Download Dermal dose (ng/day) Ingestion + dermal

Fate of Chemical and Biological
Emerging Contaminants
in Biosolids and After
Land Application
Ian L. Pepper
The University of Arizona
The Northwest Biosolids Management
Association’s 23rd Annual
Biosolids Management Conference
September 19-21, 2010
Campbell’s Conference Center
Chelan, WA
EMERGING CONTAMINANTS
● Include chemical and biological
entities
● By definition are newly discovered
contaminants
● Little information on incidence, fate
and
transport, and potential adverse impacts
on human and/or ecological health
CHEMICAL EMERGING
CONTAMINANTS
Endocrine Disrupting Compounds (EDCs)
●Pharmaceuticals and personal care products
(PPLP)
●Steroidal hormones (estrogenic activity)
●Flame retardants (polybrominated diphenyl
ethers (PBDEs)
Representative Estrogenic
Compounds
Polybrominated Diphenyl ethers
Brm
Brn
.......
.......
- Flame retardants
- 229 possible congeners
Characteristics of EDCs.
● EDCs interfere with the synthesis, secretion, transport, binding, action,
or elimination of natural hormones in the body that are responsible for
the maintenance of homeostasis (normal cell metabolism), reproduction,
development, and/or behavior.
● EDCs can be hormone mimics, with hormone-like structures and
activities. That is EDCs sometimes have chemical properties similar to
hormones and bind to hormone specific receptors in or on the cells of
target organs.
● EDCs frequently have lower potency than the hormones they mimic
(i.e., require higher dose to elicit an equivalent response), but may be
present in water at high concentrations relative to natural hormones.
Furthermore, EDCs may not be subject to normal (internal) regulations
mechanisms.
● For all known EDCs, there is some dose below which there is no
observable response.
Most potential adverse effects of EDCs focus on wildlife or ecosystems.
● Eggshell thinning and subsequent reproductive failure of waterfowl
● Reduced populations of Baltic seals
● Reproductive failure in alligators
● Development of male sex organs in female marine animals such as
whelks and snails
● Reduced or malformed frog populations
● Disruption of normal sex ratios among exposed populations of fish
THE LANDMARK USGS
1999-2000 STUDY
● Barnes et al. (2002) water-quality data
for
phamaceuticals, hormones, and other
organic wastewater contaminants in U.S.
streams, 1999-2000. USGS Open-File Report
Locations of stream sampling sites in the 1999–2000
reconnaissance of United States surface water quality by USGS.
Hormones and hormone mimics observed in
U.S. surface waters.
Compound
progesterone
testosterone
17ß-estadiol
17ß-estradiol
estriol
estrone
mestranol
19-norethisterone
17 -ethinyl estradiol
cis-androsterone
4-nonylphenol
4-nonylphenol monoethoxylate
4-nonlyphenol diethoxylate
4-octyphenol monoethyoxylate
4-octyphenoldiethoxylate
bisphenol A
Description
reproductive hormone
reproductive hormone
reproductive hormone
reproductive hormone
reproductive hormone
reproductive hormone
ovulation inhibitor
ovulation inhibitor
ovulation inhibitor
urinary steroid
detergent metabolite
detergent metabolite
detergent metabolite
detergent metabolite
detergent
plasticizer
Detection
limit
(µg L-1)
0.005
0.005
0.05
0.005
0.005
0.005
0.005
0.005
0.005
0.005
1.0
1.0
1.1
0.1
0.2
0.9
Frequency of
detection
(%)
Max.
(µg L-1)
Median
(µg L-1)
4.1
4.1
9.5
5.4
20.3
6.8
4.3
12.2
5.7
13.5
51.6
45.1
34.1
41.8
23.1
39.6
0.199
0.214
0.093
0.074
0.043
0.027
0.407
0.872
0.273
0.214
40
20
9
2
1
12
0.11
0.017
0.009
0.030
0.019
0.112
0.017
0.048
0.094
0.017
0.7
1
1
0.15
0.095
0.13
Representative pharmaceuticals measured in the 1999–2000 UGS reconnaissance
of U.S. streams. A comparison of drinking water levels with medicinal doses.
Chemical/use
Caffeine/stimulant
Percentage of
samples with
compound
71
Maximum
concentration
(µg L-1)
Medicinal dosage
6
130 mga
400 mgb
Ibuprofen/anti-inflammatory
9.5
1
Cimetidine/antacid
9.5
0.58
800 mg day1c
0.831
20–35 µgd
0.214
150–450 mge
17 -ethinyl estradiol/oral
contraceptive
Testosterone/hormone replacement
16
2.8
Erythromycin/anti-bacterial
21.5
1.7
1000 mg day1f
Ciprofloxacin/anti-bacterial
2.6
0.03
400–800 day1f
aThe
mass of caffeine in two Excedrin tablets. There is 135 mg of caffeine in an 8-oz. cup of coffee.
mass of ibuprofen in two tablets of Advil
cThe lowest adult daily dose of cimetidine
dRange of 17 -ethinyl estradiol masses in birth control pills
eRange of testosterone masses provided over 3–6 months when used for hormone replacement
fRecommended adult dosages
bThe
Physical, chemical and biochemical properties of
selected estrogenic chemicals.
