Importance of pesticides for lethal poisoning in India during 1999 to 2018: a systematic review

Toxicity and biokinetics following pulmonary exposure to aluminium (aluminum): A review

During the manufacture and use of aluminium (aluminum), inhalation exposure may occur. We reviewed the pulmonary toxicity of this metal including its toxicokinetics. The normal serum/plasma level based on 17 studies was 5.7 ± 7.7 µg Al/L (mean ± SD). The normal urine level based on 15 studies was 7.7 ± 5.3 µg/L. Bodily fluid and tissue levels during occupational exposure are also provided, and the urine level was increased in aluminium welders (43 ± 33 µg/L) based on 7 studies. Some studies demonstrated that aluminium from occupational exposure can remain in the body for years. Excretion pathways include urine and faeces. Toxicity studies were mostly on aluminium flakes, aluminium oxide and aluminium chlorohydrate as well as on mixed exposure, e.g. in aluminium smelters. Endpoints affected by pulmonary aluminium exposure include body weight, lung function, lung fibrosis, pulmonary inflammation and neurotoxicity. In men exposed to aluminium oxide particles (3.2 µm) for two hours, lowest observed adverse effect concentration (LOAEC) was 4 mg Al2O3/m3 (= 2.1 mg Al/m3), based on increased neutrophils in sputum. With the note that a similar but not statistically significant increase was seen during control exposure. In animal studies LOAECs start at 0.3 mg Al/m3. In intratracheal instillation studies, all done with aluminium oxide and mainly nanomaterials, lowest observed adverse effect levels (LOAELs) started at 1.3 mg Al/kg body weight (bw) (except one study with a LOAEL of ∼0.1 mg Al/kg bw). The collected data provide information regarding hazard identification and characterisation of pulmonary exposure to aluminium.

Development and Design of a Pediatric Case-Based Virtual Escape Room on Organophosphate Toxicity

Audience

This case-based virtual escape room (VER) serves as a didactic activity suitable for learners who require an understanding of organophosphate toxicity. Educators may use this VER for distance-based learning in settings with adequate internet access.

Introduction

India faces a concerning escalation in suicide rates, particularly among teenagers and young adults, often involving intentional pesticide ingestion, notably organophosphates.1-3 Our project addresses organophosphate ingestion by using a VER, a virtual learning platform adapted from in-person escape rooms to engage participants for educational purposes.4,5 Demonstrating success in medical, pharmacy, and nursing education, VERs increased satisfaction and competency among healthcare trainees compared to traditional learning platforms while fostering teamwork and communication in a virtual learning environment.6,7.

Educational Objectives

By the end of the activity, learners should be able to: 1) recognize risk factors, symptoms, and presentation for organophosphate poisoning; 2) understand the radiologic and laboratory findings in organophosphate poisoning; 3) distinguish and differentiate electrocardiogram findings in common toxic ingestions; 4) explain the pathophysiology of organophosphate poisoning; 5) understand the importance of decontamination of the patient and personal protective equipment for staff for organophosphate poisoning; 6) describe the airway management of organophosphate poisoning; 7) describe the medical management of organophosphate poisoning, including antidotes and the correct dosing and 8) demonstrate teamwork through communication and collaboration.

Educational Methods

The development process involved a seven-step approach, beginning with topic selection. The process involved creating a scenario, defining learning objectives, and designing an appropriate room. Clues and puzzles were tailored to align with the learning objectives and promote interactivity. The VER was hosted on Google Sites (Google LLC), accompanied by a facilitator guide offering content and technical support.

Research Methods

This VER leverages technology for distance learning, using Zoom (Zoom Video Communications Inc.) for online sessions with EM trainees. Participants were organized into small groups in breakout rooms on Zoom, following a structured format that included a pre-briefing, a timed escape room scenario, debriefing, and evaluation. Afterward, an evaluation in the format of a survey was distributed to participants. This study was Institutional Review Board exempt.

