Volume : 6, Issue : 7, July - 2017

EFFECTS OF A PYRETHROID INSECTICIDE CYPERMETHRIN ON BENTHIC OLIGOCHAETE WORM, Branchiura sowerbyi (BEDDARD, 1982)

Chandan Sarkar, Nimai Chandra Saha

Abstract :

<p>&nbsp;<span lang="EN-IN" style="text-align: justify; font-size: 12pt; line-height: 150%; font-family: &quot;Times New Roman&quot;, serif;">The present study was done to evaluate the acute toxic effects of Cypermethrin to benthic oligochaete worm, <i>Branchiura sowerbyi </i>along with the changes in their behaviour during the study. The 24, 48, 72 and 96 h LC₅₀ values of Cypermethrin to <i>B. sowerbyi </i>were 3.18</span><span lang="EN-IN" style="text-align: justify; font-size: 12pt; line-height: 150%; font-family: &quot;Times New Roman&quot;, serif;">, </span><span lang="EN-IN" style="text-align: justify; font-size: 12pt; line-height: 150%; font-family: &quot;Times New Roman&quot;, serif;">2.30</span><span lang="EN-IN" style="text-align: justify; font-size: 12pt; line-height: 150%; font-family: &quot;Times New Roman&quot;, serif;">, </span><span lang="EN-IN" style="text-align: justify; font-size: 12pt; line-height: 150%; font-family: &quot;Times New Roman&quot;, serif;">1.70 and 0.75 mg/l respectively. The rate of mortality of <i>B. sowerbyi</i> varied significantly (p&lt;0.05) at 24, 48, 72 and 96h of exposure time. The mortality rate of the worm also varied significantly (p&lt;0.05) with all exposed concentrations of the toxicant except 3.2-4.0 mg/l at 72 and 96h. The worm showed different behavioural responses like abnormal clumping tendency, less movement and excessive mucous secretion which were recorded during the study at all exposure times.</span></p> <p class="MsoNoSpacing" style="text-align:justify;line-height:150%"><span lang="EN-IN" style="font-size:12.0pt;line-height:150%;font-family:&quot;Times New Roman&quot;,serif"><o:p></o:p></span></p>