Exposure to drinking water chlorination by-products and fetal growth and prematurity: A nation wide register-based prospective study

Background: Chlorination is globally used to produce of safe drinking water. Chlorination by-products are easily formed, and there are indications that these are associated with adverse reproductive outcomes. Objectives: We conducted a nationwide register-based prospective study to assess whether gestational exposure to the four most common chlorination by-products [total trihalomethanes (TTHMs)] via tap water was associated with risk of small for gestational age (SGA), preterm delivery, and very preterm delivery. To date, this is one of the largest studies assessing drinking water TTHM-associated adverse reproductive outcomes. Methods: We included all singleton births 2005–2015 (live and stillbirths) of mothers residing in Swedish localities having >10,000 inhabitants, ≤2 operating waterworks, adequate information on chlorination treatment, and a sufficient number of routine TTHM measurements in tap water. Individual maternal second and third trimester exposure was obtained by linking TTHM measurements to residential history, categorized into no chlorination, 15μg TTHM/L. Outcomes and covariates were obtained via the linkage to Swedish health and administrative registers. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression using inverse probability weighting. We stratified the analyses by chlorination treatment (chloramine, hypochlorite). Results: Based on approximately 500,000 births, we observed a TTHM dose-dependent association with increased risk of SGA, confined to treatment with hypochlorite, corresponding to a multivariable-adjusted OR=1.20 (95% CI: 1.08, 1.33) comparing drinking water TTHM >15μg to the unexposed. Similar results were obtained when, instead of unexposed, the lowest exposure category (<5μg/L TTHM) was used as reference. No clear associations were observed for preterm delivery and very preterm delivery. Discussion: Chlorination by-products exposure via drinking water was associated with increased risk of SGA in areas with hypochlorite treatment. https://doi.org/10.1289/EHP6012This study was funded by the Swedish Research Council Formas (grant 942-2015-425

Assessment of drinking water quality at the tap using fluorescence spectroscopy

Treated drinking water may become contaminated while travelling in the distribution system on the way to consumers. Elevated dissolved organic matter (DOM) at the tap relative to the water leaving the treatment plant is a potential indicator of contamination, and can be measured sensitively, inexpensively and potentially on-line via fluorescence and absorbance spectroscopy. Detecting elevated DOM requires potential contamination events to be distinguished from natural fluctuations in the system, but how much natural variation to expect in a stable distribution system is unknown. In this study, relationships between DOM optical properties, microbial indicator organisms and trace elements were investigated for households connected to a biologically-stable drinking water distribution system. Across the network, humic-like fluorescence intensities showed limited variation (RSD = 3.5-4.4%), with half of measured variation explained by interactions with copper. After accounting for quenching by copper, fluorescence provided a very stable background signal (RSD

Bacterial composition in Swedish raw drinking water reveals three major interacting ubiquitous metacommunities

Background Surface raw water used as a source for drinking water production is a critical resource, sensitive to contamination. We conducted a study on Swedish raw water sources, aiming to identify mutually co-occurring metacommunities of bacteria, and environmental factors driving such patterns. Methods The water sources were different regarding nutrient composition, water quality, and climate characteristics, and displayed various degrees of anthropogenic impact. Water inlet samples were collected at six drinking water treatment plants over 3 years, totaling 230 samples. The bacterial communities of DNA sequenced samples (n = 175), obtained by 16S metabarcoding, were analyzed using a joint model for taxa abundance. Results Two major groups of well-defined metacommunities of microorganisms were identified, in addition to a third, less distinct, and taxonomically more diverse group. These three metacommunities showed various associations to the measured environmental data. Predictions for the well-defined metacommunities revealed differing sets of favored metabolic pathways and life strategies. In one community, taxa with methanogenic metabolism were common, while a second community was dominated by taxa with carbohydrate and lipid-focused metabolism. Conclusion The identification of ubiquitous persistent co-occurring bacterial metacommunities in freshwater habitats could potentially facilitate microbial source tracking analysis of contamination issues in freshwater sources

