Incidental Contamination Research Articles

Persistent contamination of a duodenoscope working channel in a non-clinical simulated ERCP setting.

Background To mitigate duodenoscope contamination, recent design enhancements have primarily focused on the distal tip. However, the working channels remain unchanged, which may be linked to biofilm formation. We assessed the persistence of microorganisms, indicative of biofilm formation, in reprocessed duodenoscopes in a non-clinical endoscopic retrograde cholangiopancreatography (ERCP) simulation setting. Methods Three new duodenoscopes were over-soiled in non-clinical ERCP simulations followed by reprocessing. After 40 tests, the Pseudomonas aeruginosa strain in the soil (Pa-type 1) was switched to a different P. aeruginosa strain (Pa-type 2) for 20 subsequent tests. Cultures of the tip and working channel were acquired after high level disinfection and overnight storage. Results One duodenoscope showed persistent growth of P. aeruginosa from the fifth test until the end of the study. Pa-type 1 remained present until the end of the study in the cultures of this duodenoscope, even after discontinuation of exposure to that specific strain. The other two duodenoscopes only showed incidental contamination. Conclusion Persistent contamination by Pa-type 1 was seen in one out of three duodenoscopes after exposure to supraphysiological levels of gut microorganisms. No clear explanation was found for this persistent contamination as exposure and handling were identical and no abnormalities of this particular duodenoscope were identified by borescope inspection.

Environmental contamination in a high-income country (France) by antibiotics, antibiotic-resistant bacteria, and antibiotic resistance genes: Status and possible causes.

Antimicrobial resistance (AMR) is a major global public health concern, shared by a large number of human and animal health actors. Within the framework of a One Health approach, actions should be implemented in the environmental realm, as well as the human and animal realms. The Government of France commissioned a report to provide policy and decision makers with an evidential basis for recommending or taking future actions to mitigate AMR in the environment. We first examined the mechanisms that underlie the emergence and persistence of antimicrobial resistance in the environment. This report drew up an inventory of the contamination of aquatic and terrestrial environments by AMR and antibiotics, anticipating that the findings will be representative of some other high-income countries. Effluents of wastewater treatment plants were identified as the major source of contamination on French territory, with spreading of organic waste products as a more diffuse and incidental contamination of aquatic environments. A limitation of this review is the heterogeneity of available data in space and time, as well as the lack of data for certain sources. Comparing the French Measured Environmental Concentrations (MECs) with predicted no effect concentrations (PNECs), fluoroquinolones and trimethoprim were identified as representing high and medium risk of favoring the selection of resistant bacteria in treated wastewater and in the most contaminated rivers. All other antibiotic molecules analyzed (erythromycin, clarithromycin, azithromycin, tetracycline) were at low risk of resistance selection in those environments. However, the heterogeneity of the data available impairs their full exploitation. Consequently, we listed indicators to survey AMR and antibiotics in the environment and recommended the harmonization of sampling strategies and endpoints for analyses. Finally, the objectives and methods used for the present work could comprise a useful example for how national authorities of countries sharing common socio-geographic characteristics with France could seek to better understand and define the environmental dimension of AMR in their particular settings.

Cheyletiella Dermatitis: A Case Report

Şeyletiella dermatiti (şeyletielloz); ana rezervuarı kedi, köpek ve tavşanlar olan Cheyletiella cinsi parazitlerin rastlantısal olarak insana bulaşması sonucu oluşan bir dermatit tablosudur. Hayvanların birbirleriyle ve dış ortamla temasının arttığı bahar aylarında sık görülür. Şeyletiella dermatiti hayvanla temastan ortalama 1-2 gün sonra ortaya çıkan sıklıkla eritemli ödemli papüllerle karakterizedir. Nadiren vezikülobüllöz ve nekrotizan lezyonlar da oluşabilir. Evcil hayvan taşıyıcı olduğu için insanla her temasdan sonra lezyonlar tekrarlayabilir. Lezyonlar dışında deride parazitin kendisi de nadiren görülebilmektedir. Ancak klinik olarak şüphelenilmediği takdirde tanı konulması zordur. Burada elli sekiz yaşında şeyletiella dermatiti tanısı konulan bir kadın hasta sunulmaktadır. Tekrarlayan kaşıntılı döküntü şikayeti ve özellikle kedi olmak üzere evcil hayvan yetiştirme öyküsü olan kişilerde ayırıcı tanıda şeyletiella dermatitinin de düşünülmesi gerektiğini vurgulamak için olgumuz sunulmuştur.