Chemical name
Molecular
weight
Water solubility
(mg L-1 at 20 °C)
Log Kow
(L kg-1)
Relative
Estrogenic
Activity
Nonylphenol (NP)
220
5.43
4.48
1.2 × 10-4
Nonylphenol
monoethyoxylae
264
3.02
4.17
~10-5
Octylphenol (OP)
206
12.6
4.12
×10-4
17 ß-estradiol (E2)
272
13
3.94
1.0
17 -ethinyl estradiol (EE2)
296
4.15
1.4
Estrone (E1)
270
3.43
0.5
4.8
13
SUSTAINABILITY OF
LAND APPLICATION
Huruy Zerzghi
University of Arizona
STUDY SITE
Study begun in 1986 at the U of A (Marana Agricultural Center)
Biosolids has been continually applied for 20 years (1986 -2005)
Crop grown - cotton
Marana
DESIGN OF THE EXPERIMENT
Control (# 1)
Inorganic fertilizer (# 3)
Low biosolids rate (1x, # 2)
High biosolids rate (3x, # 4)
The twentieth year of biosolids land application
(March 1-15, 2005)
8%
solids
Biosolids land
application
FATE OF LAND APPLIED
ENDOCRINE DISRUPTORS
IN SOIL
Mean congener (BDE-47, -99, and -209) concentrations
in soil in the 0X, 1X, and 3X biosolid loading rate plots.
10
20
30
40
50
0
60
0-30
0-30
30-60
30-60
Depth (cm)
Depth (cm)
0
Concentration (ng /g)
BDE 47
Concentration (ng/g)
60-90
10
20
30
BDE 99
40
50
60-90
3x
90-120
90-120
3x
1x
1x
control
120-150
control
120-150
BDE 209
Concentration (ng/g)
0
20
40
60
80
100
120
Depth (cm)
0-30
30-60
60-90
3x
90-120
1x
control
120-150
140
60
Total mean concentration of PBDE congeners* in soils
at the 0-30 cm soil depth compared to household
indoor exposure.
Source
PBDE Concentration (ng/g)
No biosolids
29.74
1X biosolids
66.99
3X biosolids
104.32
Range for indoor dust in U.S. households*
1,064 to 3,450 (mean 2,534)
From Fromme et al., 2009.
*For BDE-47, -99, -153 and -209
Nonylphenol
Soil depth 0-1’
1400
1200
Concentration (ug/kg)
1000
rep 1
800
rep 2
rep 3
600
rep 4
threshold
400
200
0
control
1x
3x
RISK ASSESSMENT FOR EXPOSURE TO PBDE
Chuck Gerba
Dermal Adsorption Daily Exposure Dose
Dermal Intake = [(C)(BSA)(SAS)(AF)(OEF)] / [(BS)(1,000)]
Where BSA = body surface area (cm2/day), SAS = soil adhered to the skin
(mg/cm2), AF = fraction of PBDE adsorbed to the skin, and BW = body weight.
Total exposure is the sum of ingestion and dermal intake.
Exposure Route
Factor
Value
Dermal Intake
Weight (Kg)
65
Body surface area (cm2/day)
4,615
Soil adhered to skin (µ/cm2)
0.096
PBDE fraction adsorbed through the skin
0.03
Outdoor exposure factor (fraction of day spent
outdoors) (assumed to be 8 hours)
0.33
Mean concentration of PBDE in soil
varies
RISK ASSESSMENT FOR EXPOSURE TO PBDE
Chuck Gerba
Ingestion Daily Exposure Dose
Daily ingestion exposure dose = [(C) (SIR) (OEF)] / BW
Where C = PBDE concentration (ng/g dry weight), SIR = soil ingestion rate
(m3/day), BW = body weight (kg), and OEF = outdoor exposure fraction (hours
spent over a day in the field to which biosolids have been added).
Exposure Route
Factor
Value
Ingestion Intake
Weight (Kg)
65
Body surface rate (g/day)
0.05
Outdoor exposure factor (fraction of day spent
outdoors) (assumed to be 8 hours)
0.33
Mean concentration of PBDE in soil (ng/g)
varies
Evaluation of hazard indices for BDE 47, 99, 153 and
209.
Congene
r
Ingestion
dose (ng/day)
Dermal dose
(ng/day)
Ingestion +
dermal
(ng/day)
RfD
µg/Kg/day
Hazard
Quotient*
47
0.00216
0.00057
0.00273
0.1
0.0000273
99
0.0075
0.00199
0.00849
0.1
0.0000849
153
0.00122
0.00032
0.00154
0.2
0.0000016
209
0.0156
0.01974
0.01974
7.
0.000000282
Hazard index is summation of Hazard Quotient values.
