Recipient Organization
LINCOLN UNIVERSITY
820 CHESTNUT ST
JEFFERSON CITY,MO 651023537
Performing Department
Agriculture
Non Technical Summary
Missouri is blessed with streams, rivers, and reservoirs that support freshwater fishes, recreation, and conservation. Fish are an important addition to the human diet because they are an excellent source of nutrients (e.g. proteins, omega-3 fatty acids, vitamins, selenium, calcium and other minerals). As a result, the American Heart Association recommends two servings of fish per week as part of a healthy diet. Despite the health benefits of eating fish, toxic elements (e.g. As, Cd, Hg, Pb, etc.) pose potential risks to consumers. These elements derive from both natural (e.g., volcanic emissions; microbial transformations of inorganic mercury to methylmercury, MeHg) and anthropogenic (e.g., burning fossil fuels, waste incineration, ore mining and refining, urban wastewater, etc.) sources. The major drivers of metal(loids) distribution to lakes and biota include landscape, surface area, atmospheric deposition, anoxic conditions, and runoffs. Consequently, all states in the nation have fish consumption advisories that protect public health. In Missouri, the Department of Health and Senior Services (DHSS) recommends that women and children under 13 years consume no more than one meal per month of large-bodied predatory fish species that have the highest mercury (Hg) concentrations. However, there is minimal data on the concentrations of other metals in fish in Missouri Reservoirs. The objectives of the project are to (1) determine the concentrations of trace elements (Hg, Se, As, Cd, Pb, Ca, Zn) in largemouth bass (LMB; skin-off fillet) from five Missouri Reservoirs and the relationships with size/age of fish; (2) describe the relationship of Hg with other metals in LMB; (3) understand trophic interactions and Hg transfer through stable isotope (δ 15N, δ 13C) studies of composite food chain (<3 inch prey fish, and crayfish) samples; and (4) investigate lake water chemistry to understand the influencing variables to metal transportation. Water analysis will involve the quantification of elemental species (over 20 elements), anions, and ammonium, dissolved organic carbon, and other water quality determinants. This work is a collaborative project with the Missouri Department of Conservation (MDC) (Dr. Knott; Resource Science Division) to address knowledge gaps from previous studies by the MDC and the DHSS. There is substantive lake water chemistry datasets such as temperature, lake landscape, etc. from the University of Missouri Limnology Research (Dr. North, University of Missouri) that also support this work. This project will increase faculty collaboration efforts, train students, and support stakeholder engagements in water quality, food chain studies, and policy on ecological risk management of Missouri reservoirs. Information gathered on this project will be disseminated through conferences and peer-reviewed research articles.
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
Trace element pathways and processes have been significantly altered by humankind, and their flux and distribution in a large fraction of all freshwater resources have increased. Consequently, the need to address water quality problems from ecological damage demands many efforts throughout our nation. Missouri is blessed with streams, rivers, and reservoirs that support freshwater fishes, recreation, and conservation. Fish are an important addition to the human diet because they are an excellent source of nutrients. However, potential toxic concentrations of elements including mercury threaten the health of fish and humans who may consume them. Missouri has a statewide fish consumption advisory recommending that women and children under 13 years consume no more than one meal per month of large-bodied predatory fish species that have the highest Hg concentrations. Currently, there is minimal data on the concentrations ofmetals in fish from Missouri Reservoirs. The goal of the project is to fill knowledge gaps on water quality chemistry and metal transfers in largemouth bass from five Missouri reservoirs and to assess the risks to human consumption of fish.The objectives of the study are:(1) determine the concentrations of trace elements (Hg, Se, As, Cd, Pb, Ca, Zn) in largemouth bass (LMB; skin-off fillet) from five Missouri Reservoirs and the relationships with size/age of fish; (2) describe the relationship of Hg with other metals in LMB; (3) understand trophic interactions and Hg transfer through stable isotope (δ 15N, δ 13C) studies of composite food chain (<3 inch prey fish, and crayfish) samples; and (4) investigate lake water chemistry to understand the influencing variables to metal transportation. The information from the project will increase knowledge, assist decision managers, and also provide scientific data on potential human health risks from consumption of fish.