Management and evaluation of sodium [131I] iodide contamination after oral administration.

Radioiodine therapy using oral administration of Iodine-131 (I) is a widespread employed strategy for the treatment of hyperthyroidism and thyroid cancer. Such a therapy requires well-trained staff, equipment and procedures regarding radiation safety. The aims of this work are to report an incidental experience of radioprotection with a 370 MBq sodium [I] iodide capsule, which arose following vomiting one minute after the oral administration in a nuclear medicine department and assessment of capsule leakage in a stomach like environment by in vitro experiment. Measurements of the radiation dose rate at the different steps of the decontamination procedure were performed and management of the situation described. Dose rate in vomit was 113 µSv/h [directional dose equivalent H'(0.07)] after capsule withdrawal and was decreased by 10 times after the first decontamination attempt. To evaluate the I release following administration to the patient, an in vitro experiment was designed to recap capsules degradation in a stomach like environment including acidic solution (pH 1) and temperature at 35-37°c. A significant release of I (<6%) was observed in the first 2 min of the in vitro experiment. Sodium [I] iodide capsules disruption occurred at 150 s for capsule 1 and 133 s for capsule 2. Incidental contamination with I in the clinics is of important concern in nuclear medicine and precautions that allow optimization and pertinent management of the situation should be known by the nuclear medicine and radioprotection community.

DNA transfer between evidence bags: is it a means for incidental contamination of items?

ABSTRACT With the increasing sensitivity of DNA profiling systems, the opportunity to detect incidental DNA transferred between evidential items has increased. Evidence bags are assumed to be DNA transfer vectors which can cause an inadvertent transfer of DNA between items, yet little has been studied to indicate the extent of this transfer. This study aimed to provide insight into the levels of DNA accumulating on evidence bags through exhibit handling and storage. Casework exhibit bags were sampled during storage and mock exhibit bags were sampled after replicating exhibit handling protocols. DNA concentrations recovered from casework exhibit packages were highly variable and produced profiles containing up to at least seven contributors. The DNA concentration and profile complexity was higher in samples taken from packages after exhibit examination. It was observed that DNA from the exhibit can be transferred to the exterior of the bag during the process of packaging and un-packing the item. Profile complexity from mock exhibit packages increased with time spent in the exhibit storeroom. With the introduction of highly sensitive DNA profiling systems, procedures involving the handling, transport and storage of exhibits should be assessed to ensure that best-practice contamination minimization procedures are being utilized.

A novel approach for tracing mycophagous small mammals and documenting their fungal diets

We developed a method combining passive baiting (animals that are not trapped) with DNA meta-barcoding of the feces acquired, to study fungi in the diet of small mammals. Mammal and fungal species were identified using genomic DNA of 596 fecal samples collected in five regions of the eastern Canadian boreal forest. For identification of the small mammal species, the cytochrome b region was used. A total of eight species of small mammals displayed hypogeous fungi consumption, with northern flying squirrels (Glaucomys sabrinus) and red-backed voles (Myodes gapperi) as the top consumers. For identification of their fungal diets, the ribosomal internal transcribed spacer (ITS) region was used. We recovered 722 taxa of Ascomycota, 429 Basidiomycota, 81 Zygomycota, 4 Chytridiomycota, 1 Glomeromycota, and 44 unidentified fungal taxa. Of these, 28 were hypogeous sequestrate fungi (underground fructification), which presumably are dug out by small mammals for consumption. Otherwise, for the remaining fungi [epigeous (above ground fructification) or microscopic fungal species], it is unclear which ones are selected by the animal as a dietary source or result from incidental contamination. Our paper presents a promising approach for tracing mycophagy in small mammals, and our results suggest that fungal diversity is important for the diet of some small mammals.

