Q fever and prevalence of Coxiella burnetii in milk

BackgroundQ fever is a zoonosis caused by Coxiella burnetii. In humans, although it has been predominantly considered an occupational hazard, in the last decades, Q fever outbreaks have also been reported in various countries, indicating its importance as an emerging public health threat. Domestic ruminants are considered as the most important sources of human infection. In fact, both symptomatic and asymptomatic infected ruminants shed the bacterium into the environment with birth products, but also in urine, faeces, vaginal mucus and milk. Q fever in humans is mainly asymptomatic, but it also may manifest itself as an acute or chronic disease with long-term sequelae. Inhalation of infectious aerosols usually causes the disease in humans, but the presence of C. burnetii in raw milk raises concern over the role of milk as a source of infection.Scope and approachIn this review data on Q fever in humans are summarized and the possible transmission of C. burnetii to humans by consumption of unpasteurized milk is discussed. In addition, an overview of the published data on the prevalence studies of C. burnetii in raw milk in various countries is provided.Key findings and conclusionsRecent surveys conducted in many countries have revealed that the prevalence of C. burnetii in raw milk can vary over a wide range from 0% to as high as 95%. Based on recent survey data, the risk of C. burnetii infection by consuming unpasteurized milk and raw milk products cannot be considered negligible.     

Inhalation exposure to haloacetic acids and haloketones during showering

Inhalation exposure to haloacetic acids (HAAs) and haloketones (HKs) in contaminated drinking water occurs during showering. The size distribution of the aerosols generated by a shower was determined using an eight size-range particle counter, which measured particles from 0.1 to >2 microm. An exponential increase in aerosol numbers was observed while the shower water was on, while the aerosol numbers declined exponentially once the water was turned off. The half-lives of the shower aerosols were longer than 5 min after the shower water was turned off. Although the majority of the shower-generated aerosols were smaller than 0.3 microm, these aerosols only contributed approximately 2% to the measured total aerosol mass. The total shower-generated particulate HAA and HK concentrations collected on an open face filter were approximately 6.3 and 0.13 microg/m3, respectively, for shower water HAA and HK concentrations of 250 and 25 microg/L, respectively. The vapor-phase HK concentrations were 25-50 microg/m3. The estimate of the dose from inhalation exposure of disinfection byproducts (DBPs) in the particulate phase indicate that they represent less than 1% of the ingestion dose, so inhalation is not expected to be an important exposure route to nonvolatile water contaminants or the portion of volatile DBPs that stay in the particulate phase, unless the lung is the target organ. The vapor-phase levels of volatile HKs, though, are significantly higher and can contribute greater than 10% of the ingestion dose during a shower. Thus, risk assessment to the these DBPs needs to consider the inhalation route.     

Estimation of Coxiella burnetii prevalence in dairy cattle in intensive systems by serological and molecular analyses of bulk-tank milk samples

A large-scale investigation on Coxiella burnetii was carried out in dairy cattle herds from a Q fever-endemic region to evaluate the degree of exposure to C. burnetii and to estimate prevalences. This study included all of the dairy cattle herds from the province of Bizkaia, Northern Spain (n=178). Herds were visited between September 2009 and February 2010, and 100mL of bulk-tank milk (BTM) per farm was collected to be analyzed by ELISA and PCR. Blood samples were also taken from about 15 animals randomly selected from each herd. One hundred nineteen of the 178 studied herds (66.9±6.9%) were positive for the presence of anti-C. burnetii antibodies in BTM. Serum samples from 1,306 cows, 654 heifers, and 502 calves were analyzed by ELISA, and cows showed a statistically significantly higher seroprevalence (12.3±1.8%) than heifers (1.1±0.8%) and calves (0.0±0.0%). Eighty-nine herds (50.0±7.3%) had at least 1 seropositive animal, but within-herd prevalences higher than 20% were only observed in 24 herds (13.5±5.0%). A significant correlation was observed between BTM ELISA sample-to-positive control ratios and within-herd seroprevalence, being higher when considering only cows (R(2)=0.21). Animals from herds with negative BTM by ELISA showed a mean seroprevalence of 2.5%, whereas animals from herds with positive BTM samples had a statistically significantly higher seroprevalence (8.9%, F=19.7, degrees of freedom=1). The proportion of herds C. burnetii positive by BTM PCR was 51.7±7.3% (92/178). The widespread distribution of C. burnetii in cattle advocates for the implementation of Q fever control strategies.     

