1. Investigating the Fate and
Transport of PPCPs in the
Environment
Ashley Funk
Advisor: Monica Higgins
Environmental Studies
Wellesley College
Funded by Sophomore Early Research Program
2. Why fate and transport of PPCPs?
Important parameters
Experimental setup and results
3. Pharmaceuticals and personal care products (PPCPs) are
frequently detected in our rivers and streams
Kolpin, D., E. Furlong, et al. (2002). "Pharmaceuticals, hormones, and other organic wastewater contaminants in US streams,
1999-2000: A national reconnaissance.“
Nonprescription Drugs
4. Pharmaceuticals and personal care products (PPCPs) are
found in our rivers and streams in low concentrations
Understanding the fate and transport of PPCPs is important to
predicting their impact on ecosystems and human health
Nonprescription drugs
Kolpin, D., E. Furlong, et al. (2002). "Pharmaceuticals, hormones, and other organic wastewater contaminants in US streams,
1999-2000: A national reconnaissance.“
5. We chose caffeine as an example PPCP because it is
frequently found and is an indicator of other contamination
6. Currently, predicting PPCP movement in the environment
relies on the soil distribution coefficient, or Kd
start
Caffeine
7. Currently, predicting PPCP movement in the environment
relies on the soil distribution coefficient, or Kd
Caffeine
equilibrium
9. In the subsurface PPCPs may not behave exactly as they do
in a laboratory flask, in part, because they are moving Drinking
Water
FLOW
Release to
Environment
10. Movement of substances in groundwater can be described
by the advection-dispersion equation
𝜕𝐶
𝜕𝑡
= 𝜆
𝜕2 𝐶
𝜕𝑥2
− 𝑣 𝑥
𝜕𝐶
𝜕𝑥
AdvectionDispersion
Concentration
Time
Dispersivity Velocity
If we know the velocity of water, we can use
concentration data from a conservative tracer
to determine the dispersivity.
Position
11. RelativeConcentration
Pore Volume
C/C0 = 1
C/C0 = 0
0 1 2
Influent
Ideal Effluent
In an ideal column, without soil, the entire effluent front
should appear at one pore volume
12. Dispersion is a function of substances traveling around and
through the soil particles
Faster
Slower
13. RelativeConcentration
Pore Volume
C/C0 = 1
C/C0 = 0
0 1 2
Ideal Effluent
Nonreactive
Tracer
Faster
Slower
Because of dispersion, the effluent front in the soil column
will center on one pore volume but have an “s” shape
14. RelativeConcentration
Pore Volume
C/C0 = 1
C/C0 = 0
0 1 2
Nonreactive
Tracer
Reactive
Chemical
The reactive chemical will have an “s” shaped front but will
be delays because of interactions with the soil particles
15. A reactive substance may move through the column more
slowly than the non-reactive tracer.
𝑅
𝜕𝐶
𝜕𝑡
= 𝜆
𝜕2 𝐶
𝜕𝑥2
− 𝑣 𝑥
𝜕𝐶
𝜕𝑥
Retardation Factor
When we know the velocity and the dispersivity of
the column, we can use concentration data from our
PPCP to determine the retardation factor.
16. In the prediction of fate and transport, it is assumed that
retardation factor is related to Kd
𝑅 = 1 +
𝜌 𝑏
𝜃
𝐾 𝑑
To answer this question we need to be able to measure or
calculate the velocity, dispersivity, and retardation factor.
Will the observations in flow-
through systems … … match what could be
predicted from the
observations in batch
system?
17. To simplify the environment, we used a one-dimensional
column system to measure caffeine movement Drinking
Water
FLOW
Release to
Environment
18. To simplify the environment, we used a one-dimensional
column system to measure caffeine movement
FLOW
19. To simplify the environment, we used a one-dimensional
column system to measure caffeine movement
Pump
Column
Effluent
Influent
We need to be able to measure or calculate the
velocity, dispersivity, and retardation factor.
20. We estimated the velocity by measuring volume of effluent
per unit time and dividing by the column area
Pump
Column
Effluent
Influent
Ultrapure
Water
flowrate ~ 5 mL/hr
velocity = 23 cm/day
21. We introduce artificial groundwater and measure the
chloride concentration as a conservative tracer
Pump
Column
Effluent
Influent
Artificial
Groundwater
22. We estimated the dispersivity by fitting experimental results
of chloride ion to the advection dispersion equation.
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
RelativeConcentration
Pore Volume
Chloride
23. We estimated the dispersivity by fitting experimental results
of chloride ion to the advection dispersion equation
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
RelativeConcentration
Pore Volume
Chloride ADE Prediction
= 0.299 cm
R2 = 0.76
24. We spike the artificial groundwater and with caffeine to find
the retardation factor
Pump
Column
Effluent
Influent
Caffeine +
Artificial
Groundwater
25. Knowing the velocity and the dispersivity, we can determine
the retardation factor of caffeine in sand columns
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
RelativeConcentration
Pore Volume
Caffeine
26. Knowing the velocity and the dispersivity, we can determine
the retardation factor of caffeine in sand columns
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
RelativeConcentration
Pore Volume
Caffeine R = 1.0
R2 = 0.87
27. Knowing the velocity and the dispersivity, we can determine
the retardation factor of caffeine in sand columns
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
RelativeConcentration
Pore Volume
Caffeine R = 1.0 R = 1.5
R2 = 0.87
28. Knowing the velocity and the dispersivity, we can determine
the retardation factor of caffeine in sand columns
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
RelativeConcentration
Pore Volume
Caffeine R = 1.0 R = 2.0
R2 = 0.49
𝑅 = 1 +
𝜌 𝑏
𝜃
𝐾 𝑑
29. Future work will vary experimental conditions to replicate
expected environmental conditions
Solution Properties:
pH
Ionic strength
Soil Properties:
Organic carbon
Minerals
PPCP Properties:
Size
Charge
Caffeine
30. Understanding the fate and transport of
PPCPs is important to assess their impact on
ecosystems and human health
The soil distribution coefficient and
the retardation factor are important
parameters that will be dependent
on environmental conditions.
We were able to estimate
the retardation factor of
caffeine in sand columns.
