Decontamination of clothing and building materials associated with the clandestine production of methamphetamine

This study was designed to determine how easily methamphetamine can be removed from clothing and building materials, utilizing different cleaning materials and methods. The study also addressed the penetration of methamphetamine into drywall and the ability of paints to encapsulate the methamphetamine on drywall. Clothing and building materials were contaminated in a stainless steel chamber by aerosolizing methamphetamine in a beaker heater. The amount of methamphetamine surface contamination was determined by sampling a grid pattern on the material prior to attempting to clean the materials. After cleaning, the materials were again sampled, and the degree of decontamination noted. We found that household clothing and response gear worn by first responders was easily decontaminated using a household detergent in a household washing machine. A single wash removed over 95% of the methamphetamine from these materials. The study also indicated that methamphetamine-contaminated, smooth non-porous surfaces can be easily cleaned to below detectable levels using only mild cleaners. More porous surfaces such as plywood and drywall were unlikely to be decontaminated to below regulatory levels even with three washes using a mild cleaner. This may be due to methamphetamine penetration into the paint on these surfaces. Evaluation of methamphetamine contamination on drywall indicated that approximately 40% of the methamphetamine was removed using a wipe, while another 60% remained in the paint layer. Stronger cleaners such as those with active ingredients including sodium hypochlorite or quaternary ammonia and commercial decontamination agents were more effective than mild detergent-based cleaners and may reduce methamphetamine contamination to below regulatory levels. Results from the encapsulation studies indicate that sprayed on oil-based paint will encapsulate methamphetamine on drywall and plywood surfaces up to 4.5 months, while latex paints were less effective.     

Transfer efficiencies of pesticides from household flooring surfaces to foods

The transfer of pesticides from household surfaces to foods was measured to determine the degree of excess dietary exposure that occurs when children's foods contact contaminated surfaces prior to being eaten. Three household flooring surfaces (ceramic tile, hardwood, and carpet) were contaminated with an aqueous emulsion of commercially available pesticides (diazinon, heptachlor, malathion, chlorpyrifos, isofenphos, and cis- and trans-permethrin) frequently found in residential environments. A surface wipe method, as typically used in residential exposure studies, was used to measure the pesticides available on the surfaces as a basis for calculating transfer efficiency to the foods. Three foods (apple, bologna, and cheese) routinely handled by children before eating were placed on the contaminated surfaces and transfers of pesticides were measured after 10 min contact. Other contact durations (1 and 60 min) and applying additional contact force (1500 g) to the foods were evaluated for their impact on transferred pesticides. More pesticides transferred to the foods from the hard surfaces, that is, ceramic tile and hardwood flooring, than from carpet. Mean transfer efficiencies for all pesticides to the three foods ranged from 24% to 40% from ceramic tile and 15% to 29% from hardwood, as compared to mostly non-detectable transfers from carpet. Contact duration and applied force notably increased pesticide transfer. The mean transfer efficiency for the seven pesticides increased from around 1% at 1 min to 55- 83% when contact duration was increased to 60 min for the three foods contacting hardwood flooring. Mean transfer efficiency for 10-min contact increased from 15% to 70% when a 1500 g force was applied to bologna placed on hardwood flooring. Contamination of food occurs from contact with pesticide-laden surfaces, thus increasing the potential for excess dietary exposure of children.     

Screening for faecal contamination in primary schools in Crete, Greece

Background   Hygienic conditions in primary schools are a major concern for both governmental organizations and families. Particularly, the occurrence of faecal indicators on children's hands and various school surfaces has been associated with increased risk of diarrhoeal diseases. The presence of faecal streptococci on environmental surfaces and children's hands and the possible correlation with socio-economic factors were examined.
Methods   Overall, 1956 samples from hands and 1470 samples from surfaces were collected from 20 primary schools in Heraklion, Crete, Greece.
Results   Faecal streptococci were found at 52.9% of children's hands and at 16.7% of other surfaces. Children, who had parents with the highest education level (>12 years), had the lowest percentage (48.8%) of faecal contamination on their hands. Furthermore, boys exhibited higher levels of hands contamination compared with girls. Among the environmental surfaces examined, the school canteen reception was the most contaminated area.
Conclusion   High faecal contamination was detected in primary schools in the examined region. Children's hands were highly infected (52.9%), while boys exhibited higher levels of contamination. The educational level of parents correlated well with the contamination of children's hands.     

