Avian Influenza outbreaks: Human infection risks for beach users - One health concern and environmental surveillance implications.

Despite its popularity for water activities, such as swimming, surfing, fishing, and rafting, inland and coastal bathing areas occasionally experience outbreaks of highly pathogenic avian influenza virus (HPAI), including A(H5N1) clade 2.3.4.4b. Asymptomatic infections and symptomatic outbreaks often impact many aquatic birds, which increase chances of spill-over events to mammals and pose concerns for public health. This review examined the existing literature to assess avian influenza virus (AIV) transmission risks to beachgoers and the general population. A comprehensive understanding of factors governing such crossing of the AIV host range is currently lacking. There is limited knowledge on key factors affecting risk, such as species-specific interactions with host cells (including binding, entry, and replication via viral proteins hemagglutinin, neuraminidase, nucleoprotein, and polymerase basic protein 2), overcoming host restrictions, and innate immune response. AIV efficiently transmits between birds and to some extent between marine scavenger mammals in aquatic environments via consumption of infected birds. However, the current literature lacks evidence of zoonotic AIV transmission via contact with the aquatic environment or consumption of contaminated water. The zoonotic transmission risk of the circulating A(H5N1) clade 2.3.4.4b virus to the general population and beachgoers is currently low. Nevertheless, it is recommended to avoid direct contact with sick or dead birds and to refrain from bathing in locations where mass bird mortalities are reported. Increasing reports of AIVs spilling over to non-human mammals have raised valid concerns about possible virus mutations that lead to crossing the species barrier and subsequent risk of human infections and outbreaks.

Scenario-based assessment of fecal pathogen sources affecting bathing water quality: novel treatment options to reduce norovirus and Campylobacter infection risks.

Wastewater discharge and runoff waters are significant sources of human and animal fecal microbes in surface waters. Human-derived fecal contamination of water is generally estimated to pose a greater risk to human health than animal fecal contamination, but animals may serve as reservoirs of zoonotic pathogens. In this study, quantitative microbial risk assessment (QMRA) tools were used to evaluate the hygienic impact of sewage effluents and runoff water from municipalities and animal farms on surface and bathing waters. The human-specific microbial source tracking (MST) marker HF183 was used to evaluate the dilution of fecal pathogens originating from the sewage effluent discharge to the downstream watershed. As novel risk management options, the efficiency of UV-LED disinfection and wetland treatment as well as biochar filtration was tested on-site for the contamination sources. According to the dilution pattern of the MST marker HF183, microbes from wastewater were diluted (2.3-3.7 log10) in the receiving waters. The scenario-based QMRA revealed, that the health risks posed by exposure to human-specific norovirus GII and zoonotic Campylobacter jejuni during the bathing events were evaluated. The risk for gastroenteritis was found to be elevated during wastewater contamination events, where especially norovirus GII infection risk increased (1-15 cases per day among 50 bathers) compared with the business as usual (BAU) situation (1 case per day). The noted C. jejuni infection risk was associated with animal farm contamination (1 case per day, versus 0.2-0.6 cases during BAU). Tertiary treatment of wastewater with wetland treatment and UV-LED disinfection effectively reduced the waterborne gastroenteritis risks associated with bathing. Based on the experiences from this study, a QMRA-based approach for health risk evaluations at bathing sites can be useful and is recommended for bathing site risk assessments in the future. In case of low pathogen numbers at the exposure sites, the MST marker HF183 could be used as a pathogen dilution coefficient for the watershed under evaluation. The full-scale implementation of novel tertiary treatment options at wastewater treatment plants (WWTPs) as well as on-site runoff water treatment options should be considered for infection risk management at locations where scenario-based QMRA implies elevated infection risks.

Climate Change Impacts on Microbiota in Beach Sand and Water: Looking Ahead.

Beach sand and water have both shown relevance for human health and their microbiology have been the subjects of study for decades. Recently, the World Health Organization recommended that recreational beach sands be added to the matrices monitored for enterococci and Fungi. Global climate change is affecting beach microbial contamination, via changes to conditions like water temperature, sea level, precipitation, and waves. In addition, the world is changing, and humans travel and relocate, often carrying endemic allochthonous microbiota. Coastal areas are amongst the most frequent relocation choices, especially in regions where desertification is taking place. A warmer future will likely require looking beyond the use of traditional water quality indicators to protect human health, in order to guarantee that waterways are safe to use for bathing and recreation. Finally, since sand is a complex matrix, an alternative set of microbial standards is necessary to guarantee that the health of beach users is protected from both sand and water contaminants. We need to plan for the future safer use of beaches by adapting regulations to a climate-changing world.

