Brain magnetic resonance imaging and histopathology findings in a dog with global brain ischaemia following cardiopulmonary arrest.

BACKGROUND: Global brain ischaemia following cardiopulmonary arrest is uncommonly reported in veterinary medicine yet neurologic injury after arrest is a known morbidity. CASE REPORT: An 18-week-old male entire Cavalier King Charles Spaniel-Poodle was referred following 3 days of neurologic abnormalities after cardiopulmonary arrest. After resuscitation, the animal had decerebrate rigidity, a stuporous mentation and intermittent episodes of vocalisation and apnoea. A brain magnetic resonance imaging (MRI) was undertaken 4 days after cardiopulmonary arrest, with standard sequences (T1-weighted, T2-weighted and fluid-attenuated inversion recovery) as well as diffusion-weighted imaging to better discern ischaemic injury and cytotoxic oedema for prognostic reasons. MRI findings were consistent with global brain ischaemia affecting the hippocampus, cerebellum and substantia nigra, the latter two not previously identified in canine cases of global brain ischaemia. The patient was euthanased on day eight post-cardiopulmonary arrest due to a lack of neurological improvement and developing sepsis as a complication. Ante-mortem identification of affected areas of the brain was confirmed on histological examination, with evidence of ischaemic injury seen in the cerebrum, hippocampus, cerebellum, basal nuclei and thalamus. CONCLUSION: This report describes ante-mortem MRI and postmortem findings in a dog with global brain ischaemia following cardiopulmonary arrest. A multimodal approach to neuroprognostication in patients recovering from cardiopulmonary arrest is recommended.

Pet health insurance reduces the likelihood of pre-surgical euthanasia of dogs with gastric dilatation-volvulus in the emergency room of an Australian referral hospital.

AIMS: To determine the association between the presence of pet health insurance and the risk of euthanasia at the time of diagnosis for dogs with gastric dilatation-volvulus (GDV). METHODS: Insurance status at the time of GDV diagnosis was sought for a cohort of 147 non-referred, confirmed cases of GDV that presented to the emergency department of a university-based veterinary hospital in Australia between 2008 and 2017. Insurance status was obtained from the medical record (n=18) or after contacting the owners by phone using a standardised questionnaire (n=129). Animal, clinical and outcome data was retrospectively compiled in a research database. The primary outcome measure was whether or not the dog was euthanised before surgery. The Mantel-Haenszel procedure was used to quantify the association between the presence of pet health insurance and the risk of euthanasia at the time of diagnosis for dogs with GDV, adjusting for the confounding effect of age at the time of presentation using Bayesian methods. RESULTS: Of the 69 dogs for which insurance information could be obtained, 10 (14%) cases were insured at the time of the GDV event and 59 (86%) cases were not. The majority of non-insured dogs (37/59; 63 (95% CI=50-74)%) were euthanised before surgery, while none (0 (95% CI=0-28)%) of the insured dogs were euthanised at that time (p<0.001). Of the 32 insured and non-insured dogs that underwent surgery, four dogs (13 (95% CI=5-28)%) did not survive to hospital discharge. Three dogs (9%) were euthanised during or after surgery and one dog (3%) experienced cardiopulmonary arrest during treatment. The majority of dogs for which insurance status was known did not survive to hospital discharge (41/69; 59%), and 90 (95% CI=7-96)% of deaths were caused by euthanasia prior to surgery. Uninsured dogs were 5.0 (95% credible interval=1.8-26) times more likely to undergo presurgical euthanasia compared with insured dogs. CONCLUSIONS: Euthanasia prior to treatment was most common cause of death in non-referred dogs with GDV; such euthanasia was entirely absent in the cohort of dogs that were insured. CLINICAL RELEVANCE: Financial considerations significantly contribute to mortality of dogs with GDV presented to an emergency room. Financial instruments to reduce the out-of-pocket expense for pet owners confronted with unexpected veterinary expenses have potential to reduce pet mortality.