Results

Out of 120 participants in the VER, 50% responded to a survey. The majority found the activity interactive, engaging, and exciting. This feedback indicated a positive reaction to the VER, consistent with the Kirkpatrick model's first level of assessment.8 The VER effectively promoted learning and reinforced clinical knowledge, contributing to the second level of the Kirkpatrick model. In this case, 84.7% of respondents were able to identify knowledge gaps, and 84.2% of respondents found this to be a feasible model to reinforce medical knowledge.

Discussion

This innovative VER addresses the value of distance-based learning in any setting with an internet connection. It has successfully enhanced collaboration and communication among participants in small groups, making it a valuable resource for medical education. This study has several limitations worth noting including a relatively low survey response rate. Baseline data was not collected prior to the VER. Additionally, the VER was not designed to be an open-book assessment; however, the absence of an in-person moderator makes it challenging to ascertain whether participants used external resources. Furthermore, the exclusive focus of this VER on a single topic may diminish its overall use compared to more traditional didactic sessions. This study is also limited by lack of long-term outcome data. Future studies could further assess knowledge improvement and clinical application. The authors plan to develop additional case-based VERs to advance EM trainees' knowledge, skills, and communication. Overall, the VER offers a promising and free educational tool for distance learning with potential benefits for various settings with internet access.

Topics

Escape room, gamification, global health, organophosphate poisoning, simulation, virtual escape rooms.

Self-inflicted ingestion of harmful chemicals in adolescents and adults: risk factors and characteristics

BACKGROUND

Injury due to ingestion of harmful chemicals has become an area of concern globally. In South Africa, paraffin has been widely implicated in multiple health outcomes, including severe ingestion injuries. A specific category of such injuries is those that are self-inflicted. A significant proportion of self-inflicted ingestion is reported to be intentional, although intentionality for self-infliction may be difficult to determine. Nonetheless, the identification of key explanatory risks and demographic factors of self-inflicted ingestion may contribute towards a better understanding of self-inflicted and harmful chemical ingestion injuries.

METHODS

This study used secondary data that had been collected on burn injuries of all causes, including those due to the ingestion of harmful chemicals, from a sample of South Africans from low-income communities close to major metropolitan centres. The current analysis focused on the risks for self-inflicted ingestion injuries and used logistic regression to determine risks for self-inflicted ingestion as differentiated from ingestion due to the actions of another person (other-inflicted ingestion) by sex and age cohort of the victim, and the presence of alcohol, by examining paraffin ingestion versus that of other chemicals.

RESULTS

The overwhelming majority of ingestion injuries (92.1%) were self-inflicted. The current findings indicate that sex (with females almost twice as likely to present with self-inflicted ingestion), age cohort (with those aged 18-29 and 30-44 years old four times more likely affected than older adults), presence of alcohol (twice as likely present than amongst individuals reporting ingestion injuries inflicted by others), and chemicals other than paraffin (three times more likely) are key explanatory factors for an increased risk for self-inflicted ingestion of harmful chemicals.

CONCLUSIONS

The study empirically confirms the role of several key risk factors in what remains a relatively unreported and understudied phenomenon, but which appears to align with the demographic and risk profile reported for suicidal injuries through chemical ingestion, i.e. intentional self-inflicted ingestion. The findings may contribute towards improved safety policies on the availability and sale of chemical products and more focussed community interventions for at-risk individuals such as females and young people. It also flags the importance of assessing for alcohol use and alcohol use disorders at hospital admission of self-ingestion injuries.

Accidental Organophosphate Poisoning in a Toddler: A Case Report

While accidental poisoning is fairly common in children, the data are sparse when organophosphate (OP) is considered the culprit toxin. Only case reports of such patients from the Southeast Asian Region have been documented, despite it contributing largely to the global burden of organophosphorus poisoning in the adult population. This can be attributed to difficulty in diagnosing children because of varied presentations in the pediatric population and unreliable or unavailable exposure history. We present a case of a 19-month-old toddler who presented to the ED with OP poisoning, which proved to be a diagnostic and management challenge because of more common differentials and the unavailability of a clear history.