Faecal contamination on children's hands and environmental surfaces in primary schools in Leeds.

Gastro-intestinal diseases continue to be a major health problem in primary schools in the UK. This study, which took place in 20 primary schools in the Leeds area, investigated the presence of faecal indicator bacteria on children''s hands and environmental surfaces. Faecal streptococci were used as an indicator of faecal contamination. A handwashing knowledge score was developed for each child. Those children with good hygiene knowledge had less faecal contamination on their hands (relative risk: 1.4, 95% CI = 1.09-1.81, P = 0.005). Those schools with higher hand counts were more likely to have had a reported outbreak of gastroenteritis in the past. Values of the Townsend Deprivation Index, an indicator of deprivation, were compared with the hand results and those schools in high deprivation areas had higher hand counts. Of the swabs taken from surfaces in the toilet areas and classrooms, the carpets in the classrooms were the most frequently contaminated surfaces.     

Proposal for the assessment to quantitative dermal exposure limits in occupational environments: Part 2. Feasibility study for application in an exposure scenario for MDA by two different dermal exposure sampling methods

OBJECTIVE: To evaluate two different techniques for assessing dermal exposure to 4,4'-methylene dianiline (MDA) in a field study. The results were used to test the applicability of a recently proposed quantitative dermal occupational exposure limit (DOEL) for MDA in a workplace scenario. METHODS: For two consecutive weeks six workers were monitored for exposure to MDA in a factory that made glass fibre reinforced resin pipes. Dermal exposure of the hands and forearms was assessed during week 1 by a surrogate skin technique (cotton monitoring gloves) and during week 2 by a removal technique (hand wash). As well as the dermal exposure sampling, biological monitoring, measurement of MDA excretion in urine over 24 hours, occurred during week 2. Surface contamination of the workplace and equipment was monitored qualitatively by colorimetric wipe samples. RESULTS AND CONCLUSIONS: Geometric means of daily exposure ranged from 81-1762 micrograms MDA for glove monitoring and from 84-1783 micrograms MDA for hand washes. No significant differences, except for one worker, were found between exposure of the hands in weeks 1 and 2. Significant differences between the mean daily exposure of the hands (for both weeks and sampling methods) were found for all workers. The results of the colorimetric wipe samples indicated a general contamination of the workplace and equipment. Excretion of MDA in 24 hour urine samples ranged from 8 to 249 micrograms MDA, whereas cumulative MDA excretion over a week ranged from 82 to 717 micrograms MDA. Cumulative hand wash and MDA excretion results over a week showed a high correlation (R2 = 0.94). The highest actual daily dermal exposure found seemed to be about 4 mg (hand wash worker A on day 4), about 25% of the external DOEL. Testing of compliance by means of a biological limit value (BLV) led to similar results for the same worker. It is concluded that both dermal exposure monitoring methods were applicable and showed a compatible performance in the present exposure scenario, where the exposure relevant to dermal absorption is considered mainly restricted to hands. The concept for a DOEL seemed to be relevant and applicable for compliance testing and health surveillance in the situation under investigation.     