[Small animal cardiopulmonary -resuscitation (CPR) in general practice]. / Kardiopulmonale Reanimation in der Kleintierpraxis.

INTRODUCTION: Cardiopulmonary arrest (CPA) is the acute cessation of systemic perfusion and ventilation. It leads to a lack of tissue oxygen delivery and, if not addressed quickly, will inevitably cause death. Cardiopulmonary resuscitation (CPR) is the only available treatment for CPA and several opportunities exist to improve the veterinary team's resuscitation approach and optimize small animal CPR patient outcomes. In 2012, the Reassessment Campaign on Veterinary Resuscitation (RECOVER) initiative generated evidence-based clinical guidelines to form the basis for training and practice of CPR in dogs and cats. When employing an evidence-based, standardized approach to small animal CPR, return of spontaneous circulation can be achieved in up to 58% of patients and up to 7% of dogs and 19% of cats can be discharged from the veterinary hospital alive. Survival for dogs and cats that suffer CPA is best in patients that suffer a peri-anesthetic arrest, so high quality CPR in the anesthesia patient population is of utmost importance and expected to be the most rewarding. To ensure the best possible outcomes for any patient suffering from CPA and undergoing CPR, a comprehensive resuscitation strategy is necessary, that includes preventive and preparedness measures, basic life support (chest compressions and ventilation), advanced life support (optimization of the patient status by targeted drug therapy, cardiac rhythm monitoring, and defibrillation), and post-cardiac arrest critical care. This article summarizes the most important RECOVER CPR guidelines for the small animal practitioner.

INTRODUCTION: L'arrêt cardiopulmonaire (ACP) est l'arrêt soudain de la perfusion systémique et de la ventilation. Il entraîne, s'il n'est pas traité rapidement, un manque d'apport en oxygène aux tissus qui conduira inévitablement au décès du patient. La réanimation cardio-pulmonaire (RCP) est le seul traitement disponible pour l'ACP. Les compétences d'une équipe vétérinaire quant à la gestion d'un ACP peuvent être améliorées afin d'optimiser les chances de réussite. Des directives cliniques ont été établies par l'initiative RECOVER (Reassessment Campaign on Veterinary Resuscitation) suite à une étude approfondie de la littérature scientifique. Ces recommandations servent de base à la formation et à la pratique de la RCP canine et féline. L'utilisation d'une technique standardisée de la RCP chez le chien et le chat permet de rétablir une circulation spontanée chez 58% des patients et de faire sortir d'hospitalisation jusqu'à 7% des chiens et 19% des chats. Les patients qui subissent un ACP péri-anesthésique ont un meilleur taux de survie. Des efforts dans la pratique de la RCP pour les patients sous anesthésie sont donc de la plus haute importance, de meilleurs résultats étant attendus dans ce contexte. Il est nécessaire de mettre en place une stratégie de réanimation complète afin de garantir les meilleures chances de survie possibles à tout patient souffrant d'ACP et subissant une RCP. Cette dernière comprend des mesures de prévention et de préparation, des soins de réanimation de base (compressions thoraciques et ventilation), des soins de réanimation avancés (optimisation de l'état du patient par une pharmacothérapie ciblée, surveillance du rythme cardiaque et traitements anti-arythmiques) et des soins intensifs à mettre en place après la RCP. Cet article résume les principales lignes directrices des recommandations RECOVER qui peuvent être mises en pratique par un vétérinaire généraliste.

SnakeMap: four years of experience with a national small animal snake envenomation registry.

