A Comparison of Screening and Refined Exposure Models for Evaluating Toluene Air Emissions from a Washing Machine

Residential clothes washing machines are potential air emission sources for volatile organic compounds (VOCs). The U.S. Environmental Protection Agency has a screening model to predict the potential inhalation exposure to VOC emissions from a washing machine into room air. They also have a refined exposure model that can be extrapolated to evaluate a washing machine. The objectives of this study were to evaluate the screening and refined models and to compare their predictions to experimental results for toluene-contaminated tap water. This study identified a number of important results and it explained why the models over predicted as well as the models’ limitations. The Exposure and Fate Screening Tool (EFAST) Consumer Exposure Module (CEM) screening model predicted the peak concentration was 340% of the experimental result and that 90% of the toluene mass was emitted. The refined Simulation Tool Kit for Indoor Air Quality and Inhalation Exposure (IAQX) model predicted the peak concentration was 35% higher than the experimental value, the Time Weighted Average (TWA)-30 min concentration was 45% higher, and about 30% of the toluene mass was emitted. The screening model provided a quick, conservative exposure result with several limitations. The refined model provided a better estimate of the potential exposure but it required more input data and effort.     

The potential impact of washing machines on laundry malodour generation

A multidisciplinary approach has been adopted to investigate and identify the source of malodour in washing machines and the potential for cross‐contamination of laundry. Four washing machines were olfactively graded, and the number of colony‐forming units (CFUs) bacteria was determined in four specific locations. Then, samples of terry‐towel and fleece were washed, without the use of detergent, in the machines, and the occurrence of malodour over a 52‐h period was assessed. Analysis of the scrapings from the four locations in the two malodorous machines identified a plethora of volatile organic compounds (VOCs) by either olfactory detection or mass spectral identification post‐gas chromatographic separation. In addition, microbiological analysis from the swabs from the four locations within all four washing machines was carried out. Quantitative analysis of VOCs from 66 microbiological isolates from either the washing machines or fabrics was carried out. In total, 10 VOCs were identified: dimethyl disulfide, 3‐methyl‐1‐butanol, 2,4‐dithiapentane, dimethyl trisulfide, 2‐tridecanone, indole, 2‐phenylethanol, isovaleric acid, isobutyric acid and 1‐undecene.

Significance and Impact of the Study

The data presented in this study highlight that the environment and odour of the washing machine can lead to cross‐contamination of laundry.     

Quantifying drivers of variability in life cycle greenhouse gas emissions of consumer products—a case study on laundry washing in Europe

Purpose

Variability in consumer behaviour can significantly influence the environmental performance of products and their associated impacts and this is typically not quantified in life cycle assessments. The goal of this paper is to demonstrate how consumer behaviour data can be used to understand and quantify the variability in the greenhouse gas emissions from domestic laundry washing across Europe.

Methods

Data from a pan-European consumer survey of product usage and washing habits was combined with internal company data on product format greenhouse gas (GHG) footprints and in-home measurement of energy consumption of laundry washing as well as literature data to determine the GHG footprint of laundry washing. The variability associated with four laundry detergent product formats and four wash temperature settings in washing machines were quantified on a per wash cycle basis across 23 European countries. The variability in GHG emissions associated with country electricity grid mixes was also taken into account. Monte Carlo methods were used to convert the variability in the input parameters into variability of the life cycle GHG emissions. Rank correlation analysis was used to quantify the importance of the different sources of variability.

Results and discussion

Both inter-country differences in background electricity mix as well as intra-country variation in consumer behaviour are important for determining the variability in life cycle GHG emissions of laundry detergents. The average GHG emissions related to the laundry washing process in the 23 European countries in 2014 was estimated to be 5?×?10² g CO_2?eq/wash cycle, but varied by a factor of 6.5 between countries. Intra-country variability is between a factor of 3.5 and 5.0 (90% interval). For countries with a mainly fossil-based electricity system, the dominant source of variability in GHG emissions results from consumer choices in the use of washing machines. For countries with a relatively low-carbon electricity mix, variability in life cycle GHG emissions is mainly determined by laundry product-related parameters.

Conclusions

The combination of rich data sources enabled the quantification of the variability in the life cycle GHG emissions of laundry washing which is driven by a variety of consumer choices, manufacturer choices and infrastructural differences of countries. The improved understanding of the variability needs to be balanced against the cost and challenges of assessing of consumer habits.