Determination of dermal exposures during mixing, spraying and wiping activities

Dermal exposure measurements were collected as part of RISKOFDERM, a European dermal exposure study which aims to improve the understanding of the nature and range of dermal exposures to hazardous substances throughout the European Union. Exposure measurements were collected to enable a predictive model to be developed for regulatory risk assessment purposes. In this paper dermal exposure data are presented for three generic job tasks: spray painting, wiping surfaces and mixing/dilution of formulations. The particular workplace settings included a dockyard and three medical laboratories. In the dockyard the tasks involved spray application and mixing of anti-foulant paint. For laboratory workers the observed tasks were preparation of biocide solution and wiping of surfaces with the disinfectant. Each dermal exposure measurement was derived from the mass of trace analyte on cotton gloves and 11 fabric patches, which were cut from whole-body dosimeters, representing the main anatomical areas of the body. The percentage mass of trace analyte in the formulation was determined by analysis to enable the total mass of the product on the anatomical areas to be calculated. The sampling periods were recorded to enable calculation of the dermal exposure rate, which is expressed as micro g total formulation/cm(2)/h. The geometric mean dermal exposure rate for the hands during spray painting was 2760 micro g/cm(2)/h (n = 24). The exposure rate for the rest of the body was 175 micro g/cm(2)/h (n = 35). Mixing of the paint involved higher exposure rates for both the hands and body, with a geometric mean of 31 200 micro g/cm(2)/h (n = 9) for the hands and 327 micro g/cm(2)/h (n = 14) for the rest of the body. For small-scale routine disinfection of surfaces using small quantities of biocide the principal anatomical area affected was the hands, with a geometric mean dermal exposure rate of 1840 micro g/cm(2)/h (n = 6). During systematic disinfection of laboratory surfaces with larger quantities of the biocide solution, the geometric mean dermal exposure rate for the hands was increased to 139 000 micro g/cm(2)/h (n = 24). In this case there was increased exposure of the body: principally the arms, legs, chest and head. The measured dermal exposure rate during preparation of the biocides (mixing) was very low, with a geometric mean value for the hands of 13 micro g/cm(2)/h (n = 16). There was a high level of variability observed in the results within each task. It is suggested that dermal exposures are partly dependent on human behaviour and on the occurrence of accidental contact with contaminated surfaces. This makes interpretation of the results difficult for predictive risk assessment purposes.     

Dermal exposure to cyclophosphamide in hospitals during preparation, nursing and cleaning activities

Objectives: To determine levels of potential and actual dermal exposure to cyclophosphamide (CP) during performance of oncology-related tasks in hospitals and to investigate the relationship with potential sources and surface contamination levels of CP. Methods: Dermal exposure to CP was determined for tasks with potential exposure to CP: preparation of CP, decanting of patients urine, washing of the patient, removal of bed sheets of treated patients and cleaning of patients toilets on oncology wards. Exposure was assessed by the collection of nitrile and latex protective medical gloves (potential exposure), washing of hands (actual exposure), from cotton pads attached to (un)covered forearms (potential or actual exposure) and a wipe sample of the forehead (actual exposure). Bulk samples (i.e. application fluids and patients excreta) and possible contact surfaces were monitored to assess the amount of CP available for dermal exposure. Results: Pharmacy technicians, oncology nurses and cleaning personnel showed actual and potential dermal exposure to CP during performance of their daily duties. Exposure occurred predominantly on the hands and sporadically on the forehead and forearms. Although all nurses used gloves during handling of patients urine and sometimes during the other nursing tasks, skin underneath gloves was repeatedly contaminated. Results of tests on bulk and surface contamination samples confirmed that patients intravenously treated with CP excrete the unmetabolised drug, which could subsequently lead to dermal exposure of hospital personnel. A clear relationship was found between dermal exposure levels and direct sources of exposure for all tasks, except for handling patients urine. Conclusions: We demonstrated for the first time that actual dermal exposure to CP is common among oncology nurses working with patients treated with this anti-neoplastic drug. Pharmacy technicians and cleaning personnel, on the other hand, are potentially exposed to CP, and protection provided by gloves seemed to be sufficient.     

