Anticoagulant rodenticide exposure in raptors from Ontario, Canada.

Anticoagulant rodenticides (ARs) are used globally to control rodent pest infestations in both urban and agricultural settings. It is well documented that non-target wildlife, including predatory birds, are at risk for secondary anticoagulant exposure and toxicosis through the prey they consume. However, there have been no large-scale studies of AR exposure in raptors in Ontario, Canada since new Health Canada legislation was implemented in 2013 in an attempt to limit exposure in non-target wildlife. Our objective was to measure levels of ARs in wild raptors in southern Ontario to assess their exposure. We collected liver samples from 133 raptors representing 17 species submitted to the Canadian Wildlife Health Cooperative (CWHC) in Ontario, Canada, between 2017 and 2019. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantitatively assess the level of exposure to 14 first- and second-generation ARs. Detectable levels of one or more ARs were found in 82 of 133 (62%) tested raptors, representing 12 species. The most commonly detected ARs were bromadiolone (54/133), difethialone (40/133), and brodifacoum (33/133). Of AR-positive birds, 34/82 (42%) contained residues of multiple (> 1) anticoagulant compounds. Our results indicate that AR exposure is common in raptors living in southern Ontario, Canada. Our finding that brodifacoum, difethialone, and bromadiolone were observed alone or in combination with one another in the majority of our sampled raptors indicates that legislative changes in Canada may not be protecting non-target wildlife as intended.

Separation and Quantification of Superwarfarin Rodenticide Diastereomers-Bromadiolone, Difenacoum, Flocoumafen, Brodifacoum, and Difethialone-in Human Plasma.

BACKGROUND: Superwarfarins, second-generation long-acting anticoagulant rodenticides, are 4-hydroxycoumarin analogues of warfarin that contain a large hydrophobic side chain. These compounds contain two chiral centers and are synthesized for commercial use as two pairs of diastereomer. OBJECTIVE: To support studies of superwarfarin pharmacokinetics and other efforts to improve clinical care for poisoning victims, a quantitative assay was developed for the measurement of diastereomer of bromadiolone, difenacoum, flocoumafen, brodifacoum, and difethialone in human plasma. METHOD: Based on ultrahigh-pressure liquid chromatography-tandem mass-spectrometry (UHPLC-MS/MS), this method was validated according to U.S. Food and Drug Administration (FDA) guidelines. Sample preparation involved simple protein precipitation followed by reversed phase UHPLC, which resolved all five pairs of cis/trans diastereomer in less than 10 min. Superwarfarins were measured using negative ion electrospray followed by selected-reaction monitoring on a triple quadrupole mass spectrometer. RESULTS: Calibration curves covered 3-4 orders of magnitude with linear regression coefficients of >0.999. The lower limits of quantitation were from 0.013 to 2.41 ng/mL, and intra-day and inter-day accuracy and precision coefficients of variation were <12%. CONCLUSIONS: A 10-min UHPLC-MS/MS assay was developed and validated for the separation and quantitative analysis of the pairs of diastereomer of five superwarfarins in human plasma. HIGHLIGHTS: This method was used to identify and measure superwarfarins and their cis/trans diastereomers in plasma obtained from patients treated for coagulopathy following consumption of contaminated synthetic cannabinoid products.

Importance of segmental hair analysis in a suspected case of attempted homicide by flocoumafen and difenacoum.

The 4-hydroxycoumarin derivatives are the most used rodenticides and act as classical anticoagulants, interfering with the production of clotting factors in liver by antagonizing the action of vitamin K reductase, thereby inhibiting recycling of vitamin K1, involved in activation of blood clotting factors, resulting in massive bleeding. In this paper, we present the case of a 72-year old man providing abnormal coagulation parameters (PT-INR between 16.1 and 19.1) after hospitalization. Blood samples tested positive for flocoumafen and difenacoum, two superwarfarin rodenticides. Patient's hair specimens, sampled 19 days after his hospitalization, showed that traces of both difenacoum and flocoumafen were detected in the first 1 cm; in the intermediate segments (1-2 and 2-3 cm), both difenacoum and flocoumafen were absent, while in the distal segment (3-4.5 cm), only difenacoum was found, but in significant amounts (140 pg/mg). Exposure to difenacoum in the past months, at least 4-5 before hospitalization, was confirmed by the presence of the rodenticide in the distal segment. Moreover, among the seized material, two specimens resulted compatible with the two rodenticides.

