Investigation of the Complex Influence of the Preparation Stomp E33(Pendimethalin) Over Daphnia Magna Straws (Dissolved in Water and Accumulated from Chlorella Kessleri)

ABSTRACT

An experiment with juvenile Daphnia magna, according to ISO 6341 (1996), in two repetitions, has been carried out. A toxicity criterion was the immobilization of D. magna.

During the cultivation of D. magna, Chlorella kessleri was added in concentration 2.10⁵ cell/ml. This number of cells was a starting point for the toxicological experiment.

Two cultures of chlorella with a different density of the cells (the first one with 2 times higher number of cells than the second one) were treated for 24h with 40 mg/l pendimethalin (this is 24h EC₅₀ for chlorella established in our experiments). A control experiment variant was put in a clean medium. Two basic variants were obtained using centrifugation of the algal suspension followed by resuspendation in the daphnia medium: the first one with final concentration 0, 4 mg/l, and second one with 0, 8 mg/l pendimethalin.

Chlorella density of was 2.10⁵ cells/ml in both cases. For more complete picture of the effect of the treated algal cultures on D. magna, each of the above mentioned variants was divided into four subvariants.

It was concluded that the variants with algal suspension influenced from pendimethalin and those with influenced algae, resuspended in Daphnia medium, were the most toxic for D. magna

Keywords:

• Chlorella kessleri
• Daphnia magna
• STOMP E33 (pendimethalin)
• toxicity
• cumulation