Evaluation of Combined Toxicity of Phenols and Lead to Photobacterium phosphoreum and Quantitative Structure–Activity Relationships

Abstract

The combined toxicity of lead (Pb) and nine phenols were measured. The result indicated that the combined toxicity is not only dependent on the Pb concentrations but also on the positions of substituted groups of phenols. Quantitative structure-activity relationship equations were built from the combined toxicity and physico-chemical descriptors of phenols in the different Pb concentrations. The combined toxicity was related to water solubility and the third order molecular connectivity index ((3)X) in low Pb concentration, to solute excess molar refractivity (E) and ionization constant (pKa) in medium Pb concentration and to dipolarity/polarizability (S) in high Pb concentration.

Combined Toxicity of Nitro-Substituted Benzenes and Zinc to Photobacterium Phosphoreum: Evaluation and QSAR Analysis

“…There are only two joint actions, synergism and antagonism, between nitro-substituted benzenes and Zn if we strictly obey the criteria of AI or TU (33% of the joint actions are synergism and 67% antagonism). It is widely acknowledged that within experimental error, it is an ideal situation and extremely difficult to obtain simple addition with M = 1 or AI = 0 [28,30,31,40,41]. Broderius et al [41] defined simple addition with M values equal to 1 ± 0.2.…”

“…Test organism, P. phosphoreum , appropriating for the experimental of joint effects, was served in the form of freeze-dry powder supplied by the Nanjing Institute of Soil Science, Chinese Academy of Science. The culture medium of P. phosphoreum was prepared according to Su et al [20,21,22,23,24,25,26,27,28,29,30,31] and Yuan et al [32]. The constituents of culture medium are shown in Table 1.…”

“…After the preliminary experiments, each compound was set five treatment concentrations from low to high by equal interval of logarithm. Three replicates were set for each treatment concentration including the control group (solution only containing 3% NaCl in deionized water) [28,29,30,31,32,33]. For each treatment concentration, a medium solution containing diluted P. phosphoreum of 0.5 mL was inoculated into a tube containing 2 mL of a tested chemical solution or a 3% NaCl solution as control.…”

Evaluation of joint toxicity of nitroaromatic compounds and copper to Photobacterium phosphoreum and QSAR analysis

“…In fact, besides simple addition (or concentration addition), the combined effects of contaminants can be larger or smaller than simple addition [10,20]. Combined ratios of mixtures might lead to different toxic response [9,13,21,22]. Using simple addition method to predict the toxicity of mixtures can result in wrong results if synergism and antagonism exist among mixture actions.…”

QSAR analysis of the toxicity of phenols and thiophenols using MLR and ANN

“…Quantitative structure-activity relationship (QSAR) modeling is a powerful approach used for studying the phenol and thiophenol toxicity governed by molecular structures [1,[7][8][9]. Particularly, an acceptable QSAR model has the advantages of increased speed and lower costs than those of the experimental tests for the evaluation of chemical toxicity.…”