The Effectiveness of Total Mercury as a Surrogate for Methylmercury in Aquatic Invertebrates
Active
By New York Water Science Center
August 28, 2015
A. BACKGROUND
Aquatic macroinvertebrates, such as dragonfly larvae or crayfish have great potential for Mercury (Hg) monitoring, both as indicator organisms (or "sentinels'), and to provide critical information on Hg in lower food webs to assist in interpreting fish Hg levels. Despite these advantages, macroinvertebrates are not widely used in Hg monitoring because of the current need to directly analyze macoinvertebrate tissue for methyl-mercury (MeHg), at much greater expense than analyzing for total Hg (THg) (i.e. as a surrogate for MeHg), as with fish tissue. This is because the ratio of MeHg to THg in macroinvertebrates exhibits large taxonomic, spatial, and temporal variation, and there is no clear empirically-based documentation on which to base decisions regarding the utility of macroinvertebrate THg levels for monitoring programs. This also precludes the effective use .of existing macoinvertebrate THg data (collected since the 1980's) from across New York State to examine MeHg trends and spatial patterns.
B. PROJECT OVERVIEW
The goal of the proposed study is to provide a tool for the effective use of macroinvertebrates in Hg monitoring by documenting MeHg:THg statistics and temporal and geographic variation in these statistics. Specific objectives are 1) calculate MeHg:THg statistics for selected macroinvertebrate taxa and feeding groups collected from New York State streams; 2) describe the extent of temporal variation in MeHg:THg ratios for these taxa, and; 3) characterize the extent to which the observed ratios are geographically robust by comparing results for Adirondack streams in New York State with those for streams in other states. A large data set will be analyzed to document ratios (and spatial and temporal variability in those ratios) of MeHg:THg for a wide variety of aquatic macroinvertebrate taxa. This will provide a critical scientific basis for decisions regarding the use of THg as a surrogate for MeHg in macroinvertebrate tissue. The resulting savings in time, complexity, and expense of tissue analysis will allow for the greater use of macroinvertebrates to determine the extent to which biota have been affected by, are recovering from, and are responding to changes in Hg deposition rates.
C. STATEMENT OF WORK
The USGS shall compile and analyze Hg species and stable isotope data for macroinvertebrates that were collected by tl!e USGS during 2004-2008 from nine (9) stream sites in the Adirondack region of New York State, and from 12 sites in other states. The USGS shall have as the primary focus of these analyses the documentation and interpretation of MeHg:THg statistics for macroinvertebrate taxa that were collected in New York State. The USGS shall use stable isotope data from these samples to estimate trophic levels, which shall be incorporated into the interpretation of results. The USGS shall incorporate data from sites in other states as needed to evaluate the geographic robustness of the MeHg:THg patterns observed for taxa from New York State streams. In addition to the USGS data, the USGS shall evaluate selected macroinvertebrate datasets from other sources (e.g. University of Maine and the Biodiversity Research Institute) that were collected in New York State, and will include these, as appropriate, in the analysis and (or) interpretation of MeHg:THg statistics.
Task I. Data Compilation
The USGS shall compile existing MeHg, THg, and stable isotope data from the USGS Mercury Topical Studies in New York, Wisconsin, Oregon, South Carolina, and Florida. The USGS shall compile these data from published data reports and from the National Water Information System, and shall communicate with the USGS Mercury Research Laboratory in Wisconsin to obtain any unpublished data that may be useful for this project. The USGS shall also evaluate relevant macroinvertebrate MeHg and THg data sets collected from New York State streams, lakes, and ponds by others, and shall compile appropriate data into the analysis data set for comparison with the findings from analysis of the USGS-collected data.
Task 2.Data Analysis
The USGS shall calculate the ratios of MeHg to THg for each macroinvertebrate sample, and shall calculate statistics (mean, median, standard deviation, minimum, maximum) for each macroinvertebrate taxon. The USGS shall statistically and graphically examine ratios to document taxonomic, trophic, spatial, and temporal variation in observed ratios for the New York State data set. The USGS shall analyze nitrogen stable isotope data in order to incorporate estimates of trophic position to incorporate or control for variation in trophic level within and among taxa in the analysis of MeHg:THg ratios. The USGS shall statistically and graphically compare MeHg:THg patterns for New York State with patterns shown by the same taxa from other states, in order to assess the geographic 'robustness' of MeHg:THg ratios observed in New York State.