     

Enteric Virus Survival during Household Laundering and Impact of Disinfection with Sodium Hypochlorite

This study was conducted to determine whether enteric viruses (adenovirus, rotavirus, and hepatitis A virus) added to cotton cloth swatches survive the wash cycle, the rinse cycle, and a 28-min permanent press drying cycle as commonly practiced in households in the United States. Detergent with and without bleach (sodium hypochlorite) was added to washing machines containing sterile and virus-inoculated 58-cm² swatches, 3.2 kg of cotton T-shirts and underwear, and a soiled pillowcase designed to simulate the conditions (pH, organic load, etc.) encountered in soiled laundry. The most important factors for the reduction of virus in laundry were passage through the drying cycle and the addition of sodium hypochlorite. Washing with detergent alone was not found to be effective for the removal or inactivation of enteric viruses, as significant concentrations of virus were found on the swatches (reductions of 92 to 99%). It was also demonstrated that viruses are readily transferred from contaminated cloths to uncontaminated clothes. The use of sodium hypochlorite reduced the number of infectious viruses on the swatches after washing and drying by at least 99.99%. Laundering practices in common use in the United States do not eliminate enteric and respiratory viruses from clothes. The use of bleach can further reduce the numbers of enteric viruses in laundry.     

Enteric virus survival during household laundering and impact of disinfection with sodium hypochlorite

This study was conducted to determine whether enteric viruses (adenovirus, rotavirus, and hepatitis A virus) added to cotton cloth swatches survive the wash cycle, the rinse cycle, and a 28-min permanent press drying cycle as commonly practiced in households in the United States. Detergent with and without bleach (sodium hypochlorite) was added to washing machines containing sterile and virus-inoculated 58-cm2 swatches, 3.2 kg of cotton T-shirts and underwear, and a soiled pillowcase designed to simulate the conditions (pH, organic load, etc.) encountered in soiled laundry. The most important factors for the reduction of virus in laundry were passage through the drying cycle and the addition of sodium hypochlorite. Washing with detergent alone was not found to be effective for the removal or inactivation of enteric viruses, as significant concentrations of virus were found on the swatches (reductions of 92 to 99%). It was also demonstrated that viruses are readily transferred from contaminated cloths to uncontaminated clothes. The use of sodium hypochlorite reduced the number of infectious viruses on the swatches after washing and drying by at least 99.99%. Laundering practices in common use in the United States do not eliminate enteric and respiratory viruses from clothes. The use of bleach can further reduce the numbers of enteric viruses in laundry.     

Potential application of Bacillus subtilis SPB1 biosurfactants in laundry detergent formulations: Compatibility study with detergent ingredients and washing performance

Surfactants play a very important role in laundry and household cleaning products ingredients. In this research, the application of lipopeptide biosurfactants, produced by Bacillus subtilis SPB1, in the formulation of a washing powder was investigated. The SPB1 biosurfactant was mixed with sodium tripolyphosphate as a builder and sodium sulfate as filler. The efficiency of the formulated detergent composition with different washing conditions to remove a stain from cotton fabric was examined. The results showed that the formulated detergent was effective in oil removal, with optimal washing conditions of pH, temperature, striate and time of washing system of 7, 65°C, 1000 RPM and 60 min, respectively. A comparative study of different detergent compositions (biosurfactant‐based detergent, combined biosurfactant‐commercial detergent, and a commercial detergent) for the removal of oil and tea stains, proved that the bio‐scouring was more effective (>75%) in terms of the stain removal than the commercial powders (<60%). Moreover, the results demonstrated that the biosurfactant acts additively with a commercial detergent and enhances their performance from 33 to 45% in removing oil stain and from 57 to 64% in removing tea stain. As a conclusion, in addition to the low toxicity and the high biodegradability of the microbial biosurfactants, the results of this study have shown that the future use of this lipopeptide biosurfactant as laundry detergent additive is highly promising.     

