Coastal pollution monitoring by an automatic multisampler coupled with a fluorescent antibody assay

New systems for continuous monitoring of the bacteriological quality of seawater are required to obtain real-time information about the health status of the environment. The use of an automatic multisampler, specially designed for the automatic collection and fixation of seawater samples, has been proposed as a useful tool for the early warning of marine pollution. The development of this new device makes the sampling phase easier and more precise than in the past, allowing also the automatic addition of chemical preservatives to the sample. In this paper the mechanical characteristics of this instrumentation and the data obtained by its first "in situ" application for the monitoring of the microbiological quality in the harbour of Messina are reported. The microscopic observation of samples collected in April 2003 by this system and stained by DAPI fluorochrome revealed a bacterioplankton density in the range of 10(5)-10(8) cells 100 ml(-1), of which a fraction equal to 54% on average was identified to belong to Escherichia coli by fluorescent antibody assay. The temporal distribution of bacterioplankton densities displayed the occurrence of daily peaks, following a cyclical trend due to their very close dependence on hydrodynamic phenomena that characterise the Messina Straits area. The coupling of the automatic sampler with the rapid microbiological method offers a useful tool for seawater pollution monitoring, enabling the detection of changes occurring in microbial water quality; it is simple to obtain time series about environmental quality levels, notice pollution episodes as soon as they happen, and establish in near real-time appropriate remediation measures.