Interactions between soil bacteria and arbuscular mycorrhizal fungi

The extraradical mycelium (ERM) of mycorrhizal fungi constitutes an important pathway for the translocation of energy-rich photoassimilates from plant to soil. Because of the large surface of the mycelium, and its provision of carbon, the ERM potentially constitutes an important site for interactions with other microorganisms in soils. The focus of this thesis is on the ERM of arbuscular mycorrhizal (AM) fungi and its interactions with soil bacteria, and the possible ecological significance of these interactions. In an in vitro study, soil bacteria differed in their ability to attach to AM fungal hyphae. These physical associations between bacteria and fungi were influenced by hyphal vitality and fungal strain. The degree of attachment of bacteria to living or dead hyphae may reflect the ecological niche differentiation of these bacteria, and consequently their trophic relationship (e.g. mutualistic or saprotrophic) to the mycorrhizal fungi. Carbohydrates of mycelial origin, mainly in the form of glucose, acetate and formiate, were identified in exudates from an AM fungus. Mycelial exudates promoted the occurrence of certain bacterial taxa in vitro, further supporting the view that specific interactions may occur between some bacteria and AM fungi. In a field study with long-term applications of different organic and inorganic fertilisers, amendments with sewage sludge or ammonium sulphate changed the bacterial community composition in root-associated soil aggregates. In addition, ammonium sulphate reduced the taxon richness and the occurrence of specific taxa of both AM fungi and bacteria in the mycorrhizosphere. These changes were primarily explained by the low pH of soils amended with sewage sludge or ammonium sulphate. However, taxon richness of both AM fungi and bacteria also appeared to be promoted by high soil organic content. In summary, interactions between bacteria and the ERM of AM fungi may be specific and physical associations and mycelial exudates may influence these interactions. Microbial interactions are important in determining soil fertility and plant health. In agricultural systems some microorganisms may be either positively or negatively affected by different types of fertilisation, therefore it is possible soil management practices could be customised to promote microorganisms that are beneficial to farming systems

Kommunikationsstrategier och konsumentperspektiv vid h\ue4ndelser p\ue5 distributionsn\ue4tet

Inom VA-verksamheten \ue4r de n\uf6jda konsumenterna oftast tysta eftersom de har begr\ue4nsade m\uf6jligheter att g\uf6ra aktiva val n\ue4r det g\ue4ller dricksvattnet. Ibland uppst\ue5r det kriser i dricksvattenf\uf6rs\uf6rjningen, och studier har visat att det \ue4r bra med goda relationer mellan beslutsfattare och allm\ue4nhet f\uf6re en kris. Det g\uf6r att krisen hanteras p\ue5 ett b\ue4ttre s\ue4tt, och att f\uf6rtroendet mellan allm\ue4nhet och beslutsfattare p\ue5verkas mindre av krisen. Ett snabbt informationsfl\uf6de \ue4r ett effektivt och viktigt s\ue4tt f\uf6r vattenleverant\uf6ren att minska de negativa sociala konsekvenserna av ett sjukdomsutbrott, f\uf6rutsatt att man har allm\ue4nhetens f\uf6rtroende.Kvaliteten p\ue5 den information som kommuniceras \ue4r avg\uf6rande f\uf6r konsumenternas f\uf6rtroende. Tidigare studier av krishantering har genomf\uf6rts efter st\uf6rre h\ue4ndelser, som vattenburna sjukdomsutbrott. En studie i Lilla Edet efter norovirusutbrottet \ue5r 2008 visade att de som upplevde att informationen var av h\uf6g kvalitet ocks\ue5 var de som upplevde l\ue4gre risk att dricka vattnet. Det kan ibland vara sv\ue5rt att tolka resultaten fr\ue5n studierna eftersom det ofta \ue4r extrema eng\ue5ngsf\uf6reteelser som har intr\ue4ffat. S\ue5dana extrema h\ue4ndelser \ue4r sv\ue5ra f\uf6r VA-ansvariga att f\uf6rutse, och de \ue4r h\ue4ndelser som kanske de flesta svenskar aldrig r\ue5kar ut f\uf6r.Syftet med den aktuella studien var att unders\uf6ka hur informations- och kommunikationsstrategier genomf\uf6rs i ett antal kommuner, samt hur kedjan h\ue4ndelse–beslut–kommunikation fungerar. Konsumenternas n\uf6jdhet med informationen har unders\uf6kts vid normala driftst\uf6rningar p\ue5 ledningsn\ue4tet. Projektet har genomf\uf6rts av forskare vid Chalmers tekniska h\uf6gskola och Livsmedelsverket. Medfinansi\ue4rer \ue4r Myndigheten f\uf6r samh\ue4llsskydd och beredskap och Svenskt Vatten Utveckling. F\uf6rfattarna l\ue4mnar f\uf6ljande rekommendationer till kommuner och dricksvattenproducenter.Rutiner. F\uf6lj regelbundet upp dokumenterade rutiner f\uf6r hur kommunikation ska ske internt och externt vid olika typer av h\ue4ndelser. F\uf6lj ocks\ue5 regelbundet upp n\uf6jdhet hos konsumenterna och utv\ue4rdera resultatet, och f\uf6lj upp tillf\ue4llen med \uf6kat antal inkommande samtal till kundtj\ue4nst. Det \ue4r sv\ue5rare att n\ue5 ut med information under kv\ue4llar och helger samt till omr\ue5den d\ue4r \ue4garna inte bor permanent.M\ue5lgrupper. M\ue5lgruppen \ue4r n\ue4stan alltid heterogen. Informationen kan anpassas f\uf6r exempelvis olika geografiska omr\ue5den, \ue5ldersgrupper, f\uf6r oroliga och missn\uf6jda konsumenter, samt f\uf6r konsumenter med annat modersm\ue5l \ue4n svenska. F\uf6r att undvika att information f\uf6rsvinner p\ue5 v\ue4gen \ue4r det viktigt att i st\uf6rsta m\uf6jliga m\ue5n rikta sig direkt till konsumenterna och undvika mellanh\ue4nder.Kommunikationskanaler. Webbplatsen \ue4r stommen i kommunikationen, och konsumenter s\uf6ker sj\ue4lvmant information p\ue5 internet och hittar till webbplatsen. Den b\uf6r d\ue4rf\uf6r h\ue5llas uppdaterad och ha information som \ue4r anpassad till m\ue5lgrupperna. Direkt kommunikation, till exempel via sms, \ue4r ett effektivt s\ue4tt att n\ue5 ut till ber\uf6rda konsumenter, men tr\ue4ffbilden f\uf6r olika kommunikationskanaler kan variera mellan olika kommuner

