APEs students against APES
Amanda Dieu, Raymond Lam, Sharon Liu, Katherine Vuong
Gabrielino High School
Abstract:
For years, society has looked towards quick fixes for their household problems. Clogged
drains were cleared with the help of chemical cleaners like Drano and Liquid Plumber. As
technology improves and scientists begin to examine particles at parts per trillion, these quick fix
cleaners have been discovered to leave harmful chemicals into our environments, including the
surfactant alkylphenol ethoxylates (APEs). APEs compounds have been found to mimic the estrogen
hormone and lead to the feminization of marine life. Although studies have found conclusive
evidence of its effects in the UK, the objective of our research is to determine whether or not APEs
are prevalent in U.S water bodies and are harming our environment. By identifying whether or not
APEs pose a serious threat to the environment, this research could be used to promptly establish
safety levels for APEs in watersheds and rivers and prevent further harm.
Introduction:
Indoor plumbing is perhaps one of the greatest modern
conveniences - yet, as with other conveniences, there are
monumental sacrifices. On average, Americans dump millions of
gallons of chemical cleaners down the drain, unknowingly causing
harm to local water treatment plants as well as watersheds.
What makes chemical drain cleaners so effective are the
corrosive active ingredients, which include ammonia, chlorides,
phosphates, sulfuric acid, and other various acidic and caustic
chemicals. It is with these corrosive qualities that the cleaner is able
to eat through drain clogs and therefore free up the drain. When
Figure 1: Diagram of nonylphenol (NP)
and octylphenol (OP)
consumers
use these drain cleaners, the chemicals travel to waste water
(Ecologiena 1994)
treatment plants, where their corrosive qualities damage the bacteria
used to clean waste in septic tanks. Through this method, the chemicals remain in the water when the
water is released back into the ecosystem. These chemicals can therefore cause imbalance in both the
abiotic and biotic factors in aquatic ecosystems.
Among the many problematic chemicals is the alkylphenol ethoxylates (APEs) class. This
class includes nonylphenol ethoxylates and octylphenol ethoxylates, as seen in Figure 1, which are
surfactants, an essential ingredient in cleaners and detergents which lowers surface tension in liquids
(Warhurst 1995). The compound allows drain cleaners to break down and clear clogs efficiently.
Theoretically these harmful chemicals should be disposed of at water treatment plants, before they
are either recycled back into municipal water districts or pumped into watersheds. However, the
APEs compounds do not dissolve but instead the compounds, nonylphenol ethoxylates and
octylphenol ethoxylates break down into nonylphenol and octylphenol (Warhurst 1995), which have
been found to be more toxic and incapable of readily biodegrading into soil and water. These
chemicals have been found in 69% of US streams tested (Organic Consumers Association 2011).
The APEs compounds have been found to mimic the estrogen hormone (Routledge and
Sumpter 1996), and are capable of damaging endocrine systems of aquatic organisms and causing
hormonal imbalance that can upset reproductive cycles. As more and more of the chemicals begin to
contaminate aquatic ecosystems, biological magnification takes effect in that the concentration of
APEs increases throughout the food web, resulting in toxicity in those organisms (Warhurst 1995).
The estrogenic characteristics the APEs compound has mimicked have been found in
multiple studies. Rainbow Trout, Oncorhynchus mykiss, when placed in water containing APEs,
produced the egg-yolk protein vitellogenin(Jobling and Sumpter 1993). In another study, solutions of
calcium alkylphenates were applied to the skin of male New Zealand White rabbits. The applications
of 25% solution of calcium alkyphenate to 10 rabbits at the rate of 2 ml kg per day, five days a week
for four weeks, led to a 70% drop in testicular weight and all 10 rabbits stopping their production of
sperm(Hewstone 1994). What highlighted the long term effects of the APEs compounds was that
even after a thirty day recovery period, two out of the five rabbits were still not producing sperm.
(Hewstone1994).
Later studies reflected that these effects were found to increase concentrations of human
breast cells by 1000-10000 levels (Soto et al. 1991). The estrogenic characteristics have affected
fetal steroid synthesis and masculinization(Soto et al. 1991). In addition, the alkyphenolic
compounds are particularly dangerous to organisms because they become concentrated in their
internal organs once consumed. Studies concerning the APEs compound have shown that current
environmental levels of APEs are sufficient to affect the hormonal control systems of some
organisms (Warhurst 1995).
But the problem becomes detrimental when the serious harms of the APEs compound are
found outside of the lab, and in natural rivers. Many studies have been done for river ecosystems in
the United Kingdom. The River Lea located in north-west London, which is a heavy source of
drinking water, was examined and it was found that a male trout placed in parts of the river produced
570,000 times the quantity of vitellogenin, a precursor protein of egg yolk, produced by a control fish
(Purdom et al). The level of vitellogenin was above that found in a female trout just prior to
ovulation. Furthermore, a quarter of Barbels, bottom dwelling fish, who inhabited the River Lea were
found to have tumors and other morphological disorders (Tyler and Everett 1993). An outrageous
number when compared to the 0%-2% in rivers like the Teme and Kennet also located in the United
Kingdom, but which received far less sewage input (Warhurst 1995).
Concerns for alkylphenols effects on humans have also increased, as studies continue to
suggest a correlation between heavily industrialized countries and the estrogenic symptoms of APEs.