Directed evolution of a fungal peroxidase

The Coprinus cinereus (CiP) heme peroxidase was subjected to multiple rounds of directed evolution in an effort to produce a mutant suitable for use as a dye-transfer inhibitor in laundry detergent. The wild-type peroxidase is rapidly inactivated under laundry conditions due to the high pH (10.5), high temperature (50 degrees C), and high peroxide concentration (5-10 mM). Peroxidase mutants were initially generated using two parallel approaches: site-directed mutagenesis based on structure-function considerations, and error-prone PCR to create random mutations. Mutants were expressed in Saccharomyces cerevisiae and screened for improved stability by measuring residual activity after incubation under conditions mimicking those in a washing machine. Manually combining mutations from the site-directed and random approaches led to a mutant with 110 times the thermal stability and 2.8 times the oxidative stability of wild-type CiP. In the final two rounds, mutants were randomly recombined by using the efficient yeast homologous recombination system to shuffle point mutations among a large number of parents. This in vivo shuffling led to the most dramatic improvements in oxidative stability, yielding a mutant with 174 times the thermal stability and 100 times the oxidative stability of wild-type CiP.     

Efficacy of lipase from Aspergillus niger as an additive in detergent formulations: a statistical approach

The efficacy of lipase from Aspergillus niger MTCC 2594 as an additive in laundry detergent formulations was assessed using response surface methodology (RSM). A five-level four-factorial central composite design was chosen to explain the washing protocol with four critical factors, viz. detergent concentration, lipase concentration, buffer pH and washing temperature. The model suggested that all the factors chosen had a significant impact on oil removal and the optimal conditions for the removal of olive oil from cotton fabric were 1.0% detergent, 75 U of lipase, buffer pH of 9.5 and washing temperature of 25°C. Under optimal conditions, the removal of olive oil from cotton fabric was 33 and 17.1% at 25 and 49°C, respectively, in the presence of lipase over treatment with detergent alone. Hence, lipase from A. niger could be effectively used as an additive in detergent formulation for the removal of triglyceride soil both in cold and warm wash conditions.     

LCA Study and Environmental Benefits for Low Temperature Disinfection Process in Commercial Laundry (12 pp)

Background, Aims and Scope

This study aims to compare the energy requirements and potential environmental impacts associated with three different commercial laundry processes for washing microbiologically contaminated hospital and care home laundry. Thermal disinfection relies mainly on a 90°C washing temperature and hydrogen peroxide, while the chemothermal disinfection uses a combination of chemicals (mainly peracetic acid) and 70°C washing temperature. The chemical disinfection process relies on a combination of chemicals used at 40°C. Currently, chemothermal processes are the most commonly used in professional laundries. Traditional chemical processes are uncommon due to drawbacks of longer residence time and high chemical requirements. However, the innovative Sterisan chemical process based on phthalimidoperoxyhexanoic acid (PAP) – which is the key subject of this Life Cycle Assessment – was designed to overcome these technical limitations.

Methods

This study is based on a screening Life Cycle Assessment (LCA) prepared in 2002 by Öko-Institut (Germany), which was carried out following the requirements of the ISO 14040 series standards. It includes energy resource consumption, water resource consumption, climate change, eutrophication and acidification potential as relevant environmental indicators. In 2004/2005, the study was further updated and broadened to include the aquatic eco-toxicity potential, photochemical oxidant formation and ozone depletion potential in order to represent the environmental burdens associated with the chemicals used.Based on available data, the system boundaries include detergent manufacturing, the professional wash process, waste water treatment, but excluding the laundry finishing process. The selected functional unit was 1kg washed hygiene laundry.

Results and Discussion

The LCA indicates that the Sterisan chemical process has a lower potential environmental impact than thermal or chemothermal treatment for six out of seven key indicators. This includes a 55% lower energy and a 46% lower water consumption. The global warming potential and acidification potential are approximately halved, while the photochemical oxidant formation potential and eutrophication potential are almost reduced to one third. By contrast, for the aquatic eco-toxicity, the thermal- and chemothermal processes have an approximately 17 fold lower impact. The worse aquatic toxicity score for the Sterisan process is mainly caused by a solvent component in the formulation.

Conclusion

The comparison of the thermal, chemothermal and Sterisan commercial laundry processes shows that the Sterisan process allows for very substantial reductions in energy and water consumption, as well as significant reductions in climate change, photochemical oxidant formation potential, air acidification potential and eutrophication potential. Yet, Sterisan has a clear disadvantage with regards to aquatic eco-toxicity potential.

