Environmental Letters

ISSN: 0013-9300 (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/lesa17

The Dynamics of Diquat in a Model Eco-System Brenda Shaw & Philip K. Hopke To cite this article: Brenda Shaw & Philip K. Hopke (1975) The Dynamics of Diquat in a Model Eco-System, Environmental Letters, 8:4, 325-335, DOI: 10.1080/00139307509437442 To link to this article: http://dx.doi.org/10.1080/00139307509437442

Published online: 02 Sep 2009.

Submit your article to this journal

Article views: 1

View related articles

Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=2esa20 Download by: [Universite Laval]

Date: 06 November 2015, At: 09:00

ENVIRONMENTAL LETTERS, 8(4), 325-335 (1975)

THE DYNAMICS OF DIQUAT I N A MODEL ECO-SYSTEM

Brenda Shaw

* and

Philip

K. Hopke

**

Lake E r i e Environmental Studies Program and Department o f - C h e m i s t r y S t a t e U n i v e r s i t y College Fredonia, New York 14063

Downloaded by [Universite Laval] at 09:00 06 November 2015

ABSTRACT Muskelunge

(Esox-masquinonqy c h i e n s i s ) f r y were used i n a 96

hour t o x i c i t y study w i t h d i q u a t and simazine.

Although t h e death o f

s u f f i c i e n t c o n t r o l f i s h i n v a l i d a t e d t h e t e s t a5 a whole, some i n t e r e s t i n g o b s e r v a t i o n s were made.

A t t h e end o f 48 hours 4 o u t o f 10

f i s h had d i e d i n the c o n t r o l t a n k and 8 had d i e d i n t h e simazine tank w h i l e a l l 10 d i q u a t - t r e a t e d f i s h appeared h e a l t h y . Two model eco-systems w i t h canponents from Chautauqua Lake, N. Y. were c o n s t r u c t e d i n 20 g a l l o n g l a s s a q u a r i a t o t r a c e t h e movement o f

I'C

labeled diquat.

A f t e r a c t i v i t y had reached near background l e v e l s

i n t h e water from t h e t e s t tank, f i s h , p l a n t s , sediments and s n a i l s

were counted i n a l i q u i d s c i n t i l l a t i o n counter t o d i s c o v e r t h e f a t e o f d i q u a t wlthin t h e system.

The c o n c e n t r a t i o n o f d i q u a t was found t o be

h i g h e s t i n sediments, f o l l o w e d by f i s h t i s s u e , s n a i l p a r t s , w i t h p l a n t s having t h e lowest measured c o n c e n t r a t i o n .

* Present Address:

**

Present Address:

Earlham College, Richmond, Indiana

47374

School o f Chemical Sciences, U n i v e r s i t y o f I l l i n o i s , Urbana, I1 1 i n o i s 61801

325 Copyright 0 1915 by hlarcel Dekker, Inc. 1\11 Rights Reserved. h'either this work nor any part m3y he reproduced 31 transmitted in any form or by any means, electronic or rnrchanic~l,including photocopying. microfilming, and recording.01 by any information storage and retrieval system. without permission in %riling from the publisher.

SHAW AND HOPKE INTRODUCTION Diquat and simazine have been used as aquatic herbicides in recreation lakes in Chautauqua County, New York (diquat in Chautauqua Lake and simazine in Findley Lake).

Little is known about the effects

of these herbicides on aquatic herbicides.

G1 iderhus' has reported

toxicity results for diquat on several species of fish including several game fish.

Walker* has reported toxicity data for the effects of

simazine on fish.

No results were reported for muskelunge

masquinongy chiensis) with either simazine or diquat.

(5-

Because of the

Downloaded by [Universite Laval] at 09:00 06 November 2015

economic importance of muskies a s game fish in the Chautauqua Lake area, acute toxicity studies .were undertaken on this species.

Because

of the continuing use of diquat as an aquatic herbicide to control macrophyte growth, its fate in the aquatic ecosystem should be better understood.

Thus a model eco-system was established t o indicate rela-

tive absorption of the herbicidal material by various elements in the full ecosystem. METHODS In order to measure the possible interaction of the herbicides with the containers, a test was performed to determine whether simazine and diquat concentrations change appreciably over time in the allglass aquaria. gallon tanks.

Demineralized tap water was added to each o f three 20 The tanks contajned 60.5 liters of water.

Because water

hardness may be a factor in the action of herbicides such as diquat,' the components of hardness were determined by flame atomic absorption spectroscopy. and Ca 0.0 ppm.

The results were:

M g < 1.0 ppm, K < 1.0 ppm,Na < 0.8 ppm

The water was allowed to stabilize at about 19' C

while being aerated.

326

DIQUAT IN MODEL ECO-SYSTEM

One tank was treated with 300 ul of 44.78, diquat (Orthodiquat manufactured by Chevron), the other with .1162 g of 80% simazine (Princep 80W manufactured by Ciba-Geigy).

This gave approximate con-

centrations of 1.4 ppm diquat in one tank and 1.4 ppm simazine in A thermometer was attached to the third tank, which con-

the other.

tained aerated demineralized water, to monitor water temperature during the experiment. and 19.4'

C.

The water temperature remained between 18.9

The tanks were covered with a thin mylar covering and

exposed to constant fluorescent room light.

Representative

water

Downloaded by [Universite Laval] at 09:00 06 November 2015

samples were removed about once a day for a week from each herbicidecontaining tank for analysis.