Building trust: the importance of democratic legitimacy in the formation of consumer attitudes toward drinking water

This study aimed to explore the role of democratic decision legitimacy in the formation of consumer attitudes toward drinking water. Using consumer-level data on the decision to change the drinking water sources in two Swedish cities, three core sets of variables were constructed: (1) the overall democratic decision legitimacy, defined as the citizens\u27 support for the decision; (2) the input, throughput and output dimensions of decision legitimacy, representing the citizens\u27 perceived opportunity to provide input, their ability to oversee, as well as their level of satisfaction with the outcome of the decision-making process; and (3) consumer attitudes toward drinking water, comprising trust, risk perception and acceptance. The results of the study provide support for the proposed mechanism that consumers that perceive a decision-making process more positively also tend to support the ultimate decision more, which in turn helps to establish more positive consumer attitudes towards their drinking water. Consequently, democratic legitimacy is an important precursor for building trust. This is particularly important if a waterborne outbreak has negatively impacted consumers\u27 trust in their water, and when political and engineering decisions must be made

Bacterial composition in Swedish raw drinking water reveals three major interacting ubiquitous metacommunities

Background: Surface raw water used as a source for drinking water production is a critical resource, sensitive to contamination. We conducted a study on Swedish raw water sources, aiming to identify mutually co-occurring metacommunities of bacteria, and environmental factors driving such patterns. Methods: The water sources were different regarding nutrient composition, water quality, and climate characteristics, and displayed various degrees of anthropogenic impact. Water inlet samples were collected at six drinking water treatment plants over 3 years, totaling 230 samples. The bacterial communities of DNA sequenced samples (n = 175), obtained by 16S metabarcoding, were analyzed using a joint model for taxa abundance. Results: Two major groups of well-defined metacommunities of microorganisms were identified, in addition to a third, less distinct, and taxonomically more diverse group. These three metacommunities showed various associations to the measured environmental data. Predictions for the well-defined metacommunities revealed differing sets of favored metabolic pathways and life strategies. In one community, taxa with methanogenic metabolism were common, while a second community was dominated by taxa with carbohydrate and lipid-focused metabolism. Conclusion: The identification of ubiquitous persistent co-occurring bacterial metacommunities in freshwater habitats could potentially facilitate microbial source tracking analysis of contamination issues in freshwater sources