Acute toxicity of atrazine to Oreochromis niloticus was undertaken to find the lethal concentration (LC) 50 of atrazine using fingerlings. Different concentrations were prepared in mg/L. There were six different concentrations with a control and each treatment was replicated three times. A total number of twenty-one aquaria were used. The highest concentration was 30mg/L. Ten test organisms were used in each aquarium. At 24, 48, 72 and 96 hours there were LC 50 of 15.6mg/L, 14mg/L, 11mg/L and 9.4, respectively. At 24, 48, 72 and 96 hours there were mean survivals of 49.0%, 34.3%, 28.6% and 28.1%, respectivel

Jiya, K.R.

Majinga, S.I.I.

Mbagwu, L.C.

English

Aquatic Commons

ACU L TOXICITY OF ATRAZINE TO ORECHROMIS NILOTICUS FINGERLINGS
*Kolo Reuben Jiya; **Mbagwu, L.C.; ***Majinga, S. II.
*Department of Fisheries Technology,
Federal UniversiO) gf Technolo. Minna ,
P.M.B. 65, Minna, Niger State.
National Institta e .for Freshwater Fisheries Research,
Kainji, New Bussa, Niger State
***inter-Continental Fisheries, Lagos.
ABSTRACT
Acute Toxicity of Atrazine to Oreachromis niloticus was un.dertaken to find the lethal
concentration (LC) 50 of atrazine using fingerlings. Different concentrations were prepared in
mg/L. There were six different concentrations with a control and each treatment were replicated
three times. A total number of twenty-one aquaria were used. The highest concentration was
30mg/L, Ten test organisms were used in cash aquarium.
At 24, 48, 72 and 96 hours there were LC 50 of 1.5.6mg/L 14mg/L, 11mWL and 9.4L
respectively. At 24, 48, 72 and 96 hours there were mean survival of 49.0%, 34.3% 28.6% and
28.1% respectively.
INTRODUCTION
The Tilapa (Oreochromis niloticus) is one of the itnportant fish which provide animal protein
source in the diet of most rural dwellers in Nigeria. Its importance hangs on the protific natural
breeding ability and her hardy nature which enables her to inhabit and survive in most freshwater
aquatic environment. Advancement in the agricultural practices and industrial activities has brought
about degradation in most aquatic ecosystems. This has prompt the western world to become
increasely concern about the excessive use of chemicals in agricultural practices. Nearly 200 years
ago studies has beeen conducted to assesed the effect fo agricultural and industrial wastes on the
environment and fish (Reish, 1987).
Several workers has reported the serious environmental problems pesticides have caused
(Kemp et al, 1983; Jacknow, 1986; Agromisa et al, 1989; Ronald, 1989). Although most of these
chemicals asre partially or completely banned in developed countries (Steward et al., 1986), most
continue to find their way to African countries for use in pests control. Some of these pesticides
have not been screened neither have their toxicity effects on the animals or on aquatic organisms
been assessd (Ita, 1991; Obiekezie and Okafor, 1995). Federal Environmental Agency (FEPA) in
1991 has set a uniform standard for all categories of pesticides allowed for discharge into inland
waters in Nigeria at less than 0.01ingil which seems impracticable because of lack of effective
monitoring of the used of pesticides or effluents discharges from pesticides industries. Some
attempts have been made to determine the levels of some pesticides and heavy metals in some
inland waters in Nigeria (Adeniji et al, 1985). He recorded high concentration of DDT and other
insecticides in the muscles of fish caught from Kainji and Jebba lakes areas of Nigeria. This was
attributed to illegal use of Garnalin 20,
Acute toxicity tests provides basis for understanding the limiting- effects of various
chemicals on organisms. One of the early reports of the use of in toxicity studies was that of Peny
130
and Adams, 1963, when the effects of chemicals used in dye works onfish was checked. Chemicals
such as pesticides are known to transfer their residual effects to the environment and the organisms
that inhabit them (Alabaster, 1981; Gunkel, 1981; Adeniji et al 1985). Pesticides industries also get
rid of their effluents through rivers and streams which ends up in larger aquatic environments.
Inspite of the upsurge in the use of pesticides in agricultural practices in Nigeria, there has been
little or no awareness of the dangers the environment is exposed to by the users. The increasing use
of these pesticides has caused unwanted degradation of aquatic environments, fish fills and food
and human poisoning (Alabaster, 1981; Rand and procclli, 1985; Joseph, 1987; Igbedioh, 1991;
Waiser and Robarts. 1997: Lanars, 1993). Apparently, information on their use, distribution and
environmental impacts are scanty in Nigeria.