Project Methods
Sampling Largemouth bass and other samples LMB represent an important recreational fish that feed at a high trophic level and serves as a bioindicator of metal transport through aquatic systems. Metrics of lake morphology including depth, surface area, and shoreline development factor (SDF = shoreline length/2(π*area)0.5) will be recorded. We will collect LMB samples (n = 15) from five lakes during the two year period for this study. MDC staff will collect the samples by electrofishing, trapping, or seine methods. The length, sex, and body mass of fish will be recorded. Harvestable sized LMB (10-20 inches) from each reservoir will be targeted. Because age 0-1 Crappie (CP), Bluegill (BG), and Gizzard Shad (GS) can make up to 90% of the LMB diet during summer (Pope et al. 2001), prey-sized CP, BG, and GS (<3 inches, n=5 of each species will be pooled) from all lakes will be collected to determine the Hg concentration and stable isotope signature. Crayfish from each reservoir will also be collected from each reservoir (n=15) and opportunistically from the stomachs (n=5, depending on availability) of LMB for metal and stable isotope analyses. Fillets will be removed from harvestable-sized fish for metals analyses, while prey-sized fish and crayfish will be analyzed whole. Otoliths will be removed from all fish for age estimation. Drainage area surrounding each reservoir will be determined through GIS mapping. Water samples (1 L) will be collected from each lake at the time of fish collection for general parameters (pH, electrical conductivity, anions, ammonium ion, dissolved organic carbon, etc.) and over 20 elemental (including Ca, As, Cd, Pb, Se, Hg, etc.) measurements. Two types of water samples will be collected from each lake; 1) samples (1 L) for general parameters such as pH, electrical conductivity (EC), alkalinity, dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and total dissolved nitrogen (TDN), and 2) Water samples (0.5 L) for dissolved metals will be collected by filtering samples in the field with a polypropylene syringe and filter cartridge (0.45 µm pore size). Filtered samples prepared for elemental detection will be preserved with 1 ml HNO3 per liter of the sample within three hours of collection. Samples will be processed and analyzed at the LU laboratory.Microwave digestion of fish samples Fish and prey samples will be digested using an UltraWave microwave digestion system (SRC-UltraWAVE™, Milestone, CT, USA), equipped with a single reaction chamber of 15 quartz vessels with the capacity to operate up to 180 bar and 275 oC during digestion.Analyses Analyses of samples for various parameters will be conducted in our laboratories at Lincoln University, Jefferson City, Missouri. Lake water samples will be analyzed for pH, electrical conductivity by a multiparameter probe, total alkalinity by potentiometric titration, ionic species - NO3−, PO43−, Br-, Cl−, SO42−, and NH4+by ion chromatography (IC), dissolved organic carbon by combustion/ nondispersive infrared detection), and TDN by chemiluminescence. Trace element analysis will also be performed at Lincoln University research laboratory. Twenty one elements (Al, As, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Sn, Sr, V, and Zn) will be measured in fish digests and filtered water samples using an Agilent 5110 vertical dual view inductively coupled plasma - optical emission spectrometer (ICP - OES) configured to an SPS 4 autosampler. Certified reference sample (SRM 1640a - trace elements in water) from the National Institute of Standards and Technology (NIST) and other quality control samples will be used for instrument validation. Method blanks, internal standards, and calibration verification standards will also be analyzed on the ICP - OES for every batch run and recalibration of the ICP after every analysis of 10 samples is completed. We will also utilize the direct mercury analyzer (DMA - 80) to quantify total mercury concentrations in fish and other food chain samples. Mercury determination using the direct mercury analyzer (DMA-80) will involve thermal decomposition of the sample, catalytic conversion followed by amalgamation and total Hg detection by atomic absorption spectrophotometry at 253.65 nm. Analysis of standard reference materials (DOLT-5, DORM-4, and other QC samples) will be performed to validate our methods and the analytical procedures for water, and the food chain samples. Subsamples of fillets from harvestable-sized and prey-sized fish will be homogenized, dried, and analyzed for stable isotope analyses to determine the LMB trophic position and proportional diet composition. Stable isotope (δ 15N, δ 13C) analysis will be performed at University of California, Davis.