Water Resources Professional Project Reports


Marwin Shendo

Document Type

Technical Report

Publication Date



Polychlorinated Biphenyls (PCBs) are distributed throughout the globe and represent an environmental threat to wildlife and human health. The New Mexico Water Quality Control Commission has established surface water standards for Wildlife Habitat and the Human Health of 14,000 and 640 pg/L respectively. Preliminary studies identified elevated levels of PCBs in stormwater samples collected from Los Alamos National Laboratory (LANL) watersheds draining the Pajarito Plateau in northern New Mexico, including the Los Alamos County town site. PCB samples were collected at 59 stormwater runoff Site Monitoring Areas (SMAs) from 1996 to 2008 at LANL. PCB Aroclor concentrations ranged from 218,070 ng/L (highest) to 50 ng/L (lowest), with the highest detections found in Los Alamos and Pueblo watersheds. The New Mexico Environmental Department (NMED) collected PCB samples around Los Alamos as part of a Total Maximum Daily Load (TMDL) evaluation in 2006 using the congener analytical method; which has a much lower detection limit of approximately 0.002 ng/L than the Aroclor method. Average blank corrected total PCB values ranged from 1.2 to 11456.7 ng/L. Runoff from Los Alamos County town site was collected and analyzed as well with values ranging from 59.2 to 10201.8 ng/L. These studies demonstrate that multiple sources of PCBs exist on the Pajarito Plateau and must be defined. To better understand the distribution of PCBs in stormwater, background concentrations of PCBs in surface and stormwaters were characterized. Understanding background concentrations of PCBs is critical to quantifying sources of PCBs in stormwater on the Pajarito Plateau. LANL was granted a National Pollutant Discharge Elimination System (NPDES) Individual Permit for Stormwater discharges from Environmental Protection Agency (EPA) on November 1, 2010. With multiple sources of PCBs running onto Laboratory property, understanding the regional background, baseline concentrations of PCBs and contributions from additional industrial and urban sources will aid permit compliance. Quantifying offsite PCB concentrations is critical to identifying the Laboratorys contribution to PCBs in stormwater runoff. This project presents data collected by the LANL Stormwater Program and NMED and defines background PCB concentrations on the Pajarito Plateau. Stormwater monitoring was conducted from 2009 through 2010. Thirty five reference samples were collected using automated stormwater samplers and analyzed for PCBs by method 1668A. PCB concentrations from the reference watersheds range from 23 to 24,000 pg/L. PCB concentrations from the western boundary locations ranged from 33.1 to 16,800 pg/L. Twenty urban samples were collected, fifteen from Los Alamos County and five from the Laboratory parking lot. The county samples ranged from 1,270 to 19,600 pg/L and the Laboratory ranged from 7,560 to 31,200 pg/L.

Language (ISO)



Polychlorinated biphenyls--Environmental aspects--New Mexico--Pajarito Plateau., Runoff--Environmental aspects--New Mexico--Pajarito Plateau., Water--Pollution--New Mexico--Pajarito Plateau., Environmental monitoring--New Mexico--Pajarito Plateau.


A Professional Project Report submitted in partial fulfillment of the requirements for the degree of Master of Water Resources, Water Resources Program, University of New Mexico.