Onychomycosis Caused by Malassezia pachydermatis in a Dog

Background: Malassezia species are commensal skin organisms of warm-blooded vertebrates that can act as opportunistic pathogens. Malassezia pachydermatis is of importance in both veterinary and human medicine. Recognised initially as causes of infection of the skin, they are now known to be superficial commensals as well as potential causes of infections in domestic animals and more serious human conditions such as fungemia. They have also been implicated in the pathogenesis of allergic and other inflammatory diseases. Onychomycosis is defined as fungal infection of the claw (nail disease) caused by dermatophytes (Microsporum and Trichophyton genus), non-dermatophyte molds (hyaline and dematiaceous) and/or yeasts. The objective of this work was to report a case of canine onychomycosis by Malassezia pachydermatis based on reference standard diagnostics of this pathology.Case: A 9-year-old male West Highland White Terrier presented history of claw abnormality: brown staining and partly brittle. The dog has no apparent history of trauma on the affected claw and no skin disease was reported. Direct examination of claw was performed using the tape strip technique revealed Malassezia organisms. Nail fragments were cultured onto Sabouraud Dextrose Agar with Chloramphenicol and Cycloheximide. After 10 days of incubation (32ºC) nail fragments allowed the isolation of pure colonies of Malassezia pachydermatis. The histopathological evaluation was performed by Sector of Veterinary Clinical Pathology, Faculdade de Veterinária (FAVET/UFRGS) and fungal infection due to Malassezia pachydermatis was confirmed by histopathologic examination (Hematoxylin and eosin and Grocott’s methenamine silver stain) of the nail, that revealed abundant yeasts (blastoconidia).Discussion: Fungal infection of the skin, hair and nails are common and are primary caused by the dermatophyte molds. Non-dermatophyte molds isolated from nails constitute a long list, but only a few species cause onychomycoses. These include Scopulariopsis brevicaulis, Fusarium sp., Acremonium spp., Aspergillus spp., Penicillium spp. Yeasts like Malassezia and Candida spp. are saprophytes and usually represent incidental contaminants associated with a non-sterile specimen at mycological culture, however in some cases they may parasite the nails and become an etiological agent of the disease. M. pachydermatis, normally present on the skin and in the ear canal of dogs and cats, can act as opportunistic pathogenic microbe and frequently causes dermatitis and otitis in mammals. In the case of onychomycosis, there is little evidence that Malassezia yeasts are implicated in nail plate invasion, although this may be a rare occurrence. All species of the genus are obligatory lipid-dependent forms, with the exception of M. pachydermatis, as well as absence of keratinolytic ability. Malassezia organisms were commonly retrieved from the subungual claw fold region of normal healthy dogs (should be considered resident microflora of the normal canine claw fold). Some authors suggests that high numbers of yeast can be detected on cytological evaluation of the skin surface of the canine claw fold from allergic dogs in both the absence and presence of concurrent signs of pruritus and paronychia.

Titanium Dioxide Nanoparticle Circulation in an Aquatic Ecosystem

Nanotechnology is a dynamically developing field of scientific and industrial interest across the entire world, and the commercialization of nanoparticles (NPs) is rapidly expanding. Incorporation of nanotechnologies into a range of manufactured goods results in increasing concern regarding the subsequent release of engineered NPs into the environment. One of the biggest threats of using NPs is the transfer and magnification of these particles in the trophic chain. The aim of the studies was the evaluation of the distribution of TiO2 NP contamination in the aquatic ecosystem under laboratory conditions. Bioaccumulation of TiO2 NPs by plants (Elodea canadensis) and fish (Danio rerio) in the source of contamination was investigated. The studies were focused on the consequences of short-term water contamination with TiO2 NPs and the secondary contamination of the components of the investigated model ecosystem (plants, sediments). It was found that in the fish and the plants exposed to NP contamination, the amount of Ti was higher than in the control, indicating an effective bioaccumulation of NPs or ions originating from NPs. It was clearly shown that the NPs present in the sediments are available to plants and fish. Additionally, the aquatic plants, an important trophic level in the food chain, can accumulate NPs and be a source of NPs for higher organisms. It was concluded that even an incidental contamination of water by NPs may result in long-term consequences induced by the release of NPs.

Assessing plant uptake and transport mechanisms of engineered nanomaterials from soil

Abstract

Sources Of Incidental Events In Collective Water Supply System

Abstract The publication presents the main types of incidental events in collective water supply system. The special attention was addressed to the incidental events associated with a decrease in water quality, posing a threat to the health and life of inhabitants. The security method against incidental contamination in the water source was described.

