International Journal of Hygiene and Environmental Health
Sediments quality must be considered when evaluating freshwater aquatic environments used for recreational activities
Graphical abstract
Introduction
Surface water is a term used to refer to both lentic and lotic aquatic environments such as rivers, creeks, wetlands, lakes, and reservoirs which are on Earth's surface. Life of many plants and animal species, including humans, depend on that water and their associated ecosystems (Vandas et al., 2002). Nevertheless, these aquatic environments are prone to continuous changes on their physicochemical and microbiological characteristics due to anthropogenic activities, agricultural and industrial activities, and climatic factors including droughts, storms, and floods (Poma et al., 2012b; David et al., 2013; Aguirre et al., 2019).
Many microorganisms, some of them pathogens, are ubiquitous in surface waters; however, the presence of fecal bacteria from human and animal sources is a crucial problem (Páll et al., 2013). They can enter into the aquatic environment by direct deposit of feces and/or by overland runoff, after which they can sediment on the bed or be transported to other locations. The contamination of water resources by fecal pollutants poses a significant risk to both human and animal health since numerous pathogens are often associated with feces (Páll et al., 2013). During recreational activities, users may have direct (i.e. bathing) or indirect (i.e. rafting, canoeing, and fishing among others) contact with water (Gutiérrez-Cacciabue et al., 2014, WHO, 2006), exposing themselves to unknown risks. Although great efforts have been made to establish strategies to control and improve water quality (Poma et al., 2012b; Gutiérrez-Cacciabue et al., 2014; Almeida et al., 2017; Rakotondrabe et al., 2018; Aguirre et al., 2019), there are still many waterborne outbreaks.
It is not possible to measure all the pathogens present in water, thus fecal indicator bacteria (FIB), such as total and thermotolerant coliforms, Escherichia coli, and enterococci have been long used to evaluate the microbiological quality of water. More recently Bacteroidales have also been adopted as water quality indicators (Bradshaw et al., 2016). They are anaerobic and the most abundant bacteria feces. Because they have a DNA fragment indicative of its host, discrimination between human and animal contamination is possible, which is the basis for Microbial Source Tracking (MST) (Kildare et al., 2007; Reischer et al., 2007; Nshimyimana et al., 2017; García-Aljaro et al., 2017).
Physicochemical measurements are also important during water monitoring, as unusual values found could indicate important changes in water quality. The main parameters to be considered are temperature, pH, dissolved and suspended solids, turbidity, conductivity, dissolved oxygen, and phosphorus and nitrogen compounds (Gupta et al., 2017).
Microorganisms in water are subjected to numerous stressors such as temperature and pH fluctuations, salinity, nutrient deficiencies, sunlight and predators (Gutiérrez-Cacciabue et al., 2016; Weiskerger et al., 2019), which have a direct impact on their fate and survival. However, a high percentage of them are attached to solid particles which provide protection against environmental factors (Fang et al., 2018). These microorganisms could settle down towards the sediments faster than the planktonic ones. Environmental conditions in sediment are quite different than in the water column due to reduced sunlight, lower temperature fluctuation, protection against predators, increased nutrient and organic carbon availability, and more colonizable surfaces, enhancing microorganism persistence and survival (Fang et al., 2018). A subsequent sediment resuspension, due to natural or anthropogenic events, may bring microorganisms back to the surface, becoming a potential health risk to bathers (Chandran et al., 2011).
Since sediments are known as potential reservoir of microorganisms in different climates and environments (Alm et al., 2014; Fang et al., 2018; Weiskerger et al., 2019), in recent years, they have gained a key role in water quality assessment. Despite that, while a lot of interest was dedicated to evaluating the situation of beaches in sea environments (Thupaki et al., 2013; Perkins et al., 2014; Zhang et al., 2016), there is little information about sediments in fresh water systems (Chandran et al., 2011; Kim and Wuertz, 2015; Zimmer-Faust et al., 2017).
Monitoring campaigns are usually performed only on the aqueous phase (Poma et al., 2012b; Gutiérrez-Cacciabue et al., 2014), neglecting sediments that could act as reservoir and source of microorganisms in natural waterbodies (Chandran et al., 2011; Perkins et al., 2014; Zimmer-Faust et al., 2017; Weiskerger et al., 2019). With that in mind, the aim of this work was to study the physicochemical and bacteriological quality of water and sediments under different seasonal events. For that two recreational aquatic environments, one lentic and one lotic, located in the province of Salta (northwest of Argentina), were selected as models. Data from wet and dry seasons were analyzed to search for correlations between physicochemical and microbiological variables and to assess water and sediment quality.
