Metals

Releases of metals to the environment have long been a concern for the public and regulators. The generation of appropriate regulatory procedures requires a sound understanding of the chemistry, toxicology, and fate of metals in the environment. Bioavailability, bioaccumulation and toxicity of metals can be strongly influenced by the presence of complexing and competing ligands, as well as organism-specific characteristics (e.g., physiology, feeding, and exposure route) complicating the assessment of hazard and risk from metals.

Water quality assessment of metals is also complicated by factors such as field sampling techniques, analytical issues with contamination, detection limits associated with routine analytical procedures, and the applicability of freshwater or marine criteria in the river's estuarine waters. Metals monitored in water, sediment, and biota by the DRBC include copper, nickel, zinc, and chromium (VI). DRBC coordination with basin states and agencies is ongoing to ensure the use of the most appropriate methods and procedures for the conduct of monitoring studies in the basin and to ensure the harmonization of water quality criteria and assessment methodologies for metals.

Monitoring for Metals
  • Assessment of Metals in Estuarine Waters - In Zone 5 of the Delaware River, which extends from the Pa.-Del. state line south to Liston Point, copper concentrations continue to be near water quality criteria with several apparent exceedances of the marine criteria in the vicinity of Pea Patch Island, Delaware. In 2012, the DRBC performed additional data collection for copper, zinc, and nickel using enhanced analytical methods and modified collection procedures in this section of the Delaware River. The technique used is called "Cleans Hands/Dirty Hands" and results in very low contamination of the sample by other metal sources. The information collected as part of this study will provide additional data to help determine metals concentrations in ambient water and whether the commission's metal criteria are exceeded. View photos of sampling effort on Flickr.
  • Lower Delaware River Metals Sampling - The DRBC's Toxics Advisory Committee has recommended that the DRBC adopt toxics criteria for the nonā€tidal Delaware River. In 2012, a project plan was developed for sampling 13 sites for metals and supplemental physical-chemical data; sampling began in January 2013. The resultant data from this monitoring effort will inform a sound technical approach for developing protective and applicable water quality criteria for metals in these non-tidal freshwaters. View photos of sampling effort on Flickr.
Reports and Other Information