Routine screening of harmful microorganisms in beach sands: Implications to public health

Abstract

Beaches worldwide provide recreational opportunities to hundreds of millions of people and serve as important components of coastal economies. Beach water is often monitored for microbiological quality to detect the presence of indicators of human sewage contamination so as to prevent public health outbreaks associated with water contact. However, growing evidence suggests that beach sand can harbor microbes harmful to human health, often in concentrations greater than the beach water. Currently, there are no standards for monitoring, sampling, analyzing, or managing beach sand quality. In addition to indicator microbes, growing evidence has identified pathogenic bacteria, viruses, and fungi in a variety of beach sands worldwide. The public health threat associated with these populations through direct and indirect contact is unknown because so little research has been conducted relating to health outcomes associated with sand quality. In this manuscript, we present the consensus findings of a workshop of experts convened in Lisbon, Portugal to discuss the current state of knowledge on beach sand microbiological quality and to develop suggestions for standardizing the evaluation of sand at coastal beaches. The expert group at the "Microareias 2012" workshop recommends that 1) beach sand should be screened for a variety of pathogens harmful to human health, and sand monitoring should then be initiated alongside regular water monitoring; 2) sampling and analysis protocols should be standardized to allow proper comparisons among beach locations; and 3) further studies are needed to estimate human health risk with exposure to contaminated beach sand. Much of the manuscript is focused on research specific to Portugal, but similar results have been found elsewhere, and the findings have worldwide implications.

Densities and antimicrobial resistance of Escherichia coli isolated from marine waters and beach sands.

“…3 Escherichia coli counts in dry and wet sands at Gonzaguinha and Ilha Porchat beaches during the study period. Error bars indicate standard error of the mean to public health, once that beachgoers spend more time in sand than in the seawater, and a widely variety of pathogens should be included for screening on different sand zones (Halliday and Gast 2011;Sabino et al 2014). …”

Assessment of the microbiological quality of recreational waters: indicators and methods

“…Pathogens may persist and/or re-grow in beach sand driven by periodic wetting through wave heights and tides and the concentration of fecal indicators in sand may be even greater than that observed in RW (Halliday and Gast 2011). Soils are also a relevant source of pathogens and may have concentrations of microorganisms up to 100-fold higher than in nearby waters (Sabino et al 2014). The pathogens can be deposited on the land surface and subsequently conveyed to the stream during and after rainfall events achieving the RW (Ogden et al 2009).…”

Dermatophyte infections in environmental contexts

“…These studies also aim to draw conclusions leading to the possibility of controlling the safety of beach sands. Of particular interest are the studies of Sabino et al [42,43] and Pereira et al [41] who investigated the beaches in Portugal and the Madeira archipelago. Sabino et al [43] found in the sand Trichophyton and Microsporum species, but no Epidermophyton.…”