# Presentation: 367566

## PCBs in Rio Grande Watershed

- 2000-2003 Surface Water and Sediment Sampling
- A Cooperative Study
**Ralph Ford-Schmid, NMED**
**Ken Mullen, LANL**
- October 2004

## PCBs

- Concentrations in fish from Cochiti Reservoir and Rio Grande could warrant fish consumption advisories based on EPA guidance

## Standards and Analytical Methods

- NMWQCC Standards
- 1.7 ng/L Human Health Standard
- 14 ng/L Wildlife Standard
- 500 ng/L EPA MCL for drinking water
- Analytical Methods
- Aroclor Method 608
- 8 Aroclors
- Detection limit -100 ng/L
- Congener Method 1668
- 209 Congeners
- Detection limit - pg/L

## NMED Total PCB Concentration in Surface Water 2000 - 2001 Source: NMED, February 26, 2003

- Note: Runoff solid bars, baseflow striped bars

**Notes:**
NMWQCC Wildlife habitat standard is 14 ng/L. Los Alamos Reservoir sample likely represents background conditions. Source of Pueblo Canyon North Tributary PCB in question. Source of downstream PCB likely historic LANL discharges. Runoff data for Pueblo Canyon, Pajarito Canyon, and Water Canyon, other data are for baseflow

## PCB Cooperative Study

- Participants:
- Los Alamos County
- Santa Fe City and County
- City of Albuquerque
- LANL
- Water Quality and Hydrology
- Ecology
- Legal
- DOE
- San Ildefonso Pueblo
- Cochiti Pueblo
- NMED Oversight and Surface Water Quality Bureaus

## Slide 6

## 2002 Surface Water PCB Results Total Concentration in Baseflow and Runoff

- Baseflow

- Baseflow

- RO

- Runoff

**Notes:**
Baseflow samples from Rio Grande and Sandia Canyon, runoff samples from Pueblo, Pajarito, and Water Canyons. Sample collection logistics prevented sampling Rio Grande baseflow on same day. Reproducibility of results for 3 Sandia Canyon samples collected on 8/8/02 and 3 Rio Grande below Ancho is good. Runoff from Pajarito Canyon at SR-4 on 8/28/02 was local runoff and not from Pajarito Canyon upstream of  TA-54. NMED sample from Pajarito Canyon at TA-18 collected on 8/5/01 was 298.2 ng/L, indicating the presence of PCBs in upper Pajarito Canyon.

## Rio Grande Runoff Events Sample Results

- Runoff collected from RG Ancho on
- 8/25/03 has slightly higher total than
- at Otowi. Runoff from RG Espanola
- 9/10/03 has higher PCB concentration
- than upstream in Rio Chama

- Runoff from Rio Grande on different
- dates have different homolog
- signatures. Runoff on 8/25/03 has
- weathered Aroclor 1260 signature, but
- appears to be coming from upstream
- of Otowi

**Notes:**
Assuming that runoff samples collected from the Rio Chama and Rio Grande on the same days represent the same runoff event, then PCB results may indicate where sources of PCB to the Rio Grande may be entering the river. Runoff from RG at Otowi on 8/25/03 had 10.5 ng/L and from Ancho had 12.8 ng/L, showing a slight increase downstream, possibly from LANL. The congener results for these samples show that the PCBs appear to be a weathered Aroclor 1260, and are similar at both Otowi and Ancho. Samples of runoff event collected on September 6, 2003 have similar total PCB concentrations at about 1 ng/L, and homolog signatures that indicate slightly more 2-3 congeners than 5-6 congeners, which would suggest most of the PCBs were  from atmospheric deposition with some industrial component. The Sample from near White Rock has the lowest total PCB concentration with a slightly higher Hexa-CB homolog, but no conclusive contribution of PCBs to the Rio Grande from LANL on that day. Samples of a runoff event from the Rio Chama at Chamita and the Rio Grande at Española on September 10, 2003 show a higher total PCB concentration at Española, and a homolog signature that is higher in 5-6 congeners, indicating an industrial source to the Rio Grande between Chamita and Española.

## Regional Runoff Total PCB Results

**Highest total PCB concentration in regional runoff samples was 925 ng/L from Santa Fe River above STP. Two samples from the San Jose Drain in ABQ were above the NMWQCC Wildlife Standard of 14 ng/L. Other runoff samples were below the standard.**

**Notes:**
The results of the Rio Chama and Rio Grande samples collected above Cochiti Reservoir are detailed in previous slides, and are shown here for comparison purposes with lower basin results. 

## NMED PCB Results in Sediments

**Notes:**
Results reported in pg/g (parts per quadrillion) and changed for charting to ug/kg, which is ppb, 1000 ug/kg is 1 mg/kg (ppm). Aroclor analyses detection limit typically about 0.01 mg/kg (ppm). 3 of 4 Sandia Canyon confirmation samples contained >1 mg/kg total PCBs, all other samples from LANL were less than 1 mg/kg. Regional sediments and soils were generally less than 1 ug/kg (ppb).

## Regional PCB Results in Sediment 

**Notes:**
Total PCB sediment concentrations in the Rio Grande near White Rock are about 5 times higher that at Otowi, however, similar to the total concentrations observed at Embudo and Chamita. Total PCB concentrations are at about 1 to 3 order of magnitude higher in the lower Rio Grande Basin.

## SPMD Results

## Slide 13

## Slide 14

## Key findings:

- There are low levels of PCBs in the upper Rio Grande watershed soils, likely due to atmospheric deposition
- Levels of PCBs in fish may warrant may consumption advisories
- Levels of PCBs in storm runoff in tributaries to the Rio Grande often exceed the wildlife habitat standard
- Levels of PCBs in the Rio Grande do not exceed the Wildlife Habitat standard but often exceed the Human Health standard
- Levels of PCBs in the Rio Grande do not exceed the EPA drinking water standard for PCBs
- Levels of dissolved PCBs in the Rio Grande (based on fat bag data) increase below Cochiti Reservoir and remain elevated through Albuquerque
- The levels of toxic congeners (based on fat bag data) increase from Cochiti Reservoir through Albuquerque