Determinants of Poison-related Mortality in Tertiary Care Hospital, South India

Aims and background

Acute poisoning is one of the most common emergencies in India and around the world. Understanding the factors associated with mortality can aid us in devising appropriate preventive strategies to curtail deaths due to poisoning. Purpose of this study is to find various factors that determine the mortality among acute poisoning cases admitted in a tertiary care center.

Materials and methods

A retrospective hospital records-based study was conducted at Chengalpattu Medical College Hospital. The study included 2,123 cases of various poisoning cases admitted for a year from January to December 2022. Cases of bites, stings, drowning, and hanging were excluded. Information on sociodemographic profile, type of poison, time since ingestion and admission, and treatment outcome were collected using a structured pro forma.

Results

The mean age of the study population was 29.90 ± 14.98 years. Poisoning was found to be predominantly among males (56.42%) and residents of rural areas (58%). Insecticide consumption (27.0%) was the most common modality, followed by oleander poisoning (20%), corrosive poison (17%), rat poison (15%), tablet poison (13%), and other poisons. The overall case fatality rate (CFR) was 5.2%, with the highest CFR of 12.25% with insecticide poisoning. In multivariate analysis, Glasgow coma scale (GCS) score at admission is the only parameter showing a statistically significant association with mortality (adjusted odds-ratio 0.271(0.2-0.38, p-value < 0.01).

Conclusion

Acute poisoning primarily affects the young and economically productive population. In the south Indian population, pesticides are still the major contributor though corrosives are a major contributor among children. Mortality is still significant, and GCS status admission is the only predictor of mortality.

How to cite this article

Krishnasamy N, Narmadhalakshmi R, Parameshwari P, Jayalakshmi R, Lokesh R, Jayanthi R, et al. Determinants of Poison-related Mortality in Tertiary Care Hospital, South India. Indian J Crit Care Med 2024;28(4):329-335.

Chronic Epilepsy and Mossy Fiber Sprouting Following Organophosphate-Induced Status Epilepticus in Rats

Organophosphate (OP) compounds are highly toxic and include pesticides and chemical warfare nerve agents. OP exposure inhibits the acetylcholinesterase enzyme, causing cholinergic overstimulation that can evolve into status epilepticus (SE) and produce lethality. Furthermore, OP-induced SE survival is associated with mood and memory dysfunction and spontaneous recurrent seizures (SRS). In male Sprague-Dawley rats, we assessed hippocampal pathology and chronic SRS following SE induced by administration of OP agents paraoxon (2 mg/kg, s.c.), diisopropyl fluorophosphate (4 mg/kg, s.c.), or O-isopropyl methylphosphonofluoridate (GB; sarin) (2 mg/kg, s.c.), immediately followed by atropine and 2-PAM. At 1-hour post-OP-induced SE onset, midazolam was administered to control SE. Approximately 6 months after OP-induced SE, SRS were evaluated using video and electroencephalography monitoring. Histopathology was conducted using hematoxylin and eosin (H&E), while silver sulfide (Timm) staining was used to assess mossy fiber sprouting (MFS). Across all the OP agents, over 60% of rats that survived OP-induced SE developed chronic SRS. H&E staining revealed a significant hippocampal neuronal loss, while Timm staining revealed extensive MFS within the inner molecular region of the dentate gyrus. This study demonstrates that OP-induced SE is associated with hippocampal neuronal loss, extensive MFS, and the development of SRS, all hallmarks of chronic epilepsy. SIGNIFICANCE STATEMENT: Models of organophosphate (OP)-induced SE offer a unique resource to identify molecular mechanisms contributing to neuropathology and the development of chronic OP morbidities. These models could allow the screening of targeted therapeutics for efficacious treatment strategies for OP toxicities.

