Thiamethoxam affects the developmental stages of banded gourami (Trichogaster fasciata).

Thiamethoxam (THM), a type III systemic neonicotinoid insecticide, is widely used in agriculture in many countries, including Bangladesh. THM can enter the aquatic systems through the runoff, spray-drift and groundwater leaching and can affect the aquatic organisms, including fish. Current environmental levels of THM in Bangladesh waters are variable. However, the presence of this chemical in the aquatic environment and its possible effects on the fish inhabiting those water bodies is concerning. To understand the effects of environmental THM on the development of embryo and larvae, the present study used banded gourami (Trichogaster fasciata), a freshwater fish species distributed in different Asian countries, including Bangladesh. In laboratory setting, fertilized eggs (n = 100) and one-day-old banded gourami larvae (n = 100) were exposed to six concentrations of THM (0, 0.02, 0.2, 2, 20, 200 mg/L) in three replicates, in which three concentrations were within the environmentally relevant levels. Hatching rate, incubation period, mortality, and malformations of embryo and larvae were observed. The hatching success and survival of embryo and larvae significantly decreased with increasing THM concentrations. The 24-h LC50 of THM for the embryo was 4.24 mg/L. The 24-h, 48-h, 72-h, and 96-h LC50 values of THM for one-day-old larvae were 12.20, 3.80, 0.78, and 0.27 mg/L, respectively. Overall developmental malformations included lordosis, notochord abnormality, yolk-sac edema, dark brown yolk sac, hemorrhage, and irregular caudal fin. These abnormalities in embryos were common across all the concentrations of THM applied. The results of the present study suggest that environmentally relevant concentrations of THM can induce developmental defects in the embryo and larvae of banded gourami.

Probabilistic public health risks associated with pesticides and heavy metal exposure through consumption of common dried fish in coastal regions of Bangladesh.

The chemical contaminants in dried fish are of great food safety concern and an emerging public health issue in Bangladesh. The aim of this study was to assess the public health risk associated with exposure to pesticides (organochlorine and organophosphorus) and heavy metals (lead, mercury, cadmium, chromium, arsenic) through the consumption of dried fish (Bombay duck, ribbon fish, silver jewfish, shrimp, Chinese promfret) in coastal districts (Cox's Bazar, Chittagong, Bhola, Patuakhali, Khulna) of Bangladesh. Dried fish consumption data were collected from 500 adult respondents (100 from each district) using a food frequency questionnaire (FFQ). Pesticide residues were determined using QuEChERS extraction coupled to gas chromatography and gas chromatography mass spectrometry, and heavy metals were estimated using an atomic absorption spectrophotometric method. The results revealed that the frequency and amount of dried fish consumption was highest for Bombay duck in Cox's Bazar (11.57 g/capita/day) and ribbon fish (12.10 g/capita/day) in Chittagong. The estimated daily intake (EDI, 7.40 × 10-5 to 1.10 × 10-4 mg/kg/day) and health risk index (HRI, 0.013 to 0.16) values expressed no health risk from pesticide residues in all the positive samples. For heavy metals, target hazard quotients (THQ) for non-carcinogenic health risk were below 1 (0.001-0.154), indicating no health risk for all samples. However, carcinogenic risk R value indicated a potential health risk for chromium (2.64 × 10-6 to 4.06 × 10-6), and carcinogenic RT value (2.82 × 10-6 to 5.71 × 10-6) indicated a potential health risk for all the metals. It is concluded that the risk of exposure to pesticides through the consumption of dried fish is low, while heavy metals pose moderate-to-high health risks to dried fish consumers in the study area. Thus, the study suggests an appropriate risk management policy that controls pesticides and heavy metals in dried fish to ensure safe food for local and global consumers, underpinned by a producers' capacity building and consumers' awareness raising strategy.

Determination of organophosphorus and synthetic pyrethroid pesticide residues and their variability in large size fruit crops.

BACKGROUND: Variability of pesticide residues in food item plays a key role for the evaluation of consumer food safety. However, variability factors (VFs) derived from the large size fruit crops are still scarce. Therefore, the present work was aimed to quantify pesticide residues and to estimate VFs in large size fruit crops of mango and guava. RESULTS: A total of 140 mango and 130 guava samples from different marketplaces in Bangladesh were collected to estimate the variability of pesticide residues (acephate, diazinon, malathion, fenitrothion, chlorpyrifos, quinalphos, dimethoate and cypermethrin) by in-house validated methods based on modified QuEChERS extraction and gas chromatography coupled with electron capture detector (ECD) and flame thermionic detector (FTD). The method was validated at three fortification levels (0.01, 0.10 and 0.30 mg kg-1 ) and satisfactory recoveries (80-111%) with relative standard deviation (RSDr ) ≤ 13% were achieved. A wide variation of residues was found in the analyzed samples. In the case of mango, the ranges of residues were 0.011-0.314, 0.015-0.04, and 0.05-0.291 mg kg-1 , respectively, for cypermethrin, chlorpyrifos, and dimethoate, while in the case of guava, the ranges were 0.04-0.113, and 0.03-0.290 mg kg-1 , respectively, for cypermethrin and acephate. The average VF for mango was 4.06 and it was 5.70 for guava. CONCLUSION: VFs originating from the marketed samples of mango and guava are reported in this study for the first time. The estimated VFs were higher than the default value of 3, therefore, the default VFs should be reconsidered when more data are obtained regarding large size crops. © 2021 Society of Chemical Industry.

Variability of pesticide residues in eggplant units collected from a field trial and marketplaces in Greece.

BACKGROUND: Variability of pesticide residues among food items is very important when assessing the risks and food safety for the consumers. Therefore, the present study was undertaken to estimate the unit-to-unit residue variability factors for eggplant. RESULTS: In total, 120 samples from a trial field and 142 samples from different marketplaces in Thessaloniki, Greece, were collected to estimate the variability of pesticide residues in eggplant units. They were extracted by the QuEChERS method and the residues were determined by LC-MS/MS. For the field samples, the unit-to-unit variability factors (VFs) obtained for cypermethrin and deltamethrin residues were 2.54 and 2.51, respectively. The mean residue levels of both pesticides were higher in the composite samples than in the individual samples. The average VFs for the marketplace samples was 3.89. The eggplant units exposed to pesticides were higher in residues than the non-exposed units. CONCLUSION: The variability factors obtained in the marketplace samples were higher than those in the samples collected from the field trial. A default VF value of 3 for field trials is appropriate for use when assessing the acute dietary intake but a VF for the marketplace samples should be reconsidered with a larger data. © 2017 Society of Chemical Industry.