Microbiological water quality and sources of contamination along the coast of the Department of Atlántico (Caribbean Sea of Colombia). Preliminary results

Preliminary Microbiological Coastal Water Quality Determination along the Department of Atlántico (Colombia): Relationships with Beach Characteristics

“…Such authors associated high E. coli counts with the presence of polluted streams outflowing directly on the beach (Table 3). Sánchez et al [12] reported low E. coli counts at Sabanilla beach that, in this study, was the beach with the highest counts (262-352 cfu/100 mL). Such differences may be related to E. coli survival time in seawater, i.e., the lapse time between the contamination event and the survey [37], that is, the intermittent nature of this kind of contamination (i.e., the contamination source is not constant) as observed by Torres-Bejarano et al [13] in Puerto Velero, or the different location of the sampled points (Table 3).…”

“…Additionally, Gram-negative bacteria lose quickly their ability to form colonies in seawater, although they can still be detected at high levels by viable counting methods [38], and E. coli in seawater by effect of solar radiation can enter into a reversible state of "viable but not cultivable": this can strongly influence count values [39]. The differences in the cfu numbers obtained for E. coli on this beach by this study and Sanchez et al [12] may be associated with the sampling season, i.e., the survey in this study was carried out during the rainy season meanwhile Sanchez et al [12] carried out the sampling during the dry season. From one side, increased runoff during rainy season favours the deposition of faecal bacteria on beaches.…”

“…The area investigated, i.e., the Department of Atlántico, is located in the Colombian Caribbean region and has a coastline length of approximately 64.5 km (4% of the Colombian Caribbean). Different studies have assessed seawater quality at specific places of such coastal sector, using only the detection of indicator bacteria of faecal contamination (e.g., Faecal Coliform, E. coli, Enterococcus and Clostridium) [12][13][14], but none took into account beach typology or used molecular techniques for the detection of pathogens (e.g., Salmonella spp. presence/absence).…”

“…INVEMAR [14] reported that Puerto Colombia, Pradomar, Salgar, Caño Dulce, Puerto Velero and Santa Veronica beaches presented thermotolerant coliforms values between 78-920 MPN/100 mL and 2-1400 MNP/100 mL in 2018 and 2019, respectively. Sánchez et al [12], which only covered the northern part of the area investigated in this paper, established the highest values of E. coli ≥ 500 cfu/100 mL on beaches located in urban areas (e.g., Salgar, Pradomar, Puerto Colombia and Northern zone of Puerto Velero), while beaches located in rural areas (Sabanilla and the southern zone of Puerto Velero) presented the lowest counts with values between 16 and 54 cfu/100 mL. Such authors associated high E. coli counts with the presence of polluted streams outflowing directly on the beach (Table 3).…”

“…on these beaches is the discharge of wastewater (from polluted streams) without prior treatment, which contains a high variety of pathogenic microorganisms (e.g., Salmonella, Shigella, Vibrio, among other) that can cause disease outbreak [50]. Sanchez et al [12] detected high concentrations of E. coli and Enterococcus in these streams, which flow directly into the beaches of the studied area. The average E. coli and Enterococcus counts reported by Sanchez et al [12] were 4.1 × 10 5 cfu/100 mL and 4.3 × 10 2 cfu/100 mL, respectively, which demonstrated the elevated pollution of those streams with faecal matter that could also contain Salmonella spp.…”