Screening level assessment of risks due to dioxin emissions from burning oil from the BP Deepwater Horizon Gulf of Mexico spill

Between April 28 and July 19 of 2010, the U.S. Coast Guard conducted in situ oil burns as one approach used for the management of oil spilled after the explosion and subsequent sinking of the BP Deepwater Horizon platform in the Gulf of Mexico. The purpose of this paper is to describe a screening level assessment of the exposures and risks posed by the dioxin emissions from these fires. Using upper estimates for the oil burn emission factor, modeled air and fish concentrations, and conservative exposure assumptions, the potential cancer risk was estimated for three scenarios: inhalation exposure to workers, inhalation exposure to residents on the mainland, and fish ingestion exposures to residents. U.S. EPA's AERMOD model was used to estimate air concentrations in the immediate vicinity of the oil burns and NOAA's HYSPLIT model was used to estimate more distant air concentrations and deposition rates. The lifetime incremental cancer risks were estimated as 6 × 10(-8) for inhalation by workers, 6 × 10(-12) for inhalation by onshore residents, and 6 × 10(-8) for fish consumption by residents. For all scenarios, the risk estimates represent upper bounds and actual risks would be expected to be less.     

Probabilistic ecological risk assessment of 1,2,4-trichlorobenzene at a former industrial contaminated site

Measured concentrations of 1,2,4-trichlorobenzene (1,2,4-TCB) in soil and groundwater detected in an industrial contaminated site were used to test several probabilistic options for refining site-specific ecological risks assessment, ranging from comparison of single effects and exposure values through comparison of probabilistic distributions for exposure and effects to the use of distribution based quotients (DBQs) obtained through Monte Carlo simulations. The results of the deterministic approach, which suggest that risk exceeds a level of concern for soil organisms, were influenced mainly by the presence of hot spots reaching concentrations able to affect acutely a large proportion of species, while the large majority of the area presents 1,2,4-TCB concentrations below those reported as toxic. Ground-(pore)water concentrations were compared with aquatic ecotoxicity data in orderto obtain an estimation of the potential risk for aquifers and streams in the adjacent area as well as for soil-dwelling organisms exposed via pore water. In this case, the risk is distributed over a large proportion of the site, while the local risk of hot spots was low, showing that risk characterization based exclusively on soil concentrations might be insufficient.     

湖南省桶装饮用水中铜绿假单胞菌膳食暴露风险评估

目的对桶装饮用水中铜绿假单胞菌的膳食暴露进行风险评估。方法依据湖南省2017年3月～12月桶装饮用水的抽检监测数据,以桶装饮用水出厂后为起点,以最终饮用完为终点,采用蒙特卡罗模拟技术,运用@risk5.5风险评估软件对铜绿假单胞菌进行膳食暴露风险评估。结果正常人群按照《中国居民膳食指南(2016版)》推荐的饮水量,且饮用水的来源全部为未经烧开的桶装饮用水,铜绿假单胞菌平均摄入量为32 CFU,大部分的消费者(众数)摄入量为0.06 CFU,摄入量大于0.15 CFU的概率为3.1%,消费者的感染概率平均值为2.4×10~(-8)。结论通过对湖南省桶装饮用水中铜绿假单胞菌的膳食风险暴露评估可知,该菌在饮用水摄入途径上,总体上处于安全水平。     

Modeling the probability of arsenic in groundwater in New England as a tool for exposure assessment

We developed a process-based model to predict the probability of arsenic exceeding 5 microg/L in drinking water wells in New England bedrock aquifers. The model is being used for exposure assessment in an epidemiologic study of bladder cancer. One important study hypothesis that may explain increased bladder cancer risk is elevated concentrations of inorganic arsenic in drinking water. In eastern New England, 20-30% of private wells exceed the arsenic drinking water standard of 10 micrograms per liter. Our predictive model significantly improves the understanding of factors associated with arsenic contamination in New England. Specific rock types, high arsenic concentrations in stream sediments, geochemical factors related to areas of Pleistocene marine inundation and proximity to intrusive granitic plutons, and hydrologic and landscape variables relating to groundwater residence time increase the probability of arsenic occurrence in groundwater. Previous studies suggest that arsenic in bedrock groundwater may be partly from past arsenical pesticide use. Variables representing historic agricultural inputs do not improve the model, indicating that this source does not significantly contribute to current arsenic concentrations. Due to the complexity of the fractured bedrock aquifers in the region, well depth and related variables also are not significant predictors.     

