Temporal trends of mercury levels in fish (dab, Limanda limanda) and sediment from the German Bight (North Sea) in the period 1995–2020

Abstract

As a toxic and harmful global pollutant, mercury (Hg) enters the marine environment through natural sources, and human activities. It bioaccumulates through the food chain and therefore, Hg is of great importance for environmental monitoring. This study aims to answer the question if Hg contamination in fish and sediment from the German Bight follows temporal trends. Therefore, 496 individual female dab (Limanda limanda) were analyzed. The Hg concentrations in the muscle of dab from the German Bight showed significant increase in function of time with an annual percental change of 1.4%, leading to a 41% increase in Hg contamination level within 25 years of monitoring. At the same time, Hg concentrations in sediment—analyzed in 86 samples—significantly decreased in the nearby North Sea environment. This surprising contradiction is shown in the present study and possible causes are discussed. It could be clearly shown that contamination in sediment and biota can follow completely different time courses and therefore, different environmental matrices should be considered in future monitoring studies. Age of the fish turned out to be a biological factor of particular importance for temporal trend analysis.

Explosives leaking from dumped munition contaminate fish from German coastal waters: a reason for chronic effects?

“…For the present study, we have chosen the bottom dwelling, territorial flat fish common dab (L. limanda) as model species. Dab has often been used as a monitoring organism regarding chemical contamination in the North Sea and in the western Baltic Sea [12,[17][18][19]34]. Furthermore, according to the OSPAR CEMP, dab is the first-choice flatfish species for chemical monitoring [31].…”

Heavy metal contamination in European conger (Conger conger, Linnaeus 1758) along the coastline of Morocco

“…People who prefer to eat local seafood in contaminated areas can be at risk of elevated Hg exposure [9]. Increasing Hg concentration in muscle tissue of fish with age is a well-known fact [22,23], so that older specimens can be expected to exhibit higher Hg contamination than younger ones. Hg accumulation is dominated by MeHg, Lang et al [25] showed that 94% of the total Hg in fish muscle was MeHg.…”

“…The concentrations of Hg, Cd and/or Pb have been revealed in fish species from other regions such as the Aegean Sea [48], the Baltic Sea [22,37], the North Sea [23,25], the North Atlantic [24] and the Pacific coast [21].…”