Tomato Seed Coat Permeability: Optimal Seed Treatment Chemical Properties for Targeting the Embryo with Implications for Internal Seed-Borne Pathogen Control

Seed treatments are frequently applied for the management of early-season pests, including seed-borne pathogens. However, to be effective against internal pathogens, the active ingredient must be able to penetrate the seed coat. Tomato seeds were the focus of this study, and the objectives were to (1) evaluate three coumarin fluorescent tracers in terms of uptake and (2) quantify seed coat permeability in relation to lipophilicity to better elucidate chemical movement in seed tissue. Uptake in seeds treated with coumarin 1, 120, and 151 was assessed by fluorescence microscopy. For quantitative studies, a series of 11 n-alkyl piperonyl amides with log Kow in the range of 0.02–5.66 were applied, and two portions, namely, the embryo, and the endosperm + seed coat, were analyzed by high-performance liquid chromatography (HPLC). Coumarin 120 with the lowest log Kow of 1.3 displayed greater seed uptake than coumarin 1 with a log Kow of 2.9. In contrast, the optimal log Kow for embryo uptake ranged from 2.9 to 3.3 derived from the amide series. Therefore, heterogeneous coumarin tracers were not suitable to determine optimal log Kow for uptake. Three tomato varieties were investigated with the amide series, and the maximum percent recovered in the embryonic tissue ranged from only 1.2% to 5%. These data suggest that the application of active ingredients as seed treatments could result in suboptimal concentrations in the embryo being efficacious.

Continuous and Automated Slug Flow Nanoextraction for Rapid Partition Coefficient Measurement

Octanol-water partition coefficients (log Kow) are widely used in pharmaceutical and environmental chemistry to assess the lipophilicity of compounds. Traditionally log Kow is determined using a shake-flask method that uses...

Drugs in the environment: Do we know the risks?

The occurrence of residual drugs in sewage and natural waters is an important international topic. The behavior of compounds in the environment and sewage treatment plants (ETEs) is influenced by their physicochemical properties, which govern partition in water, soil or biota. The present study aims to identify the presence of clonazepan, simvastatin, paracetamol, atenolol, carbamazepine and fluoxetine drugs in biosolid from TEE before and after the composting process. Based on the Environmental Protection Agency's Structure-Activity Relationship Model (ECOSAR) Program (EPA), and according to ZAGATTO (2006), the octanol/water partition coefficient (Kow) observed for ibuprofen drugs, fluoxetine and sinvastanin was 3.97, 3.82 and 4.68, respectively, denoting its bioaccumulation potential, which does not happen with the other compounds, as they present logKow < 3, being log kow = 0.03 for atenolol; 2.3 for carbamazepine; 0.49 for paracetamol and 2.53 for clorazepam. AQUINO, 2013, mentions that drugs with logKow < 2.5 have high hydrophylycity and low absorption trend in biomass and lipid fractions of suspended solids. For Log Kow values between 2.5 and 4.0, there is a moderate tendency of absorption in these matrices. Data on ecotoxicity, provided by the ECOSAR program, indicate the effects observed in fish, at the concentration of 30 μg/L for Sinvastatin and 20 μg/L for Fluoxetine. The agricultural use of biosolids is a controversial subject due to the potential adverse impacts on human health. In the name of safety, strict standards, high quality criteria and restrictions on use are imposed, and standards should be based on risk assessment, but there is a lack of data on the subject, and there is still no clarity as to what constitutes tolerable risk in the brazilian context for the composition of a pattern. Key messages According to the results obtained, it is verified that the studied compounds have the potential to cause deleterious effects on the evaluated organisms, according to the ECOSAR model. Considering the little information available on the subject, especially in relation to the incidence and persistence of drugs in the environment, the continuity of studies is necessary.

Distribution of 31 endocrine disrupting compounds in the Taihu Lake and application of the fish plasma model

