Method for evaluating biotoxicity of heavy metal by duckweed

Abstract

The invention discloses a method for evaluating biotoxicity of a heavy metal by duckweed thallus separation, which comprises the steps of: creating a correlativity of toxicological reaction of duckweed on the heavy metal, namely, two-leaf separation phenomenon of thallus and the category and concentration of the heavy metal, and evaluating the biotoxicity of a tested water sample by the separation time of the laminae. The method of the invention has the advantages that the duckweed has sensitive toxic response and short response time on certain heavy metals, such as copper and iron, and the like, thereby shortening the test time, saving the cost and simplifying the operation. The duckweed thallus has sensitive physio-ecological response on the heavy metal and the response can be directly observed, so that the duckweed thallus can be used as an effective complementary method for monitoring sewage toxicological effect system of hydrobiont.

Description

technical field [0001] The invention belongs to the field of biological detection, in particular to a method for evaluating the biological toxicity of heavy metals by using duckweed. Background technique [0002] Duckweed (Lemna minor Linn) is a higher aquatic vascular plant. As early as the 1950s, foreign toxicologists proposed the use of duckweed for toxicological tests to monitor water environment quality, and established standard test methods. The European standard (BS EN ISO 20079:2006) introduces the change of the number of duckweed leaves as a monitoring indicator. During the test, the number of growth index leaves is recorded every day, and the growth rate inhibition rate is calculated by the number of leaves to obtain EC50 ( R=(lnX t2 -lnX t1 ) / T 2 -T 1 , X tn for T n The index value measured at day time, R represents the growth rate, Ir=(Rc-Rt) / Rc×100% (Ir growth inhibition rate, Rc control group growth rate, Rt treatment group growth rate), the concentration ...

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Problems solved by technology

For the comparison with distilled water, due to the long test period and the need for nutrients for the growth of duckweed, the daily growth rate of the control group is low, and the performance is inconsistent. At the same time, there will be yellowing of leaves caused by nutrient deficiency. , the duckweed in the control group can not grow normally, thus affecting the accuracy of the control experiment; It may destroy the components of the tested water sample, and the presence of nutrients may also affect the accuracy of the toxicity test results, which will affect the EC50 value

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