representation, especially across daylight-saving transitions, midnight, time-zone boundaries, and remote instrument clocks. Record filtration, preservation, cooling, packing, custody, carrier, and laboratory-receipt times separately rather than overwriting collection time.

Correct paper and electronic records through the approved attributable process. Preserve the original entry, reason, author, and correction time; do not backdate, erase, relabel a conflicted bottle, or make field and custody records agree by changing facts. Quarantine an identity conflict for authorized reconciliation.

• Sample and container IDs are unique, stable, legible, and consistent across all records.
• Station, coordinates and datum, total depth, sample depth and reference, matrix, fraction, and collection method are recoverable.
• Collection start/end convention, dates, times, UTC offset or time zone, and clock source are unambiguous.
• Filter, preservative, container, lot, expiration, and addition details required by the method are attributable.
• Container count, requested analyses, QC relationship, cooler or shipment, and custody row reconcile.
• Corrections retain the original entry and identify who changed what, when, and why.

Sources: [12], [8], [9], [4]

For every processed sample, record whether filtration occurs in the field or laboratory and the controlling deadline. Document the filter medium and operational definition, device and lot when required, conditioning or rinse instruction, equipment train, pressure or flow constraint when controlled, processing start and end, and any clogging, breakthrough, air exposure, or substitution. A filtered result is method-defined; it is not automatically equivalent to a universal dissolved fraction.

Use only the approved preservative, container, quantity or target condition, addition point, verification, and trained handling procedure. Record whether material was laboratory-added or field-added, its identity, lot or expiration evidence when required, the addition time, handler, and any spill, omission, or uncertainty. Preserve personnel and transport safety information required for the chemical. Never guess, top off, neutralize, or transfer a compromised prepreserved bottle without authorized instruction.

Begin cooling at the point and by the packing method required for the exact method and laboratory. Record the cooling start, cooler and sample association, coolant and packing configuration, closures or seals, and the approved temperature-evidence method, for example a temperature blank, receiving measurement, or logger when the project specifies it. Cooling does not replace chemical preservation, and a receiving temperature does not prove the entire transit history unless the project has defined that inference.

1. 01

   Process the right fraction

   Confirm sample ID and matrix row, then filter, split, composite, or homogenize only by the approved procedure and within its required clock.

2. 02

   Preserve with authority

   Verify container and preservative instructions before addition; use trained personnel and required PPE; record identity, time, verification, and exception evidence.

3. 03

   Build cooling evidence

   Pack to the laboratory instruction, start the defined cooling process, associate the evidence with the correct cooler, and protect samples from meltwater, leaks, breakage, and cross-contamination.

4. 04

   Protect the clock

   Track the method-defined start and receipt or preparation cutoff; escalate a delay before the deadline when possible and preserve actual times without backdating.

Sources: [5], [10], [9], [1]

At field closeout, compare every physical container with its label, field record, requested analyses, preservation state, cooler assignment, and custody line. Resolve simple omissions through the approved attributable correction process; quarantine identity, container, or preservation conflicts. Pack bottles to prevent movement, breakage, leakage, label loss, cross-contamination, and direct contact with unsuitable coolant or meltwater. Apply custody seals or other security controls exactly where the project requires them and record seal identifiers and condition.

The chain-of-custody record should identify the sample set and containers, requested analyses, collection information, relinquishing and receiving parties, dates and unambiguous times, condition, transfer purpose, courier or carrier, shipment identifier, and secure storage intervals required by the project. Printed names and signatures or an approved authenticated electronic equivalent must be attributable. A cooler left unattended, stored overnight, or handed to a carrier still needs the project-defined custody and security evidence.

Retain a legible copy or protected image of the final field custody record, cooler inventory, seals, carrier receipt, tracking history, bill or waybill where applicable, and delay communications. Protect sensitive location, personal, and security information according to the project record plan while keeping the evidence available to authorized reviewers.

• Container identity and count reconcile to field, analysis-request, cooler, and custody records.
• Caps, labels, bags, separators, absorbent material, coolant, and outer packaging meet the approved laboratory and transport instructions.
• Custody seal or security control, cooler identifier, packing time, and responsible person are recorded.
• Each relinquishment and receipt records attributable parties, date, unambiguous time, condition, and transfer path.
• Carrier cutoff, receiving address and hours, tracking, weekend or holiday plan, and delay contact are verified.
• A field copy of the custody and shipment package is preserved before release.

Sources: [12], [9], [8]

The receiving laboratory documents arrival and custody acceptance, cooler and seal condition, temperature evidence, bottle identity and count, volume or headspace issues where applicable, breakage or leakage, preservation evidence, holding-time status, custody completeness, requested analyses, and accession identifiers under its procedure. Laboratory receipt observations should not be overwritten by the field team’s expectation.

The project team then reconciles accession and receipt records to the final field inventory and custody copy. Check every sample and QC relationship, fraction, method, analysis request, container count, collection and processing time, cooler, and exception. Resolve transcription or mapping issues through attributable communication among the field lead, laboratory, and quality authority. Do not ask the laboratory to silently correct identity, time, preservation, or custody facts.

A receipt exception does not automatically prove that a result is unusable, and successful accession does not prove that all requirements were met. Preserve the exception, affected scope, evidence, authorized decision, qualification, corrective action, and notification. The project quality process, not the collector alone, decides whether a sample is accepted, qualified, rejected, recollected, or restricted to a named use.

Sources: [10], [9], [12]

Keep the original field record, sampling-plan and matrix version, station and depth evidence, instrument records, equipment-cleaning records, bottle and filter lot evidence required by the method, photographs, blank and duplicate relationships, processing and preservation records, cooler and temperature evidence, custody forms, carrier proof, laboratory receipt and accession, discrepancy communications, and corrective-action decisions according to the project retention plan. Preserve native electronic files and audit information when available; a polished transcription is not a substitute for raw evidence.

Write an exception when the actual event differs from the approved plan or when identity, representativeness, cleanliness, processing, preservation, cooling, time, custody, or receipt is uncertain. State the fact, time discovered, affected IDs and process window, immediate containment, notifications, evidence retained, and pending authority. Avoid speculative conclusions in the field record. A recollection receives a new identity linked to the original attempt; the original record remains.

Close the field-to-receipt workflow only after inventory and accession reconcile, exceptions have owners, required evidence is retained, and the package is ready for the project’s validation, qualification, and release process. Chain of custody protects identity and transfer evidence; it does not by itself establish representativeness, analytical validity, or fitness for a decision.

1. 01

   Contain without rewriting

   Protect the affected sample and records, preserve the original ID and entries, and stop dependent actions that could spread the uncertainty.

2. 02

   Bound the affected scope

   Identify containers, analytes, stations, equipment, lots, time window, cooler, and related QC samples that may share the failure path.

3. 03

   Escalate to the named authority

   Provide facts and evidence to the project quality lead and laboratory contact; record the authorized disposition and any limitation on use.

4. 04

   Hand off the complete package

   Deliver raw evidence, receipt reconciliation, unresolved issues, and decision history to the data-validation workflow without silently filtering inconvenient records.

Sources: [7], [9], [12], [11]