Saddleback Journal of Biology - Saddleback College

Fall 2009 Biology 3B Paper
Water Quality at Doheny State Beach
Kim Chené, Brittany Harding
Department of Biological Science
Saddleback College
Mission Viejo, CA 92692
Escherichia coli is prevalent in the top layer of sand at some of the area's most popular
beaches, even when the surrounding ocean water tested "clean". By studying the water
bacteriology of a specific oceanic community, an investigator can determine if that
community is affected by differing levels of bacteria in its environment. All hillside runoff
most likely contains coliform bacteria, more specifically Escherichia coli. Testing for E. coli
is necessary, as all coli forms may be suppressed by high populations of other organisms.
Indicators of pollution include algal blooms, lichens, erotological forms of diatoms;
coliform bacteria, “sewage worms,” in addition to the more obvious signs of contamination,
such as flu symptoms in humans or disorientation in marine mammals. Three points were
selected for the collection water samples at Doheny State Beach in Dana Point, California.
The first sample was 100 meters directly west (toward the ocean) to the storm run-off; the
second, south 100 meters (along the beach); and the third, 100 meters north (along the
harbor). The samples were tested for the presence of coli form bacteria. The presence of
gas or acids in the tubes after the incubation period indicated the presence of coliform
bacteria in the sample. The most probable number (MPN) was then calculated in order to
determine the concentration of coliform organisms at each location. The investigators
hypothesized that there would be a great difference between each point that the samples
were taken from. However, an ANOVA test of the means yields p > 0.05 (0.2781). There is
no difference between the means; thus, coliform bacteria concentration is equivalent in all
three locations.
Introduction
Certain elements that are introduced to the
beaches of Southern California are extremely harmful
to the marine life and its surrounding environment.
Such elements are often referred to as pollution. If
severe, water pollution can kill large numbers of fish,
birds, and other animals, in some cases, eliminating all
members of a species in the affected area. Substantial
contamination could also affect any organism
introduced to the body of water. Pollution makes
streams, lakes, and coastal waters unpleasant to look at,
to smell, and to swim in. Fish and shellfish harvested
from polluted waters may be unsafe to eat. People who
ingest polluted water can become ill, and, with
prolonged exposure, may develop cancers or bear
children with birth defects (Hart 2008). Several studies
have concluded that it is not only unsafe for humans to
submerge themselves in such water, but in some cases
it is known to be lethal. Individuals who swam in areas
adjacent to flowing storm drains were fifty percent
more likely to develop a variety of symptoms than
those who swam further away from the same drain
(Osborne 2004). Unfortunately, among these fatalities,
the largest grouping was children under five years
because their immune systems are less developed than
that of individuals over five years of age and growing
bodies take in substances more rapidly than do mature
ones (Lear and Lewis 2008).
Another obstacle for public health is the
chlorine used to treat public water, which can turn into
chloroform when it mixes with other materials in the
water, which may increase the risk of miscarriage and
poor fetal growth. Many petroleum products are
poisonous if ingested by animals, and spilled oil
damages the feathers of birds or the fur of animals,
often causing death. In addition, spilled oil may be
contaminated with other harmful substances, such as
polychlorinated biphenyls (PCBs) (Hart 2008).
Large amounts of pollutants generated by
humans end up in the sea through rain, run-off from
streams and rivers, and directly from industrial and
municipal sources. Chemicals used to kill unwanted
animals and plants, for instance on farms or in
suburban yards, may be collected by rainwater runoff
and carried into streams, especially if these substances
132
Saddleback Journal of Biology
Spring 2010