Skip the Dip—Avoid the Risk? Integrated Microbiological Water Quality Assessment in the South-Eastern Baltic Sea Coastal Waters

Abstract

The bathing water microbiome consists of pathogenic and non-pathogenic microorganisms, such as bacteria, viruses, and protozoa. However, the targets of the Bathing Water Directive (2006/7/EC) focus exclusively on fecal pollution. This study aims to investigate fecal indicator bacteria (FIB), naturally thriving cyanobacteria, and Vibrio bacteria in the Lithuanian coastal Baltic Sea and Curonian Lagoon bathing sites, combining information into an integrated microbial risk assessment scheme. The results show that officially monitored indicators, such as FIB, do not exceed the acceptable ‘low’ risk threshold. Simultaneously, cyanobacteria and Vibrio cholerae abundance in the Curonian Lagoon sites reveal a ‘high’ probability of adverse health effects. In coastal bathing sites, a positive correlation was found between Escherichia coli, cyanobacterial harmful algae bloom (cHAB), and V. cholerae, indicating that all target microorganisms may occur at the same time, with consequently high risks for the health of bathers. Therefore, implementing new target organisms in national or even regional bathing water monitoring programs is recommended, in order to safeguard the health of beachgoers.

Vibrio Species in an Urban Tropical Estuary: Antimicrobial Susceptibility, Interaction with Environmental Parameters, and Possible Public Health Outcomes

“…Hence, another important aspect would be to consider environmental parameters and how they correlate with the bacterial community. The alignment of microbiological and environmental data provides helpful information that could be used to estimate the risks to human health and predict outbreaks [ 67 , 68 ]. Over one year, 12 environmental parameters were analyzed in three sites in Guanabara Bay.…”

“…However, this strategy overlooks other threats to human health, such as the presence of antimicrobial-resistant microorganisms, other potential pathogens, and virulence markers. In view of such limitations, the WHO has proposed several additional recommendations regarding the evaluation of water quality parameters, among which the genus Vibrio has been included as a matter of concern, especially on account of emerging infections related to the increase in water temperatures [ 68 , 71 ]. Importantly, as seen in our study, Vibrio spp.…”

“…Although culture-independent methods such as real-time polymerase chain reactions may be faster when compared to culture-dependent approaches, they may not reflect the viable bacterial community in a given ecosystem and may lead to an overestimation of health risks. This is particularly relevant when it comes to the genus Vibrio since several of its members are known to exist in a viable but non-culturable state [ 68 ]. This approach was therefore useful to suggest that these characteristics are present in GB’s waters and may reflect the bacterial adaptive process in an ecosystem severely impacted by anthropogenic pollution.…”

The Distribution of Fecal Contamination in an Urbanized Tropical Lake and Incidence of Acute Diarrheal Disease

“…Extreme weather conditions associated with natural variability or climate change could broaden the geographic distribution of microbial pathogens and facilitate their proliferation in coastal and inland waters, enhancing the incidence of water-associated diseases. − A growing number of water-associated diseases are linked to extreme weather incidents, which may be heavy rains, floods, and cyclones. Such events could promote the introduction of pathogens into natural bodies of water, as well as influence the survival, reproduction, and transmission of pathogens and vectors.…”

Implementation of the Directive 2006/7/EC in Selected EU Member States in the 2017-2019 Period

“…It is necessary to raise the society's awareness regarding negative consequences of polluting the water used for recreation purposes and the responsibility of bathers and visitors to the designated bathing areas (Galic et al, 2020). It also should be noted that the essence of the BWD is a selective choice of water quality indicators and some discussion should be had regarding changes (Gyraite et al, 2020;Pronin, 2021). The BWD is also significantly different from the American standards (Tiwari et al, 2021).…”