An Evaluation of a Reagentless Method for the Determination of Total Mercury in Aquatic Life

Abstract

Multiple treatment (i.e., drying, chemical digestion, and oxidation) steps are often required during preparation of biological matrices for quantitative analysis of mercury; these multiple steps could potentially lead to systematic errors and poor recovery of the analyte. In this study, the Direct Mercury Analyzer (Milestone Inc., Monroe, CT) was utilized to measure total mercury in fish tissue by integrating steps of drying, sample combustion and gold sequestration with successive identification using atomic absorption spectrometry. We also evaluated the differences between the mercury concentrations found in samples that were homogenized and samples with no preparation. These results were confirmed with cold vapor atomic absorbance and fluorescence spectrometric methods of analysis. Finally, total mercury in wild captured largemouth bass (n = 20) were assessed using the Direct Mercury Analyzer to examine internal variability between mercury concentrations in muscle, liver and brain organs. Direct analysis of total mercury measured in muscle tissue was strongly correlated with muscle tissue that was homogenized before analysis (r = 0.81, p < 0.0001). Additionally, results using this integrated method compared favorably (p < 0.05) with conventional cold vapor spectrometry with atomic absorbance and fluorescence detection methods. Mercury concentrations in brain were significantly lower than concentrations in muscle (p < 0.001) and liver (p < 0.05) tissues. This integrated method can measure a wide range of mercury concentrations (0-500 μg) using small sample sizes. Total mercury measurements in this study are comparative to the methods (cold vapor) commonly used for total mercury analysis and are devoid of laborious sample preparation and expensive hazardous waste.

Cross‐basin comparison of mercury bioaccumulation in Lake Huron lake trout emphasizes ecological characteristics

“…Forage fish and lake trout samples were subsampled and 0.2 g of homogenate was placed in routine‐washed (soap and water) nickel boats and analyzed 32 at a time. The automatic steps of the DMA‐80 are described in detail in Haynes et al . The DMA‐80 was calibrated prior to analysis using in house quality controls, including liquid control (W‐CntVG, 0.1 mg/L), solid wet biological tissue control (BT‐Cnt2M‐Spk, 0.1 mg/kg), and solid dry biological tissue controls (BT‐Dorm‐3, 0.4 mg/kg; BT‐Dolt 4, 2.58 mg/kg).…”

Rapidly increasing methyl mercury in endangered ivory gull ( Pagophila eburnea ) feathers over a 130 year record

“…Samples were then placed in clean, dry tubes in a fumehood and left to dry for 3 days to dry at room temperature. Total mercury was determined using A Milestonew DMA-80 direct mercury analyser [39] in accordance with Environmental Protection Agency (EPA) method 7473 [40] in an ISO 17025 accredited laboratory in the Biotron Centre for Experimental Climate Change Research at Western University, London, Ontario. A single instrument calibration with a four-point standard curve had an r 2 ¼ 0.9998.…”

Resource partitioning among five species of waterfowl (Anasspp.) at an autumn migratory stopover: combining stable isotope and mercury biomarkers

“…Total Hg concentrations in liver tissue, invertebrates and aquatic macrophytes were determined by atomic absorption spectroscopy on a DMA-80 (Milestone, Inc., Shelton, Connecticut, USA; Haynes et al 2006). Because of very high [Hg] in Blue-winged Teal livers (see Results), to explore Hg bioaccumulation further we also analysed a subset of muscle samples (n = 9) from this species that covered the range of liver [Hg].…”