A preliminary study on the ecotoxic potency of wastewater treatment plant sludge combining passive sampling and bioassays.

Sewage sludge is an inevitable byproduct produced in wastewater treatment. Reusing nutrient-rich sludge will diminish the amount of waste ending in soil dumping areas and will promote circular economy. However, during sewage treatment process, several potentially harmful organic chemicals are retained in sludge, but proving the safety of processed sludge will promote its more extensive use in agriculture and landscaping. Environmental risk assessment of sludge requires new methods of characterizing its suitability for various circular economy applications. Bioavailable and bioaccessible fractions are key variables indicating leaching, transport, and bioaccumulation capacity. Also, sludge treatments have a significant effect on chemical status and resulting environmental risks. In this study, the concentrations of polyaromatic hydrocarbons (PAHs), triclosan (TCS), triclocarban (TCC), methyl triclosan (mTCS), and selected active pharmaceutical ingredients (APIs) were determined in different sludge treatments and fractions. Passive samplers were used to characterize the bioavailable and bioaccessible fractions, and the sampler extracts along the sludge and filtrate samples were utilized in the bioassays. The TCS and PAH concentrations did not decrease as the sludge was digested, but the contents diminished after composting. Also, mTCS concentration decreased after composting. The API concentrations were lower in digested sludge than in secondary sludge. Digested sludge was toxic for Aliivibrio fischeri, but after composting, toxicity was not observed. However, for Daphnia magna, passive sampler extracts of all sludge treatments were either acutely (immobility) or chronically (reproduction) toxic. Secondary and digested sludge sampler extracts were cytotoxic, and secondary sludge extract was also genotoxic. The measured chemical concentration levels did not explain the toxicity of the samples based on the reported toxicity thresholds. Bioassays and sampler extracts detecting bioavailable and bioaccessible contaminants in sludge are complementing tools for chemical analyses. Harmonization of these methodswill help establish scientifically sound regulative thresholds for the use of sludge in circular economy applications.

Correction to: Health effects of nutrients and environmental pollutants in Baltic herring and salmon: a quantitative benefit-risk assessment.

It was highlighted that the original article [1] contained a formatting error in the equations.

Health effects of nutrients and environmental pollutants in Baltic herring and salmon: a quantitative benefit-risk assessment.

BACKGROUND: Health risks linked with dioxin in fish remain a complex policy issue. Fatty Baltic fish contain persistent pollutants, but they are otherwise healthy food. We studied the health benefits and risks associated with Baltic herring and salmon in four countries to identify critical uncertainties and to facilitate an evidence-based discussion. METHODS: We performed an online survey investigating consumers' fish consumption and its motivation in Denmark, Estonia, Finland, and Sweden. Dioxin and methylmercury concentrations were estimated based on Finnish studies. Exposure-response functions for several health endpoints were evaluated and quantified based on the scientific literature. We also quantified the infertility risk of men based on a recent European risk assessment estimating childhood dioxin exposure and its effect on sperm concentration later in life. RESULTS: Baltic herring and salmon contain omega-3 fatty acids and vitamin D, and the beneficial impact of these fishes on cardiovascular diseases, mortality, and the risk of depression and cancer clearly outweighs risks of dioxins and methylmercury in people older than 45 years of age and in young men. Young women may expose their children to pollutants during pregnancy and breast feeding. This study suggests that even in this critical subgroup, the risks are small and the health benefits are greater than or at least similar to the health risks. Value of information analysis demonstrated that the remaining scientific uncertainties are not large. In contrast, there are several critical uncertainties that are inherently value judgements, such as whether exceeding the tolerable weekly intake is an adverse outcome as such; and whether or not subgroup-specific restrictions are problematic. CONCLUSIONS: The potential health risks attributable to dioxins in Baltic fish have more than halved in the past 10 years. The new risk assessment issued by the European Food Safety Authority clearly increases the fraction of the population exceeding the tolerable dioxin intake, but nonetheless, quantitative estimates of net health impacts change only marginally. Increased use of small herring (which have less pollutants) is a no-regret option. A more relevant value-based policy discussion rather than research is needed to clarify official recommendations related to dioxins in fish.

Impacts of a changing earth on microbial dynamics and human health risks in the continuum between beach water and sand.