Silver nanoparticles and total aerosols emitted by nanotechnology-related consumer spray products

Products containing silver nanoparticles are entering the market rapidly, but little is known about the potential for inhalation exposure to nanosilver. The objectives of this work were to characterize the emissions of airborne particles from consumer products that claim to contain silver nanoparticles or ions, determine the relationship between emissions and the products' liquid characteristics, and assess the potential for inhalation exposure to silver during product use. Three products were investigated: an antiodor spray for hunters, a surface disinfectant, and a throat spray. Products emitted 0.24-56 ng of silver in aerosols per spray action. The plurality of silver was found in aerosols 1-2.5 μm in diameter for two products. Both the products' liquid characteristics and the bottles' spray mechanisms played roles in determining the size distribution of total aerosols, and the size of silver-containing aerosols emitted by the products was largely independent of the silver size distributions in the liquid phase. Silver was associated with chlorine in most samples. Results demonstrate that the normal use of silver-containing spray products carries the potential for inhalation of silver-containing aerosols. Exposure modeling suggests that up to 70 ng of silver may deposit in the respiratory tract during product use.     

Tracking airborne Legionella and Legionella pneumophila at a biological treatment plant

Biological treatment plants are frequently used to degrade organic substances in wastewater from wood refinement processes. Aeration ponds in such plants provide an optimal growth environment for many microorganisms, including Legionella species. To investigate whether legionellae could be dispersed as aerosols from the ponds and transported by the wind, the wetted-wall cyclone SASS 2000(PLUS) and the impactors MAS-100 and STA-204 were used to collect air samples directly above, upwind, and downwind of aeration ponds during a 4-month period. Computational fluid dynamics was used a priori to estimate the aerosol paths and to determine suitable air-sampling locations. Several Legionella species, including Legionella pneumophila, were identified in air samples at the biological treatment plant using microbiological and molecular methods. L. pneumophila was identified up to distances of 200 m downwind from the ponds, but, in general, not upwind nor outside the predicted aerosol paths. The highest concentration level of viable legionellae was identified directly above the aeration ponds (3300 CFU/m3). This level decreased as the distance from the aeration ponds increased. Molecular typing indicated that a single clone of L. pneumophila was dispersed from the ponds during the period of the study. Thus, our study demonstrated that aerosols generated at aeration ponds of biological treatment facilities may contain L. pneumophila, which then can be transported by the wind to the surroundings. The methods used in this study may be generically applied to trace biological aerosols that may pose a challenge to environmental occupational health.     

Leaching of metribuzin metabolites and the associated contamination of a sandy Danish aquifer

As degradation products of metribuzin have received little attention as potential groundwater contaminants, we evaluated leaching of metribuzin and its primary metabolites desaminometribuzin (DA), desaminodiketometribuzin (DADK), and diketometribuzin (DK) at a sandy test site in Denmark. Soil water and groundwater were sampled monthly over a four-year period. Leaching of metribuzin and DA was negligible. DK and DADK leached from the root zone (1 meter below ground surface (mbgs)) in average concentrations considerably exceeding the EU limit value for drinking water (0.1 microg/L). Both metabolites appear to be relatively stable and persisted in soil water and groundwater several years after application. Past application of metribuzin at the site had contaminated the groundwater with both DK and DADK, which were detected in 99% and 48%, respectively, of the groundwater samples analyzed. Except for three of the groundwater samples, the DADK concentration never exceeded the EU limit value. In contrast, the annual concentration of DK exceeded 0.1 microg/L at 90% of the screens analyzed. The present findings suggest that as the degradation products of metribuzin can leach through sandy soil in high concentrations, they could potentially contaminate the groundwater. In view of this risk DK and DADK should both be included in monitoring programs and their ecotoxicological effects should be further investigated.     