SnakeMap is a national cloud-based, veterinary snakebite registry. It was designed to prospectively collect data of the clinical circumstances and temporospatial information on cases of snake envenomation in dogs and cats. We herein introduce the project and summarise the data from the first 4 years of SnakeMap. The registry is a veterinary community-based online database allowing case entry from veterinary hospitals across Australia. Registry data comprise hospital characteristics, patient characteristics, envenoming snake type, treatment and outcome variables, including time and geolocation of the snake bite. We present summative information on select key variables from the SnakeMap registry (1 July 2015 to 30 June 2019). Twenty-eight hospitals from 6 states/territories entered 624 cases into the registry, including 419 dogs (67%) and 205 cats (33%). Bite time was available in 216 animals of which 90 (42%) were reported to be bitten in the 3 hours between 03:00 pm and 05:59 pm; median bite to presentation interval was 60 (interquartile range [IQR] 30, 211) minutes in dogs and 95 (IQR 41, 238) minutes in cats. Bites occurred in the owner's yard in 356 dogs (85%) and 53 cats (26%). A snake venom detection kit was used in 172 cases (28%) and antivenom was administered in 523 cases (85%). Most animals (n = 534, 88%) survived to discharge (median hospitalisation of 25 [IQR 16, 62] hours). SnakeMap effectively collects relevant clinical data from dogs and cats with presumed snake bite and provides locally specific information on the epidemiology of snake envenomation in small animals.

Considering the relationship between domestic violence and pet abuse and its significance in the veterinary clinical and educational contexts.

This thematic review examines the literature regarding the relationship between domestic violence (DV) and pet abuse (PA) particularly in the veterinary clinical and educational contexts. It examines the significance of this relationship for the veterinary profession including the veterinarian's role and associated legal and ethical obligations, and relevant current veterinary education standards, to identify future clinical and educational directions. Articles were sourced from online databases by searching the keywords without date restrictions. Overall, 70 articles were retrieved and reviewed. Pet abuse has been identified as a potential risk factor for DV, and DV perpetrators may harm or kill a pet to exert physical, psychological or emotional control over an intimate partner. Given that victims of DV often seek veterinary aid for their pets, veterinarians may act as frontline professionals in the recognition of the link between PA and DV. Veterinarians must assess individual cases for diagnostic indicators of non-accidental injury and consider demographic factors to identify suspected PA and DV. Despite existing legal and ethical obligations of the veterinarian relating to suspected PA and victims of DV, veterinarians have uncertainty and unpreparedness in addressing PA and DV in a clinical context. Many factors may contribute to the lack of veterinary intervention in suspected cases of PA and DV including concern for animal welfare, confusion about the reporting process and uncertainty in differentiating accidental versus non-accidental injuries in pets. Specific published guidelines regarding the recognition and reporting of PA and DV in the veterinary clinical context are required. Limited published evidence exists examining the implementation and success of veterinary training regarding the relationship between DV and PA. Ultimately, veterinary student education is needed to prepare veterinarians for their response to PA and DV in practice. Further research is required to examine the effects of the delivery of content regarding the link between PA and DV in the veterinary curriculum on veterinary student knowledge and attitudes.

Presumed secondary immune-mediated haemolytic anaemia following elapid snake envenomation and its treatment in four dogs.

CASE SERIES: This case series describes secondary immune-mediated haemolytic anaemia (IMHA) in four dogs following elapid snake envenomation and its treatment. All the dogs initially presented with clinical signs commensurate with mainland tiger snake (Notechis scutatus) envenomation. None of the dogs was anaemic at the time of presentation. IMHA was diagnosed 3-9 days following snake envenomation. The trigger for IMHA was unclear in each case and may have been a component of the snake venom, antivenom, fresh frozen plasma, concurrent morbidity, administered drugs or a combination thereof. Three of the four dogs received immunosuppressive therapy comprising corticosteroids with or without azathioprine. Resolution of the IMHA was documented 6 weeks after diagnosis for one dog and 9 months after diagnosis for two dogs, with one dog lost to follow-up. CONCLUSION: IMHA is a potential complicating factor of elapid snake envenomation and its treatment in dogs, and should be considered as a differential diagnosis for a persistent or worsening anaemia. Both the incidence and aetiopathogenesis of IMHA in the context of elapid snake envenomation and its treatment in dogs are unknown and require further examination.

