The ability of selected fungal strains to produce carboxylesterase enzymes for biodegradation and use of bifenthrin insecticide as carbon source: in vitro and in silico approaches.

Bifenthrin (BF) is a broad-spectrum type I pyrethroid insecticide that acts on insects by impairing the nervous system and inhibiting ATPase activity, and it has toxic effects on non-target organisms and high persistence in the environment. This study aimed to determine the potential of six different fungi, including Pseudozyma hubeiensis PA, Trichoderma reesei PF, Trichoderma koningiopsis PD, Purpureocillium lilacinum ACE3, Talaromyces pinophilus ACE4, and Aspergillus niger AJ-F3, to degrade BF. Three different concentrations of BF, including 0.1%, 0.2%, and 0.3% w/v, were used in the sensitivity testing that revealed a significant (p ≤ 0.01) impact of BF on fungal growth. Enzymatic assays demonstrated that both intracellular and extracellular carboxylesterases hydrolyzed BF with the enzymatic activity of up to 175 ± 3 U (µmol/min) and 45 ± 1 U, respectively. All tested fungi were capable of utilizing BF as a sole carbon source producing 0.06 ± 0.01 to 0.45 ± 0.01 mg dry biomass per mg BF. Moreover, the presence of PytH was determined in the fungi using bioinformatics tools and was found in A. niger, T. pinophilus, T. reesei, and P. lilacinum. 3D structures of the PytH homologs were predicted using AlphaFold2, and their intermolecular interactions with pyrethroids were determined using MOE. All the homologs interacted with different pyrethroids with a binding energy of lesser than - 10 kcal/mol. Based on the study, it was concluded that the investigated fungi have a greater potential for the biodegradation of BF.

High hazzard pesticides (HHPs) in Near East and North Africa (NENA), constrains and recommendations to mitigate the risk of HHPs.

This study presents an overview of the current situation of highly hazardous pesticides (HHPs) in North Africa and Near East countries (NENA). This work reviews the registered pesticides in the region and identify HHPs being used according to the criteria 1-8 for HHPs of FAO/WHO Guidelines on HHPs. In addition, to identify the weakness and the need of the region to mitigate the risk from the use of HHPs, the report ended with recommendations needed in the region to improve the pesticide managements and registration, such as improving the agricultural practices by adopting the integrated pest management IPM and including replacing HHPs with ecosystem-friendly alternatives if available. The total number of pesticides registered and used in NENA region is 642 active ingredients (IA). Eighty-nine HHPs are still in use in NENA region and 50% of them are evaluated under 1-7 criteria of GHS HHPs. This evaluation shows that 50% of HHPs are insecticides, 22% fungicides, 10% herbicides, 8% nematocides, and 10% rodenticides. The rest of 38 HHPs are identified under criteria 8. This high number of HHPs still in use in some NENA countries urges the need of technical assistance to reduce the use of HHPs. The type of assistant varies from country to other; to identify the priority of technical and legal assistant needed, a country-based assessments must be carried out at the near future.

Organochlorine pesticide residues in human milk and estimated daily intake (EDI) for the infants from eastern region of Saudi Arabia.

This study presents the level of organochlorine pesticide (OC) residues in human milk samples collected from donor mothers aged from 18 to 30 years old, from four cities in Eastern district of Saudi Arabia (Al-Hassa, Al- Khobar, Al-Jubail, and Al-Dammam). Pesticides residues were extracted from the samples and analyzed using GC-MS. The results showed that, only pp'DDE and p,pDDD, were found in 82.5% and 70% of analyzed samples respectively, the total DDT were at level of 0.37, 0.32, 0.30 and 0.46 µg/L in the four cities respectively and were far below the MRL of 50 µg/L (FAO/WHO). The estimated daily intake (EDI) of DDT ingested by infant weight 3.5 kg ranged between 0.06 and 0.10 µg/kg, which is less than the ADI issued by (EFSA, 2014). Lindane (γ-HCH) found in 91.25% of the analyzed samples at level of 0.37, 0.35, 0.35 and 0.29 µg/L. The EDIs of Lindane by infant were far below the ADI of 5 µg/kg bw/day. Dieldrin and Enderin were found in 27.5% and 58.8% of samples respectively and were lower than MRL issued by FAO/WHO, but the (EDI) was higher than the ADI issued by EFSA. The isomer A-heptachlor was detected in 51% of the samples, at levels were 15 times lower than the MRL issued by FAO/WHO, but EDIs by infants were 2-4 times higher than the ADI issued by EFSA. However, the results of the four studied areas in Saudi Arabia showed no statistically different among locations (p > 0.05).