Brodifacoum Toxicity in American Kestrels (Falco sparverius) with Evidence of Increased Hazard on Subsequent Anticoagulant Rodenticide Exposure.

A seminal question in ecotoxicology is the extent to which contaminant exposure evokes prolonged effects on physiological function and fitness. A series of studies were undertaken with American kestrels ingesting environmentally realistic concentrations of the second-generation anticoagulant rodenticide (SGAR) brodifacoum. Kestrels fed brodifacoum at 0.3, 1.0, or 3.0 µg/g diet wet weight for 7 d exhibited dose-dependent hemorrhage, histopathological lesions, and coagulopathy (prolonged prothrombin and Russell's viper venom times). Following termination of a 7-d exposure to 0.5 µg brodifacoum/g diet, prolonged blood clotting time returned to baseline values within 1 wk, but brodifacoum residues in liver and kidney persisted during the 28-d recovery period (terminal half-life estimates >50 d). To examine the hazard of sequential anticoagulant rodenticide (AR) exposure, kestrels were exposed to either the first-generation AR chlorophacinone (1.5 µg/g diet) or the SGAR brodifacoum (0.5 µg/g diet) for 7 d and, following a recovery period, challenged with a low dose of chlorophacinone (0.75 µg/g diet) for 7 d. In brodifacoum-exposed kestrels, the challenge exposure clearly prolonged prothrombin time compared to naive controls and kestrels previously exposed to chlorophacinone. These data provide evidence that the SGAR brodifacoum may have prolonged effects that increase the toxicity of subsequent AR exposure. Because free-ranging predatory and scavenging wildlife are often repeatedly exposed to ARs, such protracted toxicological effects need to be considered in hazard and risk assessments. Environ Toxicol Chem 2020;39:468-481. © 2020 SETAC.

Exposure of non-target small mammals to anticoagulant rodenticide during chemical rodent control operations.

The extensive use of anticoagulant rodenticides (ARs) results in widespread unintentional exposure of non-target rodents and secondary poisoning of predators despite regulatory measures to manage and reduce exposure risk. To elucidate on the potential vectoring of ARs into surrounding habitats by non-target small mammals, we determined bromadiolone prevalence and concentrations in rodents and shrews near bait boxes during an experimental application of the poison for 2 weeks. Overall, bromadiolone was detected in 12.6% of all small rodents and insectivores. Less than 20 m from bait boxes, 48.6% of small mammals had detectable levels of bromadiolone. The prevalence of poisoned small mammals decreased with distance to bait boxes, but bromadiolone concentration in the rodenticide positive individuals did not. Poisoned small mammals were trapped up to 89 m from bait boxes. Bromadiolone concentrations in yellow-necked mice (Apodemus flavicollis) were higher than concentrations in bank vole (Myodes glareolus), field vole (Microtus agrestis), harvest mouse (Micromys minutus), and common shrew (Sorex araneus). Our field trials documents that chemical rodent control results in widespread exposure of non-target small mammals and that AR poisoned small mammals disperse away from bating sites to become available to predators and scavengers in large areas of the landscape. The results suggest that the unintentional secondary exposure of predators and scavengers is an unavoidable consequence of chemical rodent control outside buildings and infrastructures.

First evidence of anticoagulant rodenticides in fish and suspended particulate matter: spatial and temporal distribution in German freshwater aquatic systems.