Developing probability distributions for transfer efficiencies for dermal exposure

Many dermal exposure models use stochastic techniques to sample parameter distributions derived from experimental data to more accurately represent variability and uncertainty. Transfer efficiencies represent the fraction of a surface contaminant transferred from the surface to the skin during a contact event. Although an important parameter for assessing dermal exposure, examination of the literature confirms that no single study is large enough to provide a basis for a transfer efficiency distribution for use in stochastic dermal exposure models. It is therefore necessary to combine data sets from multiple studies to achieve the largest data set possible for distribution analysis. A literature review was conducted to identify publications reporting transfer efficiencies. Data sets were compared using the Kruskal-Wallis test to determine whether they arise from the same distribution. Combined data were evaluated for several theoretical distributions using the Kolmogorov-Smirnov and chi(2)-goodness-of-fit tests. Our literature review identified 35 studies comprising 25 different sampling methods, 25 chemicals, and 10 surface types. Distributions were developed for three different chemicals (chlorpyrifos, pyrethrin I, and piperonyl butoxide) on three different surface types (carpet, vinyl, and foil). Only the lognormal distribution was consistently accepted for each chemical and surface combination. Fitted distributions were significantly different (Kruskal-Wallis test; P<0.001) across chemicals and surface types. In future studies, increased effort should be placed on developing large studies, which more accurately represent transfer to human skin from surfaces, and on developing a normative transfer efficiency measure so that data from different methodologies can be compared.     

Impact of a hygiene intervention on virus spread in an office building

Viral illnesses have a significant direct and indirect impact on the workplace that burdens employers with increased healthcare costs, low productivity, and absenteeism. Workers' direct contact with each other and contaminated surfaces contributes to the spread of viruses at work. This study quantifies the impact of an office wellness intervention (OWI) to reduce viral load in the workplace. The OWI includes the use of a spray disinfectant on high-touch surfaces and providing workers with alcohol-based hand sanitizer gel and hand sanitizing wipes along with user instructions. Viral transmission was monitored by applying an MS2 phage tracer to a door handle and the hand of a single volunteer participant. At the same time, a placebo inoculum was applied to the hands of four additional volunteers. The purpose was to evaluate the concentration of viruses on workers' hands and office surfaces before and after the OWI. Results showed that the OWI significantly reduced viable phage concentrations per surface area on participants' hands, shared fomites, and personal fomites (p?=?0.0001) with an 85.4% average reduction. Reduction of virus concentrations on hands and fomites is expected to subsequently minimize the risk of infections from common enteric and respiratory pathogens. The surfaces identified as most contaminated were the refrigerator, drawer handles and sink faucets in the break room, along with pushbar on the main exit of the building, and the soap dispensers in the women's restroom. A comparison of contamination in different locations within the office showed that the break room and women's restrooms were the sites with the highest tracer counts. Results of this study can be used to inform quantitative microbial risk assessment (QMRA) models aimed at defining the relationship between surface contamination, pathogen exposure and the probability of disease that contributes to high healthcare costs, absenteeism, presenteeism, and loss of productivity in the workplace.     

Dermal exposure during filling, loading and brushing with products containing 2-(2-butoxyethoxy)ethanol

INTRODUCTION: Limited quantitative information is available on dermal exposure to chemicals during various industrial activities. Therefore, within the scope of the EU-funded RISKOFDERM project, potential dermal exposure was measured during three different tasks: filling, loading and brushing. DEGBE (2-(2-butoxyethoxy)ethanol) was used as a 'marker' substance to determine dermal exposure to the products that workers were handling. METHODS: Potential whole body exposure was measured using self-constructed cotton sampling pads on 11 body locations. Cotton gloves were used to determine the contamination of both hands. Bulk samples were collected to determine the concentration of DEGBE so as to be able to calculate exposure to the handled product. RESULTS: A total of 94 task-based measurements were performed, 30 on filling, 28 on loading and 36 on brushing, which resulted in potential dermal hand exposure to the handled product of 4.1-18 269 mg [geometric mean (GM) 555.4, n = 30], 0.3-27745 mg (GM 217.0, n = 28) and 11.3-733.3 mg (GM 98.4, n = 24) for each of the scenarios, respectively. Potential whole body exposure to the product during filling and loading ranged from 1.67 to 155.0 (GM 15.2, n = 9) and 相似文献   

