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Sediment Quality Guidelines (Ongoing)
Sediment contamination is associated with a wide range of adverse biological effects, which may occur at all levels of biological organization.
Sediment toxicity data elucidating relationships between contaminant concentration and a particular adverse biological effect are available only for a few species.
Rarely can a single unique concentration of a contaminant be identified that would protect biological resources in the coastal zone. As a result, efforts have been made to define ranges of concentration that would be expected to produce obvious and dramatic short-term effects (such as mortality), longer term subtle effects (such as change in physiology or behavior), or no apparent effects.
CCMA scientists have developed sediment quality guidelines associated with a broad range of contaminant concentrations.
Data were ranked in terms of chemical concentrations at which adverse biological effects were observed: the 10 th percentile of the effects data for each contaminant was used to identify a threshold (Effects Range-Low or ERL) below which effects rarely occurred, and the 50 th percentile (median) of the data denoted the concentration (Effects Range-Median or ERM) above which adverse effects occurred frequently.
The ERL and ERM values were determined for both trace elements and organic compounds (Long, 1992; Long, et al., 1995). The ERL and ERM values have also been used as composite quotients that account for the presence of mixtures of contaminants in different concentrations that may have additive toxicity or other biological effects. High ERM-quotient values have been associated with impaired benthic biological communities (Long, 2000).
The ERL and ERM guidelines have been used widely, both in the United States and elsewhere. However, these values should not be interpreted in a regulatory context or as criteria for coastal management decisions; but rather to infer associations between chemical contaminants and adverse biological effects, and as a framework for follow-up research and monitoring.
Project Partners
U.S. Geological Survey
State of Florida
State of Washington
Puget Sound Ambient Monitoring
Program
References
Long, E.R. 2000. Degraded sediment quality in U.S. estuaries: A review of magnitude
and ecological implications. Ecological Applications, 10: 338-349
Long, E.R. 1992. Ranges in chemical concentrations in sediment associated with adverse biological effects. Marine Pollution Bulletin, 24: 38-45
Long, E.R., D.D. MacDonald, S.L. Smith, F.D. Calder. 1995. Incidence of adverse biological effects within ranges of chemical concentrations in marine and estuarine sediments. Environmental Management, 19: 81-97.