Anticoagulant rodenticides (ARs) have been used for decades for rodent control worldwide. Research on the exposure of the environment and accumulation of these active substances in biota has been focused on terrestrial food webs, but few data are available on the impact of ARs on aquatic systems and water organisms. To fill this gap, we analyzed liver samples of bream (Abramis brama) and co-located suspended particulate matter (SPM) from the German Environmental Specimen Bank (ESB). An appropriate method was developed for the determination of eight different ARs, including first- and second-generation ARs, in fish liver and SPM. Applying this method to bream liver samples from 17 and 18 sampling locations of the years 2011 and 2015, respectively, five ARs were found at levels above limits of quantifications (LOQs, 0.2 to 2 µg kg-1). For 2015, brodifacoum was detected in 88% of the samples with a maximum concentration of 12.5 µg kg-1. Moreover, difenacoum, bromadiolone, difethialone, and flocoumafen were detected in some samples above LOQ. In contrast, no first generation AR was detected in the ESB samples. In SPM, only bromadiolone could be detected in 56% of the samples at levels up to 9.24 µg kg-1. A temporal trend analysis of bream liver from two sampling locations over a period of up to 23 years revealed a significant trend for brodifacoum at one of the sampling locations.

An Outbreak of Synthetic Cannabinoid-Associated Coagulopathy in Illinois.

BACKGROUND: In March and April 2018, more than 150 patients presented to hospitals in Illinois with coagulopathy and bleeding diathesis. Area physicians and public health organizations identified an association between coagulopathy and synthetic cannabinoid use. Preliminary tests of patient serum samples and drug samples revealed that brodifacoum, an anticoagulant, was the likely adulterant. METHODS: We reviewed physician-reported data from patients admitted to Saint Francis Medical Center in Peoria, Illinois, between March 28 and April 21, 2018, and included in a case series adult patients who met the criteria used to diagnose synthetic cannabinoid-associated coagulopathy. A confirmatory anticoagulant poisoning panel was ordered at the discretion of the treating physician. RESULTS: A total of 34 patients were identified as having synthetic cannabinoid-associated coagulopathy during 45 hospitalizations. Confirmatory anticoagulant testing was performed in 15 of the 34 patients, and superwarfarin poisoning was confirmed in the 15 patients tested. Anticoagulant tests were positive for brodifacoum in 15 patients (100%), difenacoum in 5 (33%), bromadiolone in 2 (13%), and warfarin in 1 (7%). Common symptoms at presentation included gross hematuria in 19 patients (56%) and abdominal pain in 16 (47%). Computed tomography was performed to evaluate abdominal pain and revealed renal abnormalities in 12 patients. Vitamin K1 (phytonadione) was administered orally in all 34 patients and was also administered intravenously in 23 (68%). Red-cell transfusion was performed in 5 patients (15%), and fresh-frozen plasma infusion in 19 (56%). Four-factor prothrombin complex concentrate was used in 1 patient. One patient died from complications of spontaneous intracranial hemorrhage. CONCLUSIONS: Our data indicate that superwarfarin adulterants of synthetic cannabinoids can lead to clinically significant coagulopathy. In our series, in most of the cases in which the patient presented with bleeding diathesis, symptoms were controlled with the use of vitamin K1 replacement therapy. The specific synthetic cannabinoid compounds are not known.

Investigating spatial patterns of mercury and rodenticide residues in raptors collected near the Charlotte, NC, USA, metropolitan area.

Raptor population growth is dynamic and trends vary across species and by location in the United States. For those species that are declining, it is important to identify potential causes including chemical contaminants. Sampling wild raptors is problematic due to their small population sizes and role as a top predator. Therefore, we obtained liver samples (n = 56) from carcasses of several raptor species, including common species like red-tailed hawks, red-shouldered hawks, barred owls, great horned owls, and osprey that arrived dead or were euthanized from a non-profit rehabilitation center in Charlotte, North Carolina. Raptors were found or collected in South Carolina, North Carolina, and Virginia, but most samples were located near the metropolitan region of Charlotte, NC. We analyzed livers for total mercury residue (mg/kg, dry weight) and five anti-coagulant rodenticides (µg/kg wet weight). Mercury was analyzed using a direct mercury analyzer approach and rodenticides were quantified by LC-MS. Mercury residues were high in piscivorous birds (15.09 mg/kg for osprey and 6.93 mg/kg for great blue herons, dry weight) and relatively high in red-shouldered hawks and one eastern screech owl tested. Six of our samples exceeded a health threshold of 1 mg/kg (wet weight) including three osprey and one each of great blue heron, red-shouldered hawk, and eastern screech owl. Brodifacoum was the only rodenticide consistently detected in our samples. Brodifacoum detections exceeded 75% in barred owls, great horned owls, and red-shouldered hawks. Sixty-nine percent of owl samples were within (or exceeded) a threshold of brodifacoum residue associated with a 10-20% risk of acute toxicity. Correlations between residues and human population density were not significant for either mercury or brodifacoum. Our data suggest that mercury residues for most raptors were not of significant concern with the exception of osprey and possibly red-shouldered hawks. Rodenticide exposures associated with a risk of acute toxicity appear to be common and warrant further investigation.

