Childhood exposure to pyrethroids and neurodevelopment in Canadian preschoolers

Current-use pesticide exposures in remote Inuit communities

The global use of pesticides is increasing; however, few studies have examined the exposure of current-use pesticide exposure in Inuit populations. Some current use pesticides are also capable of long-range transport, potentially increasing exposures to northern populations. The study aim was to analyse pesticide (chlorophenoxy, organophosphates, and pyrethroid pesticide) biomarker levels in pooled samples from an Inuit population in Nunavik, Quebec. Thirty pooled samples from the Qanuilirpitaa? 2017 survey (Q2017) from individuals aged 16-80 years were included. Creatinine-adjusted arithmetic (AM) were compared by sex, age, and region sub-groups, and geometric mean concentrations (GM) were compared to those in the Canadian Health Measures Survey (CHMS). Most analysed pesticide biomarkers were detected, and PNP (a metabolite of methyl and ethyl parathion), trans-DCCA (a metabolite of pyrethroids), and 3,5,6-TCP (a metabolite of chlorpyrifos) had the highest concentrations. Concentrations in Q2017 were largely similar to or less than CHMS concentrations. Although not significant, there was a general increase in 2,4-D (a chlorophenoxy biomarker), 3,5,6-TCP, 3-PBA (a metabolite of pyrethroids), and trans-DCCA with increasing age. Concentrations were also somewhat higher in females versus males, but these were not significant. Environmental exposures to current use pesticides were detected in Nunavik and concentrations were similar to or less than those in the general Canadian population. Regular monitoring of current use pesticide exposures is recommended given the increasing global use of pesticides.

Common consumer residual insecticides lack efficacy against insecticide-susceptible and resistant populations of the German cockroach (Blattodea: Ectobiidae)

The German cockroach, Blattella germanica (L.) (Blattodea: Ectobiidae), is a ubiquitous pest in affordable housing. They represent a major threat to human health due to their contribution of asthma-exacerbating allergens and the potential to transfer pathogenic microorganisms indoors. Despite well-documented pyrethroid resistance, pyrethroid-based broadcast residual insecticide products are often used by residents to control cockroaches in their homes. Additionally, there is little empirical independent testing of these products. Thus, it remains unclear how effective these commonly used do-it-yourself products are at controlling German cockroaches. This study represents a comprehensive examination of the efficacy of these products with direct, limited, and continuous exposure assays on a variety of common household surfaces on field populations of cockroaches with varying levels of pyrethroid resistance. While most products performed well when applied directly to test insects, mortality was substantially lower across all surfaces with limited exposure (30 min). In continuous exposure assays on a nonporous surface, products took at least 24 hr to cause 100% mortality in a field population, with some products taking up to 5 d to achieve 100% mortality. The findings of this study demonstrate a lack of residual efficacy from common pyrethroid-based consumer-use pesticides products. Given that it is not feasible to find and treat every cockroach in a home directly, the residuality of spray-based formulations is critical for products designed to control German cockroaches. Without residual efficacy, as shown in the consumer aerosol and spray products tested, we expect these products to add little to no value to cockroach control.

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.