When you connect to the NBII Metadata Clearinghouse you will be able to search through metadata-based descriptions of biological data sets and information products from many different sources to identify those that meet your particular search criteria.
The NBII Metadata Clearinghouse: http://metadata.nbii.gov/
The NBII Home Page: http://www.nbii.gov/
Powered by Mercury
Carlson
Macrophytes and Six Species of Algae to Atrazine,
Metribuzin, Alachlor, and Metolachlor
Division, Columbia Environmental Research Center
(formerly known as Environmental and Contaminants
Research Center)
five species of aquatic macrophytes and six
species of algae to four commonly used herbicides
(atrazine, metribuzin, alachlor, and metoachlor).
Toxicity tests consisted of 96 hour (duckweed and
algae) or 14 day (submerged macrophytes) static
exposures. The triazine herbicides (atrazine and
metribuzin) were significantly more toxic to
aquatic plants than were the acetanilide
herbicides (alachlor and metolachlor). Toxicity
studies ranked metribuzin > atrazine > alachlor >
metolachlor in decreasing order of overall
toxicity to aquatic plants. Relative
sensitivities of macrophytes to thse herbicides
decreased in the order of Ceratophyllum > Najas >
Elodea > Lemna > Myriophyllum. Relative
sensitivities of algae to herbicides decreased in
the order of Selenastrum > Chlorella >
Chlamydomonas > Microcystis > Scenedesmus >
Anabaena. Algae and macrophytes were of similar
overall sensitivities to herbicides. Data
indicated that Selenastrum, a commonly tested
green alga, was generally more sensitive compared
to other plant species. Lemna minor, a commonly
tested floating vascular plant, was of
intermediate sensitivity, and was fivefold less
sensitive than Ceratophyllum, which was the most
sensitive species tested. The results indicated
that no species was consistently most sensitive,
and that a suite of aquatic plant test species may
be needed to perform accurate risk assessments of
herbicides.
sensitivities of five species of macrophytes and
six species of algae to atrazine, metribuzine,
alachlor, and metolachlor.
Division, Columbia Environmental Research Center
Carlson
Macrophytes and Six Species of Algae to Atrazine,
Metribuzin, Alachlor, and Metolachlor.
algae were exposed to four commonly used
herbicides to determine their relative
sensitivities.
temperature and lighting conditions as the
cultures. Algal tests were conducted using
modifications of an ASTM method. Primary
modifications of the standard procedure involved
testing the algae in foam-stoppered 15-ml tubes
(5-ml ASTM medium; 20,000 cells/ml initial
density) and use of a 16 hour:8 light:dark
schedule. Test tubes were randomly positioned at
a 30 degree angle from horizontal on the light
table to maximize the air to water surface ratio
and minimize CO2 limitation. Algal biomass was
estimated at 48, 72, and 96 hour using in vivo
fluorescence measures with a Turner Model 10
Fluorometer (Turner Designs, Sunnyvale, CA).
Fluorescence measurements were taken by mixing the
tube on a mechanical shaker and then directly
inserting the test tube into the Flurometer
counting chamber (i.e., no sub-sampling or
extraction).
vulgaris, Chlamydomonas reinhardi, Scenedesmus
quadricauda, Microcystis sp., and Anabaena
flosque) and three species of macrophytes (Lemna
minor, Ceratophyllum demersum, and Elodea
canadensis) were obtained from commercial sources.
Myriophyllum heterophyllum and Najas sp. were
obtained from ponds located at the Columbia
Environmental Research Center, U.S. Geological
Survey, Columbia, Missouri. All plants were
cultured under the same lighting (16 hours:8 hours
light:dark cycle; 60 microE meters squared per
seconds intensity; cool-white fluorescent bulbs)
and temperature conditions (25 degrees C) except
for the blue-green algae (Anabaena and Microcystis
species), which were cultured and tested at 30
micro E meters squared per second light intensity.
Algae were cultured in 250 ml. Erlenmeyer flasks
containing American Society for Testing and
Materials (ASTM) medium which was originally the
algal assay medum of Miller et al. Fresh algal
cultures were started every 2 weeks from the
existing stock by reinoculating in fresh medium.
