96h acute toxicity tests were performed using commercial grade metasystox on the marine wedge clam, Donax cuneatus during summer 1985. The behaviour and mortality rates were recorded periodically. Most of the dams responded in opening the shell valves and extending the siphons quicker in low test concentrations (0.004-0.0052 p.p.m) but this was slow and late in high concentrations (0.0056-0.008 p.p.m). Mortality began to occur in 0.008 p.p.m. from 12 h, whereas, in 0.0052 p.p.m. from 60 h onwards. The observed LC sub(0) value was 0.004 p.p.m. and LC sub(50) 0.0064 p.p.m. The regression equation established was Y = 79.0891 + 33.4523 X. The rate of oxygen concentration increased at LC sub(0) and LC sub(50) values compared to control indicating the disturbed physiological adjustment. The results are correlated with physico-chemical parameters of seawater and discussed in the light of pesticide toxicity to the dam

Akarte, S.R.

Kulkarni, D.A.

Muley, D.V.

Rao, K.R.

Aquatic Commons

Acute Toxicity of Metasystox to \Nedge Clam, 
Donax cuneatus m Coast 
D. V. MULEY, S. R. AKARTE, D. A. KULKARNI and K. R. RAO 
Department of Zoology, Marathwada University, Aurangabad - 431 004 
96 h acute toxicity tests were performed using commerciaI grade metasystox on the 
marine wedge clam, Donax cuneatus during summer 1985. The behaviour and mortality 
rates were recorded periodically. Most of the dams responded in opening the shell 
valves and extending the siphons quicker in low test concentrations (0.004-0.0052 p.p.m) 
but this was slow and late in high concentrations (0.0056-0.008 p.p.m). Mortality began 
to occur in 0.008 p.p.m. from 12 h, whereas, in 0.0052 p.p.m. from 60 h onwards. The 
observed LC0 value was 0.004 p.p.m. and LC50 0.0064 p.p.m. The regression equation 
established was Y = 79.0891 + 33.4523 X. The rate of oxygen concentration 
increased at LC0 and LC50 values compared to control indicating the disturbed 
physiological adjustment. The results are correlated with physico-chemical para-
meters of seawater and discussed in the light of pesticide toxicity to the dam. 
The wedge clam, Donax cuneatus, is widely 
distributed in the fl.at intertidal sand of Mirya 
Bay at Ratnagiri and eaten by poor people. 
Biology ot this clam has been studied by 
Talikhedkar (1975). Our earljer studies have 
shown that the lamellibranch molluscs are 
sensitive to pesticide toxicity in summer than 
in monsoon. and winter (Mane & Hiwale, 
1984; Mane & Muley, 1984; Akarte, 1985). 
Considering the commerical importance of 
this wedge clam, we report here the acute 
toxicity of metasystox in summer. 
Materials and Methods 
D. cuneatus, were collected from the high 
tide at Mirya Bay, Ratnagiri during May 
1985. They were batched into eight groups 
of 10 adults of 18-20 mm shell length in 
aquarium containing 10 litres charcoal :filtered 
seawater. The water was changed after 
11-12 h. After 24 h, the water of such 
aquarium was taken out along with the adults 
and appropriate test concentrations of 
metasystox (commercial grade - a product 
of Bayer India Ltd., Bombay) were prepared 
in seven test aquaria ranging from 0.004 to 
0.008 p.p.m. A control was also run simul-
taneously. The water of these test concen-
trations and of control was renewed twice 
a day at an interval of 11-12 h for a period 
of 96 h, and before changing the water, 
Vol. 24, 1987 
behaviour and mortality of clams were noted. 
The physico-chemical parameters of the 
sea water waE' also determined. The glass 
aquaria were painted black from outside 
(since these clams burrow in the sand as the 
tide runs). The experiments were repeated 
twice. The results were statistically analysed 
and regression equation between fog con-
centrations (in p.p.m.) (X) and pro.bit mor-
tality (Y) using the formula Y=a+bx was 
established according to Finney (1971). The 
rate of oxygen consumption from control, 
LC0 and LC1;o groups was determined using 
Winkler'~ technique and 5tatistically analysed 
for confirmation. 
Results and Discussion 
The physico-chemical parameters of the 
seawater used in the experiments were -
temperature 25-28.5°C, salinity 28.8-30.5 %0 , 
oxygen tension 4.2-5.2 ml/L and pH 7.0-7.l. 
TotaUy seven different test concentrations 
were required to obtain LC0 and LC50 values 
during 96 h. The behaviour pattern showed 
that in control group the clams after immer-