Aiming for a Better Tomorrow

How to cite this article: Kharbanda M. Aiming for a Better Tomorrow. Indian J Crit Care Med 2024;28(1):11-12.

Recent Advances in the Detection of Food Toxins Using Mass Spectrometry

Edibles are the only source of nutrients and energy for humans. However, ingredients of edibles have undergone many physicochemical changes during preparation and storage. Aging, hydrolysis, oxidation, and rancidity are some of the major changes that not only change the native flavor, texture, and taste of food but also destroy the nutritive value and jeopardize public health. The major reasons for the production of harmful metabolites, chemicals, and toxins are poor processing, inappropriate storage, and microbial spoilage, which are lethal to consumers. In addition, the emergence of new pollutants has intensified the need for advanced and rapid food analysis techniques to detect such toxins. The issue with the detection of toxins in food samples is the nonvolatile nature and absence of detectable chromophores; hence, normal conventional techniques need additional derivatization. Mass spectrometry (MS) offers high sensitivity, selectivity, and capability to handle complex mixtures, making it an ideal analytical technique for the identification and quantification of food toxins. Recent technological advancements, such as high-resolution MS and tandem mass spectrometry (MS/MS), have significantly improved sensitivity, enabling the detection of food toxins at ultralow levels. Moreover, the emergence of ambient ionization techniques has facilitated rapid in situ analysis of samples with lower time and resources. Despite numerous advantages, the widespread adoption of MS in routine food safety monitoring faces certain challenges such as instrument cost, complexity, data analysis, and standardization of methods. Nevertheless, the continuous advancements in MS-technology and its integration with complementary techniques hold promising prospects for revolutionizing food safety monitoring. This review discusses the application of MS in detecting various food toxins including mycotoxins, marine biotoxins, and plant-derived toxins. It also explores the implementation of untargeted approaches, such as metabolomics and proteomics, for the discovery of novel and emerging food toxins, enhancing our understanding of potential hazards in the food supply chain.

DNA Methylation Profiling of Ovarian Tissue of Climbing Perch (Anabas testudienus) in Response to Monocrotophos Exposure

Epigenetic modifications like DNA methylation can alter an organism's phenotype without changing its DNA sequence. Exposure to environmental toxicants has the potential to change the resilience of aquatic species. However, little information is available on the dynamics of DNA methylation in fish gonadal tissues in response to organophosphates. In the present work, reduced-representation bisulfite sequencing was performed to identify DNA methylation patterns in the ovarian tissues of Anabas testudienus exposed to organophosphates, specifically monocrotophos (MCP). Through sequencing, an average of 41,087 methylated cytosine sites were identified and distributed in different parts of genes, i.e., in transcription start sites (TSS), promoters, exons, etc. A total of 1058 and 1329 differentially methylated regions (DMRs) were detected as hyper-methylated and hypo-methylated in ovarian tissues, respectively. Utilizing whole-genome data of the climbing perch, the DMRs, and their associated overlapping genes revealed a total of 22 genes within exons, 45 genes at transcription start sites (TSS), and 218 genes in intergenic regions. Through gene ontology analysis, a total of 16 GO terms particularly involved in ovarian follicular development, response to oxidative stress, oocyte maturation, and multicellular organismal response to stress associated with reproductive biology were identified. After functional enrichment analysis, relevant DMGs such as steroid hormone biosynthesis (Cyp19a, 11-beta-HSD, 17-beta-HSD), hormone receptors (ar, esrrga), steroid metabolism (StAR), progesterone-mediated oocyte maturation (igf1ar, pgr), associated with ovarian development in climbing perch showed significant differential methylation patterns. The differentially methylated genes (DMGs) were subjected to analysis using real-time PCR, which demonstrated altered gene expression levels. This study revealed a molecular-level alteration in genes associated with ovarian development in response to chemical exposure. This work provides evidence for understanding the relationship between DNA methylation and gene regulation in response to chemicals that affect the reproductive fitness of aquatic animals.