[Guidelines for certification of International Normalized Ratio (INR) for vitamin K antagonists monitoring according to the EN ISO 22870 standards]. / Recommandations pour l'accréditation de l'International normalized ratio (INR) pour la surveillance des traitements par antivitamine K en biologie délocalisée selon la norme EN ISO 22870.

Point of care testing (POCT) must comply with regulatory requirements according to standard EN ISO 22870, which identify biologists as responsible for POCT. INR for vitamin K antagonists (VKAs) monitoring is a test frequently performed in haemostasis laboratories. Bedside INR is useful in emergency room, in particular in case of VKAs overdosage but also for specific populations of patients like paediatrics or geriatrics. INR POCT devices are widely used at home by the patients for self-testing, but their use in the hospital by the clinical staff for bedside measurement is growing, with devices which now comply with standard for POCT accreditation for hospital use. The majority of point of care devices for INR monitoring has shown a good precision and accuracy with results similar to those obtained in laboratory. With the aim to help the multidisciplinary groups for POCT supervision, the medical departments and the biologists to be in accordance with the standard, we present the guidelines of the GFHT (Groupe français d'étude sur l'hémostase et la thrombose, subcommittee "CEC et biologie délocalisée") for the certification of POCT INR. These guidelines are based on the SFBC guidelines for the certification of POCT and on the analysis of the literature to ascertain the justification of clinical need and assess the analytical performance of main analysers used in France, as well as on a survey conducted with biologists.

A Tier-I leaching risk assessment of three anticoagulant compounds in the forested areas of Hawai'i.

The anticoagulant rodenticides brodifacoum, chlorophacinone, and diphacinone have been proposed for broadcast application in some forested areas in Hawai'i to protect rare and endangered native bird species from introduced mice and rats. Groundwater resources in Hawai'i are prone to contamination due to the intrinsic aquifer vulnerability to leaching from the land surface. Because of the hydrogeologic complexity, Hawai'i uses a Tier-I leaching assessment tool, CLERS, to make registration decisions for new or existing chemicals. The CLERS tool uses soil and pesticide properties as well as water recharge through the soil profile in a GIS framework to estimate mass attenuation of the chemicals at a given depth and compares against this attenuation factor against those of a known leacher and a non-leacher. Disturbed soil samples were collected across the state of Hawai'i, including the islands of Hawai'i, Kaho'olawe, Kaua'i, Lana'i, Maui, Moloka'i, and O'ahu, with two sampling locations per island, except for Kaua'i which had three. As only limited information on chemical properties of these anticoagulants in soils is available, laboratory experiments were performed to determine the sorption capacity (Kd) and the degradation rate (T1/2) of brodifacoum, chlorophacinone, and diphacinone to construct a proper chemical database. Depending on the soil type, T1/2 values ranged between 37 and 248days for diphacinone, between 39 and 1000days for chlorophacinone, and between 72 and 462days for brodifacoum. These data were used in the CLERS tool to estimate leaching risks for these chemicals primarily in forested areas of the state where the chemicals are likely to be applied. The results from the CLERS tool indicate low risks of leaching of these three compounds into aquifers in five out of six major Hawaiian Islands. Diphacinone showed medium risk of leaching in a few remote areas in Maui.

The rapid determination of bromadiolone in liver and blood plasma by in-injector pyrolysis gas chromatography - Ion trap tandem mass spectrometry.

