Challenges of Conducting Analytical Chemistry in Environmental Matrices May 8 th 2006 Meg Sedlak and Don Yee San Francisco Estuary Institute Oakland, California

Outline Overview of the Regional Monitoring Program for Water Quality (RMP) Challenges of environmental samples –Ubiquitous contaminants, trace concentrations, complex matrices Specific examples – PAH and PBDEs Summary

Regional Monitoring Program Founded in 1993 Monitoring trends and distribution of pollutants Estimating loads Measuring exposure and effects

Funded by NPDES dischargers Collaborative - Quarterly meetings with dischargers, regulators, & staff Core element – Status and Trends Pilot and special studies RMP Structure

Status & Trends Annual Monitoring Summer Water, sediment, bivalves, & sportfish Analytes: –Trace elements (Ag, As, Cd, Cu, Fe, Hg, MeHg, Mn, Ni, Pb, Se, Zn) –Organics (PCBs, PBDEs, Pesticides, PAHs) –Toxicity (sediment & water) 5 different laboratories

Regulatory standards vs. Environmental concentrations Protecting analyst from sample Protecting sample from the analyst

Collect sample Extract Chemical Analysis “Clean” Containers Supplies & Equipment Laboratory Environment Reagents Glassware Field Crew Result Field blankProof Lab blank Cleaning Field Environment Sampling & Analysis Chain

Collect sample Extract Chemical Analysis “Clean” Containers Supplies & Equipment Laboratory Environment Reagents Glassware Field Crew Result Field blankProof Lab blank Cleaning Field Environment Sampling & Analysis Chain “External” Sources of Contamination “Internal” Sources of Contamination

AXYS system 1 m below surface 100 liters Prefilter, glass filter (1 um pore size) and XAD resin Extract split 5 ways Water Organics- Collection

Water - Organics Glass Filters and XAD resin –Soxhlet extracted –12 hrs, closed loop distillation Silica gel cleanup Analysis by GC/MS for PAHs

PAH Blanks 2002 vs. 2003

Water Organics- What changed? Cleaning –2003 switched to acid- cleaning of glassware Change in solvent –stabilizer in toluene (proprietary) PAH Formation –Mechanism unknown –Activation sites/heat? =Si-OH ?

Alternatives Considered Other solvents –Acetonitrile/Dichloromethane- recovery problems w/ other analytes (pesticides) Splitting samples –XAD possible –Filters? No clean-sawing SOP developed

Alternatives Considered (cont’d) Whole water samples – Pros and Cons Cons –5-fold increase in detection limits Would lose some PAHs (e.g., acenaphthene) –A lot of water samples needed…. 4 liters per analyte 31 sites => 620 L => 620 kgs …meaning a whole lot of weight.

Alternatives – Whole Water Cons: –Liquid-liquid extraction –Time-consuming to extract 4 liter samples Pros: –Weight training

Alternative Chosen Ambient Temperature eXtraction (ATX) –Developed by AXYS Analytical Filters sonicated in acetonitrile and hexane Good recovery for all analytes

2003 vs PAH Blanks

2005 Total PAH Concentrations in Water

PBDEs Emerging Contaminant Wide-spread use Increase scrutiny –Health effects –Phase out in EU & CA Deca highest use Source: Stapleton et al., ES&T 39(4); Wilford et al., 2005 ES&T 39(18); and BSAF.

PBDEs An Emerging Challenge Blank contamination in lab environment? –Present in plastics, soft furnishing, electronic equipment

PBDEs: A spec of dust is important no matter how small …. Source: Stapleton et. al, ES&T 39 (4)

Similar challenges with other Emerging Contaminants Ubiquitous, trace levels, complex matrices Perfluorinated Compounds Teflon liners, tubing, septa, textiles Phthalates Gloves and septa

Summary Large-scale environmental monitoring programs require adaptive management –Off-the-shelf methods may not work Modification of methods Working with laboratories to solve the problem –Many sources of contamination Internal contamination (function of the method) External contamination (introduced as a result of lab environment, supplies, equipment, staff, etc.) Need strong QA/QC New analytes = new sources and challenges

Acknowledgements Brian Fowler and Dale Hoover ( Francois Rodigari and Saskia van Bergen (

Questions? All of RMP data and reports are available on-line at