Download PPCPs - Undergraduate Research

Environmental Studies
Adsorption of Pharmaceuticals and Personal Care Products (PPCPs) to North
Carolina Soils and Clay Minerals
Abstract
The use of pharmaceuticals and personal care products (PPCPs) has significantly
increased over the past few decades due to advances in medical technology. The Environmental
Protection Agency defines PPCPs as any product used by individuals for personal health or
cosmetic reasons or used by agribusiness to enhance growth or health of livestock (EPA 2010).
PPCPs include a variety of things that society uses everyday, including prescription and overthe-counter drugs, perfumes, veterinary drugs, cosmetics and sunscreens. These products have
been detected in soils, surface water, and groundwater systems, but have not been found to be
toxic at environmental concentrations. However, studies show that exposure to even these low
concentrations have negatively affected wildlife. For example, exposure to synthetic estrogen has
been shown to alter developmental and reproductive cycles of fish.
Previous research has shown that organic matter and negatively charged clay minerals
have a great effect on the mobility of these organic contaminants. The proposed study will focus
on how PPCPs interact with clay minerals in North Carolina soils in order to determine the effect
the mineralogy of a soil has on the mobility of the compounds. The chemical structure of the
PPCPs tested will also be analyzed, providing further insight into the mechanisms of adsorption
of these substances onto clay minerals. The data collected from this study will provide useful
parameters for more accurately predicting the movement of PPCPs through soils.
Description of Project:
Pharmaceuticals and other personal care products (PPCPs), including hormones, caffeine,
acetaminophen and other daily household products, are a growing environmental concern due to
their possible presence in soil and groundwater systems. PPCPs have been detected in soils,
surface water, and groundwater (Wilcox 2009). These compounds are often introduced into the
environment from human and animal waste through septic systems, wastewater treatment plants,
and agricultural practices. These compounds have not been found to be toxic at natural
environmental concentrations, but continuous exposure to such compounds may pose long-term
risks for non-target organisms (Fent et al. 2006; Daughton and Ternes 1999). This is due to the
persistent nature of pharmaceuticals, which do not break down into inert substances immediately
after ingestion and are specifically designed to produce biological responses (Halling-Sorenson
et al. 1998; Kummerer 2004).
Non-target organisms including fish, other aquatic organisms, and even birds have been
negatively affected by PPCPs. For example, exposure to low levels of synthetic estrogen has
been shown to alter the development of flathead minnow males, as well as decreasing egg
fertilization in females (Lange at al., 2001; Parrott and Blunt, 2005). Synthetic estrogen has also
been found to cause gonadal feminization in zebrafish, which inhibits reproduction (Fenske et al.
2005). The anti-inflammatory pharmaceutical diclofenac has been shown to cause gill alteration
and renal lesions in rainbow trout (Schwaiger et al. 2004). Additionally, the diclofenac in
livestock has been linked to the dramatic decline (> 95%) in Oriental white-backed vultures in
India and Pakistan (Oaks et al. 2004). Therefore, due to these negative environmental effects, the
mobility of PPCPs through soils and groundwater is a growing concern.
Research into the mechanism of groundwater transport of PPCPs has been previously
performed (Wilcox 2007; Scheytt et al. 2004). The mobility of PPCPs is determined by their
interactions with soil particles and minerals. Soil and contaminant interactions include sorption
and ion exchange, particularly to clay minerals and organic material (Wilcox 2007). Organic
matter and clay minerals have a net negative charge, which attract cations and other compounds,
like PPCPs. Studies have shown that soils with high amounts of organic matter also have the
highest amount of sorption of organic compounds (Das et al. 2004; Sangsupan et al., 2006). Dr.
Wilcox’s previous research shows that sorption to mineral surfaces and ion exchange are
important components influencing the mobility and transport of contaminants in the absence of
organic matter (Wilcox 2007).