The unintentional poisoning of off-target animals by bromadiolone, a second generation anticoagulant rodenticide, is an undesirable outcome requiring sensitive analytical methods. In this study, a rapid and sensitive method for the determination of bromadiolone in liver and blood plasma by means of gas chromatography coupled with tandem mass spectrometry without need for derivatization was developed. The method is based on the in-injector pyrolysis of bromadiolone and subsequent gas chromatography coupled with ion trap tandem mass spectrometry with electron ionization. Sample preparation includes extraction with methanol, evaporation under nitrogen stream, and dissolution in toluene. The pyrolysis of bromadiolone was carried out in an injector at 390°C. Chromatographic separation of the pyrolytical fragment of bromadiolone was achieved using a VF-5ms column with helium as the mobile phase. Tandem in-time mass spectrometry of the separated pyrolytical fragment of bromadiolone was carried out using an ion trap mass spectrometer after electron ionization. Recovery ranged from 94 to 98%. The method showed good linearity up to 1000µgkg-1 for liver and 1000µgL-1 for plasma. The limit of detection was 0.38µgkg-1 for liver and 0.26µgL-1 for plasma. The developed method was used successfully in several animal poisoning cases.

Simultaneous determination of seven anticoagulant rodenticides in agricultural products by gel permeation chromatography and liquid chromatography-tandem mass spectrometry.

A sensitive and reliable method for the simultaneous determination of hydroxycoumarin-type (brodifacoum, bromadiolone, coumatetralyl, and warfarin) and indandione-type (chlorophacinone, diphacinone, and pindone) rodenticides in agricultural products by gel permeation chromatography (GPC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The procedure involved extraction of the rodenticides from samples with acetone, followed by liquid-liquid partitioning with hexane/ethyl acetate (1:1, v/v) and 10% sodium chloride aqueous solution, then cleanup using GPC, and finally, analysis using LC-MS/MS. High recoveries from the GPC column were obtained for all rodenticides tested using a mobile phase of acetone/cyclohexane/triethylamine (400:1600:1, v/v/v). An ODS column, which contains low levels of metal impurities, gave satisfactory peak shapes for both hydroxycoumarin- and indandione-type rodenticides in the LC-MS/MS separation. The average recoveries of rodenticides from eight agricultural foods (apple, eggplant, cabbage, orange, potato, tomato, brown rice, and soybean) fortified at 0.0005-0.001 mg/kg ranged from 76 to 116%, except for bromadiolone in orange (53%) and diphacinone in soybean (54%), and the relative standard deviations ranged from 1 to 16%. The proposed method effectively removed interfering components, such as pigments and lipids, and showed high selectivity. In addition, the matrix effects were negligible for most of the rodenticide/food combinations. The results suggest that the proposed method is reliable and suitable for determining hydroxycoumarin- and indandione-type rodenticides in agricultural products.

Comprehensive characterization of anticoagulant rodenticides in sludge by liquid chromatography-tandem mass spectrometry.

The occurrence of 10 commonly used anticoagulant rodenticides in centrifuged sludge of 27 wastewater treatment plants was evaluated using solid-liquid extraction (SLE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Activated carbon, alumina, and Florisil cartridges with methanol/dichloromethane as eluting solvents were tested in combination with primary-secondary amine (PSA) to optimize an efficient sample cleanup. PSA in combination with Florisil was the best methodology to extract anticoagulant rodenticides in sludge providing recoveries between 42 ± 0.5 and 100 ± 2 %. Warfarin, bromadiolone, ferulenol, and coumachlor were the most ubiquitous compounds in sludge at concentrations up to 84.2 ng g(-1) for the latter. Coumatetralyl, dicoumarol, and brodifacoum were detected sporadically at levels between 6.1 and 17.4 ng g(-1). On the contrary, acenocoumarol, difenacoum, and flocoumafen were not detected in any sample. Finally, we estimated the amount of anticoagulant rodenticides discharged via sludge in order to determine the potential impact to agricultural soil according to different sludge usage practices in the region investigated. This study demonstrates that anticoagulant rodenticides are accumulated in sludge during activated sludge treatment and that the application of sludge as fertilizers may pose a future environmental risk, if not controlled.

Determination of Anticoagulant Rodenticides and α-Chloralose in Human Hair. Application to a Real Case.

