Combined toxic effect of potassium butyl xanthate and oil on duckweed (Lemna minor)

21 Apr 2021, 14:50
15m
oral Clean water Clean water

Speakers

Michael Saksonov (Irkutsk State University) Alina Stom (Irkutsk State University)

Description

Potassium butyl xanthate (PBX) is widely used as a reagent in ore dressing by flotation. For this reason, it is present in the wastewater of these industries [Goryachev, 2014; Ignatkina, 2014]. Oil products are found even more often in a wide variety of waste waters. They, like flotation reagents, have a depressing effect on aquatic organisms. At present, biotesting methods are widely used to assess the quality of water bodies and predict the consequences of pollution. They allow an integral assessment of the quality of the environment. This is their important advantage over analytical chemistry methods. The latter are intended, as a rule, to determine individual compounds or certain groups of them [Zhmur, 2018]. The study of the combined action of oil and flotation reagent by biotesting methods in a multifactorial experiment makes it possible to reveal the nature of this interaction (additive, antagonistic or synergistic) [Zholdakova, 2012; Gelashvili, 2016].
The purpose of this work is to study the isolated and combined effect of potassium butyl xanthate and oil on an aquatic plant – duckweed (Lemna minor).
Concentrations of PBX and oil in experiments with isolated action on small duckweed were 10.0; 50.0; 100.0; 500.0; 1000.0 mg / l. The toxicity of the samples was assessed by the increase in the number of L. minor fronds in the samples [GOST 32426-2013]. The study was carried out in three independent experiments, three replicates each. Statistical data processing was performed using the Microsoft Office software package.
The toxic effect of PBX and oil in the concentration range of 10.0-1000.0 mg / l on the increase in the number of duckweed fronds was quantitatively determined.
Using probit analysis, the concentrations of PBX and oil were found that inhibit the studied reaction parameters by 25% (ICR25), 50% (ICR50), 75% (ICR75). Concentrations of PBX solutions causing an inhibitory effect on the increase in the number of duckweed fronds by 25%; 50% and 75% were 3.8mg / L; 21.9mg / L and 46.8mg / L, respectively. Concentration of oil emulsion causing similar effects - 9.4 mg / l; 53.6 mg / L and 500.0 mg / L, respectively.
These concentrations served as three levels of variation of the PBX-oil factors in terms of a full factorial experiment.
When designating the concentrations of the two substances included in the combination as x1 and x2, the toxic effect on small duckweed under the combined effect of the mixture was determined according to the results of nine experiments as the dependence y = f (x1, x2) and expressed as a second-order polynomial.
When performing a full two-factor experiment with the combined action of oil and PBX, the regression equation was obtained:

y=71,64+11,87x_1+18,62x_2+2,73x_1^2-2,82x_2^2-9,35x_1 x_2

The analysis of the equation made it possible to conclude that the action of substances is unidirectional, interdependent (b12 ≠ 0), and the interaction is expressed quite strongly. Isolated introduction of oil with an increase in concentration from ICR50 to ICR75 causes an increase in the toxic effect by 15%, and PBX – by 16%, while with combined action – by 21%. Thus, we can conclude that the nature of the combined action of PBX and oil is interdependent, antagonistic, less than additive.

This work was supported by the RFBR grant 19-29-05213 MK "Mechanisms of the complex interaction of soils with oil, oil products and surfactants in the processes of oil pollution and bioremediation". The studies were carried out using the Center for Collective Use of the Baikal Museum of the Irkutsk Scientific Center («Collection», http://ckp-rf.ru/ckp/495988/).

Affiliation of speaker Irkutsk State University
Publication IOP Conference Series: Earth and Environmental Science

Primary authors

Michael Saksonov (Irkutsk State University) Natalya Khorina (Baikal Museum of Irkutsk Scientific Center) Alina Stom (Irkutsk State University) Geogry Ilyin (Baikal Museum of Irkutsk Scientific Center) Anna Mataevskaya (Irkutsk State University)

Presentation Materials