WI DNR Field Procedures Manual
Intranet Edition

Scope

Toxicity and bioaccumulation tests on whole sediment are generally conducted to assess whether the sediment might adversely affect benthic and aquatic biota in situ. Sediments collected in the field are placed into exposure vessels with test organisms under controlled laboratory conditions. Various endpoints such as mortality, growth and reproduction are used to measure toxicity of the sediment. Toxicity test data can be evaluated in conjunction with resident benthic invertebrate community structure and bulk chemistry data to provide an integrative assessment of sediment quality. Chemical analysis is often performed on the sediment sample to provide a chemical data to compare with the toxicity and any other test results, although toxicity tests and chemical data alone should cannot reliably predict the contaminants responsible for observed effects.

Toxicity and bioaccumulation tests on sediment for the DNR are predominantly conducted at the Wisconsin State Laboratory of Hygiene - Aquatic Life Toxicity Testing Laboratory (ALTTL), also known as the Biomonitoring Lab.

Equipment

Sediment Collection

1. Preparation

   1. The quality of the samples collected is directly related to the quality and reliability of the resulting toxicity test data. A sampling plan and quality control measures should be decided upon and written down before sampling begins.
   2. Toxicity and bioaccumulation tests must be scheduled ahead of time with the Biomonitoring lab so that sediment samples will not be held for longer than two weeks prior to the beginning of the tests. Because a finite number of tests can be run during any given week, the schedule of the lab and the collecting schedule should be coordinated.
   3. After the tests are scheduled, the amount of sediment necessary to run all tests should be calculated, and sampling strategies for collecting adequate amounts of sediment should be determined. Remember, core or grab samples may need to be composited to obtain enough sediment from each site for the selected tests and analyses.
2. Collecting sediment samples

   Collection procedures described in section 701.4 General Sediment Sampling Equipment and Procedures should be followed with the following exceptions and reminders:

   1. Remember to collect enough sediment for all tests and analyses such as particle size, organic carbon content, moisture content, and chemical analysis.
   2. The depth and type of sediment to be collected should be kept in mind when selecting sampling equipment. Usually the top 2-15 cm are the biologically active sediment layers of interest for toxicity and bioaccumulation tests, but deeper sediments may also be tested depending on the objectives of the study.
   3. Sediment can be collected by any method that targets the study objectives, including the use of a grab or corer as described in section 701.4. More than one grab or core full of sediment may be necessary to obtain enough sediment for all tests and analyses. When this is the case, be careful to sample only undisturbed sediment with each grab or core attempt.
   4. When possible, sites should be sampled in order of increasing contamination to reduce cross-contamination. All sampling equipment contacting the samples should be cleaned between discreet samples with a non-ionic detergent and distilled, deionized water if in the field. The following cleaning procedure is recommended by ASTM (1990), and may be used where if appropriate waste handling containers and techniques can be followed: "1) soap and water wash, 2) distilled water rinse, 3) methanol rinse, 4) methylene chloride rinse, and 5) site water rinse." Waste solvents should be collected in labelled hazardous waste containers, not dumped at the site or on the ground.
   5. If there is concern about oxygen-sediment interaction during transport, fill the sample containers to the top so no air space exists.
3. Chemical analysis of sediment and tissue samples

   The biomonitoring lab will subsample sediments for chemical and physical analysis when the sediment is homogenized for the biological tests. Appropriate sample containers for each analysis must be provided to the Biomonitoring lab (see section 701.4 General Sediment Sampling Equipment and Procedures), and the DNR is responsible for getting sediment and tissue samples to the appropriate laboratory for chemical or physical analyses.

Description Of Toxicity And Bioaccumulation Tests

The in situ toxicity of a sediment may be unavoidably altered by the manipulations of collecting, handling and storing sediment samples. Sediments in situ have a biological, chemical and physical integrity which affects the availability of contaminants and the subsequent toxicity to organisms. Thus, manipulation of sediments may increase or decrease the toxicity of sediment samples in the laboratory tests.