In the past fifty years, there has been a noticeable drop in human sperm count in industrialised areas,
and even when taking uncertainties into consideration, the correlation gains more support with the
finding that there has been a two to four fold increase in testicular cancer in these industrialized
countries (Stone 1994). A clear warrant for the correlation comes through a study that discovered that
male offspring from pregnant mice exposed to high levels of estradiol, which these APEs compounds
mimic, have an increased rate of testicular cancer (Stone 1994).
With the clear harms that the APEs compounds have against our watersheds, as well as the
strong evidence suggesting that the APEs compounds are starting to effect humans as well, it is
greatly disturbing that around 69% of U.S rivers have tested positive for the APEs chemicals. It
should be acknowledged that as of now, APEs falls under the category ECC: emerging chemical of
concern. The concentrations as compared to other toxic chemicals may seem rather insignificant. But
early research, especially when there is high potential for harmful effects, may prove to be cost
effective. Thus, the purpose becomes researching the in vivo estrogenic effects of nonylphenol,
including whether existing environmental levels are high enough to show an effect, and what
metabolism level of APCs occurs within organisms. Hopefully, by identifying whether APEs pose a
serious threat to the environment, this research used to promptly establish safety levels for APCs in
watersheds and rivers.
Objective:
Household drain cleaners and industrial cleaners are often corrosive and contain chemicals
that could potentially cause damage to natural ecosystems. The objective of our research is to
determine whether or not the APCs are prevalent in U.S water bodies and are harming our
environment.
Hypothesis:
If the concentration of alkylphenols (APs) in water bodies increases when situated near water
treatment facilities, then compared to water bodies further away, regions near treatment facilities will
demonstrate the impact of APs through changes in marine life,
water samples, and environmental observations.
Methods and Materials:
The area of study will encompass blocks consisting of two
rivers: the first, the San Gabriel River, seen in Figure 2, is situated
within 10 kilometers of a water treatment plant in a municipal
district. Its water primarily comes from output of the water
treatment plant. The approximate population of the surrounding
cities, which is the general Los Angeles County area, surpasses
Figure 2: San Gabriel River, Los Angeles
500,000. This is relevant under the preconception that there is
causation between population density and increased consumption
(Rutherford 2011)
of drain cleaner products and other detergents. The second, also
called the San Gabriel River, is located in Burnet County in Texas, and will be used as a control, and
located at least 100 kilometers from a sewage drain. For each of the rivers, the area to be sampled
will not exceed 5 square kilometers in area to ascertain consistency and eliminate extraneous
variables such as the distance from the sewage treatment plant or the tendency for the nonrandom
extremities in organism characteristics in a particular region along the river.
Because the experimental design is that of a matched pair, a stipulation is that San Gabriel
River in Texas, the control, and the San Gabriel River in California need to have very similar
characteristics, and must contain at least one species, or similar species, in common. In this case, the
fish to be studied is the fathead minnow (Pimephales promelas), which is small in size, has a short
reproductive cycle, and easy to study. Through this comparison, it will become possible to compare
species between the two river locations. First, we must determine the reproductive cycle of the
organism, and the minute differences between those in San Gabriel River and those in the San
Gabriel River in Texas.
The experimentation will last a total of 3 years. The first 6 months will primarily involve
observational study, consisting of careful evaluation of abiotic and biotic elements of the two rivers,
to ascertain that they are indeed similar except for the one variable of contamination from leftover
chemicals of water treatment plants. In the following two and a half years, 2 liters of water will be
collected from both river sites every two weeks and tested for its concentration of APEs, as well as
any other chemicals in the alkylphenol class.
After confirming that the two rivers are suitable for use as a matched pair, water samples of
up to 50 L will be taken back to the laboratory. A quantity of 20 to 30 fathead minnow that were
cultured and are suitable for scientific experimentation will be purchased and observed over a 12week period after being put into the sample water. The organisms will be assessed for all behavioral
and physical characteristics that may be influenced by estrogen mimics, such as reproductive cycles,
instances of tumors in the organism’s skin, muscle, and internal organs, estrogenic levels in the
bloodstream, as well as any other abnormalities. Physical dissection will be used to evaluate any
abnormalities with tumors. Furthermore, gas-liquid chromatography and mass spectrometry
techniques will be used to evaluate estrogenic concentration, at a microscopic level. In addition, the
ELISA (enzyme-linked immunosorbent assay) will be use to evaluate the concentration of the
vitellogenin protein, which is a protein involved in the production of egg yolk. The procedure will be
repeated in a duplicate study conducted on the fathead minnow that will be taken from the San
Gabriel River in California.
Lastly, field studies will be conducted on the fathead minnow. They will be observed in their
natural environments, in both the rivers in California and Texas. Research will observe several areas
of study including whether there are any changes in the reproductive cycle of the species. The studies
will be conducted during the fall season, which is before the fish become reproductively active, and
therefore will not cause discrepancies with large fluctuations in the estrogenic levels. Twenty-five
males and twenty-five females will be tagged, and the fish will be routinely checked upon for a 12week period. Evaluations of the population will include population density,sex ratios, age distribution
within the population, as well as irregularities in dietary patterns.
After all the data has been collected, a comparison will be made between the wide range of
data, specifically between the effects of the water from the San Gabriel River in California with the
control river.
Materials:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Gas-liquid chromatography kit
Mass spectrometry machine
APE (alkylphenol ethoxylate) ELISA test kit
Aquatic tanks with capacities of up to 50-L
Fish-catching nets
20-30 fathead minnow fish
Small fish to feed to large-mouth bass
Dissection tools
50 2-L reusable water containers
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