A study quantifying the hand-to-face contact rate and its potential application to predicting respiratory tract infection

A substantial portion of human respiratory tract infection is thought to be transmitted via contaminated hand contact with the mouth, eyes, and/or nostrils. Thus, a key risk factor for infection transmission should be the rate of hand contact with these areas termed target facial membranes. A study was conducted in which 10 subjects were each videotaped for 3 hr while performing office-type work in isolation from other persons. The number of contacts to the eyes, nostrils, and lips was scored during subsequent viewing of the tapes. The total contacts per subject had sample mean x = 47 and sample standard deviation s = 34. The average total contact rate per hour was 15.7. The authors developed a relatively simple algebraic model for estimating the dose of pathogens transferred to target facial membranes during a defined exposure period. The model considers the rate of pathogen transfer to the hands via contact with contaminated environmental surfaces, and the rate of pathogen loss from the hands due to pathogen die-off and transfer from the hands to environmental surfaces and to target facial membranes during touching. The estimation of infection risk due to this dose also is discussed. A hypothetical but plausible example involving influenza A virus transmission is presented to illustrate the model.     

Transfer of bacteriophage MS2 and fluorescein from N95 filtering facepiece respirators to hands: Measuring fomite potential

Contact transmission of pathogens from personal protective equipment is a concern within the healthcare industry. During public health emergency outbreaks, resources become constrained and the reuse of personal protective equipment, such as N95 filtering facepiece respirators, may be needed. This study was designed to characterize the transfer of bacteriophage MS2 and fluorescein between filtering facepiece respirators and the wearer's hands during three simulated use scenarios. Filtering facepiece respirators were contaminated with MS2 and fluorescein in droplets or droplet nuclei. Thirteen test subjects performed filtering facepiece respirator use scenarios including improper doffing, proper doffing and reuse, and improper doffing and reuse. Fluorescein and MS2 contamination transfer were quantified. The average MS2 transfer from filtering facepiece respirators to the subjects' hands ranged from 7.6–15.4% and 2.2–2.7% for droplet and droplet nuclei derived contamination, respectively. Handling filtering facepiece respirators contaminated with droplets resulted in higher levels of MS2 transfer compared to droplet nuclei for all use scenarios (p = 0.007). MS2 transfer from droplet contaminated filtering facepiece respirators during improper doffing and reuse was greater than transfer during improper doffing (p = 0.008) and proper doffing and reuse (p = 0.042). Droplet contamination resulted in higher levels of fluorescein transfer compared to droplet nuclei contaminated filtering facepiece respirators for all use scenarios (p = 0.009). Fluorescein transfer was greater for improper doffing and reuse (p = 0.007) from droplet contaminated masks compared to droplet nuclei contaminated filtering facepiece respirators and for improper doffing and reuse when compared improper doffing (p = 0.017) and proper doffing and reuse (p = 0.018) for droplet contaminated filtering facepiece respirators. For droplet nuclei contaminated filtering facepiece respirators, the difference in MS2 and fluorescein transfer did not reach statistical significance when comparing any of the use scenarios. The findings suggest that the results of fluorescein and MS2 transfer were consistent and highly correlated across the conditions of study. The data supports CDC recommendations for using proper doffing techniques and discarding filtering facepiece respirators that are directly contaminated with secretions from a cough or sneeze.     

Residual moisture determines the level of touch-contact-associated bacterial transfer following hand washing.

