Other Monitoring Programs & Studies
DRBC staff monitoring metals. Photo by DRBC. 
DRBC staff monitoring metals.
Photo by DRBC. 

Releases of metals to the environment and impacts on aquatic life have long been a concern for the public and regulators.

DRBC monitors metals, such as copper, zinc, nickel, chromium (VI) and mercury, in ambient water, sediment and tissues of aquatic life of the Delaware Estuary to ensure compliance with water quality criteria. 

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. 


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.

Examples of sampling efforts:

  • 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.

  • 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.
Reports & Related Info


Related Info