Analysis And Assessment Of The Security Method Against Incidental Contamination In The Collective Water Supply System

Abstract The paper presents the main types of surface water incidental contaminations and the security method against incidental contamination in water sources. Analysis and assessment the collective water supply system (CWSS) protection against incidental contamination was conducted. Failure Mode and Effects Analysis (FMEA) was used. The FMEA method allow to use the product or process analysis, identification of weak points, and implementation the corrections and new solutions for eliminating the source of undesirable events. The developed methodology was shown in application case. It was found that the risk of water contamination in water-pipe network of the analyzed CWSS caused by water source incidental contamination is at controlled level.

Using a forensic science approach to minimize environmental contamination and to identify microfibres in marine sediments

There is growing evidence of extensive pollution of the environment by microplastic, with microfibres representing a large proportion of the microplastics seen in marine sediments. Since microfibres are ubiquitous in the environment, present in the laboratory air and water, evaluating microplastic pollution is difficult. Incidental contamination is highly likely unless strict control measures are employed. Here we describe methods developed to minimize the amount of incidental post-sampling contamination when quantifying marine microfibre pollution. We show that our protocol, adapted from the field of forensic fibre examination, reduces fibre abundance by 90% and enables the quick screening of fibre populations. These methods therefore allow an accurate estimate of microplastics polluting marine sediments. In a case study from a series of samples collected on a research vessel, we use these methods to highlight the prevalence of microfibres as marine microplastics.

High-Throughput Biosensors for Multiplexed Food-Borne Pathogen Detection

Incidental contamination of foods by pathogenic bacteria and/or their toxins is a serious threat to public health and the global economy. The presence of food-borne pathogens and toxins must be rapidly determined at various stages of food production, processing, and distribution. Producers, processors, regulators, retailers, and public health professionals need simple and cost-effective methods to detect different species or serotypes of bacteria and associated toxins in large numbers of food samples. This review addresses the desire to replace traditional microbiological plate culture with more timely and less cumbersome rapid, biosensor-based methods. Emphasis focuses on high-throughput, multiplexed techniques that allow for simultaneous testing of numerous samples, in rapid succession, for multiple food-borne analytes (primarily pathogenic bacteria and/or toxins).

Previously uncharacterized Salmonella enterica genes required for swarming play a role in seedling colonization

Incidences of bacterial foodborne illness caused by ingestion of fresh produce are rising. Instead of this being due to incidental contamination, the animal pathogen Salmonella enterica utilizes specific molecular mechanisms to attach to and colonize plants. This work characterizes two S. enterica genes of unknown function: a putative periplasmic protein, STM0278, and a putative protein with a hydrolase in the C-terminus, STM0650. STM0278 and STM0650 are important for seedling colonization but appear to have different roles during the process of colonization. Mutants of either STM0278 or STM0650 showed reduced colonization of alfalfa seedlings at 24 h, and the STM0278 mutant also showed reduced colonization at 48 h. Both genes were expressed in planta at 4 h following inoculation of 3-day-old seedlings and at 72 h after seed inoculation. This suggests that the role of STM0650 in seedling colonization is less important later in the process or is duplicated by other mechanisms. Mutants of STM0278 and STM0650 were defective in swarming. The STM0278 mutant failed to swarm in 24 h, while swarming of the STM0650 mutant was delayed. Addition of surfactant restored swarming of the STM0278 mutant, suggesting that STM0278 is involved in surfactant or osmotic agent production or deployment. Alfalfa seed exudates as the sole nutrient source were capable of perpetuating S. enterica swarming. Sequence analysis revealed sequences homologous to STM0278 and STM0650 in plant-associated bacteria, but none in Escherichia coli. Phylogenetic analysis of STM0650 showed similar sequences from diverse classes of plant-associated bacteria. Bacteria that preferentially colonize roots, including S. enterica, may use a similar hydrolase for swarming or biofilm production on plants. Multicellular behaviours by S. enterica appear central to plant colonization. S. enterica genes involved in plant colonization and survival outside of a host are most likely among the 'function unknown' genes of this bacterium.

