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| Bacteria and
nutrient loads in the bay routinely exceed
Department of Health standards, but data has been
skimpy, and not enough testing has been done to
identify sources of pollution. - Tribune-Herald
| |
Closer to improving Hilo Bay
Initial data shows water not
always safe for swimming
by Bret Yager
Tribune-Herald
Staff Writer
Recent
testing by the University of Hawaii at Hilo's Marine Biology
Department is gathering some of the first hard data on Hilo
Bay water quality.
There are still a few months of
testing to go, but preliminary results are justifying the
caution that many residents already take about swimming in the
bay, especially right after a rain.
Following heavy
rain storms, nitrates and turbidity in the water are well
above state Department of Health standards.
Scientists
are sampling four sites in the bay and two outside the
breakwater. Testing is done on stormy and calm days for pH,
salinity, suspended solids, temperature, and nutrients that
include ammonium, phosphorus silicate, chlorophyl and
nitrates, which are regulated by the Department of
Health.
Test results
will be used by the Army Corps of Engineers to create a
computer model of the bay's circulation, with an eye toward
improving water quality.
UH-Hilo oceanographer and
assistant professor Tracy Wiegner spoke to about 40 people at
a meeting Thursday evening at the Mokupapapa Discovery Center
in Downtown Hilo. Wiegner said potential ways of improving
water quality include breaching the breakwater to improve
water flow.
The $200,000 study of water clarity and
nutrient loads began in January and will wrap up early next
year. Results will be submitted in a report to Hawaii County
and will constitute baseline data about the bay's water
quality. The study was funded by Hawaii County and the
National Science Foundation.
Mayor Harry Kim in 2005
asked the Army Corps for help in improving water quality,
concerned that pollution was keeping people away from the
bay.
Bacteria and nutrient loads in the bay
routinely exceed Department of Health standards, but data has
been skimpy, and not enough testing has been done to identify
sources of pollution. The new studies by UH-Hilo bring the
answers a step closer, but not enough is yet known to support
policy decisions aimed at curbing pollution, Wiegner
said.
For instance, high levels of enterococci in the
bay might come from overflowing cesspools. They may also
originate naturally in tropical soils, Wiegner said. The only
way to know for sure is to test for other chemicals that show
up in human wastewater.
The Environmental Protection
Agency deemed the bay "impaired" in 1998 because of high
nutrient loads and turbidity, but the designation was based on
merely looking at the murky water as testing wasn't done. So
scientists don't know how bad the bay is or how much pollution
is manmade.
Wiegner said that other scientists are
studying bacteria levels in the bay, and that she focused on
excess turbidity (cloudiness) and nutrients because those are
the factors that led to the EPA listing.
"This data is
desperately needed to see if the bay is in compliance; we
really don't know," Wiegner said.
Wiegner said it
appears clear that many of the pollutants originate from the
Wailuku and Wailoa rivers.
"I'd say management within
the watershed -- keeping the materials from reaching the bay
-- could be less costly than modifying the breakwater," she
said.
In reference to breaching the breakwater, "that's
a lot of steps away," Wiegner added.
Connections
Charter School science teacher Bill Ebersol detailed the water
monitoring and cleanup activity of about 55 students. Kids
tested salinity, measured beach volume, studied sand
composition and tracked current speeds, sometimes using such
simple devices as a watch and a floating coconut. They also
plan to do more intricate lab work to test for bacteria,
Ebersol said.
"We're finding that the kids are
enthusiastic," Ebersol said. "They're out of the classroom and
actually watching these natural processes. We hope they're
going to go home more environmentally
aware."
Scientists have encouraged such partnerships
and student involvement as one of the best hopes for making
sure the bay stays healthy into the future.
Bret Yager
can be reached at byager@hawaiitribune-herald.com.
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