The influence of organic matter in PPCP mobility in groundwater and soil systems is
clear, so this study aims to address the importance of the other primary source of negatively
charged particles in the soil, which are clay minerals. We also hope to determine how the
chemical structure of PPCPs affects their ability to interact with the negatively-charged clay
particles and how the mineralogy of soils may affect the movement of these compounds. Results
from the proposed research will be relevant to broader environmental and health impacts, as the
binding of PPCPs to clay mineral substrates directly affects the mobility and transport of these
compounds in soil and groundwater systems. These experiments will allow us to identify the
importance of clay minerals and their role in PPCP storage and transport and will help us to
better understand the chemical make-up of PPCPs. This knowledge will help in the protection of
wildlife, as well as possible drinking water contamination from PPCPs.
Objectives:

To test different combinations of PPCPs with North Carolina soils and pure clay-mineral
specimens in hopes of discovering how the mineralogy of the soil affects the adsorption
of PPCPs.

To examine the chemical structure of each PPCP in order to identify the mechanism of
adsorption to the negatively clay minerals in the soils.
Methods:
This project will test the sorption of PCPPs onto a variety of North Carolina soils and
clay minerals. Several samples of local soil with varying texture and clay content will be tested.
Pure clay minerals will also be tested including Montmorillonite, Vermiculite, Gibbsite, Chlorite,
Illite, and Kaolinite. The small, negatively charged clay minerals are expected to adsorb a high
amount of PPCPs, much like organic matter. The PPCPs to be tested include caffeine, hormones,
ibuprofen, and acetaminophen. Batch experiments will be used to test the sorption levels of each
mineral and PPCP.
In these batch experiments, known concentrations of PPCPs (2, 4, 6, 8, and 10 ppm) will
be added to vials containing a known mass of a specific soil or clay mineral. The vials will then
be sealed and placed in a shaker to be agitated for a period of 24 hours. The vials will be placed
in a centrifuge in order to separate the solid material from the liquid. This liquid will be
decanted and analyzed using a High Performance Liquid Chromatograph (HPLC), which will
allow us to evaluate the amount of PPCPs left in solution. From this value, the quantity of PPCPs
adsorbed to the surface of the clay minerals can be calculated.
With the values collected, I will create adsorption isotherms, using the Freundlich
isotherm equation to find the amount of PPCP sorbed onto the soil and clay particles at particular
concentrations (Kehew 2001). The equation is as follows:
S = K CN
Where:
S = mass sorbed in micrograms/gram
K = distribution coefficient (Kd)
C = concentration in milligrams/liter
N = indication of linear relationship (n=1) or slightly concave (n=0.5)
Once the isotherm for each mixed sample is tested, the sorption coefficients (K values) can be
compared for different compounds and different soils/minerals, providing insight into how the
mineralogy of a soil affects PPCP adsorption.
Timeline:
Week
Progress
1
Experimental Set-up and begin running tests
2
Run Experiments
3
Run Experiments
4
Run Experiments
5
Data Analysis
6
Data Analysis
7
Continue data analysis and work on write-up (draft)
8
Finalize paper and prepare for dissemination of results
June 6th – July 1st (4 weeks): I will work from 11:00 am to 5:00 pm Monday through Friday,
resulting in 120 hours worked in the first half of the summer term.
July 5th – July 30th (4 weeks): I will work from 2:00 to 5:00 pm Monday through Thursday
because I have a morning class. Over the course of 4 weeks I will accumulate another 48 hours
of research. The bulk of the experiments should be completed by this time, leaving data analysis
and draft writing, making required time in the lab more flexible.
Budget:
I am requesting this stipend since I will working on this project in lieu of another summer job.
Most of the necessary lab equipment and materials are already available in Dr. Wilcox’s lab.
However, the following list of materials are either particular to my proposed study or will be
uses to replenish the disposable supplies I will be using throughout the summer.
Expense
Amount
Source
$1,500
N/A
$470
Perkin Elmer, Fisher Scientific
Laboratory Supplies
Box of filters, $150
Sample vials, $150
Microcentrifuge vials, $50
Pipettor tips, $75
$425
Fisher Scientific
Clay Mineral Specimens
$40
Ward’s Scientific
Student Stipend
HPLC Supplies
Column, $400
HPLC-grade methanol, $70
Total:
$2,435
Dissemination of Results:
Data collected form this project will be presented at the Fall 2011 UNCA Undergraduate
Research Symposium and will be presented at either the national Geological Society of America
(GSA) conference this October or the regional GSA conference next March (2012).