"Subsampling, compositing, or homogenization of sediment samples is often necessary and the optimal methods will depend on study objectives. Important considerations include: loss of sediment integrity and depth profile; changes in chemical speciation by means of oxidation and reduction or other chemical interactions; chemical equilibrium disruption resulting in volatilization, sorption, or desorption; changes in biological activity; completeness of mixing; and sampler container contamination." (ASTM E 1391)

Documentation

See Section 701.3. on field notes.

All measurements and observations occurring during the laboratory tests will be documented by staff at the Biomonitoring lab and will accompany the test results.

Preservation and Shipping

For preservation, sediment samples must be placed on ice as soon as possible after collection and maintained on ice or refrigerated at ~4°c until tests are begun. Sediment suspected of containing volatile organic chemicals should be packed into sample containers so that no air space exists. This should reduce the chances of oxidation of the sediment.

If samples are of suitable size for shipping, pack them to prevent breakage and with enough ice or cold packs to maintain the preservation temperature of ~ 4°c. Make sure melting ice cannot leak during shipment. Also refer to Sample Shipping Requirments.

If hazardous samples are to be transported or shipped, consult 49 CFR 100-177 for current Department of Transportation regulations.

Data Reporting and Analysis

The following data are reported by the Biomonitoring Lab for each site and/or replicate depending on the test:

1. Initial and Final Chemistries and Measurements

   Dissolved Oxygen (DO), pH, Conductivity, Alkalinity, Hardness, Total Ammonia, Un-ionized Ammonia, temperature, total suspended solids, percent survival, mean length and weight, # of young produced.

2. Statistical and Biological Significance

   The replicate data are used to statistically test for significant differences between results from reference and test sites. Each test must meet specific test acceptability requirements for data interpretation.

   Questions about results or testing procedures should be directed to either Linda Talbot at (608) 266-8148 or Steve Geis at the Biomonitoring Lab. Phone: (608) 265-4023.

Decontamination

Clean, five-gallon plastic (polyethylene) pails with tight fitting lids are generally used to contain, transport and store sediments for toxicity tests. Clean pails are available from the Biomonitoring lab. These pails are used because enough sediment must be collected at each site for all replicates of toxicity tests and chemical and physical analyses. The sediment will be subsampled for the chemical and physical analyses at the Biomonitoring laboratory, so separate sample containers are not necessary.

The following steps for cleaning new or used sediment sample containers are recommended by EPA (1994):

1. Soak 15 min in tap water, and scrub with detergent.

2. Rinse twice with tap water.

3. Rinse once with fresh, dilute (10% V:V) hydrochloric or nitric acid. To prepare a 10% solution of acid, add 10 ml of concentrated acid to 90 ml of deionized water.

4. Rinse twice with deionized water.

5. Rinse once with full-strength, pesticide-grade acetone (use a fume hood or canopy).

6. Rinse three times with deionized water.

7. Rinse field collection equipment with site water immediately before use. Lab equipment should be rinsed with test dilution water immediately before use in a test.

References

1. ASTM. 1991. Standard guide for collection, storage, characterization, and manipulation of sediments for toxicological testing. Method E1391-90. In: Annual Book of ASTM Standards, Water and Environmental Technology, Vol. 11.04. American Society for Testing and Materials, Philadelphia, PA.

2. EPA. 1985. Sediment Sampling Quality Assurance User's Guide. 600/4/85/048. Environmental Monitoring and support lab, Las Vegas, NV.

3. EPA. 1994, (In-Press). QA/QC Guidance for Sampling and Analysis of Sediments, Water, and Tissues for Dredged Material Evaluations. Phase I - Chemical Evaluations. U.S. Environmental Protection Agency, Office of Water, Washington DC.

4. WDNR. DRAFT 1990. Quality Assurance Guidance for Inplace Pollutant Monitoring Activities. Unpublished document on file at Office of Technical Services, Bureau of Water Resources Management.