Anticoagulant rodenticides are the largest group of poisons used to kill harmful rodents. Their fundamental mode of action consists in the inhibition of the vitamin K epoxide reductase, which causes blood-clotting alteration, ultimately leading to hemorrhagic events as the cause of death. In this study, we developed an UHPLC-MS-MS for the simultaneous determination of 10 anticoagulant hydroxycoumarine rodenticides, plus α-chloralose in human hair, with the scope of detecting potential trace of chronological poison exposure in clinical and forensic cases. The method was fully validated and applied to a case of intentional poisoning perpetrated by administration of difenacoum and α-chloralose to a 97-year-old woman, who was hospitalized because of severe symptoms, including drowsiness, convulsions, pallor and hematoma. Hair sample from the victim was segmentally analyzed. Difenacoum was detected in the proximal 3-cm hair segment at the concentration of 2.9 pg/mg. To our knowledge, this is the first study to report that exposure to difenacoum is detectable in real hair samples. The other target analyte found in the hair sample was α-chloralose, which was detected in the 0-3 cm segment at the concentration of 85 pg/mg. The two subsequent and consecutive segments (3-6 cm and 6-9 cm) showed only traces of difenacoum (below LOQ) and low but quantifiable concentrations of α-chloralose (29 and 6 pg/mg, respectively). Therefore, hair segmental analysis allowed us to conclude that the victim was repeatedly exposed to two poisons in the period corresponding to the first segment of hair.

LC-MS-MS Analysis of Brodifacoum Isomers in Rat Tissue.

Brodifacoum (BDF) is a second-generation anticoagulant rodenticide structurally related to warfarin but containing two chiral centers. Highly stable, BDF can contaminate food and water supplies causing accidental poisoning of humans and nontarget animals. To determine the distribution of BDF isomers in serum and tissues, a quantitative method was developed and validated according to FDA guidelines based on high-performance liquid chromatography-tandem mass spectrometry. A single liquid-liquid extraction step provided recoveries exceeding 93%. Reversed-phase chromatographic separations required <6 min, and quantitative analysis utilized a triple-quadrupole mass spectrometer equipped with negative ion electrospray and selected reaction monitoring. The standard curve had a linear regression coefficient of 0.999 and intra- and inter-assay variations of <10%. The chromatographic method enabled the resolution and measurement of pairs of BDF diastereomers in commercial materials as well as in rat tissues. This method is suitable for measuring BDF exposure as well as basic science studies of the distribution and elimination of BDF diastereomers to various tissues.

Residue profiles of brodifacoum in coastal marine species following an island rodent eradication.

The second-generation anticoagulant rodenticide brodifacoum is an effective tool for the eradication of invasive rodents from islands and fenced sanctuaries, for biodiversity restoration. However, broadcast application of brodifacoum bait on islands may expose non-target wildlife in coastal marine environments to brodifacoum, with subsequent secondary exposure risk for humans if such marine wildlife is harvested for consumption. We report a case study of monitoring selected marine species following aerial application of brodifacoum bait in August 2011 to eradicate Norway rats (Rattus norvegicus) from Ulva Island, New Zealand. Residual concentrations of brodifacoum were detected in 3 of 10 species of coastal fish or shellfish sampled 43-176d after bait application commenced. Residual brodifacoum concentrations were found in liver, but not muscle tissue, of 2 of 24 samples of blue cod (0.026 and 0.092 µg/g; Parapercis colias) captured live then euthanized for tissue sampling. Residual brodifacoum concentrations were also found in whole-body samples of 4 of 24 mussels (range=0.001-0.022 µg/g, n=4; Mytilus edulis) and 4 of 24 limpets (range=0.001-0.016 µg/g, n=4; Cellana ornata). Measured residue concentrations in all three species were assessed as unlikely to have eventually caused mortality of the sampled individuals. We also conducted a literature review and determined that in eleven previous accounts of residue examination of coastal marine species following aerial applications of brodifacoum bait, including our results from Ulva Island, the overall rate of residue detection was 5.6% for marine invertebrates (11 of 196 samples tested) and 3.1% for fish (2 of 65 samples tested). Furthermore, our results from Ulva Island are the first known detection of brodifacoum residue in fish liver following an aerial application of brodifacoum bait. Although our findings confirm the potential for coastal marine wildlife to be exposed to brodifacoum following island rodent eradications using aerial bait application, the risk of mortality to exposed individual fish or shellfish appears very low. There is also a very low risk of adverse effects on humans that consume fish or shellfish containing residual concentrations in the ranges reported here. Furthermore, any brodifacoum residues that occur in marine wildlife decline to below detectable concentrations over a period of weeks. Thus potential human exposure to brodifacoum through consumption of marine wildlife containing residual brodifacoum could be minimized by defining 'no take' periods for harvest following bait application and regular monitoring to confirm the absence of detectable residues in relevant marine wildlife.