The objective of this work is to determine the toxicity of Atrazine (2-chloro-4-ernyl amino-
o-iso ropyiaminol, 3, 5-triazine) to Oreochromis niloticus fingerlings. Atrazine is one of the
commonent pesticides used in Nigeria to control weeds and pests in numerous crops. As reported
by Van Schoubroeck, 1989; it is a white crystaline substance sold under a variety of trade name
which include Primatol, Aatrex, Atranex, Actazin, Argeisin, Atrotol, Zeazin
Studies on Atrazine
Agricultural uses of atrazine has been reported in some African countries, Australia, New
zealand, Venezueia and in most European countries. The major producer is Ciba Geigy
corporation. The products are usually used as water spray or liquified fertilizers which could
applied as pre-mergence or post-mergence fertilizer Atrazine is leached into the soil by ram or
irrigation water and its also taken away by runoff water (Ronald, 1989). Kemp et al, (1983) have
associated the application of herbicides, atrazine inclusive to the over all decline in the abundance of
fish and wildlife in many aquatic systems as a consequence to serious disturbance in the ecological
balance which cummulate in the decline of sea grasses and freshwater submerged vascular plants
which provides food for the entire habitat. Denoyelles et al., (1982) also observed that atrazine
concentrations between 1 and 5ug/1 adversely affected higher levels of the food chain beginning
with zooplankton. At concentrations of 1 to 5ug/1 and exposure period of 5 minutes to 7 weeks,
Mayasich et al., (1986) also reported adverse effects in sensitive species. Meck et al., (1976)
reported that adverse effect level to selected species of aquatic invertebrates and fishes ranged from
12Oug/1 to 50Oug/1 based on life time exposure. However, Deway (1986) as cited by Ronald
(1989) observed that ambient concentrations of as low as 2Oug/1 have beeen associated with
adverse effects on freshwater aquatic fauna, including benthic insects. In the studies of Kettle et al.,
(1987) cited by Ronald (1989) it was noted that the production of channel catfish (Lctalurus
punctatus) and blucgills as measured by number of young per pond was reduced by more than
95%. It was also reported that the number of prey items in stomach were significantly higher in
control ponds than in the treated ponds. He thus concluded that the effects of atrazine on channel
catfish and bluegills were probably indirect, and that the reduction of macrophytcs that had
provided habitat for fodd items led to improvished diets and more canibalism by adult blue gills
Bioaccumulation of atrazine from freshwater into aquatic organism muscles is limited and
food chain biomagnification is negligible. Studies have shown that in a farm pond treated once with
300ug atra7ine/1, residues at 120 days post treatment ranged between 204 and 264ug/kg in mud
and water (Kadoum, 1979; cited by Ronald, 1989). Gunket (1981) in his studies with freshwater
snail (Achylus fluviatilis) and fry of white fish (Coregonus fera) found that atrazine was rapidy
accumulated from the medium by both species and saturation was reached within 12 - 24 hours.
Materials and Methods
The was obtained through induced breeding from the hatchery facilities of National
Institute for Freshwater Fisheries (NIFFR), Kainji New Busaa, Nigeria. The fishes were of the
same approximate size, each weighing about 1 3gms and measuring 3-4cm. They were kept in
131
glass aquaria measuring 60 x 30 x 30 cm in the diseases and mortality on daily basis. The fishes
were maintained on dried commercial fish feed produced by N1FFR, but the fishes were starved for
twenty-four hours prior to the test. They were also exposed to sixteen hours of light and eight
hours of darkness as described by APHA Standard methods (1980) during acclimatization and
experiment. The wide spectrum fourescent tubes were used as a light source similar to day light
During acclimatization and the experiment, aerators pumps were used to aerate each
aquarium tank so as to maintained dissolved oxygen level close to saturation. Municipal water was
used for the test and it was analysed for some physico-chernical parameters (Temperature,
Hydrogen ion (pH), Dissolved oxygen and Hardness).
Preparation of the Stock Solution
Atrazine powder was dissolved in water with the aid of ethanol as an organic solvent which serves
as the ispersing agent. The powder contains 80% pure atrazin.e. A correction factor for obtaining
the exact quanties of pure atrazine was then calculated as follows: % contents of pure atrazine in
the atrazine powder X weight of atrazine powder in grams/100. The correction factor being in
grams was further reduced to milligrams by multiplying it by 1.000. The correction factor was then