Recommendation and Perspective

Based on a current hygiene laundry volume of approx. 584000 tons of linen washed per year by commercial laundries in Germany, a full substitution of the market to the Sterisan process could potentially allow a primary energy saving of ~750000 GJ/year (roughly equivalent to the residential primary energy consumption of 23500 German citizens or the overall energy demand of approx. 6000 German citizens). In terms of improvements to the respective processes, the chemothermal and thermal process could benefit from a reduction of water volume, and change of detergent composition to reduce the eutrophication potential. As the washing temperature is an essential factor, only slight improvements for the energy consumption indicator can be obtained, e.g. by choosing green electricity and reducing the amount of water to be heated. The Sterisan process could be improved by lowering the solvent use, although for perspective, the current aquatic eco-toxicity score of the Sterisan process is still lower than that of a typical domestic laundry product.

     

Formaldehyde as a pre-treatment for dermal collagen heterografts

The preparation, stability both in vitro and in vivo and resistance to bacterial collagenase of trypsin-purified pig dermal collagen cross-linked with a range of concentrations of formaldehyde in phosphate-buffered saline, was studied using ¹⁴C-labelled formaldehyde as a tracer. Washing in phosphate-buffered saline at 37°C produced rapid loss of formaldehyde over 6 weeks before stability was reached. After 19 weeks washing, 12–20% of the initial radioactivity remained, representing 6, 18 and 35 μmol formaldehyde/g of collagen after 21 days reaction with 0.1, 1 and 5% formaldehyde, respectively. Collagen, incorporating stable-bound formaldehyde arising from reaction with formaldehyde in concentrations of 0.5% or over, was totally resistant to bacterial collagenase.The stabilizing effect of formaldehyde cross-linking was also demonstrated by implants of fibrous pig dermal collagen in rats. After 8 weeks a significant constant amount of formaldehyde was retained in all implants. There was no net loss of mass over a 24 week period when pre-treated with 1% formaldehyde but some loss when pre-treated with 0.1% formaldehyde.     

Removal efficiency and mechanisms of formaldehyde by five species of plants in air-plant-water system

The foliar uptake and transport rates of formaldehyde as well as the abilities of leaf extracts to breakdown formaldehyde were investigated to discuss the formaldehyde removal efficiency and mechanism by five species of plants from air. Results showed that formaldehyde could be transported from air via leaves and roots to rhizosphere water. When exposed to 0.56 mg·m^?3 formaldehyde, the formaldehyde removal rate ranged from 18.64 to 38.47 μg·h^?1g^?1 FW (fresh weight). According to the mass balance in the air–plant–water system, the main mechanism of the formaldehyde loss was its breakdown in plant tissues caused by both enzymatic reaction and redox reaction. Higher oxidation potentials of the leaf-extracts of Wedelia chinensis and Desmodium motorium corresponded well to higher abilities to breakdown added formaldehyde than other plants. Based on the different abilities of fresh and boiled leaf-extracts to dissipate formaldehyde, the enzymatic reaction in Chenopodium album L. was the dominant mechanism while the redox reaction in Kochia scoparia (L.) Schrad. and Silene conoidea L. was the main formaldehyde breakdown mechanism when exposed to low-level formaldehyde in air. The redox mechanism suggested that the formaldehyde removal may be increased by an increasing level of reactive oxygen species (ROS) induced by the environmental stress.     

Environmental Risk Assessment: Comparison of Receptor and Air Quality Models for Source Apportionment

Source apportionment of particulate matter has been commonly performed using receptor models, but studies suggest that the assumptions in receptor models limit the accuracy of results. An alternative approach is the use of three-dimensional source-oriented air quality models. Here, a comparison is conducted between the PM_2.5 apportioned from the Chemical Mass Balance (CMB) receptor model using organic tracers as molecular markers with those from the source-based Community Multiscale Air Quality (CMAQ) model. Source apportionment was conducted at sites in the southeastern United States for July 2001 and January 2002. PM_2.5 source apportionment results had moderate discrepancies, which originate from different spatial scales, fundamental limitations, and uncertainties of the two models. Results from CMB fluctuated temporally more than real variation due to measurement and source profile errors and uncertainties, whereas those from CMAQ could not capture daily variation well. In addition, results from CMB are mass contributions for the monitoring location, whereas those from CMAQ represent the average mass contributions of the model's grid. It is difficult to assess which approach is “better.” Indeed, both models have strengths and limitations, and each model's strengths can be utilized to help overcome the other model's limitations.     

