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The zebrafish embryo is an important model in ecotoxicology but the spatial distribution of chemicals and the relation to observed effects is not well understood. Quantitative imaging can help to gain insights into the distribution of chemicals in the zebrafish embryo. Laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) is used to quantify the uptake and the uptake kinetics of the bromine (Br) containing organophosphate naled (Dibrom®, dimethyl-1,2-dibromo-2,2-dichloroethylphosphate) and its distribution in zebrafish embryos using Br as the marker element. During exposure, the Br amounts increase in the embryos parallel to the irreversible inhibition of the acetylcholinesterase (AChE). The final amount of Br in the embryo (545 pmol/embryo) corresponds to a 280-fold enrichment of naled from the exposure solution. However, LC-MS/MS analyses showed that the internal concentration of naled remained below the LOD (7.8 fmol/embryo); also the concentration of its known transformation product dichlorvos remained low (0.85 to 2.8 pmol/embryo). These findings indicate the high reactivity and high transformation rate of naled to other products than dichlorvos. 12 C normalized intensity distributions of Br in the zebrafish embryo showed an enrichment of Br in its head region. Kernel density estimates of the LA-ICP-MS data were calculated and outline the high reproducibility between replicated and the shift in the Br distribution during exposure. The Br enrichment indicates a preferential debromination or direct covalent reaction of naled with AChE in this region. Graphical abstract ᅟ.

Background: Organophosphate insecticides (OPs) are used worldwide, yet despite nearly ubiquitous exposure in the general population, few have been studied outside the laboratory. Fetal brains undergo rapid growth and development, leaving them susceptible to long-term effects of neurotoxic OPs. The objective here was to investigate the extent to which prenatal exposure to OPs affects infant motor development., Methods: 30 OPs were measured in umbilical cord blood using gas chromatography tandem mass spectrometry in a cohort of Chinese infants. Motor function was assessed at 6-weeks and 9-months using Peabody Developmental Motor Scales 2nd edition (PDMS-2) (n=199). Outcomes included subtest scores: reflexes, stationary, locomotion, grasping, visual-motor integration (V-M), composite scores: gross (GM), fine (FM), total motor (TM), and standardized motor quotients: gross (GMQ), fine (FMQ), total motor (TMQ)., Results: Naled, methamidophos, trichlorfon, chlorpyrifos, and phorate were detected in ≥10% of samples. Prenatal naled and chlorpyrifos were associated with decreased 9-month motor function. Scores were 0.55, 0.85, and 0.90 points lower per 1ng/mL increase in log-naled, for V-M (p=0.04), FM (p=0.04), and FMQ (p=0.08), respectively. For chlorpyrifos, scores were 0.50, 1.98, 0.80, 1.91, 3.49, 2.71, 6.29, 2.56, 2.04, and 2.59 points lower for exposed versus unexposed infants, for reflexes (p=0.04), locomotion (p=0.02), grasping (p=0.05), V-M (p<0.001), GM (p=0.007), FM (p=0.002), TM (p<0.001), GMQ (p=0.01), FMQ (p=0.07), and TMQ (p=0.008), respectively. Girls appeared to be more sensitive to the negative effects of OPs on 9-month motor function than boys., Conclusions: We found deficits in 9-month motor function in infants with prenatal exposure to naled and chlorpyrifos. Naled is being aerially sprayed to combat mosquitoes carrying Zika virus, yet this is the first non-occupational human study of its health effects. Delays in early-motor skill acquisition may be detrimental for downstream development and cognition., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Three Florida native larval butterflies (Junonia coenia, Anartia jatrophae, Eumaeus atala) were used in the present study to determine the acute toxicity, hazard, and risk of a 24h ingestion of leaves contaminated with the adult mosquito control insecticides permethrin, naled, and dichlorvos to late 4th and early 5th in-star caterpillars. Based on 24-h LD50s for ingestion, naled was more acutely toxic than permethrin and dichlorvos to caterpillars. Hazard quotients using the ratio of the highest doses and the 90th percentile doses from field measurements in host plant foliage following actual mosquito control applications to the toxicological benchmarks from laboratory toxicity tests indicate potential high acute hazard for naled compared to permethrin and dichlorvos. Based on probabilistic ecological risk methods, naled exposure doses in the environment also presented a higher acute risk to caterpillars than permethrin and dichlorvos. The acute toxicity laboratory results and ecological risk assessment are based only on dietary ingestion and single chemical doses. It does not include other typical exposure scenarios that may occur in the environment. It is thus plausible to state that the ecological risk assessment presented here underestimates the potential risks in the field to caterpillars. However, one assumption that is scientifically feasible and certainly real from the results - if the environmental exposure doses of mosquito control operations are similar or higher to those presented here in leaves from the field, after applications, there will likely be significant mortalities and other adverse effects on caterpillar populations., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Pesticides are applied seasonally in the Florida Keys to control nuisance populations of mosquitoes that pose a health threat to humans. There is, however, a need to investigate the effects of these pesticides on non-target marine organisms. We tested naled and permethrin, two mosquito adulticides used in the Keys, on a critical early life-history stage of queen conch (Strombus gigas). We conducted 12-h exposure experiments on competent (i.e., capable of undergoing metamorphosis) queen conch larvae using environmentally relevant pesticide concentrations. We found that there was little to no mortality and that the pesticides did not induce or interfere with metamorphosis. However, after introduction of a natural metamorphic cue (extract of the red alga Laurencia potei), a significantly greater proportion of larvae underwent metamorphosis in the pesticide treatments than in those with the alga alone. In addition to the morphogenetic pathway that induces metamorphosis when stimulated, there thus appears to be a regulatory pathway that enhances the response to metamorphic triggers, as suggested by the increased sensitivity of the queen conch larvae to the algal cue after pesticide exposure (i.e., the pesticides stimulated the regulatory pathway). The regulatory pathway probably plays a role in the identification of high-quality habitat for metamorphosis, as the increased response to the algal cue suggests. Aerial drift and runoff can carry these pesticides into nearshore waters, where they may act as a false signal of favorable conditions and facilitate metamorphosis in suboptimal habitat, thus adversely affecting recruitment in nearshore queen conch populations.

This project was undertaken as the initial monitoring program to determine if mosquito adulticides applied along the Florida Keys cause adverse ecological effects in the Florida Keys National Marine Sanctuary (FKNMS). The study monitored the distribution and persistence of two mosquito adulticides, permethrin and dibrom (naled), during three separate routine applications by the Florida Keys Mosquito Control District. The approach was to determine if toxic concentrations of the pesticides entered the FKNMS by aerial drift or tidal transport. The amount of pesticide entering the FKNMS by way of aerial drift was monitored by collection on glass fiber filter pads, set on floats in a grid pattern on either side of the FKNMS. Permethrin was recovered from filter pads on the leeward side for each of the three applications, ranging from 0.5 to 50.1 microg/m(2) throughout the study. Tidal current transport was monitored by collection of surface and subsurface water samples at each grid site. Tidal transport of naled and dichlorvos (naled degradation product) was apparent in the adjacent waters of the FKNMS. These compounds were detected in subsurface, offshore water at 0.1 to 0.6 microg/1, 14 hr after application. Permethrin was not detected in offshore water samples; however, concentrations ranging from 5.1 to 9.4 microg/l were found in surface water from the canal system adjacent to the application route. Comparison of the observed environmental concentrations with toxicity data (permethrin LC-50, 96 hr for Mysidopsis bahia = 0.02 microg/l) indicated a potential hazard to marine invertebrates in the canals with possible tidal transport to other areas.