Значение и использование

Contaminated sediments may affect natural populations of aquatic organisms adversely. Sediment-dwelling organisms may be exposed directly to contaminants by the ingestion of sediments and by the uptake of sediment-associated contaminants from interstitial and overlying water. Contaminated sediments may affect water column species directly by serving as a source of contaminants to overlying waters or a sink for contaminants from overlying waters. Organisms may also be affected when contaminated sediments are suspended in the water column by natural or human activities. Water column species and nonaquatic species may also be affected indirectly by contaminated sediments by the transfer of contaminants through ecosystems (7, 8).

The procedures described in this guide may be used and adapted for incorporation in basic and applied research to determine the ecological effects of contaminated sediments. These same methods may also be used in the development and implementation of monitoring and regulatory programs designed to prevent and manage sediment contamination.

Sediment tests with aquatic organisms can be used to quantify the acute and chronic toxicity and the bioavailability of new and presently used materials. Sediment toxicity may also result from environmental processes such as ammonia generation, pH shifts, or dissolved oxygen fluctuation. In many cases, consideration of the adverse effects of sediment-associated contaminants is only one part of a complete hazard assessment of manufactured compounds that are applied directly to the environment (for example, pesticides) and those released (for example, through wastewater effluents) as by-products from the manufacturing process or from municipalities (7).

Sediment tests can be used to develop exposure-response relationships for individual toxicants by spiking clean sediments with varying concentrations of a test chemical and determining the concentration that elicits the target response in the test organism (Guide E 1391). Sediment tests can also be designed to determine the effects that the physical and chemical properties of sediments have on the bioavailability and toxicity of compounds.

Sediment tests can provide valuable information for making decisions regarding the management of contaminated sediments from hazardous waste sites and other contaminated areas. Biological tests with sediments can also be used to make defensible management decisions on the dredging and disposal of potentially contaminated sediments from rivers and harbors. ((7, 8), Test Method E 1706.)

Область применения

1.1 As the contamination of freshwater and saltwater ecosystems continues to be reduced through the implementation of regulations governing both point and non-point source discharges, there is a growing emphasis and concern regarding historical inputs and their influence on water and sediment quality. Many locations in urban areas exhibit significant sediment contamination, which poses a continual and long-term threat to the functional condition of benthic communities and other species inhabiting these areas (1). Benthic communities are an important component of many ecosystems and alterations of these communities may affect water-column and nonaquatic species.

1.2 Biological tests with sediments are an efficient means for evaluating sediment contamination because they provide information complementary to chemical characterizations and ecological surveys (2). Acute sediment toxicity tests can be used as screening tools in the early phase of an assessment hierarchy that ultimately could include chemical measurements or bioaccumulation and chronic toxicity tests. Sediment tests have been applied in both saltwater and freshwater environments (2-6). Sediment tests have been used for dredge material permitting, site ranking for remediation, recovery studies following management actions, and trend monitoring. A particularly important application is for establishing contaminant-specific effects and the processes controlling contaminant bioavailability (7).

1.3 This guide is arranged as follows:

Section Referenced Documents 2 Terminology 3 Application 4 Summary of Guide 5 Significance and Use 6 Hazards 7 Sediment Test Types 8 Biological Responses 9 Test Organisms10 Experimental Design Considerations11 Data Interpretation12 Keywords13

1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.