Insulin-euglycemia therapy in acute aluminum phosphide poisoning: a randomized clinical trial

Introduction: Aluminum phosphide is a pesticide that is used in developing countries. Aluminum phosphide poisoning has a high mortality rate and there is no known antidote. This study aimed to evaluate the safety and efficacy of insulin-euglycemia therapy in the management of patients with acute aluminum phosphide poisoning.Methods: This trial was prospectively registered in the Pan African Clinical Trials Registry (PACTR202008534546951). A total of 108 patients were randomly allocated to two groups. The intervention group received insulin-euglycemia therapy in addition to standard treatment (norepinephrine and supportive care); the control group received standard treatment plus placebo. The main outcome measures were survival, blood pressure, and laboratory investigations.Results: The two groups had similar baseline parameters. Insulin-euglycemia therapy was associated with a significant reduction in mortality compared with that in the control group (64.8 percent and 96.3 percent, respectively; P value <0.001). Patients randomized to insulin-euglycemia also required lower doses of vasopressors (median was 7 mg versus 26 mg in control group; P value 0.006) and fewer patients needed intubation (61.1 percent versus 81.5 percent in the control group; P value 0.019). Insulin-euglycemia therapy significantly improved blood pressure (systolic, diastolic, and mean arterial pressure) (median at 6h post-admission was 80 mmHg, 55 mmHg and 65 mmHg compared with 20 mmHg, 10 mmHg and 13 mmHg in the control group respectively; P value <0.001) and bicarbonate and lactate concentrations.Conclusion: Insulin-euglycemia therapy appears to be a safe and effective treatment option for patients with aluminum phosphide poisoning. Vasopressor only therapy was associated with very poor outcomes in acute aluminum phosphide poisoning.

Associations between dietary pesticide residue mixture exposure and mortality in a population-based prospective cohort of men and women

BACKGROUND

There is a concern that pesticide residues, regularly detected in foods, might pose a health risk to the consumer, but epidemiological evidence is limited. We assessed the associations between dietary exposure to a mixture of pesticide residues and mortality.

METHODS

Food consumption was assessed in 68,844 participants from the Swedish Mammography Cohort and the Cohort of Swedish Men, 45-83 years at baseline (1997). Concentrations of pesticide residues detected in foods on the Swedish market (1996-1998), mainly fruits and vegetables, were obtained via monitoring programs. To assess mixture effects, we summed per food item the ratios of each single pesticide mean residue concentration divided by its acceptable daily intake to create for each participant a Dietary Pesticide Hazard Index (adjusted for energy intake and expressed per kilogram of body weight). Multivariable-adjusted Cox proportional hazards models were used to estimate hazard ratios (HR) and 95 % confidence intervals (95 %CI).

RESULTS

During 15 years of follow-up (1998-2014), a total of 16,527 deaths occurred, of which 6,238 were caused by cardiovascular disease (CVD) and 5,364 by cancer. Comparing extreme quintiles of Dietary Pesticide Hazard Index, the highest category was inversely associated with CVD mortality HR, 0.82 (95 % CI, 0.75-0.90) and with cancer mortality HR 0.82 (95 % CI 0.75-0.91). In analyses stratified by high/low Dietary Pesticide Hazard Index, similar inverse associations were observed by increasing fruit and vegetable consumption.

CONCLUSIONS

We observed no indications that dietary exposure to pesticide residue mixtures was associated with increased mortality, nor any clear indications that the benefits of fruit and vegetable consumption on mortality was compromised. Yet, our results need to be interpreted with caution.