Lemna as cultured in 4-L round aquaria containing
the modified ASTM medium described by Taraldsen
and Norberg. Submerged macrophytes (Elodea,
Ceratophyllum, and Myriophyllum) were cultured in
large aquaria (approximately i m long x 0.5 m wide
x 0.1 m deep) containing ASTM medium with no
substrates. Plants were cultured for a minimum of
2 weeks prior to testing.
bottle test: Experimental Design, application, and
data interpretation protocol.
Wastewater.
hour static test method of Taraldson and
Norberg-King. Twelve fronds were added to 25 ml
of nutrient-enriched water (i.e., NEW medium;
which is basically a 10 times solution of the
algal medium [with no ethylenediaminetetraacetic
acid] amended with a commercial soil added at
10g/L). Beakers were shaken once daily. Fronds
were counted under a magnifying glass (10x) at 48,
72, and 96 hour exposure intervals.
duckweed (Lemna minor)
or one apical, multibranched clump (for
Ceratophyllum) were tested under static conditions
in 1-L beakers containing sediment (100 ml volume
wet pond sediment) and ASTM medium (800 ml) with
no aeration. On days 7 and 14 the plants were
removed, wet-blotted, and weighed (0.01 g) for wet
weight. This testing design was adopted following
pilot studies that compared the effects of
sediment, aeration, and nutrient-enriched medium
on macrophyte growth. Results showed that
aeration had no positive effects. The presence of
sediments resulted in good growth but minimized
accumulation of nuisance algae on macrophyte
surfaces, which often occurred with high-nutrient
aqueous medias. Although the presence of sediment
can alter the availability of hydrophobic
contaminants, the investigators believed that this
would not be a major factor in this study due to
the relatively low octanol-water partition
coefficients (i.e., < 200) of these herbicides.
obtained from experimental ponds at CERC and were
characterized for particle size, pH, ammonium-N,
nitrate-N, and organic matter content by the UMC
Soils Lab located in Mumford Hall, University of
Missouri, Columbia, Missouri. Total organic
carbon was measured at CERC using a Coulometrics
Model 1050 Carbon Analyzer (UIC, Joliet, IL).
Sediments were classified as a silty-clay loam
soil (consisting of 18% sand, 52% silt, and 30%
clay; 6.1% organic carbon; 9.7% organic matter;
7.2 pH; 7.1 ppm NH4-N; and 36.1 ppm NO3-N).
seedlings that naturally germinated from the same
pond sediments described in the experimental ponds
at CERC. One-liter beakers containing 100-ml of
sediment and 800-ml ASTM medium were incubated
under the standard test conditions of light and
temperature until plants germinated and grew to
approximately 3 cm height (approximately 2 weeks).
At this point the herbicides were added for a 14
day exposure similar to the other macrophytes. On
day 14 plants were sieved, removed, washed, and
weighed (+/- 0.01 g) for wet weight.
Algal median effective concentrations (EC50s) were
determined using inverse nonlinear regression and
SAS/STAT software. Macrophyte EC50s were
determined using the trimmed Spearman-Karber
technique using TOXSTAT software. Graphic
interpolation was used to estimate EC50 values in
cases where the lowest concentration tested
resulted in greater than 50% decrease compared to
controls. Comparisons of the relative
sensitivities of various plant species within and
across the four test chemicals were made using
analysis of variance of ranked data (p < or =
0.05) using SAS/STAT.
of algae; Associated attributes - Toxicity to
aquatic plants, 96 hour test, 14 day test.
Division, Columbia Environmental Research Center
successfully on a computer system at the U.S.
Geological Survey, no warranty expressed or
implied is made regarding the accuracy or utility
of the data on any other system or for general or
scientific purposes, nor shall the act of
distribution constitute any such warranty. This
disclaimer applies both to individual use of the
data and aggregate use with other data. It is
strongly recommended that these data are directly
acquired from a U.S. Geological Survey server, and
not indirectly through other sources which may
have changed the data in some way. It is also
strongly recommended that careful attention be
paid to the contents of the metadata file
associated with these data. The U.S. Geological
Survey shall not be held liable for improper or
incorrect use of the data described and/or
contained herein.
Services (ITSS)
Information Infrastructure Metadata