We report here a new and critical determinant of the effectiveness of hand hygiene procedures, namely the amount of residual moisture left on the hands after washing and drying. When samples of skin, food and utilities were touched with wet, undried hands, microbial numbers in the order of 68000, 31000 and 1900 respectively translocated to these representative surfaces. Bacterial numbers translocating on touch contact decreased progressively as drying with an air or cloth towel system removed residual moisture from the hands. A 10 s cloth towel-20 s air towel protocol reduced the bacterial numbers translocating to skin, food and utilities on touch contact to 140, 655 and 28 respectively and achieved a 99.8, 94 and 99% reduction in the level of bacterial translocation associated with wet hands. Careful hand drying is a critical factor determining the level of touch-contact-associated bacterial transfer after hand washing and its recognition could make a significant contribution towards improving handcare practices in clinical and public health sectors.     

Methodology for assessing occupational dermal exposure

BACKGROUND: Dermal risk assessment of exposure to chemicals is difficult due to the lack of standardisation of the methods used in exposure quantification; further limits concern the extent of skin contamination and especially dermal absorption of different substances. To solve these problems many authors proposed conceptual models founded on theoretical assumptions and experimental data, but their use in occupational settings revealed many difficulties. A possible alternative is the use of a check-list that permits evaluation of occupational dermal contamination hazards. AIMS: To propose a simplified method for dermal risk assessment. METHODS: Dermal contamination risk evaluation, chemical hazard quantification and duration of exposure are the basic features of the method. The first step assesses working conditions, use of protective devices, skin contamination directly observed, personal hygiene of workers: all information, collected by a trained observer, is scored according to literature data and/or to authors'personal experience. Chemical hazard quantfication is obtained from safety data sheet evaluation (R phrases classification and chemical-physical characteristics of the chemical in use). The method allows a preliminary dermal exposure assessment to be made, subdivided on hazard bands. RESULTS: The method permits a rapid dermal exposure assessment to be made and suggests intervention measures to decrease dermal risk. CONCLUSIONS: A check-list is proposed that can be a useful and easy method to assess dermal exposure to chemicals, particularly in small- and medium-sized enterprises.     

An assessment of dermal exposure to heavy fuel oil (HFO) in occupational settings

Heavy fuel oil (HFO) components are a group of heavy petroleum streams produced in oil refineries from crude oil. Due to its physicochemical properties, the dermal route is an important route of exposure. However, no information on dermal exposure levels for HFO has previously been published. A method for measuring dermal HFO levels was developed using wipe sampling and measuring phenanthrene and naphthalene as markers of HFO exposure. Measurement surveys were carried out in four different types of facilities: oil refineries, distribution terminals, energy providers, and an engine building and repair company. Dermal wipe samples were collected from different anatomical regions: neck, hands, and forearms. The frequency of tasks with potential for dermal HFO exposure was generally low at these facilities, with the exception of the distribution terminals and the engine building and repair site. The geometric mean (GM) dermal load on the hands was ～0.1 μg cm(-2) for both left and right hand and 0.013 and 0.019 μg cm(-2) for the left and right forearm, respectively. With one exception, all results from the neck samples were below the limit of detection. The highest dermal loads for the hands and forearms were found in the engine building and repair facility (hands: GM = 1.6 μg cm(-2); forearms: GM = 0.41 μg cm(-2)). The tasks with the highest dermal loads were the maintenance (hands: GM = 1.7 μg cm(-2)) and cleaning tasks (hands: GM = 0.24 μg cm(-2)). Actual dermal loads were low when compared with workplace dermal exposure measurements reported by other researchers for similar scenarios with other substances. This may be explained by high compliance of gloves use by workers during HFO handling tasks and likely avoidance of contact with HFO due to its high viscosity and the requirement to keep HFO at elevated temperatures during storage, transport, and use.     