Organophosphorus and carbamate pesticides: Molecular toxicology and laboratory testing

Population and food requirements are increasing daily throughout the world. To fulfil these requirements application of pesticides is also increasing. Organophosphorous (OP) and Organocarbamate (OC) compounds are widely used pesticides. These pesticides are used for suicidal purposes too. Both inhibit Acetylcholinesterase (AChE) and cholinergic symptoms are mainly used for the diagnosis of pesticide poisoning. Although the symptoms of the intoxication of OP and OC are similar, recent research has described different targets for OP and OC pesticides. Researchers believe the distinction of OP/OC poisoning will be beneficial for the management of pesticide exposure. OP compounds produce adducts with several proteins. There is a new generation of OP compounds like glyphosate that do not inhibit AChE. Therefore, it's high time to develop biomarkers that can distinguish OP poisoning from OC poisoning.

Bioaccumulation of pesticides in fish resulting toxicities in humans through food chain and forensic aspects

A crucial component for agricultural productivity is pesticide application. Increased usage of pesticides has significantly increased agricultural output, reduced grain losses in storage, and overall enhanced human wellbeing. Globally, every year approximately 3 billion kg of pesticides are used which budgets around 40 billion USD. Pesticide use can leave behind unwanted residues that can contaminate food, the environment, and living tissues. They are known to spread from agricultural regions that have been treated into the wider environment, where they affect non-target creatures. All tiers of biological organisms, directly impacted by this exposure. Pesticides at sub-lethal levels alter every aspect of a fish's physiology, including histology, haematology, defence mechanisms, and behaviour. The same topic of pesticide toxicology is the emphasis of this article, which also addresses some important induced chronic toxicological effects of pesticides in fish and the extent of their bioaccumulation in fish tissues. The data represents the largest bodies of water, such as rivers and lakes, that have been contaminated by pesticides, notably due to pesticide drift. It has been discussed how readily pesticides are absorbed into fish bodies and how this enters the food chain inducing harmful impacts on human health when consumed.

Protective Effect of Quercetin and Ginger (Zingiber officinale) Extract against Dimethoate Potentiated Fluoride-Induced Nephrotoxicity in Rats

This study aimed to determine the potential of quercetin and Zingiber officinale (ZO) Roscoe extract to alleviate the renal damage induced by dimethoate (DM) and fluoride (F^-) alone and by their combined exposure in rats. A total of 54 adult Wistar rats were randomly allocated to nine groups (n = 6). A sub-lethal dose of DM (1/10th of the median lethal dose) was administered by oral gavage alone and along with F^- (4.5 ppm, three-fold the permissible limit) in their drinking water continuously for 28 days. Chromatographical analysis revealed the presence of quercetin, curcumin, and other phytochemicals with strong antioxidant properties in ZO-rhizome extract. Severe changes were observed in the levels of the renal biomarkers and histoarchitecture after co-administration of the toxicants, indicating greater kidney damage. The administration of ZO extract (300 mg/kg) along with either or both toxicants led to a significant restoration of the biochemical markers and renal antioxidant profile and histology.

Suicides by pesticide ingestion in Pakistan and the impact of pesticide regulation

INTRODUCTION

Suicide is a major public health problem in Pakistan, accounting to approximately 19,331 deaths every year. Many are due to consumption of acutely toxic pesticides; however, there is a lack of national suicide data, limiting knowledge and potential for intervention. In this paper, we aimed to review the literature on pesticide self-poisoning in Pakistan to identify the most problematic pesticides in relation to national pesticide regulations.

METHODS

Information on the currently registered and banned pesticides was obtained from Ministry of National Food Security and Research while data on pesticide import and use was extracted from FAOSTAT. We searched the following sources for articles and research papers on poisoning in Pakistan: Cumulative Index to Nursing and Allied Health (CINAHL), Google Scholar, Applied Social Sciences Index and Abstracts (ASSIA), Excerpta Medica (EMBASE), National Library of Medicine's MEDLINE (PUBMED), PS102YCHINFO and Pakmedinet.com using the search terms 'self-poisoning', 'deliberate self-harm', 'suicide', 'methods and means of suicide', 'organophosphate', 'wheat pill', 'aluminium phosphide', 'acute poisoning', OR 'pesticides', AND 'Pakistan'.

