1.Effect of sublethal α-cypermethrin exposure on main macromolecules concentration, energy content, and malondialdehyde concentration in free-f
Rodríguez-Estrada J1,2, Sobrino-Figueroa AS3, Martínez-Jerónimo F4. Fish Physiol Biochem. 2015 Dec 19. [Epub ahead of print]
α-Cypermethrin (Cyp) is a synthetic insecticide used to control pests in agricultural crops and to protect human health against noxious insects; this toxic can reach aquatic systems through ground infiltration or by runoff and could affect the aquatic biota. The present study was aimed at evaluating the acute toxicity of Cyp on zebrafish (Danio rerio) exogenous feeding larvae of 10 and 20 days post-fertilization (dpf), and of sublethal concentrations on only 10-dpf larvae. Proteins, lipids, carbohydrates, glycogen concentration, and total energy contents, as well as malondialdehyde (MDA) quantification, through thiobarbituric acid reactive substances, as a lipid peroxidation biomarker, were assessed in free-feeding larvae exposed to sublethal Cyp concentrations. The LC50 for 10-dpf larvae was 1.94 µg L-1, and these were more sensitive than 20-dpf larvae (3.56 µg L-1). The amount of protein, carbohydrates, and glycogen were not significantly affected (p > 0.
2.Effects of Two Surfactants and Beta-Cyclodextrin on Beta-Cypermethrin Degradation by Bacillus licheniformis B-1.
Zhao J1, Chi Y1, Liu F1, Jia D1, Yao K1. J Agric Food Chem. 2015 Dec 23;63(50):10729-35. doi: 10.1021/acs.jafc.5b04485. Epub 2015 Dec 8.
The biodegradation efficiency of beta-cypermethrin (β-CY) is low especially at high concentrations mainly due to poor contact between this hydrophobic pesticide and microbial cells. In this study, the effects of two biodegradable surfactants (Tween-80 and Brij-35) and β-cyclodextrin (β-CD) on the growth and cell surface hydrophobicity (CSH) of Bacillus licheniformis B-1 were studied. Furthermore, their effects on the solubility, biosorption, and degradation of β-CY were investigated. The results showed that Tween-80 could slightly promote the growth of the strain while Brij-35 and β-CD exhibited little effect on its growth. The CSH of strain B-1 and the solubility of β-CY were obviously changed by using Tween-80 and Brij-35. The surfactants and β-CD could enhance β-CY biosorption and degradation by the strain, and the highest degradation was obtained in the presence of Brij-35. When the surfactant or β-CD concentration was 2.4 g/L, the degradation rate of β-CY in Brij-35, Tween-80, and β-CD treatments was 89.
3.A Locomotor Deficit Induced by Sublethal Doses of Pyrethroid and Neonicotinoid Insecticides in the Honeybee Apis mellifera.
Charreton M1,2, Decourtye A2,3,4, Henry M1,2, Rodet G1,2, Sandoz JC5, Charnet P6, Collet C1,2. PLoS One. 2015 Dec 14;10(12):e0144879. doi: 10.1371/journal.pone.0144879. eCollection 2015.
The toxicity of pesticides used in agriculture towards non-targeted organisms and especially pollinators has recently drawn the attention from a broad scientific community. Increased honeybee mortality observed worldwide certainly contributes to this interest. The potential role of several neurotoxic insecticides in triggering or potentiating honeybee mortality was considered, in particular phenylpyrazoles and neonicotinoids, given that they are widely used and highly toxic for insects. Along with their ability to kill insects at lethal doses, they can compromise survival at sublethal doses by producing subtle deleterious effects. In this study, we compared the bee's locomotor ability, which is crucial for many tasks within the hive (e.g. cleaning brood cells, feeding larvae…), before and after an acute sublethal exposure to one insecticide belonging to the two insecticide classes, fipronil and thiamethoxam. Additionally, we examined the locomotor ability after exposure to pyrethroids, an older chemical insecticide class still widely used and known to be highly toxic to bees as well.
4.Non-hazardous pesticide concentrations in surface waters: An integrated approach simulating application thresholds and resulting farm income effects.
Bannwarth MA1, Grovermann C2, Schreinemachers P3, Ingwersen J4, Lamers M4, Berger T2, Streck T4. J Environ Manage. 2016 Jan 1;165:298-312. doi: 10.1016/j.jenvman.2014.12.001. Epub 2015 Oct 1.
Pesticide application rates are high and increasing in upland agricultural systems in Thailand producing vegetables, fruits and ornamental crops, leading to the pollution of stream water with pesticide residues. The objective of this study was to determine the maximum per hectare application rates of two widely used pesticides that would achieve non-hazardous pesticide concentrations in the stream water and to evaluate how farm household incomes would be affected if farmers complied with these restricted application rates. For this purpose we perform an integrated modeling approach of a hydrological solute transport model (the Soil and Water Assessment Tool, SWAT) and an agent-based farm decision model (Mathematical Programming-based Multi-Agent Systems, MPMAS). SWAT was used to simulate the pesticide fate and behavior. The model was calibrated to a 77 km(2) watershed in northern Thailand. The results show that to stay under a pre-defined eco-toxicological threshold, the current average application of chlorothalonil (0.