Although infectious disease risk from recreational exposure to waterborne pathogens has been an active area of research for decades, beach sand is a relatively unexplored habitat for the persistence of pathogens and fecal indicator bacteria (FIB). Beach sand, biofilms, and water all present unique advantages and challenges to pathogen introduction, growth, and persistence. These dynamics are further complicated by continuous exchange between sand and water habitats. Models of FIB and pathogen fate and transport at beaches can help predict the risk of infectious disease from beach use, but knowledge gaps with respect to decay and growth rates of pathogens in beach habitats impede robust modeling. Climatic variability adds further complexity to predictive modeling because extreme weather events, warming water, and sea level change may increase human exposure to waterborne pathogens and alter relationships between FIB and pathogens. In addition, population growth and urbanization will exacerbate contamination events and increase the potential for human exposure. The cumulative effects of anthropogenic changes will alter microbial population dynamics in beach habitats and the assumptions and relationships used in quantitative microbial risk assessment (QMRA) and process-based models. Here, we review our current understanding of microbial populations and transport dynamics across the sand-water continuum at beaches, how these dynamics can be modeled, and how global change factors (e.g., climate and land use) should be integrated into more accurate beachscape-based models.

Public health and economic risk assessment of waterborne contaminants and pathogens in Finland.

This study shows that a variety of mathematical modeling techniques can be applied in a comprehensive assessment of the risks involved in drinking water production. In order to track the effects from water sources to the end consumers, we employed four models from different fields of study. First, two models of the physical environment, which track the movement of harmful substances from the sources to the water distribution. Second, a statistical quantitative microbial risk assessment (QMRA) to assess the public health risks of the consumption of such water. Finally, a regional computable general equilibrium (CGE) model to assess the economic effects of increased illnesses. In order to substantiate our analysis, we used an illustrative case of a recently built artificial recharge system in Southern Finland that provides water for a 300,000 inhabitant area. We examine the effects of various chemicals and microbes separately. Our economic calculations allow for direct effects on labor productivity due to absenteeism, increased health care expenditures and indirect effects for local businesses. We found that even a considerable risk has no notable threat to public health and thus barely measurable economic consequences. Any epidemic is likely to spread widely in the urban setting we examined, but is also going to be short-lived in both public health and economic terms. Our estimate for the ratio of total and direct effects is 1.4, which indicates the importance of general equilibrium effects. Furthermore, the total welfare loss is 2.4 times higher than the initial productivity loss. The major remaining uncertainty in the economic assessment is the indirect effects.

Do historical sediments of pulp and paper industry contribute to the exposure of fish caged in receiving waters?

Field experiments were conducted in early summer 2004 by caging brown trout (Salmo trutta m. lacustris) in Southern Lake Saimaa (SE Finland) for 10 days. Cages were positioned into two depths at four distances (5 to 17 km) from the pulp and paper mill; one set with direct contact to the sediment and other locating at the three meters' depth from the water surface. Resin acids were measured from sediment, water, and fish bile. Possible toxicities were investigated by measuring liver EROD-activity, HSP70-protein, and gene expression profiles by microarray. The concentration of resin acids in the sediment showed clear gradient along the distance from the mill, and their concentrations in water ranged approximately from one to 30 microg L(-1). In the trout bile, concentrations were higher near the surface than on the bottom, indicating the role of current releases as sources of resin acids. When compared to trout held upstream from the effluent source, no differences were found in liver EROD nor HSP70 in bottom cages. However, near surface, a slight but statistically significant increase in EROD and HSP70 was found. Altogether 145 genes were found to be differentially regulated at downstream sites when compared 10 km upstream from the mill. The numbers of genes at each site varied from 5 to 45 without consistent differences between bottom and surface cages. Overall, neither expression profiles nor composition of the transcription signatures made possible to conclude an overt toxicity in exposed brown trout.

Uptake of organic xenobiotics by benthic invertebrates from sediment contaminated by the pulp and paper industry.

Uptake of pulp and paper mill-derived pollutants by benthic invertebrates from sediment in Southern Lake Saimaa, eastern Finland, was studied. Two groups of benthic invertebrates (Diptera and Oligochaeta) were analyzed for their concentrations of resin acids (RAs), chlorophenolics (CPs) and beta-sitosterol. The samples were collected 1 and 3km downstream from the mill. In laboratory experiments Chironomus plumosus (a dipteran) and Lumbriculus variegatus (oligochaete) were exposed for 14d to sediments collected from the same locations. The concentrations of RAs, CPs and beta-sitosterol were higher in the areas downstream from the mill than those in the upstream reference area in both the feral and laboratory-exposed animals. Examination of the possible conjugation of contaminants revealed hydrolyzable fractions of RAs in Diptera, C. plumosus and L. variegatus. The results indicate both the bioavailability uptake of contaminants and uptake by benthic fauna when exposed to pulp and paper mill-contaminated sediment.

