Schmitt, C.J. and McKee, M.J., 2016, Tables of lead and calcium concentrations measured in fillet samples of longear sunfish (Lepomis megalotis) and suckers (Catostomidae) collected in 2005‒12 from the Big River, in southeastern Missouri, U.S. Geological Survey data release, http://dx.doi.org/10.5066/F7125QR2
The Big River (BR) and Flat River (FR), a tributary of the BR, drain the Old Lead Belt (OLB), a historical lead (Pb) and zinc mining area in Southeast Missouri USA (Fig. 1). About 180 km (81%) of the BR, from the upper end of the OLB near Leadwood downstream to its confluence with the Meramec River (MR), have been contaminated by Pb and other metals. The Big River Mine Tailings/St.Joe Minerals Site has been on the U.S. Environmental Protection Agency (USEPA) National Priories List since 1992, and much of the FR and BR have been designated as “impaired” due to elevated concentrations of Pb and other metals in sediments and fish (Missouri Department of Natural Resources 2010). There is a “Do Not Consume” advisory due to elevated Pb in suckers (Catostomidae), longear sunfish (Lepomis megalotis; sunfish), other sunfish species, and common carp (Cyprinus carpio) due to elevated fillet Pb concentrations [Missouri Department of Health and Senior Services (MDHSS) 2016]. Fillet Pb in these species often exceeds 300 ng/g wet-weight (ww), the concentration at which MDHSS issues consumption advisories when considered together with other factors and exposure pathways [U.S. Environmental Protection Agency (USEPA) 2016]. Concentrations are typically lower in black bass (Micropterus spp.; Czarnezki 1985; Schmitt and Finger 1987; Gale et al. 2004), which are not included in the consumption advisory. Reduction of tailings inputs to the BR and FR has been a focus of environmental remediation in the OLB. Additional remediation, to include contaminated sediment removal, has been proposed. One long-term goal of remediation is to reduce Pb concentrations in fish and rescind the consumption advisory. Lead occurs in animals as a trace contaminant of calcium (Ca) that accumulates in tissues such as bone and scale (Settle and Patterson 1980). Mucus is also rich in Ca; it can bind waterborne metals and may represent a pathway for metal excretion (Varanasi and Markey 1978). Muscle Pb concentrations are usually low, but the inclusion of bone or scale, contact with mucus, or sample contamination can substantially influence measured Pb concentrations and increase sample-to-sample variability (Schmitt and Finger 1987; Schmitt et al. 2007). Consequently, much of the Pb in fillets from BR fish has been attributed to the presence of material other than muscle in fillet samples. Concentrations of Pb in BR fish have been monitored since the early 1980s (Czarnezski 1985; Schmitt and Finger 1987; Gale et al. 2004). However, determining whether fillet Pb concentrations have changed is difficult because collection and sample preparation procedures have differed among investigators and over time and Ca has not always been measured. Our objectives were therefore to determine whether Pb concentrations in BR fish have declined relative to historical concentrations after accounting for Ca, and to establish a baseline for future monitoring with a uniform protocol that includes accounting for Ca.