Scavenging of rodent carcasses following simulated mortality due to field applications of anticoagulant rodenticide.

Worldwide, agricultural uses of anticoagulant rodenticides (ARs) cause poisonings of non-target wildlife as observed in France where bromadiolone is used to control water vole outbreaks. Following bromadiolone field application, a part of the vole population may die aboveground of the treated plots and thus, can represent an important risk of secondary poisoning for scavengers. In this study, water voles were trapped in a non-treated area and their carcasses were placed aboveground in plots located in an area where a vole outbreak occurred. Then, the environmental persistence, the diurnal and nocturnal scavenging rates of water vole carcasses were assessed in autumn 2011 and in spring 2012. The diurnal scavenger species were also identified. The environmental persistence of the carcasses to reach at least a scavenging rate of 87.5 % was 0.5-1.5 day. The average rates of diurnal and nocturnal scavenging ranged from 67 to 100 % and 5 to 100 %, respectively. They depended on the composition of the scavenger community present near the monitored plots; diurnal scavenging rates being higher with corvids than with raptors. In autumn, the red kite and the common buzzard were the main scavengers in one of the plots, what suggests a high risk of poisoning for these raptors during post-nuptial migration. So, the collection of vole carcasses after treatments and the limitations of bromadiolone applications when high densities of predators/scavengers are observed could be implemented to mitigate the risks of secondary poisoning.

Occurrence, elimination, and risk of anticoagulant rodenticides and drugs during wastewater treatment.

Anticoagulants are biocides widely used as pest control agents in agriculture, urban infrastructures, and domestic applications for the control of rodents. Other anticoagulants such as warfarin and acenocoumarol are also used as drugs against thrombosis. After use, anticoagulants are discharged to sewage grids and enter wastewater treatment plants (WWTPs). Our hypothesis is that WWTP effluents can be a source of anticoagulants to receiving waters and that these can affect aquatic organisms and other nontarget species. Therefore, the objective of the present study was to determine the occurrence of 11 anticoagulants in WWTPs receiving urban and agricultural wastewaters. Warfarin was the most ubiquitous compound detected in influent waters and was partially eliminated during the activated sludge treatment, and low nanograms per liter concentration were found in the effluents. Other detected compounds were coumatetralyl, ferulenol, acenocoumarol, flocoumafen, brodifacoum, bromadiolone, and difenacoum at concentrations of 0.86-87.0 ng L(-1). Considering water volumes of each WWTP, daily emissions were estimated to be 0.02 to 21.8 g day(-1), and thus, WWTPs contribute to the loads of anticoagulants to receiving waters. However, low aquatic toxicity was observed using Daphnia magna as a model aquatic organism.

[Method for determining brodifacoum in workplace air by high-performance liquid chromatography].

OBJECTIVE: To establish a method for determining brodifacoum in workplace air by high-performance liquid chromatography (HPLC). METHODS: Brodifacoum in workplace air was collected with a polytetrafluoroethylene filter and desorbed by mixed solution of methanol and dichloromethane (20:80, V:V), and was then separated using an ODS column and determined by an ultraviolet detector; retention time was used for identification, and peak area was used for quantification. RESULTS: The concentration of brodifacoum showed a linear relationship with peak area within 0.2∼10.0 µg/ml; the elution efficiency was 91.6%∼95.1%; the detection limit was 0.08 µg/ml (injection volume: 20 µl eluate); the minimum detectable concentration was 0.000 67 mg/m(3) (calculated by 240 L air sample). CONCLUSION: This HPLC method is convenient and simple for air collection and sample preparation and meets the methodological requirements. Therefore, this method can be used for the determination of brodifacoum in workplace air.