A risk-assessment model to rate the occurrence and relevance of adventitious agents in the production of influenza vaccines

Influenza vaccine production has traditionally relied on the use of embryonated chicken eggs for virus isolation and propagation, but recently, cell-culture-derived manufacturing methods have been introduced. During influenza vaccine production, by either conventional or cell culture methods, there is a risk of incidental contamination by adventitious agents. Thus, a risk-assessment model has been developed to qualitatively assess the potential risk of vaccine process contamination by viral pathogens. The model takes into account the basic growth characteristics of each virus, its ability to grow in different cell substrates and resistance to processing steps during vaccine manufacture. The risk-assessment model has been applied to various pathogens to determine potential risk and relevance in different manufacturing scenarios, using different cell substrates for virus propagation, including Madin–Darby canine kidney (MDCK) cells. Avian viruses, introduced via use of embryonated eggs for virus isolation, were found to present the greatest risk, irrespective of the substrate used for influenza virus propagation. The use of MDCK cells to propagate vaccine virus from egg-isolated influenza virus strains does not introduce a new or greater adventitious virus risk, compared with egg-based vaccine production. Indeed, the adventitious virus risk is potentially reduced as fewer viruses are able to grow in MDCK cells.

Can povidone-iodine solution be used safely in a spinal surgery?

Intra-operative incidental contamination of surgical wounds is not rare. Povidone-iodine solution can be used to disinfect surgical wounds. Although povidone-iodine is a good broad-spectrum disinfecting agent, it has occasionally been reported to have a negative effect on wound healing and bone union. Therefore, its safety in a spinal surgery is unclear. A prospective, single-blinded, randomized study was accordingly conducted to evaluate the safety of povidone-iodine solution in spinal surgeries. Ascertained herein was the effect of wound irrigation with diluted povidone-iodine solution on wound healing, infection rate, fusion status and clinical outcome of spinal surgeries. From January 2002 to August 2003, 244 consecutive cases undergoing primary instrumented lumbosacral posterolateral fusion due to degenerative spinal disorder with segmental instability had been collected and randomly divided into two groups: the study group (120 cases, 212 fusion levels) and the control group (124 cases, 223 fusion levels). Excluded were those patients with a prior spinal surgery, spinal trauma, malignant tumor, infectious spondylitis, rheumatoid arthritis, ankylosing spondylitis, metabolic bone disease, skeletal immaturity or with an immunosuppressive treatment. In the former group, wounds were irrigated with 0.35% povidone-iodine solution followed by normal saline solution just before the bone-grafting and instrumentation procedure. However, only with normal saline solution in the latter. All the operations were done by the same surgeon with a standard technique. All the patients were treated in the same postoperative fashion as well. Later on, wound healing, infection rate, spinal bone fusion and clinical outcome were evaluated in both groups. A significant improvement of back and leg pain scores, modified Japanese Orthopedic Association function scores (JOA) and ambulatory capacity have been observed in both groups. One hundred and seven patients in the study group and one hundred and nine in the control group achieved solid union. There was no infection in the study group but six deep infections in the control group. Wound dehiscence was noted in one group 1 and two group 2 patients. A subsequent statistical analysis revealed higher infection rate in the control group (P<0.05), but no significant difference in fusion rate, wound healing, improvement of pain score, function score and ambulatory capacity between the two groups. Diluted povidone-iodine solution can be used safely in spinal surgeries, and it will not influence wound healing, bone union and clinical outcome.

Occurrence and growth characteristics ofEscherichia coliand enterococci within the accumulated fluid of the northern pitcher plant (Sarracenia purpureaL.)

Sarracenia purpurea L., a carnivorous bog plant (also known as the pitcher plant), represents an excellent model of a well-defined, self-contained ecosystem; the individual pitchers of the plant serve as a microhabitat for a variety of micro- and macro-organisms. Previously, fecal indicator bacteria (Escherichia coli and enterococci) were shown as incidental contaminants in pitcher fluid; however, whether their occurrence in pitcher fluid is incidental or common has not been established. The purpose of this study was to investigate the occurrence, distribution, and growth potential of E. coli and enterococci in pitcher plant fluid from a protected bog in northwest Indiana. Escherichia coli and enterococci were recovered in pitcher fluids (n=43 plants), with mean densities (log CFU mL-1) of 1.28+/-0.23 and 1.97+/-0.27, respectively. In vitro experiments showed that E. coli growth in fluid not containing insects or indigenous organisms was directly proportional to the fluid concentration (growth was 10-fold in 24 h in 100% fluid); however, in the presence of other indigenous organisms, E. coli and enterococci were only sustained for 5 days at 26 degrees C. Pulsed-field gel electrophoresis (PFGE) analysis showed that the plant Enterococcus faecalis isolates were genetically distinct from the human isolates; identical PFGE patterns were observed among plant isolates that fell into one of six clonal groups. These findings suggest that (i) E. coli and enterococci occurrence in pitcher plants is rather common in the bog studied, although their originating source is unclear, and (ii) the pitcher fluid contains adequate nutrients, especially carbon and energy sources, to promote the growth of indicator bacteria; however, under natural conditions, the biotic factors (e.g., competition for nutrients) may restrict their growth.