Leaching of biocides from façades under natural weather conditions.

Biocides are included in organic building façade coatings as protection against biological attack by algae and fungi but have the potential to enter the environment via leaching into runoff from wind driven rain. The following field study correlates wind driven rain to runoff and measured the release of several commonly used organic biocides (terbutryn, Irgarol 1051, diuron, isoproturon, OIT, DCOIT) in organic façade coatings from four coating systems. During one year of exposure of a west oriented model house façade in the Zurich, Switzerland area, an average of 62.7 L/m(2), or 6.3% of annual precipitation came off the four façade panels installed as runoff. The ISO method for calculating wind driven rain loads is adapted to predict runoff and can be used in the calculation of emissions in the field. Biocide concentrations tend to be higher in the early lifetime of the coatings and then reach fairly consistent levels later, generally ranging on the order of mg/L or hundreds of µg/L. On the basis of the amount remaining in the film after exposure, the occurrence of transformation products, and the calculated amounts in the leachate, degradation plays a significant role in the overall mass balance.

Leaching of additives from construction materials to urban storm water runoff.

Urban water management requires further clarification about pollutants in storm water. Little is known about the release of organic additives used in construction materials and the impact of these compounds to storm water runoff. We investigated sources and pathways of additives used in construction materials, i.e., biocides in facades' render as well as root protection products in bitumen membranes for rooftops. Under wet-weather conditions, the concentrations of diuron, terbutryn, carbendazim, irgarol 1051 (all from facades) and mecoprop in storm water and receiving water exceeded the predicted no-effect concentrations values and the Swiss water quality standard of 0.1 microg/L. Under laboratory conditions maximum concentrations of additives were in the range of a few milligrams and a few hundred micrograms per litre in runoff of facades and bitumen membranes. Runoff from aged materials shows approximately one to two orders of magnitude lower concentrations. Concentrations decreased also during individual runoff events. In storm water and receiving water the occurrence of additives did not follow the typical first flush model. This can be explained by the release lasting over the time of rainfall and the complexity of the drainage network. Beside the amounts used, the impact of construction materials containing hazardous additives on water quality is related clearly to the age of the buildings and the separated sewer network. The development of improved products regarding release of hazardous additives is the most efficient way of reducing the pollutant load from construction materials in storm water runoff.

Preclinical assessment of the neutralizing capacity of antivenoms produced in six Latin American countries against medically-relevant Bothrops snake venoms.

Species of the genus Bothrops induce the vast majority of snakebite envenomings in Latin America. A preclinical study was performed in the context of a regional network of public laboratories involved in the production, quality control and development of antivenoms in Latin America. The ability of seven polyspecific antivenoms, produced in Argentina, Brazil, Peru, Bolivia, Colombia and Costa Rica, to neutralize lethal, hemorrhagic, coagulant, defibrinogenating and myotoxic activities of the venoms of Bothrops neuwiedi (diporus) (Argentina), Bothrops jararaca (Brazil), B. neuwiedi (mattogrossensis) (Bolivia), Bothrops atrox (Peru and Colombia) and Bothrops asper (Costa Rica) was assessed using standard laboratory tests. Despite differences in the venom mixtures used in the immunization of animals for the production of these antivenoms, a pattern of extensive cross-neutralization was observed between these antivenoms and all the venoms tested, with quantitative differences in the values of effective doses. This study reveals the capacity of these antivenoms to neutralize, in preclinical tests, homologous and heterologous Bothrops venoms in Central and South America, and also highlight quantitative differences in the values of Median Effective Doses (ED50s) between the various antivenoms.

Synthetic TiO2 nanoparticle emission from exterior facades into the aquatic environment.