Drowning in disinfection byproducts? Assessing swimming pool water

Disinfection is mandatory for swimming pools: public pools are usually disinfected by gaseous chlorine or sodium hypochlorite and cartridge filters; home pools typically use stabilized chlorine. These methods produce a variety of disinfection byproducts (DBPs), such as trihalomethanes (THMs), which are regulated carcinogenic DBPs in drinking water that have been detected in the blood and breath of swimmers and of nonswimmers at indoor pools. Also produced are halogenated acetic acids (HAAs) and haloketones, which irritate the eyes, skin, and mucous membranes; trichloramine, which is linked with swimming-pool-associated asthma; and halogenated derivatives of UV sun screens, some of which show endocrine effects. Precursors of DBPs include human body substances, chemicals used in cosmetics and sun screens, and natural organic matter. Analytical research has focused also on the identification of an additional portion of unknown DBPs using gas chromatography (GC)/mass spectrometry (MS) and liquid chromatography (LC)/MS/MS with derivatization. Children swimmers have an increased risk of developing asthma and infections of the respiratory tract and ear. A 1.6-2.0-fold increased risk for bladder cancer has been associated with swimming or showering/bathing with chlorinated water. Bladder cancer risk from THM exposure (all routes combined) was greatest among those with the GSTT1-1 gene. This suggests a mechanism involving distribution of THMs to the bladder by dermal/inhalation exposure and activation there by GSTT1-1 to mutagens. DBPs may be reduced by engineering and behavioral means, such as applying new oxidation and filtration methods, reducing bromide and iodide in the source water, increasing air circulation in indoor pools, and assuring the cleanliness of swimmers. The positive health effects gained by swimming can be increased by reducing the potential adverse health risks.     

低压供气式射流器的性能研究

设计加工了一套供气式射流曝气器清水充氧性能测试装置,并利用该装置对新型的低压供气式射流曝气器进行清水充氧性能研究。清水试验表明：低压供气式射流曝气器氧利用率达16．34％;理论动力效率达2．65～3．05kgO2／kWh。优于其它形式的曝气设备,能有效降低能耗。     

Sorption and desorption of arsenic to ferrihydrite in a sand filter

Elevated arsenic concentrations in drinking water occur in many places around the world. Arsenic is deleterious to humans, and consequently, As water treatment techniques are sought. To optimize arsenic removal, sorption and desorption processes were studied at a drinking water treatment plant with aeration and sand filtration of ferrous iron rich groundwater at Elmevej Water Works, Fensmark, Denmark. Filter sand and pore water were sampled along depth profiles in the filters. The sand was coated with a 100-300 microm thick layer of porous Si-Ca-As-contaning iron oxide (As/Fe = 0.17) with locally some manganese oxide. The iron oxide was identified as a Si-stabilized abiotically formed two-line ferrihydrite with a magnetic hyperfine field of 45.8 T at 5 K. The raw water has an As concentration of 25 microg/L, predominantly as As(II). As the water passes through the filters, As(III) is oxidized to As(V) and the total concentrations drop asymptotically to a approximately 15 microg/L equilibrium concentration. Mn is released to the pore water, indicating the existence of reactive manganese oxides within the oxide coating, which probably play a role for the rapid As(III) oxidation. The As removal in the sand filters appears controlled by sorption equilibrium onto the ferrihydrite. By addition of ferrous chloride (3.65 mg of Fe(II)/L) to the water stream between two serially connected filters, a 3 microg/L As concentration is created in the water that infiltrates into the second sand filter. However, as water flow is reestablished through the second filter, As desorbs from the ferrihydrite and increases until the 15 microg/L equilibrium concentration. Sequential chemical extractions and geometrical estimates of the fraction of surface-associated As suggest that up to 40% of the total As can be remobilized in response to changes in the water chemistry in the sand filter.     