医院纺织品洗涤质量管理标准化研究

北京协和医院在结合欧洲EN 14065卫生洗涤标准等行业标准的基础上,通过对医院洗衣房的整体规划和改造,积极探索医院纺织品洗涤质量管理标准化。医院洗衣房的建筑布局以隔离式洗衣机为中心进行设计,设置相对独立的污染区和清洁区,遵循纺织品由污染区向清洁区运行的单项流程,减少院内感染的风险。在此基础上完善相关规章制度,以保障洗衣房的正常运行。纺织品洗涤的各个环节均应由经过专业培训的人员按照标准化的流程进行操作,同时需关注工作人员的职业防护,并在保障洗涤质量的前提下减少能源消耗。     

Sanitation in self-service automatic washers.

The potential for microbial transfer in self-service laundry washing machines was investigated by obtaining swab samples from the interior surfaces of commercial machines and wash water samples before and after disinfectant treatment. Three disinfectants (chlorine, a quaternary ammonium product, and a phenolic disinfectant) were used. Four self-service laundry facilities were sampled, with 10 replications of the procedure for each treatment at each location. Although washers were set on a warmwater setting, the wash water temperatures ranged from 24 to 51 degrees C. The quaternary ammonium product seemed most effective, averaging a 97% microbial kill; chlorine was the second most effective, with a 58% kill, and the phenolic disinfectant was least effective, with only a 25% kill. The efficacies of the chlorine and phenolic disinfectants were reduced at low water temperatures commonly experienced in self-service laundries. Interfamily cross-contamination in self-service facilities is a potential public health problem, which is aggravated by environmental conditions, such as water temperature and the practices of the previous users of the equipment. Procedural changes in laundering are recommended, including the use of a disinfectant to maintain adequate levels of sanitation.     

Analysis of the Reaction between Formaldehyde and Amide

The reaction between formaldehyde and acetamide which affords a model compound for an amino acid having an amide group was analyzed to investigate the role of formaldehyde as a cross-linking reagent. One of the products was isolated by Sephadex G-10 column chromatography and was identified as N-hydroxymethyl acetamide (FA) by NMR spectrometry and mass spectrometry. Another product, which could not be isolated, was estimated to be N, N-dihydroxymethyl acetamide (F₂A) by kinetic analysis and mass spectrometry. The formation of N, N′-methylene diacetamide was not observed. The mechanism of the reaction between formaldehyde and acetamide was estimated by the kinetic analyses of NMR data, and the rate constants were calculated from the data by the optimization method with a digital computer. On the other hand, formaldehyde cross-linked product was obtained in the reaction of formaldehyde with acetamide and alanine, Its decomposing reaction was analyzed with an NMR spectrometer to study the stability of the formaldehyde cross-linked product. The degradation was dominantly initiated with the release of acetamide.

Consequently, it was estimated that the C–N bond between formaldehyde and amide is so labile that amide-bound formaldehyde does not react further with amides or amines, and that the amide-formaldehyde-amine condensation product is unstable and easily decomposes by releasing the amide.     

Laundry detergent compatibility of the alkaline protease from Bacillus cereus

The endogenous protease activity in various commercially available laundry detergents of international companies was studied. The maximum protease activity was found at 50 degrees C in pH range 10.5-11.0 in all the tested laundry detergents. The endogenous protease activity in the tested detergents retained up to 70% on incubation at 40 degrees C for 1 h, whereas less than 30% activity was only found on incubation at 50 degrees C for 1 h. The alkaline protease from an alkalophilic strain of Bacillus cereus was studied for its compatibility in commercial detergents. The cell free fermented broth from shake flask culture of the organism showed maximum activity at pH 10.5 and 50 degrees C. The protease from B. cereus showed much higher residual activity (more than 80%) on incubation with laundry detergents at 50 degrees C for 1 h or longer. The protease enzyme from B. cereus was found to be superior over the endogenous proteases present in the tested commercial laundry detergents in comparison to the enzyme stability during the washing at higher temperature, e.g., 40-50 degrees C.     

Sanitation in self-service automatic washers.

