Total mercury, methylmercury, and selenium concentrations in blue marlin Makaira nigricans from a long-term dataset in the western north Atlantic

P J Rudershausen; F A Cross; B J Runde; D W Evans; W G Cope; J A Buckel

doi:10.1016/j.scitotenv.2022.159947

Total mercury, methylmercury, and selenium concentrations in blue marlin Makaira nigricans from a long-term dataset in the western north Atlantic

Sci Total Environ. 2023 Feb 1;858(Pt 2):159947. doi: 10.1016/j.scitotenv.2022.159947. Epub 2022 Nov 4.

Authors

P J Rudershausen¹, F A Cross², B J Runde³, D W Evans², W G Cope⁴, J A Buckel³

Affiliations

¹ North Carolina State University, Department of Applied Ecology, Center for Marine Sciences and Technology, 303 College Circle, Morehead City, NC 28557, USA. Electronic address: pjruders@ncsu.edu.
² NOAA, Southeast Fisheries Science Center, 101 Pivers Island Road, Beaufort, NC 28516, USA.
³ North Carolina State University, Department of Applied Ecology, Center for Marine Sciences and Technology, 303 College Circle, Morehead City, NC 28557, USA.
⁴ North Carolina State University, Department of Applied Ecology, Box 7617, Raleigh, NC 27695, USA.

PMID: 36336054
DOI: 10.1016/j.scitotenv.2022.159947

Abstract

Mercury in seafood is a neurotoxicant that threatens human health. Dynamic rates of mercury emission, re-emission, and atmospheric deposition warrant studies into mercury concentrations in fish because many are consumed by humans and can serve as sentinels of mercury levels in the environment. We modeled trends in total mercury content in an apex marine fish predator, Atlantic blue marlin Makaira nigricans, whose muscle tissues were opportunistically sampled from North Carolina (USA) sportfishing tournaments over a discontinuous time period: between 1975 and 77 and 1998-2021 (n = 148). The model-estimated influence of marlin weight on total mercury concentration was constant across years (shared slope) allowing for comparisons of weight-corrected mercury concentrations among years. Weight-corrected total mercury concentrations revealed an inter-decadal decline of approximately 45 % between the 1970s and late 1990s and then variable but relatively stable concentrations through 2021. The mean (SD) wet weight concentration of total mercury was 9.47 (4.11) from 1975 to 77 and 4.17 (2.61) from 2020 to 2021. Methylmercury and selenium were measured on a subset of fish to address questions related to human health and consumption. Methylmercury levels (mean = 0.72 μg/g) were much lower than total mercury (mean = 4.69 μg/g) indicating that total mercury is not a good proxy for methylmercury in Atlantic blue marlin. Selenium, examined as a Se:Hg molar ratio and as a selenium health benefit value (HBV_Se), showed high protective value against mercury toxicity. Long-term trends in the concentration of mercury in blue marlin should continue to be monitored to determine whether policies to mitigate anthropogenic contributions to global mercury are achieving their intended goals and to provide information to inform safe human consumption.

Keywords: Fish consumption; Human health; Marine apex predator; Mercury; Methylmercury; Neurotoxicant; Selenium.

MeSH terms

Animals
Fishes
Humans
Mercury* / analysis
Methylmercury Compounds*
Perciformes*
Selenium*
Water Pollutants, Chemical* / analysis

Substances

Mercury
Methylmercury Compounds
Selenium
Water Pollutants, Chemical