sion opened the shell valves and extended 
the foot as wen as siphons within 2-3 min 
to circulate the water through the body for 
respiration. The faecal matter was present 
in the aquarium throughout the period. 
28 D. V. MULEY, S. R. AKARTE, D. A. KULKARNI AND K. R. RAO 
There was protrusion of mantle margin along 
the sheU valves in the dams at the time when 
the clams extended the siphons to the maxi-
mum extent. Compared to control, within 
30 min after immersion, in low test concen-
trations, 0.004 to 0.0052 p. p. m. most of 
the clams showed extension of siphons and 
foot as they did in controls but there was 
no pmtrusion of m:tfft1e margin whereas in 
0.0064 to 0.008 p.p.m. there was no exten-
sion of siphons excepting foot protrusion 
by a few clams. No extension of mantle 
margin was seen. In 0.004 p.p.m. almost 
au dams with the lapse of time extended foot 
and siphons ·with little extension of mantle 
margin till 84 h but at 96 h half of the popu-
lation extended only siphons and the rest 
only foot. In 0.0052 p.p.m. the clams 
extended siphons were more than those 
extended foot. Few clams tightly closed 
shell valves and frequently opened for water 
circulation. In 0.0056 p.p.m. 3-4 clams 
simultaneously showed extension of siphons 
and foot but remaining were with valves 
tightly closed. In 0.006 p.p.m.. there was 
similar condition in 2-3 clams and others 
were with valves closed. In 0.0064 p.p.m. 
upto 48 h all the clams either extended the 
siphons or foot but from 60 h onwards mo~t 
of the survivors were with valves closed. 
In 0.0068 p.p.1n. upto 24 h 1-2 clams could 
extend the foot and siphons but from 36 h 
onwards almost all the survivors extended 
foot and siphons. In 0.008 p.p.m. survivors 
i1pto 24 h could extend foot and siphons 
and rest of them were with shell valves 
.dosed. From 36 h onwards all the survi-
vors either extended foot or siphons. In 
0.0052 to 0.008 p.p.m. from 12 h onwards 
the mantle protrusion outside the valves 
and the faecal matter acctnnu1mion were 
less. Death occurred from 60 h in 0.0052 and 
0.0056 p.p.m. but in 0.006 and 0.0064 p.p.m. 
it occurred from 48 h. In 0.0068 p.p.m. 
clams died from 36 h and in 0.008 p.p.m. 
from 12 h. Total mo.rtality at the end of 
96 h was 20, 30, 40, 50, 70 and l 00% in 0.0052, 
0.0056, 0.006, 0.0064, 0.0068 and 0.008 p.p.m. 
:respectively. Thus the observed LC0 
value was 0.004 p.p.m. and the LC50 value 
was 0.0064 p.p.m. The calculated LC50 
was 0.0061 p.p.m. whereas the 95 % fiducial 
limits (F.L.) were from 0.006 to 0.0063 p.p.m. 
The regression equation established is, Y = 
79.0891+33.4523 X (Fig. 1). 
The pollutant induced mortality pattern, 
particularly the pesticides, in m2.ny marine 
invertebrates were shown to he measurably 
related to various physico-chemical para-
meters of water used in the tests (Eisler, 
1968). These include temperature, salinity, 
pH, type and concentration o.f pesticide as 
well as duration of exposure. Since then 
many investigators have shown that some 
orga.nophosphorus insecticides are more 
toxic under conditions of high temperature, 
high salinities and low oA.rygen content 
(Mane & Hiwale, 1984; Akarte, 1985; Muley, 
1985; Mane, 1973). While studying the 
acute toxicity of nuvan to two estuarine 
edible bivalves, Mane & Hiwale (1984) 
showed that both the species were sensitive 
to pesticide during the high temperature 
and salinity of summer than in monsoon. 
6 
5 
4 
3 
Y= 79·0891+33-4523 logX 
0 
LC5 o'" 0·0061 ppm 
F.L. = 0·0059-0·0062 ppm 
log ppm 
Fig. 1. Acute toxicity of metasystox to Donax 
cuneatus showing regression line 
With freshwater bivalves also few investi-
gators have shown that the bivalves are 
sensitive to pesticides in summer (Mane & 
Muley, 1984; Akarte, 1985). Variations 
in the opening of the shell valves, extension 
of siphons, protrusion of mantle edge and 
accumulation of excreta in the aquaria were 
also shown to be related to the pes:~icide typ::, 
duration of exposure and type of concen-
trations by the above workers. ·In the present 
study also similar findings were recorded. 
Since D. cuneatus, occurs along the tidal 
zone of sandy fl.a.ts, they are washed with 
the tide and with ingoing tide they burrow 
quickly in the sand. Because of this, it is 
FISHERY TECHNOLOGY 
TOXICITY OF METASYSTOX TO WEDGE CLAM 29 