Section snippets
Study area
Salta is a province in the northwest of Argentina, with total land area of 155,488 km2 and estimated population of 1.3 million. It is in a sub-tropical zone with warm climate in general. The wet season is coincident with the summer (December to March) with temperatures between 20 and 40 °C, while the dry season lasts from April to November with wide thermal amplitude between day and night (0–28 °C). Mean annual precipitation ranges 600–1200 mm, mainly concentrated in the wet season (
Physicochemical variables
A total of seven and four physicochemical variables were measured in all water and sediment samples, respectively. The variations along sampling events (in each RAE) were analyzed (Table 1). By Kruskal–Wallis test statistically significant differences (Table 1, p < 0.05) were found for almost all the variables determined, except for organic matter and ashes in WR and GB sediments, and pH in GB water (Table 1, p > 0.05). For water, pHw values were between 6.9 and 8.6 in WR, reaching the highest
Discussion
Water quality from different recreational aquatic environments has been studied and discussed around the world (Ishii et al., 2014; Ng et al., 2015; Schreiber et al., 2015; Partyka et al., 2017) and also in this geographical area (Poma et al., 2012b; Gutiérrez-Cacciabue et al., 2014; Aguirre et al., 2019). However, little importance has been given to sediments quality from freshwater environments and to the interaction of sediments with the aquatic phase, even though nowadays they are
Conclusions
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Microbiological loads in sediments were clearly higher than in water in both recreational aquatic environments.
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Microbiological water quality was influenced by the season (especially rain events), intense recreational activities, and physicochemical conditions showing variations along the samples. In addition, fecal indicator bacteria exceeded in many cases the limit values established by international regulation for recreational water during wet season. Microbiological sediments quality
Acknowledgments
This research was funded by projects PICT 2013-2319 from Agencia Nacional de Promoción Científica y Tecnológica in Argentina (ANPCyT, Argentina), PIP 1122015-0100603 CO from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, Argentina), and Proyect 2361 from Consejo de Investigaciones de la Universidad Nacional de Salta (CIUNSa, Argentina). Lucía Chávez Díaz was a recipient of a graduate fellowship from CONICET.
References (54)
- et al.
Characterizing relationships among fecal indicator bacteria, microbial source tracking markers, and associated waterborne pathogen occurrence in stream water and sediments in a mixed land use watershed
Water Res.
(2016) - et al.
An assessment of potential public health risk associate with the extended survival of indicator and pathogenic bacteria in freshwater lake sediments
Int. J. Hyg Environ. Health
(2011) - et al.
Distribution comparison and risk assessment of free-floating and particle-attached bacterial pathogens in urban recreational water: implications for water quality management
Sci. Total Environ.
(2018) - et al.
Mobilisation of microbial indicators, microbial source tracking markers and pathogens after rainfall events
Water Res.
(2017) - et al.
Effect of physicochemical and biological parameters on the quality of river water of Narmada, Madhya Pradesh, India
Water Sci.
(2017) - et al.
How long can culturable bacteria and total DNA persist in environmental waters? The role of sunlight and solid particles
Sci. Total Environ.
(2016) - et al.
16S rRNA-based assays for quantitative detection of universal, human-, cow-, and dog-specific fecal Bacteroidales: a Bayesian approach
Water Res.
(2007) - et al.
Survival and persistence of host-associated Bacteroidales cells and DNA in comparison with Escherichia coli and Enterococcus in freshwater sediments as quantified by PMA-qPCR and qPCR
Water Res.
(2015) - et al.
Bacteroidales markers for microbial source tracking in Southeast Asia
Water Res.
(2017) - et al.
Monitoring bacterial indicators of water quality in a tidally influenced delta: a Sisyphean pursuit
Sci. Total Environ.
(2017)
Towards a rational strategy for monitoring microbiological quality of ambient waters
Sci. Total Environ.
Validation of hollow fiber ultrafiltration and real-time PCR using bacteriophage PP7 as surrogate for the quantification of viruses from water samples
Water Res.
Water quality assessment in the Bétaré-Oya gold mining area (East-Cameroon): multivariate Statistical Analysis approach
Sci. Total Environ.
Detection of the human specific Bacteroides genetic marker provides evidence of widespread sewage contamination of stormwater in the urban environment
Water Res.
The impact of land use on microbial surface water pollution
Int. J. Hyg Environ. Health
Influence of resuspension on the fate of fecal indicator bacteria in large-scale flumes mimicking an oligotrophic river
Water Res.
Correlations between pathogen concentration and fecal indicator marker genes in beach environments
Sci. Total Environ.
Effect of freshwater sediment characteristics on the persistence of fecal indicator bacteria and genetic markers within a Southern California watershed
Water Res.
Searching variables to assess recreational water quality: the presence of infectious human enterovirus and its correlation with the main variables of water pollution by multivariate statistical approach in Córdoba, Argentina
Environ. Sci. Pollut. Res. Int.
Patterns and persistence of antibiotic resistance in faecal indicator bacteria from freshwater recreational beaches
J. Appl. Microbiol.
Dealing with deep uncertainties in landslide modelling for disaster risk reduction under climate change
Nat. Hazards Earth Syst. Sci.
Diarrhea and parasitosis in Salta, Argentina
J. Infect. Dev. Ctries
Manual del usuario (Infostat user manual)
Water Quality Assessments-A Guide to the Use of Biota, Sediments and Water in Environmental Monitoring
Spatial and temporal trends in water quality in a Mediterranean temporary river impacted by sewage effluents
Environ. Monit. Assess.
InfoStat Versión 2016. Grupo InfoStat, FCA
Standard Methods for the Examination of Water and Wastewater
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