Spirolides in Bivalve Mollusk of the Galician (NW Spain) Coast: Interspecific, Spatial, Temporal Variation and Presence of an Isomer of 13-Desmethyl Spirolide C

Abstract

Spirolides are cyclic imines whose risks to human health have not been sufficiently evaluated. To determine the possible impact of these compounds in Galicia (NW Spain), their presence and concentration in bivalve mollusk were studied from 2014 to 2021. Only 13-desmethyl spirolide C (13desmSPXC) and an isomer have been detected, and always at low concentrations. Mussel, Mytilus galloprovincialis, was the species which accumulated more spirolides, but the presence of its isomer was nearly restricted to cockle, Cerastoderma edule, and two clam species, Venerupis corrugata and Polititapes rhomboides. On average, the highest 13desmSPXC levels were found in autumn-winter, while those of its isomer were recorded in spring-summer. Both compounds showed decreasing trends during the study period. Geographically, the concentration tends to decrease from the southern to the north-eastern locations, but temporal variability predominates over spatial variability.

The Temporal Distribution of Cyclic Imines in Shellfish in the Bays of Fangar and Alfacs, Northwestern Mediterranean Region

“…SPX-1 and GYM-A have a greater presence during the autumn/winter period and then decrease, appearing in trace concentration values during the spring/summer period (Figures 3 and 6). The same seasonal pattern of SPX-1 was observed in Blanco et al [21], where the highest levels were found during the late autumn-early winter and the lowest at the end of summer [21]. In accordance with Lamas et al [34], the maximum percentage of GYM-A prevalence was in February and the minimum was in July in Galician waters (Spain) [29].…”

“…Spirolides, including SPX-1, in mussels ( M. galloprovincialis ) from Galicia (NW Spain) were recorded, presenting low levels ranging from 1.2 µg/kg to 6.9 µg/kg of SPX-1 [ 35 ] in 18 samples sampled in May 2015. This study has just been updated with an eight-year study by Blanco et al [ 21 ], describing the 75% of the results below 10 µg/kg with a maximum of 80 µg/kg for SPX-1 from 2014 to 2021 [ 21 ]. SPX-1 was also described in Lake Ingril, France (from 1 µg/kg to 19 µg/kg of SPX-1) [ 29 ], in the four-year survey on that area and in the EMERGTOX project from 2018 to 2022, where spirolides (SPX-1 and SPX-DesMeD) were systematically present with a maximum concentration of 69 µg/kg [ 25 ].…”

“…SPXs are polyether compounds that contain a spiro group attached to tricyclic ethers and are mainly produced by Alexandrium ostenfeldii, a thecate dinoflagellate that was first isolated in Iceland and described by Paulsen in 1904 [ 14 , 15 , 16 ]. They were identified, for the first time, in mussels off the coast of Nova Scotia (Canada, 1995) [ 17 ], although they are currently found in countries such as Spain, France, Italy, Scotland, Norway, Denmark, Mozambique, Chile, and Asia–Pacific countries [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. The reference compound for this group is 13-desmethyl SPX-C (SPX-1) [ 26 ], which, together with SPX-C and 20-methyl SPX-G, is the most toxic compound [ 8 ].…”

“…This group of toxins is produced by the dinoflagellate Vulcanodinium rugosum [ 9 ] and includes seven analogues whose chemical structure is very similar to that of the SPXs [ 3 ], where pinnatoxin-G (PnTX-G) is the reference compound [ 26 ]. These compounds are currently appearing in oysters ( T. chilensis ), mussels ( M. galloprovincialis ), razor clams (Ensis magnus) , and clams (Ruditapes decussates) from many countries such as Mozambique, Chile, Japan, China, South Australia, New Zealand, Canada, Norway, France, and Spain [ 8 , 19 , 21 , 22 , 23 , 24 , 25 ].…”

Five Years Monitoring the Emergence of Unregulated Toxins in Shellfish in France (EMERGTOX 2018–2022)

“…In Europe, SPX was found in shellfish in Norway [ 9 ], Spain [ 63 , 64 ], and Italy [ 65 ], whereas PnTX was found in mussels in various parts of the Norwegian coast [ 13 , 66 ]. Recently, a three-year survey (2019–2021) was carried out in Greece on the contamination of shellfish by cyclic imines, implementing an LC-MS/MS method.…”