The use of pesticides in agricultural sectors is rising due to the growing demand for food in the world, but the presence of pesticide residues in agricultural commodities has become a major health concern for consumers and is associated with problems of food safety. Thus, the present study determined pesticide residues (17 organochlorine, 5 pyrethroid and 3 organophosphate) in 77 fish feed, 112 fish and 135 vegetables samples (total of 324) from the different locations in Bangladesh, using quick easy cheap effective rugged and safe (QuEChERS) extraction followed by gas chromatography-mass spectrometry (GC-MS) analysis. The 77 fish feed samples analyzed with this method appeared to be free of pyrethroid pesticide residues. Organochlorine pesticide residues aldrin (0.03 ± 0.01 mg/kg) and pyrethroid pesticide residues permethrin (0.08 ± 0.01 mg/kg) were detected in fish samples of catla ( Catla catla ) from Rajshahi Durgapur and bata ( Labeo bata ) from Satkhira Kaligonj, respectively. Among 135 vegetable samples (country bean, green chili, tomato, eggplants and red amaranth), 27.4% were found positive for organophosphate pesticide residues of which 89.2% exceeded maximum residue limits (MRLs) set by the Codex Alimentarius Commission. The study revealed that few fish (catla and bata) but the majority of vegetable samples tested positive for pesticide residues exceeding MRLs. Finally, the study suggests that an effective management strategy is needed for strict regulation and regular monitoring of pesticides in fish feed, fish and vegetables to make aware the farmers and consumers about the harmful effect of pesticides on human health.

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In this study, zinc oxide (ZnO) nanoparticle was synthesized by a novel route of microwave assisted method using ascorbic acid and PVA as capping agent and stabilizing agent. A prominent peak at 378 nm by UV absorption ensured the synthesis of ZnO nanoparticles. The crystalline property revealed that synthesized ZnO nanoparticle is highly crystalline having wurtzite structure. A significant band at ~ 498 to 557 cm −1 in FTIR was assigned to the characteristic stretching mode of Zn-O bond. EDX spectrum showed that ZnO nano particles were composed only with Zinc and oxygen. SEM image disclosed that ZnO nanoparticles were spherical in shape with an average particle size of 70-90 nm for the combined effect. The antimicrobial and ant-biofilm application of synthesized ZnO nanoparticle was studied against Salmonella typhi, Klebsiella spp. SK4, E. coli RN89, E. coli (gram-negative) and S. aureus-8a (gram-positive) bacteria and exhibited excellent activity against the strains. Prepared nanoparticle also found to possess outstanding photocatalytic activity against methylene blue degradation under sunlight with a T 50 and T 80 value of 71.44 and 165.87 min respectively.

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