We present direct evidence of the release of synthetic nanoparticles from urban applications into the aquatic environment. We investigated TiO(2) particles as these particles are used in large quantities in exterior paints as whitening pigments and are to some extent also present in the nano-size range. TiO(2) particles were traced from exterior facade paints to the discharge into surface waters. We used a centrifugation based sample preparation which recovers TiO(2) particles between roughly 20 and 300nm. Analytical electron microscopy revealed that TiO(2) particles are detached from new and aged facade paints by natural weather conditions and are then transported by facade runoff and are discharged into natural, receiving waters. Microscopic investigations are confirmed by bulk chemical analysis. By combining results from microscopic investigations with bulk chemical analysis we calculated the number densities of synthetic TiO(2) particles in the runoff.

Influence of interactions between NOM and particles on UF fouling mechanisms.

This study focused on the mechanistic effects of molecular interactions between inorganic particles (kaolinite) and the two main NOM fouling fractions of polysaccharides (alginate) and humics (humic acids) in ultrafiltration. Fouling effects were studied during the dead-end filtration of individual and mixed compounds as well as during the subsequent filtration of individual compounds. SEM analyses were performed to further study the fouling-layer structure. A significant synergistic effect was observed during combined particle-NOM fouling, which was considerably greater than the sum of particle and organic fouling alone. Synergistic fouling could be explained by NOM-particle interactions in the feed solution and during the fouling process. Kaolinite alone formed a fouling layer of particle aggregates, whereas humic acid adsorption onto kaolinite resulted in a fouling layer of stabilized colloids of humic acid and kaolinite. In the case of alginate, simultaneous pore-blocking and cake-layer formation of NOM and kaolinite dominated the fouling. In both cases, incorporation of the organics in the kaolinite fouling layer resulted in a fouling cake of significantly reduced porosity compared to individual particle filtration. Irreversible fouling by NOM could not be prevented by kaolinite. SEM images showed patches of the particle-fouling layer remaining on the membrane surface after backwashing, which can be linked to particle-membrane associations by NOM bridging.

Size, number and chemical composition of nanosized particles in drinking water determined by analytical microscopy and LIBD.

In this paper we comprehensively characterized particles in drinking water originating from a lake water source. We focused on particles smaller than a few hundred nm. Several analytical techniques were applied to obtain information on number concentration, size distribution, morphology and chemical composition of the particles. Morphological information was obtained by atomic force microscopy (AFM) analysis. Two types of particles, spherical aggregates up to a few tens of nm and elongated fibers were identified. Similar structures were also observed in transmission electron microscope (TEM) images. A size distribution of the particles was obtained by applying image analysis (IA) tools on the TEM images. IA results showed an exponential increase of the particle number concentration down to 40 nm, which is the lower detection limit of our setup. The total number of particles down to 10 nm and the average particle diameter were determined with the laser-induced breakdown detection (LIBD) method. The results were in good agreement with the TEM-IA data and showed a total number concentration of roughly 10(8) particles/mL in the purified water. The carbon of the particles was investigated with scanning transmission X-ray microscopy (STXM), which revealed that most particles were organic matter; the C-1s spectra were typical for dissolved organic matter. The methods were applied to characterize the particles from two different drinking waters treated with different methods (conventional vs. ultrafiltration (cut-off 100 kDa)). The results showed that the particle number density following ultrafiltration was lower by a factor of 5-10, compared to conventional treatment. However, the average particle diameter in the finished water of both treatment trains was roughly the same.

Potency evaluation of antivenoms in Brazil: the national control laboratory experience between 2000 and 2006.

Envenoming from snakebites is an important public health issue in Brazil. In 2005, 28,597 cases were notified (15 cases/100,000 inhabitants), 87.5% due to Bothrops and 9.2% to Crotalus genus. Antivenoms available in Brazil are liquid preparations containing purified equine Fab'2. Since 1987, the National Institute for Quality Control in Health (INCQS/FIOCRUZ) has been testing all lots prior to batch release. Between 2000 and 2006, 619 lots of antivenoms were tested, comprising 2,513,690 ampoules. The potency assay was performed only for bothropic and crotalic antivenoms (485 lots corresponding to 1,866,726 ampoules) due to the unavailability of the other reference venoms. This paper aims to report the last 7-year activities of INCQS on the quality control, batch release and potency evaluation of antivenoms.