used to determine the amount of powder needed to prepare a known concentration of stock
solution.
Preparation of the test Solution
The test solution was prepared OD litre basis, so as to get a test solution containing the
required concentration per litre. This was done by pipeting the required quantity of the stock
solution and introducing it into a known volume of water in each aquaria to get the test solution of
a required concentration.
Test Procedures
Six different atrazine test solutions were prepared. Each concentration was replicated
twice. A control was set up which was replicated twice also. Ten specimens of test organisms (O.
niloicus) were kept in each aquaria tank. Each tank was observed daily for a period of 96 hours.
Observations were made at 15 and 30 minutes, 1,2,4,8,12,16, 20 and 24 hours on the fish day of
the experiment Subsequent observations were ast intervals of 6 hours on daily basis.
Temperature, pH, dissolved oxygen and hardness concentration of each ta,nk were taken on daily
basis. Test organisms were not feed during the test period so as to minimized the accumulation of
fecal materials. Each experimental units were observed closely for any abnormal swiming behavior,
hyperventilation or mortality. Death was the adverse effect used to reflect acute toxicity of the test
solution. This was indicated by lack of movement of the operculum and response to stimulus.
Results
The calculation of the LCso at 24 - 96 hours by the arithematic graph method are shown in
figures 1 - 6. Percentage survival, mortality data and the 24h LCso, 48h LCso, 72h LCso, and 26h
LC)o for the various atrazine concentrations are presented in tables 1 and 2 respectively. No death
was recorded in the controls and fishes in the lower concentrations of test solution did not show
any abnormal behavior, however, at lethal concentrations fishes showed signs of stress, loss of
equillibrium therefore shows cratic swiming behavior, gulping for air near water surface, over
turning when swiming, slogishness and finally death results.
The pH and the dissolved oxygen values ranges between 6.09 and 7.03 and 2.13mg/1 and
2.94gm11 respectively. Hardness decreases with increase in the exposure period. Its value ranges
between 9 to 17 3mg/l. The mean variations in these parameters are shown in table 3.
(insert 2 graph here).
132
Table 1: Records on percentage survival and percentage nrunrtality rates of O. niloticus
fingerlings in different concentrations of atrazine solution.
conc. concentration x%suurv. mean percentage survival; x% mort mean percentage
mortality.
Table 2: The experimental duration and LC50 of atrazine toxicity to the fingerlings of
O. nilolucus.
133
{PRIVATE }Period of exposure in hours LCso
24 15.6mg/1
48 14mg/1
72 1 ling/1
96 9.4mg/1
24 HOURS 48 HOURS 72 fIOURS 96 HOURS
Celle. x%surv. x%
mort
x%surv.x%
mort
x%surv.x%
mort
x%surv.x%
mort
100 0 100 0 100 0 100 0
100 0 100 0 83.3 16.7 83.3 16.7
76.7 23.3 20 80 1.33 86.7 13.3 86.7
15mg/i 56.7 433 167 833 33 90 0 100
20mg/i 10 90 33 96.7 0 100 0 100
25mg/1 0 100 0 100 0 100 0 100
30mg/f 100 0 100 0 100 0 100
{PRIVA EXPERIMENTAL DURATION
TE}
Table 3: Mean variations in some physico-chemical parameters measured in the
experimental units.
Conc. - concentration in mg/1, DO - Dissolved oxygen, pH - Hydrogen ion; Hard - Hardness.
Discussion
There were great significant differences at different concentrations. Swimming in a.n airrniess
and erratic manner, gulping for air near water suiface, overtu.ming whilke swimming, dullness
and finally death were the common responses of the test organisms to the test solution. These
behaviours were also observed when Liong et al (1988) studied toxic effects of twenty-seven
pesticides on Tilapia fish. There was 100% mortality at 96 hours at a concentration of 15mg/1
and at less than 5mg/1 the fish did not seem to be affected in any way.
134
{PRIV
ATE}
24 hours 48 hours 72 hours 96 hours
Cone DO pH Hard DO pH Hard DO pH Hard DO pH Hard
0mg/1 2.73 7.06 16.3 2.80 7.09 16.6 2.50 6.98 17.3 3.00 6.99 17.3
5ing/1 2.13 6.95 15.6 2.40 6.09 16.0 2.66 6.92 15.6 2.53 6.93 16.3
10rng/1 2.73 6.95 13.3 3.20 6.98 12.6 2.73 6.96 12.3 2.80 6.94 12.6
15mg/1 2,60 6.89 13.3 2.80 6.95 13.0 2.66 6.92 12.3 2.60 6.92 12.0
20mg/1 2.66 6.95 11.3 2.40 6.00 11.0 2.60 6.91 10.3 2.73 6.92 10.0
25mg/1 2.80 7.09 10.3 2.86 7.02 10.6 3.00 6.99 9.6 2.80 6.99 9.3
30mg/1 2.93 7.03 10.0 2,86 7.02 9.6 3.00 6.97 9.0 3.00 6.96 9.0


Acute toxicity of atrazine to Oreochromis niloticus fingerlings

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Acute toxicity of atrazine to Oreochromis niloticus fingerlings

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