Additional funding:
Dr. Wilcox submitted a large grant proposal to NSF last year that received favorable
reviews, but was not funded. He is planning to resubmit the grant proposal this summer. While
my proposed project will not be directly impacted by this grant one way or another, the data I
collect may be used to help strengthen the resubmission.
Bibliography
Daughton CG and Ternes TA. (1999) Pharmaceuticals and personal care products in the
environment: agents of subtle change?. Environmental Health Perspectives
107(Supplement 6): 907-938.
Das BS, Lee LS, Rao PSC, and Hultgren RP. (2004) Sorption and degradation of steroid
hormones in soils during transport: Column studies and model evaluation. Environmental
Science & Technology 38(5): 1460-1470.
EPA. 2011. Pharmaceuticals and Personal Care Products (PPCPs). EPA. [cited 2011 Apr 18]
Available from: http://www.epa.gov/ppcp/.
Fenske, M., Maack, G., Schafers, C. and Segner, H., 2005. An environmentally relevant
concentration of estrogen induces arrest of male gonad development in zebrafish, Danio
rerio: Environmental Toxicology and Chemistry, v. 24, no. 5, p. 1088-1098.
Fent K, Weston AA, and Caminada D. (2006) Ecotoxicology of human pharmaceuticals: aquatic
toxicology 76(2): 122-159.
Halling-Sorenson, B., Nielsen, S.N., Lanzky, P.F. Ingerslev, F., Lutzhoft, H.C.H., and Jorgensen,
S.E. 1998. Occurrence, fate and effects of pharmaceutical substances in the
environment—a review: Chemosphere, v. 36, no. 2, p. 357-394.
Kehew, Alan E. 2001. Applied Chemical Hydrogeology: New Jersey, Prentice-Hall Inc., p. 113.
Kummerer, K., ed. 2004. Pharmaceuticals in the environment: sources, fate, effects and risks:
Berlin, Germany, Springer, 527 p.
Lange R, Hutchinson TH, Croudace CP, and Siegmund F. (2001) Effects of the synthetic
estrogen 17-ethinylestradiol on the life-cycle of the fathead minnow (Pimephales
promelas). Environmental Toxicology and Chemistry 20(6): 1216-1227.
Oaks, J.L., Gilbert, M., Virani, M.Z., Watson, R.T., Meteyer, C.U., Rideout, B.A., Shivaprasad,
H.L., Ahmed, S., Chaudhry, M.J.I., Arshad, M., Mahmood, S., Ali, A., and Khan, A.A.
2004. Diclofenac residues as the cause of vulture population decline in Pakistan: Nature,
v. 427, no. 6975, p. 630-633.
Parrott JA and Blunt BR. (2205) Life-cycle exposure of fathead minnows (Pimephales promelas)
to an ethinylestradiol concentration below 1 ng/L reduces egg fertilization success and
demasculinizes males: Environmental Toxicology 20(2): 131-141.
Sangsupan HA, Radcliffe DE, Hartel PG, Jenkins MB, Vencill WK, and Cabrera ML. (2006)
Sorption and transport of 17ß-estradiol and testosterone in undisturbed soil columns.
Journal of Environmental Quality 35(6): 2261-2272.
Scheytt TJ, Mersmann P, and Heberer T. (2006) Mobility of pharmaceuticals carbamazepine,
diclofenac, ibuprofen, and propyphenazone in miscible-displacement experiments.
Journal of Contaminant Hydrology 83(1-2): 53-69.
Schwaiger, J., Ferling, H., Mallow, U., Wintermayr, H., and Negele, R.D. 2004. Toxic effects of
the non-steroidal anti-inflammatory drug diclofenac, part 1: histopathological alterations
and bioaccumulation in rainbow trout: Aquatic Toxicology, v. 68, no. 3, p. 405-410.
Wilcox, JD. (2007) Transport and fate of organic wastewater contaminants beneath unsewered
residential subdivisions. Madison, Wisconsin, University of Wisconsin, PhD.
Dissertation, pp. 1-13; 183.
Wilcox JD, Bahr JM, Hedman CJ, Hemming JDC, Barman MAE, and Bradbury KR. (2009)
Removal of organic wastewater contaminants in septic systems using advanced treatment
technologies. Journal of Environmental Quality 38: 149-156.