Biocides used in building materials and their leaching behavior to sewer systems.

There is increasing concern about diffuse pollution of aquatic systems by biocides used in urban areas. We investigated sources and pathways of biocides significant for the pollution of storm water runoff. Main sources seem to be building envelopes, i.e. facades (paints, plasters) and roof sealing membranes. First results from a defined urban catchment drained by a separated sewer system without any agricultural activities reveal a substantial occurrence. Even after the first flush, concentrations of terbutryn, carbendazim, mecoprop as well as Irgarol 1051 and its metabolite exceeded the Swiss water quality standard of 0.1 microg/L. In laboratory experiments, leaching of mecoprop used as a root protection agent in bitumen sheets for roof waterproofing was determined. The concentrations differed in 16 different sheets two orders of magnitude, depending on the product composition. Using optimized products, it is expected to be the most efficient and sustainable way to reduce the environmental impact. To understand transport dynamics and environmental risk, further storm water events will be analyzed. Based on the ongoing project URBIC, first measures will be proposed to limit the release to surface and ground water.

Pilot experiments with electrodialysis and ozonation for the production of a fertiliser from urine.

Pilot tests were performed with a process combination of electrodialysis and ozonation for the removal of micropollutants and the concentration of nutrients in urine. In continuous and batch experiments, maximum concentration factors up to 3.5 and 4.1 were obtained, respectively. The desalination capacity did not decrease significantly during continuous operation periods of several weeks. Membrane cleaning after 195 days resulted in approximately 35% increase in desalination rate. The Yeast Estrogen Screen (YES), a bioassay that selectively detects oestrogenic compounds, confirmed that about 90% of the oestrogenic activity was removed by electrodialysis. HPLC analysis showed that ibuprofen was removed to a high extent, while other micropollutants were below the detection limit. In view of the fact that ibuprofen is among the most rapidly transported micropollutants in electrodialysis processes, this result indicates that electrodialysis provides an effective barrier for micropollutants. Standardised plant growth tests were performed in the field with the salt solution resulting from the treatment by electrodialysis and subsequent ozonation. The results show that the plant height is comparable to synthetic fertilisers, but the crop yield is slightly lower. The latter is probably caused by volatilisation losses during field application, which can be prevented by improved application technologies.

Interplay of different NOM fouling mechanisms during ultrafiltration for drinking water production.

Ultrafiltration is an emerging technology for drinking water production, but a main challenge remains the lack of understanding about fouling. This paper investigates the impact of molecular interactions between different natural organic matter (NOM) compounds on ultrafiltration fouling mechanisms. We performed dead-end filtration experiments with individual and mixed humic acid and alginate (polysaccharide). Alginate showed detrimental, but mostly reversible, flux decline and high solute retention. Our results indicate that this was caused by pore blocking transformed into cake building and weak molecular foulant-membrane and foulant-foulant interactions. In the presence of calcium, aggravated fouling was observed, related to complexation of alginate and its subsequently induced gel formation. With humic acid, more severe irreversible fouling occurred due to humic acid adsorption. Minor adsorption of alginate onto the membrane was also observed, which probably caused the substantial irreversible flux decline. The fouling characteristics in the mixtures reflected a combination of the individual humic acid and alginate experiments and we conclude, that the individual fouling mechanisms mutually influence each other. A model elucidates this interplay of the individual fouling mechanisms via hydrophobic and electrostatic interactions. In our study such an interplay resulted in an alginate cake, or gel in the presence of calcium, which is relatively irreversibly adsorbed onto the membrane by humic acid associations. This study shows the importance of mutual influences between various foulants for improved understanding of fouling phenomena. Furthermore it shows that substances with a minor individual influence might have a large impact in mixed systems such as natural water.

