Sebastian Völker

The impact of blue space on human health and well-being – Salutogenetic health effects of inland surface waters: A review

Water is one of the most important physical, aesthetic landscape elements and possesses importance e.g. in environmental psychology, landscape design, and tourism research, but the relationship between water and health in current literature is only investigated in the field of environmental toxicology and microbiology, not explicitly in the research field of blue space and human well-being. Due to the lack of a systematic review of blue space and well-being in the various fields of research, the aim of this review is to provide a systematic, qualitative meta-analysis of existing studies that are relevant to this issue. Benefits for health and well-being clearly related to blue space can be identified with regard to perception and preference, landscape design, emotions, and restoration and recreation. Additionally, direct health benefits have already been stated. The studies included in the review are mostly experimental studies or cross-sectional surveys, focusing on students as the subject group. There is a need for more qualitative and multi-faceted, interdisciplinary studies, using triangulation as a method to achieve a resilient image of reality. A broader study design considering all age groups would contribute to identifying benefits for the whole of society. The inattentiveness to blue space makes it difficult to measure long-term effects of blue space on well-being. There is still little respect for water and health in planning issues, although salutogenetic health benefits can be identified. To close the gap regarding missing systematic concepts, a concept for assessing salutogenetic health effects in blue space is provided. Blue space is considered therein as a multi-dimensional term including four dimensions of appropriation, as well as at least five ontological dimensions of substantiality. The aim of the concept is to support researchers and practitioners analysing health effects in blue space.

Drinking water quality in household supply infrastructure—A survey of the current situation in Germany

As a result of the amendment to the German Drinking Water Ordinance in 2001, local public health authorities are obliged to monitor the water supply in installations providing water for public use (Section 18 German Drinking Water Ordinance). With a systematic and nationwide survey of locally available data relating to hygienic drinking water quality and the existing drinking water infrastructure in buildings, the extent of microbial contamination of in-building distribution systems in Germany is intended to be assessed. To gain an overview of the microbial contamination of drinking water in public buildings all 419 local public health authorities in Germany were contacted in 2007. In a detailed study with a representative cooperation level of 5% of these local public health authorities, the available data relating to microbiological, chemical, physical and technical parameters gained from in-building distribution systems were collected. Drinking water parameters were combined with regard to the total number of analyses and the absolute number as well as the percentage of limit compliance failures (n=108,288). Limits exceeded were classified as the failure to comply with the German Drinking Water Ordinance, DVGW technical regulations and Federal Environment Agency recommended limits. The highest rates of samples exceeding these limits were found for the parameter Legionella sp. which contaminated 12.8% of all samples (n=22,786; limit: 100 CFU/100ml), followed by heterotrophic plate count at 36 degrees C (3.5%, n=10,928; limit: 100 CFU/1 ml) and Pseudomonas sp. (2.9%, n=3468; limit: 0 CFU/100ml). Legionella sp. and Pseudomonas sp. pose a direct health risk to immunosuppressed users. Additionally, for some chemical parameters, such as nickel, iron and lead, a potential risk for the health of consumers was detected. Further data analysis may reveal whether this contamination is related to stagnation where there is only sporadic use or whether other factors are involved in the process of microbial growth in installation systems.

Modelling characteristics to predict Legionella contamination risk – Surveillance of drinking water plumbing systems and identification of risk areas

For the surveillance of drinking water plumbing systems (DWPS) and the identification of risk factors, there is a need for an early estimation of the risk of Legionella contamination within a building, using efficient and assessable parameters to estimate hazards and to prioritize risks. The precision, accuracy and effectiveness of ways of estimating the risk of higher Legionella numbers (temperature, stagnation, pipe materials, etc.) have only rarely been empirically assessed in practice, although there is a broad consensus about the impact of these risk factors. We collected n = 807 drinking water samples from 9 buildings which had had Legionella spp. occurrences of >100 CFU/100mL within the last 12 months, and tested for Legionella spp., L. pneumophila, HPC 20°C and 36°C (culture-based). Each building was sampled for 6 months under standard operating conditions in the DWPS. We discovered high variability (up to 4 log(10) steps) in the presence of Legionella spp. (CFU/100 mL) within all buildings over a half year period as well as over the course of a day. Occurrences were significantly correlated with temperature, pipe length measures, and stagnation. Logistic regression modelling revealed three parameters (temperature after flushing until no significant changes in temperatures can be obtained, stagnation (low withdrawal, qualitatively assessed), pipe length proportion) to be the best predictors of Legionella contamination (>100 CFU/100 mL) at single outlets (precision = 66.7%; accuracy = 72.1%; F(0.5) score = 0.59).

Field testing hot water temperature reduction as an energy-saving measure – does the Legionella presence change in a clinic's plumbing system?

Legionella spp. represent a significant health risk for humans. To ensure hygienically safe drinking water, technical guidelines recommend a central potable water hot (PWH) supply temperature of at least 60°C at the calorifier. In a clinic building we monitored whether slightly lowered temperatures in the PWH system led to a systemic change in the growth of these pathogens. In four separate phases we tested different scenarios concerning PWH supply temperatures and disinfection with chlorine dioxide (ClO2). In each phase, we took 5 sets of samples at 17 representative sampling points in the buildings drinking water plumbing system. In total we collected 476 samples from the PWH system. All samples were tested (culture-based) for Legionella spp. and serogroups. Additionally, quantitative parameters at each sampling point were collected, which could possibly be associated with the presence of Legionella spp. (Pseudomonas aeruginsoa, heterotrophic plate count at 20°C and 36°C, temperatures, time until constant temperatures were reached, and chlorine dioxide concentration). The presence of Legionella spp. showed no significant reactions after reducing the PWH supply temperature from 63°C to 60°C and 57°C, as long as disinfection with ClO2 was maintained. After omitting the disinfectant, the PWH system showed statistically significant growth rates at 57°C. PWH temperatures which are permanently lowered to less than recommended values should be carefully accompanied by frequent testing, a thorough evaluation of the buildings drinking water plumbing system, and hygiene expertise.

Chances for health within the new water management

The European Water Framework Directive and the Protocol on Water and Health are two legally binding documents, which exist parallel to one another. A multi-disciplinary management of surface waters, which includes the participation of health experts, is necessary if the Protocol on Water and Health is to have an impact on human health rather than randomly promoting the effects of water management within the European Water Framework Directive.