Respirator Filter Reuse Test Using the Laboratory Simulant Mycobacterium Tuberculosis (H37RA Strain)

All respirators certified under Title 42, Code of Federal Regulations, Part 84, can be used by healthcare workers for protection against Mycobacterium tuberculosis (Mtb). Questions have been raised regarding the possibility of the respirator becoming contaminated with Mtb or other organisms due to reuse, handling, and storage in plastic bags. This study was conducted to: (1) determine whether, and for how long, avirulent Mtb (strain H37Ra) survives on respirator material, and (2) measure levels of contamination (assess contamination by environmental bacteria and fungi due to storage in airtight bags) potentially spread to the respirator's interior surface due to normal mechanical handling (removal and re-insertion of the respirator into airtight bag). Six models of filtering facepiece respirators were challenged with a concentration of 105 to 106 colony forming units (CFUs) H37Ra per liter of air in a steady flow system. Respirator interior and exterior surfaces were swab sampled on days -1 (prior to exposure), 0 (day of exposure), 1, 3, 7, 10, 14, 21, and 28. Between samplings, each respirator was stored at room temperature in a Zip-lock™ bag. Seven days after exposure the number of viable organisms decreased from a mean range of 27 to 131 colony forming units per square centimeter (CFU/cm2) to zero CFU/cm2 on the exterior of the different respirator models. While several respirators had interior contamination immediately following challenge, no transfer of exterior H37Ra was observed. Some colony growth was recoverable from day 14 to 28 indicating there was some incidental contamination with environmental bacteria to the interior of the respirator after repeated handling and storage.

Fate of Bacterial Pathogens and Indicator Organisms in Liquid Sweeteners

The survival of pathogenic and indicator microorganisms in liquid sweeteners was studied. Seven sweeteners—liquid sucrose, 42% high-fructose corn symp (HFCS), 55% HFCS, 25 DE (dextrose equivalent) com syrup (CS), 36 DE CS, 63 DE CS, 50% medium invert sucrose, and 65% high-maltose com syrup (HMCS) were inoculated with Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and coliforms at a level of 105 cells per g. The inoculated products were stored both at or near their normal holding temperatures (32 to 46°C) and at 26.7°C (the lower limit during transportation). In most of the products the number of microorganisms fell below the detection limit in less than 3 days when the sweeteners were stored at their normal holding temperatures. However, in liquid sucrose S. aureus survived up to 2 weeks. When the products were stored at 26.7°C, the reduction in the number of microorganisms occurred at a slower rate. At 26.7°C the fastest rates of reduction were observed in 42 and 55% HFCS and in 50% medium invert sucrose. In these products the number of bacteria fell below the detection limit in 3 to 6 days. The slowest rate of the reduction was observed in the liquid sucrose, in which S. aureus survived up to 1 month. These results indicate that incidental contamination of liquid sweeteners with microbial pathogens will not present a public health or regulatory hazard.

Glyphosate–sediment interactions and phytotoxicity in turbid water

AbstractIn aquatic situations it was expected that adsorption by sediments and suspended solids would influence the movement of glyphosate away from the application zone and attenuate its phytotoxicity. However, the results of two experiments showed that only a minor proportion of glyphosate was adsorbed onto suspended solids, even in turbid irrigation water. Phytotoxicity, as measured by the effect on the root growth of safflower (Carthamus tinctorius L.), was not significantly reduced. Where glyphosate was intentionally injected into flowing water of contrasting quality to simulate incidental contamination of water during foliage treatment, adsorption by benthic sediments attenuated loads of glyphosate only slowly. The attenuation was 13–27% for each kilometre of travel downstream, as compared to 31% observed previously. However, when glyphosate was sprayed onto the sediment exposed after channel draining, less than 7% of the glyphosate applied was subsequently eluted. Consequently, draining before treatment should be an effective strategy for minimising the contamination of irrigation water.