RESULTS

As of May 2021, 382 pesticide active ingredients (substances) were registered in Pakistan, of which five were WHO hazard class Ia (extremely hazardous) and 17 WHO hazard class Ib (highly hazardous). Twenty-six pesticides, four formulations, and seven non-registered pesticides had been banned, of which two were WHO class Ia and five Ib. We identified 106 hospital-level studies of poisoning conducted in Pakistan, of which 23 did not mention self-poisoning cases and one reported no suicidal poisoning cases. We found no community or forensic medicine studies. Of 52,323 poisoning cases identified in these papers, 24,546 [47%] were due to pesticides. The most commonly identified pesticide classes were organophosphorus (OP) insecticides (13,816 cases, 56%) and the fumigant aluminium phosphide (3 g 56% tablets, often termed 'wheat pills'; 686 cases, 2.7%). Few studies identified the particular pesticides involved or the resulting case fatality.

CONCLUSION

We found pesticide poisoning to be a major cause of poisoning in Pakistan, with OP insecticides and the fumigant aluminium phosphide the main pesticides identified. Withdrawal of Class I pesticides (as proposed to occur nationally in 2022) and high concentration aluminium phosphide tablets should rapidly reduce suicidal deaths by reducing the case fatality for low-intention poisoning cases. National cause of death data and forensic toxicology laboratory data identifying the pesticides responsible for deaths will be important to assess impacts of the proposed national ban.

Lethal Neurotoxicity in Lambda-Cyhalothrin Poisoning: A Rare Case Report

ABSTRACT

Agricultural poisons (insecticides and pesticides) are the most common types of poison implicated in the morbidity and mortality associated with acute poisoning. Suicidal ingestion is more frequent than accidental or homicidal poisonings. Pyrethroids are considered relatively safer than other insecticides. Lambda-cyhalothrin (LCH) belongs to the fourth-generation, type II synthetic pyrethroid. To the best of our knowledge, fatalities after LCH exposure have not yet been reported in the literature. Here, we describe a case of LCH poisoning in a 54-year-old male farmer after an accidental pipe burst in a sprayer while spraying in the field. The patient died 10 days after poisoning due to severe neurotoxicity resulting in bilateral parieto-occipital and brainstem infarcts. The histopathological features of the brain associated with LCH poisoning have been discussed in this report.

Validity of Geolocation and Distance to Exposure Sources from Geographical Information Systems for Environmental Monitoring of Toxic Metal Exposures Based on Correlation with Biological Samples: a Systematic Review

PURPOSE OF REVIEW

In epidemiologic studies, biomarkers are the best possible choice to assess individual exposure to toxic metals since they integrate all exposure sources. However, measuring biomarkers is not always feasible, given potential budgetary and time constraints or limited availability of samples. Alternatively, approximations to individual metal exposure obtained from geographic information systems (GIS) have become popular to evaluate diverse metal-related health outcomes. Our objective was to conduct a systematic review of epidemiological studies that evaluated the validity of GIS-based geolocation and distance to pollutant sources as an approximation of individual metal exposure based on correlation with biological samples.

RECENT FINDINGS

We considered 11 toxic metals: lead (Pb), cadmium (Cd), antimony (Sb), aluminum (Al), arsenic (As), chromium (Cr), nickel (Ni), mercury (Hg), tungsten (W), uranium (U), and vanadium (V). The final review included 12 manuscripts which included seven metals (Pb, Cd, Al, As, Cr, Hg, and Ni). Many studies used geolocation of the individuals to compare exposed (industrial, urban, agricultural, or landfill sources) and unexposed areas and not so many studies used distance to a source. For all metals, except lead, there was more animal than human biosampling to conduct biological validation. We observed a trend towards higher levels of Cd, Cr, Hg, and Pb in biosamples collected closer to exposure sources, supporting that GIS-based proxies for these metals might approximate individual exposure. However, given the low number and heterogeneity of the retrieved studies, the accumulated evidence is, overall, not sufficient. Given the practical benefits and potential of modern GIS technologies, which allow environmental monitoring at a reasonable cost, additional validation studies that include human biosampling are needed to support the use of GIS-based individual exposure measures in epidemiologic studies.