found in the experiments that none rem'.rined 
with shell valves open and siphons extended 
for a longer period. In higher test concen-
tration at the initial period mostly these clams 
closed the shell valves but in the latter period 
opened the valves. Very low concentrations 
were tolerable but as the pesticide medium 
penetrated in the body, mortality occurred. 
This was earlier in high test media than low. 
Same pesticide when tested for acute toxicity 
to an estuarine clam, Paphia laterisulca, it 
was observed that LC0 value was 0.002 
p.p.m. and LC50 value 0.0045 p.p.m. indi-
cating that the estuarine clam is more sen-
sitive to metasystox toxicity than marine 
molluscs. 
The rate of oxygen consumption of con-
trols, LC0 and LC50 groups· showed a flu-
ctuation of 0.139+0.002 to 0.188 +0.002 
ml O.)g/1during96h of experimental period. 
In LC0 group it fluctuated from 0.111 ±0.005 
w 0.322±0.016 ml 0 2/g/1 during 90 h study. 
In LC50 group, on the other hand, it fluc-
tuated from 0.167 + 0.004 to 0.461 + 0.008 
ml 02/g/l during the study. The rate of 
oxygen consumption in LC0 group increased 
at 12 h and declined upto 24 h, but at 48 
and 96 h increased significantly than in con-
trols (p< 0.01). Similarly in LC50 group 
the rate increased at 12h(p<0.0l)butdecre-
ased till 48 h and increased considerably 
(p<0.01) at 96 h. The pesticide at both the 
concentrations elevated the respiration in 
the begining but depleted afterwards and 
once again rose at 96 h (Fig. 2). 
050 
04 
032 
~ 026 
' ~ 
E 0·20 
o"' 
0·16 
012 
0 
~ ConrroJ 
o-·-o LC50 
tr---~ LCo 
12 24 48 96 
Ttme in hours 
Fig. 2. Effect of metasystox on the rate of respiration 
of D. cuneatus. 
Similar elevated rate of oxygen consum-
ption was recorded m Katelysia opima by 
Vol. 24, 1987 
Mane et al. (l 9S3) and in Paphia laterisulca 
(Akarte, et al., 1985a). Rice et al. (1977) 
stated that a part of increased oxygen con-
sti.mptio.n is required to support enhanced 
physiological activities in metabolising and 
eliminatingpollutants by the exposed animals. 
Akarte et al. (1985b) showed that L. nwr-
ginalis stored large amounts of metabolites 
in different parts of the body and were 
utilized in energy crisis after exposure to 
folithion. Such paramete1s are necessary 
to evaluate on D. cuneatus, an 'active' inter-
tidal dam, in order to ascertain the mode 
of metabolic diversions.. 
This work is supported by Department of Science 
and Technology, Government of India in the form 
of a research project given to Dr. U .H. Mane, Reader, 
Department of Zoology, Marathwada University. 
The authors are thankful to the authorities and also 
to Dr. Mane for kind guidance in completion of this 
work. 
References 
Akarte, S. R. (1985) Effect of Organophos-
phorus Insecticides on Bivalve Molluscs. 
Ph.D. Thesis, Marathwada University, 
Aurangabad 
Akarte, S. R., Kulkarni, D. A. & Mane, 
U. H. (1985a) Proc. Symp. Assess. 
Environ. Pollut. Aurangabad, 173 
Akarte, S. R., Rao, K. R. & Kulkarni, D.A. 
(1985b) Int. J. Ecol. Environ. Sci. 
(in press) 
Eisler, R. (1968) Bull. Am. Litt. Soc. 11 
Finney, D. J. (1971) Probit Analysis, 
Cambridge University Press, p. 26 
Mane, U. M. (1973) Some Aspects of the 
Biology of Marine Clam,Katelysia opima. 
Ph.D. Thesis, Marathwada University, 
Aurangabad 
Mane, U. H. & Hiwale, V. V. (1984) 
Proc. Sem. Eff. Pest. Aq. Fau. Jlllhow 
India, 169 
Mane, U. H. & Muley, D. V. (1984) 
Toxicol. Lett. 23, 147 
Mane, U. H., Muley, D. V. & Akarte, S.R. 
(1983) Indian J. Comp. Anim. Physiol. 
1, 1 
30 D. V. MULEY, S. R. AKARTE, D. A. KULKARNI AND K. R. RAO 
Muley, D. V. (1985) Effect of Pollutants 
on Freshwater Molluscs from Godavari 
River at Paithan. Ph.D. Thesis, I\1ara-
thwada Univer~ity, Aurangabad 
Rice, S. D., Thomas, L. E. & Short, J. W. 
(1977) In Physiological Responses of 
Marine Biota to Pollutants (Vernberg, 
F. J., Calabrase A., Thurberg, F. P. 
and Vernberg, W. B., eds.) p. 259. 
Academic Press, New York 
Talikhedkar, P. M. (1975) Studies on the 
Biology of the Marine Bivalve, Donax 
cuneatus. Ph. D. Thesis, Marathwada 
University, Aurangabad 
FISHERY TECHNOLOGY 


Acute toxicity of metasystox to wedge clam, Donax cuneatus from west coast

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Acute toxicity of metasystox to wedge clam, Donax cuneatus from west coast

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