RISK
Non Cancer Risk
● Hazard Index is several orders of magnitude < 1
suggesting very low risk
Cancer Risk
● BDE 209 is only congener where information
available to evaluate carcinogenicity
- Mean concentration for 3X plot = 61.4 ng/g
- Dermal and ingestion exposure = 0.0197
ng/kg/day6
Life Time Risk of Cancer = 9.11 x 10-14
SURVIVAL OF PRIONS IN
CLASS B BIOSOLIDS
Kazue Takizawa, Chuck Gerba, and Ian Pepper
The University of Arizona
Kazue Takizawa
● M.S. degree in SWES
● Optimized extraction of prion proteins
from Class B biosolids
● Evaluated survival of prions in Class B
biosolids at mesophilic and thermophilic
temperatures
Prion Characteristics
● A normal prion (PrPc) is
composed of mostly alphahelicies
● An infectious prion (PrPsc) is
dominated by beta-sheets
● Resistant to inactivation by
proteolytic enzymes,
conventional disinfectants,
and standard sterilization
methods
http://www.le.ac.uk/biology/research/phyto/prions.jpg
Infectious Prion Conversion
PrPc
PrPsc
●
When a infectious
prion PrPsc comes in
contact with a normal
prion PrPc, it causes PrPc
to convert to PrPsc
●
Disease occurs when
PrPsc concentration
threshold is reached
Prion Pathogenesis
●
Infectious prion
proteins (PrPsc) cause
Transmissible
Spongiform
Encephalopathy (TSE)
diseases which affects
humans and animals
●
Most common
Creutzfeldt-Jakob
disease (CJD)
Soto et al. 2004
TSEs in Animals
● Affects sheep, goats, minks, mules, deer,
cows, cats, exotic felines, and ungulates
● Most common TSE in animals is called
scrapie which affects sheep and goats
● Chronic Wasting Disease (CWD)affecting deer and elk
- Affecting deer population in U.S. :Colorado,
Wyoming, Nebraska, New Mexico, South
Dakota, Wisconsin
FATE OF PRIONS IN THE
ENVIRONMENT
● PrPsc adsorbs to clay and organic colloids
● Sorbed prions reported to remain infective
● Prions reported to survive mesophilic
anaerobic digestion during wastewater
treatment
● Detection via Western Blot technology—did
not assess infectivity
POTENTIAL ROUTE OF
EXPOSURE TO PRIONS VIA
LAND APPLICATION
Animal
Slaughterhouse
Wastewater
Treatment
Wastewater
Humans
Cows
Biosolids
Land Application
METHODOLOGY
● Class B biosolids—7% solids
● CAD 1A2DS (CAD5) cell line
● Source of prions: Rocky Mountain Laboratory
(RML)—infected mouse brain
● Enzyme-linked immunosorbent spot
(ELISPOT) assay
Approximately 1,000 prion infected CAD5 cells
The original plan was to use ScN2a cells which yielded
0.001% infectivity rate
●
Currently, ELISPOT assays performed with CAD5
cells has dramatically increased the yield to a 50%
infectivity rate.
●
Decreased assay by 8 days
EVALUATION OF
EXTRACTANTS OF PRION
PROTEINS FROM BIOSOLIDS
● Phosphate buffer saline (PBS)
● 3% beef extract
● Sodium dodecyl sulfate (SDS)
● 8M urea
RECOVERY OF PRIONS FROM
BIOSOLIDS
Extractant
% Recovery
PBS
0.01
3% beef extract
<0.001
SDS
4
8M urea (room temperature)
< 0.002
*4M urea at 80◦C
17.2% with no toxicity to cells
REDUCTION OF INFECTIOUS PRIONS AT
MESOPHILIC (37◦C) AND
THERMOPHILIC (60◦C) TEMPERATURES
A) In PBS
Mesophilic: log10 N/N0 (15 days) = ‐1.13
Thermophilic: log10 N/N0 (10 days) = ‐1.80
B) Class B biosolids
Mesophilic: log10 N/N0 (15 days) = ‐2.43
Thermophilic: log10 N/N0 (10 days) = ‐3.41
INACTIVATION OF PRIONS IN
BIOSOLIDS > PBS
● Mechanism: protolytic enzymes that
denature proteins
● Ammonia or other substances in
biosolids
COMPARISON OF STUDIES
● Maluquer de Motes et al. (2008)
- prion survival in raw sewage
- Western blot technology
- 90% reduction of prions after 32.6 days at 20◦C
● Our study
- 99.1% reduction after 15 days at 37 ◦C
- 99.9% reduction after 10 days at 60 ◦C
Reason: infectivity assay
SUMMARY
● 4M urea an effective extractant of prions
from biosolids
● Significant inactivation in biosolids at
mesophilic and thermophilic temperatures
● Data needed on inactivation during actual
wastewater treatment
ONGOING PRION WORK
● Evaluating wastewater treatment effects on
prion inactivation
- miniature anaerobic digesters (test tubes)
- mesophilic anaerobic digestion 37°C
- thermophilic anaerobic digestion 60°C
- composting
FATE OF EMERGING
CONTAMINANTS: CONCLUSIONS
● Estrogenic compounds added to soil via land application of
biosolids degrade quickly within a matter of weeks
● PBDEs are strongly hydrophobic and sorbed to soil colloids
with low solubility and bioavailability
● Overall risk from PBDE via land application is very low.
● Prions are inactivated in biosolids at mesophilic and
thermophilic temperatures
● Overall more research is needed in both areas of concern