Challenges of Conducting Analytical Chemistry in Environmental Matrices

May 8th 2006 Meg Sedlak and Don Yee

San Francisco Estuary InstituteOakland, 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 ProgramRegional Monitoring Program

Founded in 1993 Founded in 1993 Monitoring trends and Monitoring trends and distribution of pollutantsdistribution of pollutants

Estimating loadsEstimating loads

Measuring exposure and effectsMeasuring 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

W =4

S =8

W =6

S =8

W =4

S =8

W =10

S =8

W =4

S =8

Rivers

SuisunSan

PabloBay

CentralBay

SouthBay

Lower SouthBay

Water: 31 total

Sediment: 47 total

= Historical fixed station

W =4

S =8

W =6

S =8

W =4

S =8

W =10

S =8

W =4

S =8

Rivers

SuisunSan

PabloBay

CentralBay

SouthBay

Lower SouthBay

Water: 31 total

Sediment: 47 totalW =4

S =8

W =5

S =8

W =4

S =8

W =9

S =8

W =4

S =8

Rivers

SuisunSan

PabloBay

CentralBay

SouthBay

Lower SouthBay

Rivers

SuisunSan

PabloBay

CentralBay

SouthBay

Lower SouthBay

Water: 31 total

Sediment: 47 total

= Historical fixed station = Historical fixed station

Regulatory standards vs. Environmental concentrations

0

2

4

6

8

10

12

Cadmium Lead PCBs Mercury

Hazardous Waste (mg/L)

Water Quality Criteria (ug/L)

SF Bay (ng/L)

Protecting analyst from sample

Protecting sample from the analyst

Collect sample

Extract

Chemical Analysis

“Clean” Containers

Supplies & Equipment

Laboratory Environment

ReagentsGlassware

Field Crew

Result

Field blankProof Lab blank

Cleaning

FieldEnvironment

Sampling & Analysis

Chain

Collect sample

Extract

Chemical Analysis

“Clean” Containers

Supplies & Equipment

Laboratory Environment

ReagentsGlassware

Field Crew

Result

Field blankProof Lab blank

Cleaning

FieldEnvironment

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

0

100

200

300

400

500

600

700

800

900

2002 2003

Anthracene

Co

nc

. (p

g/L

)

MDL

Blank

Field Sample

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

2002 2003

Biphenyl

Co

nc

. (p

g/L

)

MDL

Blank

Field Sample

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. 2005 PAH Blanks

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

2003 2005

Con

cent

ratio

n (p

g/L)

Biphenyl

Anthracene

2005 Total PAH Concentrations in Water

PBDEsEmerging Contaminant

• Wide-spread use• Increase scrutiny

– Health effects– Phase out in EU &

CA

• Deca highest use

Source: Stapleton et al., 2005. ES&T 39(4); Wilford et al., 2005 ES&T 39(18); and BSAF.

0

10000

20000

30000

40000

50000

60000

70000

80000

1992 1999 2001 2003

Year

Prod

uctio

n in

Ton

nes

PBDEsAn Emerging Challenge

• Blank contamination in lab environment?– Present in plastics, soft furnishing, electronic equipment

0

50

100

150

200

250

BDE047

BDE099

BDE100

BDE153

BDE209

Av

era

ge

Co

nc

en

tra

tio

n (

pg

/L)

Blank

Field Sample

PBDEs: A spec of dust is important no matter how small ….

Source: Stapleton et. al, ES&T 39 (4)

1

10

100

1000

10000

100000

2004 RMPSediment

House dustPB

DE

Co

nc

en

tra

tio

n (

ug

/kg

)

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(www.AXYStechnologies.com)

Francois Rodigari and Saskia van Bergen(www.EBMUD.com)

Questions?

All of RMP data and reports are available on-line at www.sfei.org