Biological Laboratory Information

Unit Main Number 919-743-8401

All toxicity analyses reported by dischargers must, by water quality regulations, be performed by a biological laboratory certified by the state of North Carolina. This certification program is operated by the Aquatic Toxicology Branch and includes laboratory inspections, data tracking and performance evaluation testing.

Laboratory Certification
 

NC DWR Whole Effluent Toxicity (WET) Procedures
 

*New: NC Biological Laboratory Proficiency Testing (PT)

PT Study Requirements

Proficiency testing is conducted annually to maintain certification for toxicity testing in North Carolina. An “acceptable” PT result is necessary for all certified categories and parameters. Participation in the Quality Assurance Study Program is a federal requirement (EPA DMR-QA Requirement) – however, North Carolina has received a waiver to operate their own PT program to fulfill this requirement (Administrative Code Section 15A NCAC 02H.1103 (10)). 

In 2023, NCDEQ began requiring North Carolina WET-certified labs to purchase official PT toxicity samples. Each laboratory must obtain samples that are part of the official DMR-QA program (DMR-QA 43 or equivalent water study) provided by an approved vendor. The approved vendor must be accredited by a Proficiency Testing Provider Accreditor (PTPA) that meets The NELAC Institute (TNI) requirements and is accepted by the NC WW/GW LC program.

List of NELAC-approved PT vendors

As of 2023, EPA has confirmed that ERA and Phenova are approved for and provide WET samples. The opening and closing dates for the DMR-QA 43 study are assigned by the EPA; equivalent water studies must also be performed during this timeframe. When submitting PT results, be sure to list NC Aquatic Toxicology Branch as the reporting agency. 

It is important to note that these samples require following EPA Whole Effluent Toxicity methods. 

PT Study Corrective Action

If a laboratory receives a “Not Acceptable” evaluation on their final report, the corresponding test must be repeated. A corrective action report must be written and submitted to ATB within 30 days of receiving the “Not Acceptable” result. A follow-up test must be completed with a Quik/Rapid Response sample. This data must be reported to the PT provider by their published closing date or within 60 days of receiving the “Not Acceptable” result, whichever is earlier.

Water Sciences Section 1621 Mail Service Center Raleigh, NC 27699-1621 919.743.8400