Influence of sebum and stratum corneum hydration on pesticide/herbicide collection efficiencies of the human hand

The adhesion of house dust particles and chemical residues to the hands after contact with a variety of surfaces can yield significant exposures to children. Chemicals present on the surface or absorbed into house dust particles may adhere to the hands and subsequently are available for ingestion or absorption through the skin under normal physiological conditions. Contact of a hand with a surface occurs primarily through a thin layer of sebum and sweat on the skin surface. The study presented here examined the effect of the composition of the sebum and sweat layer on the adhesion of a mixture of pesticides and a herbicide to a hand after contact with a house-dust-laden surface. Collection efficiencies on the hand for atrazine and malathion were correlated with sebum levels on the palm of an individual hand. The increase in sebum values measured in this study caused a 13 percent and 8 percent reduction in collection efficiency, respectively, for atrazine and malathion applied to house-dust-laden surfaces. Diazinon and chlorpyrifos collection efficiencies were correlated with skin hydration levels measured on the palm of the individual's hand. The increased skin hydration measured in this study caused a 7 percent and 5 percent reduction in collection efficiency, respectively, for diazinon and chlorpyrifos.     

Influence of wear, pile height, and cleaning method on removal of mite allergen from carpet

Carpet is a major sink for house dust mite allergen. Vacuum extraction methods have been shown to reduce concentrations of such allergen in dust, but the influence of carpet construction and cleaning parameters on the efficiency of extraction is poorly understood. The objective of this study was to determine the effect of construction, degree of wear, and cleaning method on ease of removal of the primary allergen (Der f I) derived from the North American house-dust mite, Dermatophagoides Farinae. Carpets of different pile heights were seeded with house dust, some were then subjected to artificial wear, and all were then either dry vacuumed or wet extracted. The Der f I content of carpet cores was measured at each stage. As a result, the degree of wear and pile height were shown to be the two most important factors determining ease of Der f I removal from carpet. For worn carpet, dry vacuuming of short pile constructions was shown to be significantly more effective (p 61%) for unworn carpet than for worn carpet (<30%). Only minor differences between types of cleaning method (wet vs. dry) were found. This study suggests that carpets differ greatly in their propensity to retain allergens, and that a consideration of carpet age, construction, and cleaning regime is important when advising the merits of different floor covering types, and on allergen avoidance techniques.     

Decanting--a source of contamination of enteral feeds?

The techniques of opening and decanting ready-to-use enteral feeds packaged in bottles (crown-cap and screw-cap), cans and tetrapaks were evaluated as potential routes for the contamination of these feeds. It was found that the outsides of the feed containers, bottle openers, scissors and the experimenters' hands all acted as sources of contamination during the transfer of feeds to the nutrient container. The main source of contamination appeared to be the experimenters' hands with counts up to 10(2) cfu ml(-1) being recorded for feeds that had been decanted from screw-cap bottles, cans and tetrapaks by experimenters with either unprotected bare hands or hands experimentally contaminated with K. aerogenes. Levels of contamination and the number of samples contaminated after opening and decanting were consistently higher for cans and tetrapaks than for crown-cap or screw-cap bottles. Disinfection of feed containers followed by the use of sterile gloves and/or disinfected openers yielded bacteria-free feed from all the types of feed container studied.     

Transferability of six pesticides from agricultural sprayer surfaces

Secondary exposure to pesticide residues on the external surfaces of sprayers does not currently form part of the risk assessment process. A measure of the ease with which residues may be transferred from the sprayer surface to the operator would enhance the accuracy of any such assessment. This study quantified the dislodgeability of six pesticides from sprayer surfaces in order to calculate the transfer efficiencies. The transfer efficiency was compound dependent, ranging from 80% for azoxystrobin to <25% for flusilazole and tebuconazole. When the washed and unwashed surfaces were analysed separately, more pendimethalin and isoproturon residues were removed from the wet surface compared with the dry surface. The variation in results for the different compounds highlights the need to consider a range of compounds to form generic statements to support guidelines regarding operator exposure to pesticide residues on sprayers.