Exposure assessment of fishes to a modern pulp and paper mill effluents after a black liquor spill.

Conjugated resin acids (RAs) in fish bile are considered a sensitive chemical indicator of exposure to pulp and paper mill effluent, and were used in this study to monitor the post-spill situation of a lake area (Southern Lake Saimaa) contaminated by black liquor discharged from a mill in June 2003. From the exposure perspective of populations of wild roach and perch, which were studied for their bile RAs at four time periods (July 2003, September 2003, May 2004, July 2004), the exceptional event passed in 2 months or less. Perch had lower concentration of RAs in bile than roach in all sampling areas and all times. Besides the current emissions present in the water column, part of the exposure status of the roach population to RAs seemed to derive from historically contaminated sediments. In order to test this hypothesis, a laboratory experiment with perch and roach, along with three teleosts (rainbow trout, brown trout and whitefish), was conducted. The species were simultaneously exposed for 7 days to RAs (23 microg/l). We calculated a perch/roach-ratio to investigate the difference in origin of exposure between perch and roach populations in the wild and in the laboratory. One year after the spill, the perch/roach-ratio of bile RAs was 0.25 (CV 25%) at 1 km from the mill. This is in contrast to that found under the sole waterborne conditions (0.44; CV 24%), supporting the idea that sediments serve as an additional source of RAs in roach. Additionally, bioconcentration factor log BCF(bile(RA)) was calculated to assess hepatobiliary performance and the capacity to excrete RAs in fish.

Time- and concentration-dependent metabolic and genomic responses to exposure to resin acids in brown trout (Salmo trutta m. lacustris).

The presence of metabolically conjugated resin acids (RAs) in the bile is considered to be a sensitive indicator for exposure of fish to pulp and paper industry effluents; however, to our knowledge, no comprehensive kinetic study of this response has been made. Juvenile brown trout (Salmo trutta m. lacustris) were exposed to a waterborne mixture of seven RAs (wood rosin) in time (0.1-192.0 h; average concentration, 8 microg/L) and dose (average concentrations, 0, 0.6, 4, 14, and 78 microg/L; 10 d) series, and total RAs were analyzed in bile. In time-dependent exposure, total RAs in bile increased up to 24 h. In concentration-dependent exposure, RAs increased along with the concentration of RAs in water, revealing a high-capacity biotransformation and elimination system in trout liver. In concentration-dependent exposures, the effects on the hepatic transcriptome was studied using a high-density cDNA microarray, and dose-dependent changes were found in a large number of genes. Resin acids interfered with iron metabolism, as evidenced by the decrease in transcripts for iron transporters and heme-containing proteins. Expression of genes encoding for enzymes degrading reactive oxygen species also decreased. Coordinated down-regulation of the protein biosynthesis machinery could result from inhibition of the energy metabolism. A number of changes in gene expression indicated recovery and remodeling of hepatic tissues. We conclude that analysis of total RAs in the bile provides a sensitive and quantitative tool for assessing the exposure of fish to waterborne RAs, whereas multiple gene expression analyses are able to elucidate simultaneous cellular functions for use as potential biomarkers of RAs.

Dissolution of resin acids, retene and wood sterols from contaminated lake sediments.

The dissolution potency of hydrophobic resin acids (RAs), retene and wood sterols from sediments was studied. These wood extractives and their metabolites are sorbed from pulp and paper mill effluents to downstream sediments. With harmful components like these, sediments can pose a hazard to the aquatic environment. Therefore, sediment elutriates with water were produced under variable conditions (agitation rate and efficiency, time), and concentrations of the dissoluted compounds were analyzed. Both naturally contaminated field sediments and artificially spiked sediments were studied. By vigorous agitation RAs can be released fast from the sediment matrix and equilibrium reached within 3 days. Compared to RAs, desorption of retene from lake sediment was slower and did not completely reach equilibrium in 23 days. Sterols spiked to pristine sediment with a 33-day contact time desorbed faster than those associated authentically with industrial sediment of from a contaminated lake. Simulating the water turbulence adjacent to a sediment surface by low and high rate of agitation in the laboratory, an increase in the mixing rate after 43-day elutriation suddenly released a high amount of wood sterols. The results indicate wide variation between hazardous chemicals in their tendency to dissolution from sediment solids. Erosion and hydrology adjacent to the sediment surface, as well as risks from dredging activities of sediments, may expose lake biota to bioactive chemicals.