Challenges of Conducting Analytical Chemistry in Environmental Matrices May 8 th 2006 Meg Sedlak and...
-
Upload
duane-booker -
Category
Documents
-
view
214 -
download
0
Transcript of Challenges of Conducting Analytical Chemistry in Environmental Matrices May 8 th 2006 Meg Sedlak and...
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