Treatment of source-separated urine by a combination of bipolar electrodialysis and a gas transfer membrane.

Urine contains nutrients which can be applied usefully as a fertiliser in agriculture, but the relatively high pH can lead to ammonia evaporation. Electrodialysis with bipolar membranes was combined with an additional mass transfer unit in order to render a product containing ammonium and phosphate at a low pH. In one case, the additional mass transfer unit consisted of bubble columns placed in acid and basic concentrate streams, connected with a circulating gas phase. In the other case, the unit consisted of a gas-filled (hydrophobic) membrane placed in between the circulating acid and basic concentrate streams. The results showed that ammonia was transferred through the gas phase, but also carbonate, which is present in stored urine originating from the hydrolysis of urea. Although the pH in the product stream decreases initially, it rises above pH 7 at longer operation times. This pH increase can be attributed to a combination of proton compensating effects. The use of ammonia-selective membranes for the transfer into the acid concentrate could provide a solution to generate an ammonium phosphate product at low pH and high recoveries.

Copper and zinc removal from roof runoff: from research to full-scale adsorber systems.

Large, uncoated copper and zinc roofs cause environmental problems if their runoff is infiltrated into the underground or discharged into receiving waters. Since source control is not always feasible, barrier systems for efficient copper and zinc removal are recommended in Switzerland. During the last few years, research carried out in order to test the performance of GIH-calcite adsorber filters as a barrier system. Adsorption and mass transport processes were assessed and described in a mathematical model. However, this model is not suitable for practical design, because it does not give explicit access to design parameters such as adsorber diameter and adsorber bed depth. Therefore, for e.g. engineers, an easy to use design guideline for GIH-calcite adsorber systems was developed, mainly based on the mathematical model. The core of this guideline is the design of the depth of the GIH-calcite adsorber layer. The depth is calculated by adding up the GIH depth for sorption equilibrium and the depth for the mass transfer zone (MTZ). Additionally, the arrangement of other adsorber system components such as particle separation and retention volume was considered in the guideline. Investigations of a full-scale adsorber confirm the successful application of this newly developed design guideline for the application of GIH-calcite adsorber systems in practice.

Characteristics of particle-associated PAHs in a first flush of a highway runoff.

Runoff monitoring of six rainfall events was carried out in a highway, Winterthur, Switzerland focusing on first flush (runoff volume up to 2.88 mm). Six runoff events were used to investigate the characteristics of particle-associated PAHs in first flush. The fine fraction (< 45 microm) had a relatively higher contribution than the coarse fraction. A significant contribution of the coarse fraction was observed at some periods when the runoff flow rapidly increased. Fluctuation of PAH content during a runoff event was significant in the coarse fraction and, in contrast, the PAH content in the fine fraction was less fluctuating. The weighted average PAH content in each event ranged from 17 to 62 microg/g in total SS, from 23 to 54 microg/g in the fine fraction and from 16 to 84 microg/g in the coarse fraction. The loading of particle-associated PAHs from the first flush of highway runoff ranged from 0.06 to 0.22 g/ha in a total of 12 PAH species.

Dynamic behavior of fractional suspended solids and particle-bound polycyclic aromatic hydrocarbons in highway runoff.

A long-term continuous runoff monitoring was carried out in a highway in Winterthur, Switzerland. The total suspended solids (TSS) samples were fractionated into fine (< 45 microm) and coarse (> 45 microm) fraction and their wash-off behavior was studied. The fine and coarse fraction showed different wash-off behaviors. During the runoff the concentration of the fine fraction was less fluctuated compared to coarse. The fluctuation of the coarse fraction was more influenced by TSS concentration. The PAH content measurement in fine fraction showed less fluctuation compared to the coarse fraction. The PAH content in the coarse fraction was found decreasing with increasing the coarse fraction contribution to TSS.