The potential for microbial transfer in self-service laundry washing machines was investigated by obtaining swab samples from the interior surfaces of commercial machines and wash water samples before and after disinfectant treatment. Three disinfectants (chlorine, a quaternary ammonium product, and a phenolic disinfectant) were used. Four self-service laundry facilities were sampled, with 10 replications of the procedure for each treatment at each location. Although washers were set on a warmwater setting, the wash water temperatures ranged from 24 to 51 degrees C. The quaternary ammonium product seemed most effective, averaging a 97% microbial kill; chlorine was the second most effective, with a 58% kill, and the phenolic disinfectant was least effective, with only a 25% kill. The efficacies of the chlorine and phenolic disinfectants were reduced at low water temperatures commonly experienced in self-service laundries. Interfamily cross-contamination in self-service facilities is a potential public health problem, which is aggravated by environmental conditions, such as water temperature and the practices of the previous users of the equipment. Procedural changes in laundering are recommended, including the use of a disinfectant to maintain adequate levels of sanitation.     

A Method for Assessing Leaching Potential for Petroleum Hydrocarbons Release Sites: Multiphase and Multisubstance Equilibrium Partitioning

This article presents the rationale for the mathematical fate and transport model, which has been provided in the accompanying spreadsheet (GWProt). This spreadsheet model may be used as a simple and scientifically defensible regulatory tool for determining the risk-based soil clean up level of petroleum release sites to protect groundwater quality. The model incorporates either a three- or four-phase partitioning equilibrium mechanism, depending on the detection of Non-Aqueous Phase Liquid phase presence mathematically, as well as Raoult's Law convention and default dilution and attenuation factors. A database of contaminant-specific parameters, including solubility and organic-carbon partition-coefficient, molecular weight, and Henry's Law constant, is assembled for benzene, toluene, ethylbenzene, xylenes, and 12 other TPH equivalent carbon fractions. In addition to distributing organic chemicals among aqueous, sorbed solid, air, and NAPL phases, according to traditional partitioning equations, the algorithm incorporates equations for the conservation of mass and volume. A unique solution is obtained by solving a series of mass balance equations simultaneously using the iterative spreadsheet routine built in MICROSOFT EXCEL^TM Solver — with the restrictions that the volume is conserved and the sum of the mole fractions is equal to one. Sample calculations are presented for a range of parameter values to illustrate the use of the model and the relative leach-ability of a wide range of representative fuels. Sensitivity analysis was also performed to quantify the effects of uncertainty in the estimates of the key model parameters on model results. Model predictions were compared with the results from a water-fuel experiment. The noncar-cinogenic Hazard Index (HI) for groundwater through direct ingestion was calculated using predetermined oral reference dose (R_fd) values. Applications and limitations of the model are also discussed.     

A Comparison of Washing Methods for Hair Mineral Analysis: Internal Versus External Effects

A major difficulty in hair elemental (mineral) analysis for biomonitoring is adequate understanding of the effectiveness of washing procedures. A review of washing protocols used in hair analysis publications showed little consensus with regard to solvents and surfactants used, washing times, and number of washing stages. Two washing approaches were subsequently used to compare their influence on internal and external surface elemental signals determined with time-of-flight secondary ion mass spectrometry. Na, K, Ca, Mg, and Fe were assessed with regard to their relative signal compared to carbon. Both washing methods had similar effect. All elements except for Fe appear to be removed from the surface of the hair as well as from inside the hair. Only the internal Fe content changed with washing and could indicate that external surface bound Fe may not be removed with most washing procedures. It is shown that washing procedures can have a significant effect on reducing the internal elemental signal levels in hair.     

ADAPTATION OF CUTANEOUS TACTILE RECEPTORS : VI. INHIBITORY EFFECTS OF POTASSIUM AND CALCIUM

1. Both solutions of Ringer plus fifteen times the normal K content, and solutions of Ringer plus fifteen times the normal Ca content markedly hasten the adaptation of single freely branching axon endings in frog''s skin to repetitive air puff stimuli. 2. The K effect is produced more rapidly than is that of Ca. The K effect is reversible by washing with Ringer''s solution, while the Ca effect is not. The Ca inhibition can, however, be reversed and recovery effected by washing with K rich solutions. 3. Evidence is discussed which indicates that Ca probably plays no rôle in normal adaptation, and the experiments are interpreted as substantiating the hypothesis of adaptation due to K.