Development of lead source-specific exposure standards based on aggregate exposure assessment: Bayesian inversion from biomonitoring information to multipathway exposure

Exposure of children to lead is of great concern, and the exposure standards for different media are important for protecting public safety. However, these media-specific standards often fail to ensure the safety of children even when environmental lead levels are lower than the quality standards since humans are often exposed to lead via multiple pathways. To establish exposure standards to protect children from hazards associated with exposure to lead, an analytical tool for assessing aggregate exposure to lead based on Bayesian hierarchical model was developed, and then was used to update the external lead exposure of diet, paint, soil, air and drinking water using the blood lead levels in Chinese children aged 1-6 years. On the basis of updated external exposure, the source allocations for diet, paint, soil, air, and drinking water in China were 65.80 ± 7.92%, 16.98 ± 7.88%, 13.65 ± 5.05%, 3.36 ± 1.75%, and 0.20 ± 0.14%, respectively. Based on the estimated source allocations, the exposure standards were evaluated to be 0.2 μg/m(3), 24.25 mg/kg, 0.027 μg/L, 0.051 μg/mg, 0.042 μg/mg, 38.02 μg/mg for air, soil, water, grains, vegetables, and paint, respectively. Since the standards setting procedure was based on the multipathway aggregate exposure assessment of lead, the newly proposed exposure standards should ensure the safety of children.     

Estimating exposure to chemical contaminants in drinking water

A model is developed that predicts exposure and absorbed dose for chemical contaminants in household drinking water via three pathways: inhalation, direct and indirect ingestion, and dermal penetration. Extensive probability distributions for building characteristics, activity and water use patterns, operating conditions of water devices, and physiological characteristics of the general population are developed. The impacts of different operating conditions on mass transfer coefficients for the shower, bath, washing machine, dishwasher, and faucet are established. Dichlorobromomethane, inorganic lead, and endosulfan, three compounds associated with adverse birth outcomes that have significantly different chemical properties, are selected for analysis. The primary exposure pathways for dichlorobromomethane are inhalation (62%) and ingestion (27%). Seventy percent of total exposure to endosulfan comes from ingestion, and 18% from dermal sorption with the remaining 12% due to inhalation. Virtually all (99.9%) of the exposure to lead occurs via ingestion. A nested Monte Carlo analysis shows that natural variability contributes significantly more (a factor of 10) toward total uncertainty than knowledge uncertainty (a factor of 1.5). Better identification of certain critical input variables (ventilation rate in the shower and bathroom, ingestion rate, the boiling water mass transfer coefficient, and skin permeability) is required.     

Risks and new challenges in the food chain: Viral contamination and decontamination from a global perspective,guidelines, and cleaning

Even during the continuing world pandemic of severe acute respiratory syndrome coronavirus 2 (SARS CoV-2), consumers remain exposed to the risk of getting infected by existing, emerging, or re-emerging foodborne and waterborne viruses. SARS-CoV-2 is different in that it is transmitted directly via the airborne route (droplets and aerosols) or indirect contact (surfaces contaminated with SARS-CoV-2). International food and health organizations and national regulatory bodies have provided guidance to protect individuals active in food premises from potential occupational exposure to SARS-CoV-2, and have recommended chemicals effective in controlling the virus. Additionally, to exclude transmission of foodborne and waterborne viruses, hygiene practices to remove viral contaminants from surfaces are applied in different stages of the food chain (e.g., food plants, food distribution, storage, retail sector, etc.), while new and enhanced measures effective in the control of all types of viruses are under development. This comprehensive review aims to analyze and compare efficacies of existing cleaning practices currently used in the food industry to remove pathogenic viruses from air, nonfood, and food contact surfaces, as well as from food surfaces. In addition, the classification, modes of transmission, and survival of food and waterborne viruses, as well as SARS-CoV-2 will be presented. The international guidelines and national regulations are summarized in terms of virucidal chemical agents and their applications.     

Salmonella in surface and drinking water: Occurrence and water-mediated transmission

Salmonella is one of the leading causes of intestinal illness all over the world as well as the etiological agent of more severe systemic diseases such as typhoid and paratyphoid fevers. While water is known to be a common vehicle for the transmission of typhoidal Salmonella serovars, non-typhoidal salmonellae are mainly known as foodborne pathogens. This paper provides a brief review of the last ten years of peer reviewed publications on the prevalence of Salmonella in natural freshwaters and drinking waters, and on the relevance of these sources for Salmonella dissemination. In industrialized countries, Salmonella was rarely reported in water-borne outbreaks despite it being frequently detected in surface waters including recreational waters and waters used for irrigation or as a drinking water source. Consistent contamination with irrigation waters has been shown to be a common route of crop contamination in produces related Salmonella outbreaks. Multiple drug resistant (MDR) Salmonella strains, that represent an increased hazard for human health and that may contribute to the dissemination of drug resistances were also detected in surface water in developed countries. Surface runoff was shown to play a main role as driver of Salmonella load in surface waters. Accordingly, analysis of serovars indicated a mixed human and animal origin of Salmonella contribution to surface waters, emphasizing the role of wild life animals in water contamination. Data relating to Salmonella prevalence in surface and drinking water in developing countries are quite rare. Nevertheless, data on water-borne outbreaks as well as case control studies investigating the risk factors for endemic typhoid fever confirmed the relevance of water as source for the transmission of this disease. In addition epidemiological studies and Salmonella surveys, consistently provided an undeniable evidence of the relevance of MDR Salmonella Typhi strains in water-borne typhoid fever in developing countries.     

