Online solid phase extraction high-performance liquid chromatography - Isotope dilution - Tandem mass spectrometry quantification of organophosphate pesticides, synthetic pyrethroids, and selected herbicide metabolites in human urine

Evaluation of gestational nonpersistent pesticide exposure with newborn size and gestational length in rural Ghana using a novel time-varying extension of multiple informant models

BACKGROUND

Gestational pesticide exposure may negatively affect newborn outcomes. Prior results evaluating nonpersistent pesticides are inconsistent.

OBJECTIVE

To examine associations between gestational exposure to nonpersistent pesticides and newborn outcomes and identify critical windows of susceptibility.

STUDY DESIGN

In a Ghanaian pregnancy cohort, we measured select biomarkers of organophosphate, pyrethroid, and herbicide pesticides in repeated urine samples (1-5/participant). We developed a new model for assessing critical windows of vulnerability from irregularly-timed measurements of nonpersistent pesticides, leveraging strengths from multiple informant and distributed lag models. We estimated associations of biomarker concentrations with newborn anthropometrics and gestational length, adjusting for confounders and exploring effect modification by infant sex and placental malaria.

RESULTS

1,211 pregnant women contributed 3,786 gestational urinary samples. In models assuming constant associations with exposures across pregnancy, in a given week a doubling of 3-phenoxybenzoic acid (pyrethroid biomarker) was associated with a -15.8 g difference in birth weight (95 % CI:-28.1,-3.6), and a doubling of the 2,4-dichlorophenoxyacetic acid (2,4-D, herbicide biomarker) was associated with an 11.1 g increase in birth weight (95 % CI:1.0,21.1). In time-varying models, significant associations were identified for pyrethroid exposure measured between weeks 16-27, and for 2,4-D exposure measured during weeks 25-33. Organophosphates were not associated with birth weight. No associations were found for birth length or head circumference for any pesticide. In constant association models, a doubling of weekly 2,4-D was associated with a 0.05 week increase in gestational length (95 %CI:0.01,0.09); no associations were found with other biomarkers.

CONCLUSIONS

We identified associations between gestational exposure to nonpersistent pesticides and both birth size and gestational length. Extending multiple informant models to account for the complex data structure allowed us to discern effects in opposing directions by distinct pesticide classes. While estimated effects for a given week were modest, prolonged or repeated exposures could result in larger cumulative impacts.

Method optimization for a simultaneous determination of neonicotinoid, carbamate/thiocarbamate, triazole, organophosphate and pyrethroid pesticides and their metabolites in urine using UPLC-MS/MS

An accurate and sensitive method for the determination of a total of 23 pesticides and their metabolites in human urine has been optimised. The methodology is based on a previously published method based on solid-phase extraction with methanol and acetone followed by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) in the selected reaction mode (SRM) with both positive and negative electrospray ionization (ESI+/-). The detection settings of the previous method, which allowed to determine the metabolites from 6 organophosphate and 2 pyrethroid pesticides, were optimised in order to include further pesticide groups, such as 11 neonicotinoids, 3 carbamates/thiocarbamates and 2 triazoles. The 5-windows method enduring 22 min was optimized with acceptable results in relation to accuracy (recoveries >75 %), precision (coefficients of variation <26 %) and linearity (R2> 0.9915). The limits of detection ranged between 0.012 ng/mL and 0.058 ng/mL. Samples from the German External Quality Assessment Scheme (G-EQUAS) encompassing 2 pyrethroids, 2 organophosphate and one neonicotinoid (6-chloronicotinic acid, a common metabolite of imidacloprid and acetamiprid) were analysed, and the latter, included in this newest optimization, provided good reference results. The method is optimal as a human biomonitoring tool for health risk assessment in large population surveys.

Occurrence, distribution, and health risk assessment of pyrethroid and neonicotinoid insecticides in aquatic products of China

Synthetic pyrethroid insecticides (SPIs) and neonicotinoid insecticides (NEOs), now dominant in the insecticide market, are increasingly found in aquatic environments. This study focused on six SPIs and five NEOs in aquatic products from four Chinese provinces (Shandong, Hubei, Shanxi and Zhejiang) and the risk assessment of the safety for the residents was conducted. It revealed significantly higher residues of Σ6SPIs (6.27-117.19 μg/kg) compared to Σ5NEOs (0.30-14.05 μg/kg), with SPIs more prevalent in fish and NEOs in shellfish. Carnivorous fish showed higher pesticide levels. Residues of these two types of pesticides were higher in carnivorous fish than in fish with other feeding habits. In the four regions investigated, the hazard quotient and hazard index of SPIs and NEOs were all <1, indicating no immediate health risk to human from single and compound contamination of the two types of pesticides in aquatic products. The present study provides valuable information for aquaculture management, pollution control and safeguarding human health.