Background: The successful application of Fish plasma model (FPM) will greatly simplify the risk assessment of drugs. At present, the FPM has been applied to the risk assessment of several human drugs with high hydrophobicity. However, its applicability to a wide variety of compounds needs to be tested. Filed work about distribution characteristics of endocrine disrupting compounds (EDCs) in water and in fish plasma plays a key role in promoting the successful application of FPM. However, there are few reports on the distribution of EDCs in fish, especially in wild fish plasma. Results: The distribution of 31 EDCs, including seven estrogens, eight androgens, six progesterones, five glucocorticoids, and five industrial compounds, in water and plasma of five categories of wild fishes in Taihu Lake was studied and the typical FPM was tested by the field data. The detected concentration of most compounds is relatively low (< 10 ng/L), and the industrial compounds are the predominant pollutants with the highest concentration up to 291.7 ng/L (Bisphenol A) in water. In general, glucocorticoids were detected at the highest concentrations in plasma of all kinds of fishes, followed by industrial compounds and estrogens. Except for glucocorticoids (up to 43.61 for Cortisone), the average concentrations of the other four categories of EDCs in fish plasma were generally low (< 10 μg/L). The available measured bioaccumulation factors (BAFs) of 20 kinds of EDCs were in the range of 0 to 5626. The bioaccumulation of EDCs in fish plasma is not only hydrophobicity dependent, and it is both fish species-specific and compound-dependent. The classical FPM was tested and the results indicated that the good coincides of measured log BAFs and the theoretical log BCFs was only observed for limited EDCs (7 out of 20). The present available FPM generally underestimated the Log BAFs of most hydrophilic EDCs (log Kow <3.87, 11 out of 20) whereas overestimated the Log BAFs of several high hydrophobic EDCs (Log Kow >3.87) in fish plasma. Conclusion：Although the present FPM is barely satisfactory, it is still promising for predicting the accumulation of EDCs in fish plasma and for further environmental risk assessment.

Experimental Determination of Octanol-Water Partition Coefficients of Selected Natural Toxins

Natural toxins are ubiquitously occurring highly diverse organic compounds produced by e.g., plants or fungi. In predictive environmental fate and risk assessment of organic chemicals for regulatory purposes, the octanol-water partition coefficient (Kow) remains one of the key parameters. However, experimental data for natural toxins is largely missing and current estimation models for Kow show limited applicability for multifunctional, ionizable compounds. Thus, log Kow data was first experimentally derived for a diverse set of 45 largely ionizable natural toxins and then compared to predicted values from three different models (KOWWIN, ACD/Percepta, Chemicalize). Both approaches were critically evaluated with regards to their applicability for multifunctional, ionizable compounds. The miniaturized shake-flask approach allowed reliable quantification of pH dependent partitioning behavior for neutral, acidic and basic ionizable natural toxins. All analyzed toxins are rather polar with an average log Kow < 1 and an observed maximum log Kow of 2.7. Furthermore, the comparison of experimental data to those of commonly used prediction models showed that the latter match the former with only minorly increased errors. The Chemicalize tool gave overall best predictions with a mean absolute error of 0.49 and thus should be preferred in comparison to ACD/Percepta and KOWWIN.

Experimental Determination of Octanol-Water Partition Coefficients of Selected Natural Toxins

Natural toxins are ubiquitously occurring highly diverse organic compounds produced by e.g., plants or fungi. In predictive environmental fate and risk assessment of organic chemicals for regulatory purposes, the octanol-water partition coefficient (Kow) remains one of the key parameters. However, experimental data for natural toxins is largely missing and current estimation models for Kow show limited applicability for multifunctional, ionizable compounds. Thus, log Kow data was first experimentally derived for a diverse set of 45 largely ionizable natural toxins and then compared to predicted values from three different models (KOWWIN, ACD/Percepta, Chemicalize). Both approaches were critically evaluated with regards to their applicability for multifunctional, ionizable compounds. The miniaturized shake-flask approach allowed reliable quantification of pH dependent partitioning behavior for neutral, acidic and basic ionizable natural toxins. All analyzed toxins are rather polar with an average log Kow < 1 and an observed maximum log Kow of 2.7. Furthermore, the comparison of experimental data to those of commonly used prediction models showed that the latter match the former with only minorly increased errors. The Chemicalize tool gave overall best predictions with a mean absolute error of 0.49 and thus should be preferred in comparison to ACD/Percepta and KOWWIN.

pH dependent octanol–water partitioning coefficients of microcystin congeners

Hazardous algal blooms can generate toxic compounds with significant health impacts for exposed communities. The ubiquitous class of algal toxins known as microcystins exhibits significant heterogeneity in its peptide structure, which has been minimally studied, given the significant impact this has on hydrophobicity, acid/base character and related environmental fate and health effects. Octanol–water partition coefficients for the microcystin congeners MCLR, MCRR, MCLY, MCLF, and MCLA were calculated over an environmentally and physiologically relevant pH range. Microcystin-LR log(Kow) partition coefficient values were found to be consistent with previously established literature values, 1.67 to −1.41 between pH 1 and 8. Microcystin RR was found to be pH insensitive with a log(Kow) of −0.7. The remaining congeners exhibit similar pH dependence as MCLR, with systematic increases in hydrophobicity driven by the introduction of more hydrophobic residues to their variable amino acid region. The variation in pH dependent hydrophobicity suggests increased propensity for bioaccumulation and alternate environmental fates for differing microcystin forms, requiring further investigation.