饮用水中重金属的暴露评估

目的：通过对饮用水中的重金属的暴露评估,为饮用水中化学物质的暴露评估提供方法参考。方法：运用@risk4.5软件建立膳食暴露模型,对饮用水中的8种重金属（锌、镍、锰、铁、砷、汞、铅、铬）进行概率暴露评估。结果：人群中所有人对饮用水中的镍、汞和铅的暴露水平都小于对应的ADI。铬、砷、锌、铁、锰的暴露水平大于对应ADI的人群比例分别是0.03%、0.17%、0.29%、0.37%、3.01%。结论：镍、汞和铅的暴露水平不会对成年人群造成健康风险。铬、砷、锌、铁、锰的暴露水平对很小一部分人群的健康造成风险。     

Comparative risk analysis of six volatile organic compounds in California drinking water

The widespread use and storage of volatile organic compounds (VOCs) in the United States has led to releases of these chemicals into the environment, including groundwater sources of drinking water. Many of these VOCs are commonly found in public drinking water supplies across the nation and are considered by state or federal agencies to be potentially carcinogenic to humans. In this paper, we evaluate the detection frequencies, detected concentrations, and relative cancer risks of six VOCs in drinking water sources in California from 1995 to 2001. We find that during this 7-year period, the most frequently detected VOCs in sampled drinking water sources were chloroform (12-14%), PCE (11-13%), and TCE (10-12%). Detection frequencies in water were lower for 1,1-DCE (3-6%), MTBE (1-3%), and benzene (<1%). Mean detected concentrations were also consistently above California's primary maximum contaminant level for some VOCs, including benzene, PCE, and TCE. Although none of the six VOCs necessarily poses a significant public health threat from drinking water exposures, 1,1-DCE and benzene werefound to pose the greatest cancer risk relative to the other VOCs. However, after adjusting for the occurrence of each VOC in drinking water, chloroform and PCE were found to pose the greatest relative cancer risk. Despite media reports about significant MTBE contamination of drinking watersupplies in California, MTBE detections were infrequent and this chemical was found to pose the least cancer risk relative to the other VOCs.     

Effect of ultraviolet germicidal irradiation on viral aerosols

Ultraviolet (UV) germicidal air disinfection is an engineering method used to control the airborne transmission of pathogenic microorganisms in high-risk settings. Despite the recent emergence of respiratory viral pathogens such as SARS and avian influenza viruses, UV disinfection of pathogenic viral aerosols has not been examined. Hence, we characterized the UV disinfection of viral aerosols using the bacteriophage MS2, adenovirus, and coronavirus. Our objectives were to characterize the effect of nebulization and air sampling on the survival of important viral pathogens, quantitatively characterize and estimate the UV susceptibility of pathogenic viral aerosols, and evaluate the effect of relative humidity (RH) on the susceptibility of viral aerosols, to 254 nm UV-C. The viruses were aerosolized into an experimental chamber using a six-jet Collison nebulizer, exposed to 254 nm UV, and sampled using an AGI-30 liquid impinger. Both the MS2 and adenovirus aerosols were very resistant to UV air disinfection, with a reduction of less than 1 logarithm in viable viral aerosols at a UV dose of 2608 microW s/cm2. The susceptibility of coronavirus aerosols was 7-10 times that of the MS2 and adenovirus aerosols. Unlike bacterial aerosols, there was no significant protective effect of high RH on UV susceptibility of the tested viral aerosols. We confirmed that the UV disinfection rate differs greatly between viral aerosols and viruses suspended in liquid.