Underestimation of chemical contamination in marine fish muscle tissue can be reduced by considering variable wet:dry weight ratios

• Published in: Marine pollution bulletin Vol. 123; no. 1-2; pp. 279 - 285
• Main Authors: Cresson, Pierre, Travers-Trolet, Morgane, Rouquette, Manuel, Timmerman, Charles-André, Giraldo, Carolina, Lefebvre, Sébastien, Ernande, Bruno
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.10.2017; Elsevier BV; Elsevier
• Subjects: Animal tissues; Animals; Aquatic Organisms - chemistry; Carbon - analysis; Carbon-nitrogen ratio; Chemical contamination; Chemical pollution; Contaminant concentration; Contaminants; Contamination; Conversion factor; Conversion factors; Dry weight; Ecological risk assessment; England; Fish; Fishes; human health; Humans; Life Sciences; lipid content; Lipids; Lipids - analysis; Lipids - chemistry; Marine chemistry; Marine fish; Marine fishes; Marine pollution; muscle tissues; Muscles; Muscles - chemistry; Nitrogen - analysis; Percentage of humidity; risk; Sciences of the Universe; Species; Tissue; tracer techniques; Tracers; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry; water pollution; Weight reduction; Wet:dry ratio; Percentage of humidity; Conversion factor; Marine fish; Wet:dry ratio; Contaminant concentration
• ISSN: 0025-326X; 1879-3363; 1879-3363
• DOI: 10.1016/j.marpolbul.2017.08.046

Whether considered as a risk for human health or as ecological tracers, contaminants' concentrations measured in fish muscles are commonly expressed relative to wet or dry mass. Comparison of results required conversion factors (CF) but accurate values are scarce and case-specific. The present paper is aimed at investigating errors linked with the use of the theoretical value. Muscles dry and wet masses were measured in 15 fish species to determine the actual CF. Most CF were lower than the theoretical wet:dry ratio of 5 classically used, with variations at individual and species level. Muscle lipid content (inferred by C/N ratios) was a crucial factor explaining discrepancies, claiming for caution when working with lipid-rich species. The observed variability demonstrated that using the theoretical CF may be inaccurate, when actual CF largely differs from the theoretical value. Dedicated measurement is the better approach when accuracy is required. [Display omitted] •Conversion factor differs between fish species.•Most values were different from 5, whereas this factor is largely used.•Lipid was a major driver of discrepancies.•Sanitary decision based on converted values may be dubious.