Toxic substances used as chemical weapons present a number of particularities that affect the surrounding environment, having a wide range of action by disrupting the ecological balance: they may infect soil or air, or form aerosols through smoke or toxic fog. Such substances can have a long duration of action, from minutes to weeks, which is why they are used in military attacks. This study evaluated the toxicological character of o-chlorobenzyliden malonitrile (CBM) in order to study the toxicity limit of this substance using microbiological cultures of Saccharomyces sp., Chlorella sp., Lactobacillus sp. and Paramecium sp., which were used to determine their rate of growth in the presence of different concentrations of o-chlorobenzyliden malonitrile and their ability to respond to this toxic stimulus.

Chemical compounds, such as the CS gas employed in military operations, have a number of characteristics that impact the ecosystem by upsetting its natural balance. In this work, the toxicity limit and microorganism’s reaction to the oxidative stress induced by O-chlorobenzylidenemalonitrile, a chemical found in CS gas, were assessed in relation to the green algae Chlorella pyrenoidosa. A number of parameters, including the cell growth curve, the percent inhibition in yield, the dry cell weight, the percentage viability and productivity of algal biomass flocculation activity, and the change in oxygen production, were analyzed in order to comprehend the toxicological mechanisms of O-chlorobenzylidenemalonitrile on algal culture. Using fluorescence and Fourier transform infrared spectroscopy (FTIR), the content of chlorophyll pigments was determined. The values obtained for pH during the adaptation period of the C. pyrenoidosa culture were between 6.0 and 6.8, O₂ had values between 6.5 and 7.0 mg/L, and the conductivity was 165–210 µS/cm. For the 20 µg/mL O-chlorobenzylidenemalonitrile concentration, the cell viability percentage was over 97.4%, and for the 150 µg/mL O-chlorobenzylidenemalonitrile concentration was 74%. The EC_b50 value for C. pyrenoidosa was determined from the slope of the calibration curve; it was estimated by extrapolation to the value of 298.24 µg/mL. With the help of this study, basic information on the toxicity of O-chlorobenzylidenemalonitrile to aquatic creatures will be available, which will serve as a foundation for evaluating the possible effects on aquatic ecosystems. The management of the decontamination of the impacted areas could take the results into consideration.

This study investigated the optimization of chemical methods for the removal of petrochemical pollutants from wastewater. The novelty of this research lies in identifying the optimal concentration of coagulants, particularly the combination of IP1140 polyelectrolyte with Fe2+ ions. Five identical reactors were tested using a mixture of FeSO4 (3%), IP1140 polyelectrolyte (0.2 ppm), and Ca(OH)2 (20%) in different molar ratios per 100 mL (v:v:v): 1:1:2, 1:2:2, 2:1:1, 2:1:2, and 2:2:1. Parameters, such as the pH value, COD, BOD, the amount of extractable, and residue, were evaluated. The results demonstrated that after 10 min, the pH increased from 6.5 to 6.8 in reactor A and to 7.2 in reactor E. After 30 min, the pH values ranged from 7.0 to 7.5, reaching a maximum of 8.5 in reactor E after 120 min. The chemical treatment resulted in COD reductions of up to 89% in reactor B and 91.8% in reactor C; BOD reductions of up to 76% in reactor B and 87% in reactor E; extractable substances were reduced by up to 92% in reactor D and 88% in reactor A; while residue decreased by up to 87% in reactor B and 84% in reactor D. The BOD/COD ratio ranged between 0.3 and 0.5, with the best chemical treatment ratio carried out in reactor E with molar ratio/100 mL (v:v:v) 2:2:1.