Heavy Metals and the Occurrence of Ulcerative Dermal Necrosis (UDN) in Sea Trout from the RIVER REGA, Poland—Consumer Health Assessment

Abstract

Various factors, including heavy metals, can make fish more susceptible to disease. This study investigated, inter alia, the relationship between Pb, Cd, and Hg contamination of the organs and muscles of sea trout from the river Rega (Poland) and the occurrence of UDN (ulcerative skin necrosis) symptoms. Moreover, the dietary risk of Pb, Cd, and Hg uptake from the muscles of healthy sea trout was assessed based on estimated daily intake (EDI), target hazard quotient (THQ), benchmark dose lower confidence limits (BMDL01 and BMDL10), and tolerable weekly intake (TWI). The metal concentrations varied, depending on the fish organs and the fish condition. A significantly higher amount of Pb was found in the gonads, gills, and muscles, Cd in the kidneys, and Hg in the muscles of sea trout with UDN symptoms. The lowest concentrations of Pb and Cd were detected in the muscles, and of Hg in the gonads. Dietary exposure to Pb, Cd, and Hg accounted for: 0.4% of BMDL01 and 1.0% of BMDL10, 0.56% of TWI, and 16.5% of TWI, respectively. THQs for each metal and the HI value for combined metals were below 1. The weakening of fish due to UDN-like disease probably increased the accumulation of Pb in the gonads, gills, and muscles, and of Cd in the kidneys, of the sea trout. As regards the maximum levels (MRLs), the muscles of healthy sea trout are safe for consumption. The risk assessment suggests no concern for the health of consumers.

Potential role of climate change on the spread of salmonid skin condition: the biogeochemical hypothesis on ulcerative dermal necrosis on the Słupia River - Poland

“…The question arises if changing acid-base (AB) conditions in estuaries may impair mucous cells in fish skin and thereby reduce mucous production and/or secretion. Some studies link ulcers in salmonids with heavy metals such as aluminium or copper in water (Segner et al, 1988;Berntssen et al, 1997;Noga, 2000;Rajkowska-Mysĺiwiec et al, 2022), but the abundance and bioavailability of heavy metal ions are strictly correlated with acid-base conditions (Jin et al, 2021).…”