The Delaware River Basin Commission Wednesday adopted updated water quality criteria for polychlorinated biphenyls (PCBs) in the Delaware Estuary and Bay and also for pH in interstate tidal and non-tidal reaches of the main stem Delaware River.
The updated PCB criteria for the protection of human health from carcinogenic effects is 16 picograms/liter. This number, based upon the most current methodology and scientific data available, is now a uniform value for the entire Delaware Estuary and Bay (DRBC Water Quality Zones 2-6).
The criteria previously varied according to the water quality zone, differed from that of the basin states, and did not take into account site-specific data and current U.S. Environmental Protection Agency guidance on the development of human health criteria.
This update was originally proposed in 2009, but action was deferred pending further refinement of an implementation strategy to support achievement of the revised PCB water quality criteria. While comment on an updated implementation strategy was solicited simultaneously with the current PCB criteria revision, there was no planned commission action on the strategy.
The Delaware Estuary and Bay are considered impaired for PCBs, and the U.S. EPA has established total maximum daily loads (Stage I TMDLs) for these waterbodies. A TMDL expresses the maximum amount of a pollutant that a waterway can receive and still attain water quality standards.
With DRBC's adoption of revised PCB criteria, it is anticipated that the U.S. EPA will establish new TMDLs (Stage 2 TMDLs) corresponding to the updated criteria. In the associated report announcing the Stage 2 TMDLs, the U.S. EPA will include the proposed implementation strategy as an appendix and will solicit comment on the report and strategy in 2014.
PCBs have been classified by the U.S. EPA as a probable human carcinogen. The U.S. banned the manufacture and general use of PCBs in the late 1970s, but not before 1.5 billion pounds of the substance was produced.
The updated PCB criteria was developed under the guidance of the commission's Toxics Advisory Committee, comprised of representatives of the four basin states - Delaware, New Jersey, New York, and Pennsylvania - and members of the academic, agricultural, public health, industrial and municipal sectors, and non-governmental environmental community.
The rulemaking was noticed in the federal and state registers, with the full text of the proposed rule changes and related materials posted on the DRBC website on August 1. A public hearing was held on September 10, with written comments accepted through September 20.
The commissioners at the December 4 meeting, which was held at the Washington Crossing Historic Park Visitor Center, also adopted revised pH water quality criteria for the main stem Delaware River and tidal tributaries up to the head of tide.
DRBC's pH criteria have not been updated since being established in 1967. The old pH criteria were expressed as ranges and were different for the tidal (between 6.5 and 8.5) and non-tidal (between 6 and 8.5) river.
The approved criteria range (between 6.5 and 8.5) is now uniform for the entire main stem Delaware (except towards natural conditions in certain sections of the river), minimizes regulatory inconsistencies between DRBC criteria and that of the basin states and the U.S. EPA, and better addresses natural pH cycles in the main stem Delaware River.
The revisions to the pH criteria were unanimously endorsed by the DRBC's Water Quality Advisory Committee, comprised of regulators, municipal and industrial dischargers, academicians, and environmental organizations, which advises the commissioners on technical matters relating to water quality within the basin.
The rulemaking was noticed in the federal and state registers, with the full text of the proposed rule changes and related materials posted on the DRBC website on September 20. A public hearing was held on October 24, with written comments accepted through November 21.For more information, visit the DRBC’s website.