Samples were stored in plastic bottles

and kept in the dark to inhibit possible decomposition. Diquat samples were analyzed by U.V.

spectrophotometry utilizing

a Cary 14 spectrophotmeter with an absorption scale expansion slidewire.

Absorbances were measured at the peak maxima at approximately

310 run.

to 2000

A similar method was used for simazine with a scan from 2500

8.

As a measure o f Comparison, standard solutions of simazine

were run at 1.0 ppm and 1.5 ppm. 0.105 and 0.157 absorbance units.

Table 1.

The absorbance in each case was Absorbance values are recorded in

Because diquat and simazine data obtained f r m the Cary 14

has questionable accuracy at this time, results are reported only as absorbance to show a comparison of relative concentrations over time rather than the actual concentration of each sample.

Both the con-

centration of simazine and that of diquat seem t o have remained reasonably constant under the conditions that existed during this experiment.

Therefore, the potential problems of herbicide absorp-

tion on the glass aquaria was eliminated.

Similarly, the photo de-

composition due to room light was eliminated as a possible variable.

327

SHAW AND HOPKE TABLE 1 Herbicide Concentrations Over Time

Downloaded by [Universite Laval] at 09:00 06 November 2015

Hours from start

Diquat in absorbance units

Simazine in absorbance units Run 1 Run 2

-

-

2

0.130

0.139

0.136

7

0.128

0.121

0.128

17.5

0.131

0.140

0.125

48

0.131

77

0.129

119

0.127

143

0.128

-

0.147

0.151

Toxicity Studies This test was carried our according to Doudoroff4 except where stated otherwise.

Each tank was filled to a depth of 10 cm with creek

water from Canadaway Creek near Laona, New York. of about 18.7 liters in each tank. average length

- 4 cm) were

Thirty-five muskie fry (approximate

divided between three tanks of water five

days before the addition of herbicide. died.

This gave a volume

One day later five fish had

60 ul of c m e r c i a l grade Orthodiquat (44.7$)

to achieve a concentration of approximately 1.4 ppn.

was added to one A concentration

of about 1.5 p p o f simazine was obtained by adding 0.0350 grams of Princep BOW (80$ simazine) to the second tank.

In order to help check

pathogens which may have been killing the fish, the staff of the Chautauqua Fish Hatchery suggested adding formaldehyde to the water. part of formaldehyde to 3000 parts water was r e c m e n d e d . 2 m l formaldehyde was added to each tank.

One

Therefore,

Air temperature, water tem-

perature and water chemistry are reported in Table 2.

Water hardness

DIQUAT IN HODEL ECO-SYSTEM

TABLE 2 Water Conditions

Tempe r a t u r e A i r temperature

Downloaded by [Universite Laval] at 09:00 06 November 2015

Time

Water temperature i n c o n t r o l tank

2 4 hours

20.40

c

19.4'

C

48 hours

18.20

c

19.5'

C

96 hours

17.2'

C

18.90

c

Dissolved Oxyqen Time -

Diquat tank

Simazine tank

Control tank

24 hours

10.0 ppm

10.0 ppm

9.9 Ppm

48 hours

11.0 ppm

11.1 ppm

10.8 ppm

96 hours

11.3 ppm

11.3 ppm

11.0 ppm

Water Chemistry

30.14 ppm

A l k a l i n i t y as CaCo3

PH diquat tank

8.19

simazine t a n k

8.36

contro l tank

8.30

Hardness

Mg

7.6 Ppm

K

2 . 2 Ppm

Na

3. 0 Ppm

Ca

4 4 . 5 ppm

329

SHAW AND HOPKE was determined by a t m i c adsorption spectroscopy, alkalinity by H2S04 titration and pH with a pH probe. The toxicity study was carried out for 96 hours.

The fish were

fed minnows for the first 3 days. Water samples were taken 24, 48, and 96 hours after the start.

Table 3 shows the survival rate of the

fish. Because more than 10% of the control fish died, the results are far from concl~sive.~Sane interesting observations were made, however.

The water in the simazine tank was very cloudy.

Bubbles

appeared in all the tanks about 48 hours into the experiment. The

Downloaded by [Universite Laval] at 09:00 06 November 2015

simazine tank showed a high death rate

- 80$ in two days.

Thus the

use of simazine as an aquatic herbicide may result in undesirable

effects on the fish populations. Further study in this area is required. Model Eco-System Two 20 gallon tanks were filled with sediments, plants, animals and water from Chautauqua Lake.

Sediments were taken directly from

the lake bottom in about 1 meter o f water. A study done near the area where these sediments were taken showed the following canponents: sand 14.76$, silt 58.24% and clay 27$.5

Approximately one gallon of

sediment was placed in each tank along with the animals which were living in it

-- snails, worms, etc.

About 43 liters of lake water

(see Table 4 for water chemistry) were added to the tanks followed TABLE 3

Fish Living (out of ten) Time

Control

Diquat

Sirnazine

24 hours

10

10

10

48 hours

6

10

2

96 hours

6

6

2

330

DIQUAT IN MODEL ECO-SYSTEM TABLE 4 Model Eco-System Water Chemistry

-

approximate average Alkalinity 50 ppn as CaCo3 ( d a t a f o r s i t e 9 was n o t a v a i l a b l e )

Downloaded by [Universite Laval] at 09:00 06 November 2015

As Cd Ca Ch1o r ide Cr cu Fe Hg Mn Nitrate

9.4 ppb PPb 24.2 ppn 5.9 P p n