Pesticide use, agricultural outputs, and pesticide poisoning deaths in Japan

OBJECTIVE

Although pesticide poisonings occur worldwide, most high-income countries have not been severely affected. Japan is a key exception, with pesticide suicides becoming a major public health concern in the 1980s. We here report the epidemiology of lethal pesticide poisoning in Japan in relation to its pesticide regulation and agricultural output.

METHODS

We obtained data on pesticide registration and sales from the Japan Plant Protection Association's annual Pesticide Handbook, National Food and Agricultural Materials Inspection Center, and Food and Agriculture Organization of the United Nations. Data on deaths due to pesticide poisoning and population were obtained from Vital Statistics of Japan. We reviewed the registration status and hazard classification of pesticides in Japan and analysed the relationships between the use/sales, pesticides fatalities, and agricultural output.

RESULTS

Five hundred and twenty-nine pesticide active ingredients are currently registered in Japan, including four WHO hazard class IB organophosphorus and carbamate insecticides. Paraquat was registered in 1962 as a liquid SL20 formulation. In 1986, restrictions were imposed on its sale/use and a 4.3% paraquat ion/4.1% diquat ion combination product registered by ICI. There were 221 pesticide poisoning fatalities in 2019, down from 2648 in 1986, a 92% reduction over 33 years. Self-poisoning was responsible for most pesticide deaths in both 1985 (2013/2476, 81.3%) and 2019 (146/221, 66.1%). Pesticide poisoning made up 8.6% of all suicides in 1985, down to 0.7% in 2019. Unintentional pesticide poisoning deaths also all fell by 83.8%, from 463 to 75. These reductions were associated with reduced sales of both OP/carbamate insecticides and paraquat/diquat but no apparent change in agricultural output across a broad range of crops.

CONCLUSIONS

Reduced use of highly hazardous pesticides and lowered concentration formulations in Japan were associated with major decreases in all deaths from pesticide poisoning and the proportion of all suicides due to pesticide ingestion.

Transcriptome-Based Identification of Genes Responding to the Organophosphate Pesticide Phosmet in Danio rerio

Organophosphate pesticides (OPPs) are one of the most widely used insecticides. OPPs exert their neurotoxic effects by inhibiting acetylcholine esterase (AChE). Most of the gross developmental abnormalities observed in OPP-treated fish, on the other hand, may not be explained solely by AChE inhibition. To understand the overall molecular mechanisms involved in OPP toxicity, we used the zebrafish (ZF) model. We exposed ZF embryos to an OPP, phosmet, for 96 h, and then analyzed developmental abnormalities and performed whole transcriptome analysis. Phenotypic abnormalities, such as bradycardia, spine curvature, and growth retardation, were observed in phosmet-treated ZF (PTZF). Whole transcriptome analysis revealed 2190 differentially expressed genes (DEGs), with 822 and 1368 significantly up-and downregulated genes, respectively. System process and sensory and visual perception were among the top biological pathways affected by phosmet toxicity. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed significant enrichment of metabolic pathways, calcium signaling pathway, regulation of actin cytoskeleton, cardiac muscle contraction, drug metabolism-other enzymes, and phototransduction. Quantitative real-time PCR results of six DEGs agreed with the sequencing data expression profile trend. Our findings provide insights into the consequences of phosmet exposure in ZF, as well as an estimate of the potential risk of OPPs to off-target species.