Microcystin Contamination in Sea Mussel Farms from the Italian Southern Adriatic Coast following Cyanobacterial Blooms in an Artificial Reservoir

Abstract

An experimental study was performed in 2009-2010 to investigate the polluting effect of eutrophic inland waters communicating with the sea coast. The study was planned after a heavy and long-lastingPlanktothrix rubescensbloom occurred in the Lake Occhito, an artificial reservoir. The waters of the reservoir flow into the southern Adriatic Sea, near several marine breeding ofMytilus galloprovincialismussels, a typical seafood from the Apulia region (Southern Italy). A monitoring study of water and mussels from the sea coast of northern Apulia region and on the Occhito reservoir was carried out over twelve months, to get more information regarding the contamination by cyanobacteria and related cyanotoxins. Elisa immunoassay analyses estimated total microcystin amounts from 1.73 to 256 ng/g in mussels, up to 0.61 μg/L in sea water and up to 298.7 μg/L in lake water. Analyses of some samples of free-living marine clams as well as of marine and freshwater fish proved microcystin contamination. Selective confirmatory analyses by LC/ESI-Q-ToF-MS/MS on some mussel samples identified the microcystin desMe-MC-RR as the major toxin; this compound has been reported in the literature as a specific marker toxin ofPlanktothrix rubescensblooms. Our study describes for the first time the direct relationship between environmental pollution and food safety, caused by seafood contamination from freshwater toxic blooms.

Transfer of microcystin from freshwater lakes to Puget Sound, WA and toxin accumulation in marine mussels (Mytilus trossulus)

“…MCs from freshwater sources have been detected in near-shore marine systems (Robson and Hamilton, 2003;Miller et al, 2010;Gibble and Kudela, 2014), yet monitoring for the toxin in marine waters and seafood has been limited (De Pace et al, 2014). Our findings provide the first documentation of MC presence in Puget Sound waters and the first to establish a direct relationship outside the laboratory, in the United States, between MC in inland lakes and marine seafood intoxication.…”

“…4). Other studies have also reported detection of MC in biota even in the absence of MC in surrounding waters (Prepas et al, 1997;Miller et al, 2010;De Pace et al, 2014). Because field-sampling techniques can significantly affect MC detection (Tillmans et al, 2007) our MC measurements in water samples, especially marine waters, should be considered conservative.…”

“…However, MCs are stable and can be environmentally persistent in both freshwater and marine ecosystems (Tonk et al, 2007, Miller et al, 2010. Recent studies show that MC contaminated freshwater can deliver toxins into marine environments (Miller et al, 2010, De Pace et al, 2014, Gibble and Kudela, 2014 raising concerns that biota may accumulate and potentially transfer MC through marine food webs (Kozlowsky-Suzuki et al, 2012). In 2007, waters in Monterey Bay National Marine Sanctuary tested positive for MC after receiving inflow from three rivers draining freshwater lakes with HABs.…”

Persistence of microcystin production byPlanktothrix agardhii(Cyanobacteria) exposed to different salinities

“…Salinity is an important abiotic factor that affects physiological and ecological performance of phytoplankton species, including cyanobacteria (De Pace et al 2014;Teikaki et al 2018;Tonk et al 2007). We focused on the morphological and physiological changes of P. agardhii, a dominant species from a brackish pond that might therefore be pre-adapted to varying salinities (Vergalli 2013).…”

“…those acclimated to high salt concentrations near full seawater, have genes for sucrose synthesis with a suite of general and salt-stress-specific genes and regulatory systems enabling them to cope with changing environments (Tanabe et al 2018;Teikaki et al 2018Teikaki et al , 2019. Earlier studies reported controversial results on cyanobacterial responses and capacity to cope with salt-stress (De Pace et al 2014;Tolar 2012;Tonk et al 2007), even at the intraspecific level (Otsuka et al 1999). While some Microcystis strains resisted 10 g l −1 of NaCl (Orr et al 2004;Tonk et al 2007), others reached their limit at 2 g l −1 , leading the authors to consider this as a strain-specific halotolerance rather than as a species-specific trait (Orr et al 2004).…”