Task 3.Manuscript Preparation
The USGS shall interpret findings from the above analyses and shall summarize these findings and interpretations in a manuscript for submission to a scientific journal for peer review.
Project Location by County
Fulton
County, NY, Hamilton County, NY, Herkimer County, NY , Saratoga County, NY, Warren County, NY,
Washington County, NY, Schenectady County, NY, Rensselaer County, NY, Albany County, NY, Greene County, NY, Ulster County, NY, Columbia County, NY, Dutchess County, NY, Putnam County, NY, Westchester County, NY Orange County, NY, New York County, NY, Bronx County, NY
- Source: USGS Sciencebase (id: 55e0afa8e4b05561fa1eef65)
A. BACKGROUND
Aquatic macroinvertebrates, such as dragonfly larvae or crayfish have great potential for Mercury (Hg) monitoring, both as indicator organisms (or "sentinels'), and to provide critical information on Hg in lower food webs to assist in interpreting fish Hg levels. Despite these advantages, macroinvertebrates are not widely used in Hg monitoring because of the current need to directly analyze macoinvertebrate tissue for methyl-mercury (MeHg), at much greater expense than analyzing for total Hg (THg) (i.e. as a surrogate for MeHg), as with fish tissue. This is because the ratio of MeHg to THg in macroinvertebrates exhibits large taxonomic, spatial, and temporal variation, and there is no clear empirically-based documentation on which to base decisions regarding the utility of macroinvertebrate THg levels for monitoring programs. This also precludes the effective use .of existing macoinvertebrate THg data (collected since the 1980's) from across New York State to examine MeHg trends and spatial patterns.
B. PROJECT OVERVIEW
The goal of the proposed study is to provide a tool for the effective use of macroinvertebrates in Hg monitoring by documenting MeHg:THg statistics and temporal and geographic variation in these statistics. Specific objectives are 1) calculate MeHg:THg statistics for selected macroinvertebrate taxa and feeding groups collected from New York State streams; 2) describe the extent of temporal variation in MeHg:THg ratios for these taxa, and; 3) characterize the extent to which the observed ratios are geographically robust by comparing results for Adirondack streams in New York State with those for streams in other states. A large data set will be analyzed to document ratios (and spatial and temporal variability in those ratios) of MeHg:THg for a wide variety of aquatic macroinvertebrate taxa. This will provide a critical scientific basis for decisions regarding the use of THg as a surrogate for MeHg in macroinvertebrate tissue. The resulting savings in time, complexity, and expense of tissue analysis will allow for the greater use of macroinvertebrates to determine the extent to which biota have been affected by, are recovering from, and are responding to changes in Hg deposition rates.
C. STATEMENT OF WORK
The USGS shall compile and analyze Hg species and stable isotope data for macroinvertebrates that were collected by tl!e USGS during 2004-2008 from nine (9) stream sites in the Adirondack region of New York State, and from 12 sites in other states. The USGS shall have as the primary focus of these analyses the documentation and interpretation of MeHg:THg statistics for macroinvertebrate taxa that were collected in New York State. The USGS shall use stable isotope data from these samples to estimate trophic levels, which shall be incorporated into the interpretation of results. The USGS shall incorporate data from sites in other states as needed to evaluate the geographic robustness of the MeHg:THg patterns observed for taxa from New York State streams. In addition to the USGS data, the USGS shall evaluate selected macroinvertebrate datasets from other sources (e.g. University of Maine and the Biodiversity Research Institute) that were collected in New York State, and will include these, as appropriate, in the analysis and (or) interpretation of MeHg:THg statistics.
Task I. Data Compilation
The USGS shall compile existing MeHg, THg, and stable isotope data from the USGS Mercury Topical Studies in New York, Wisconsin, Oregon, South Carolina, and Florida. The USGS shall compile these data from published data reports and from the National Water Information System, and shall communicate with the USGS Mercury Research Laboratory in Wisconsin to obtain any unpublished data that may be useful for this project. The USGS shall also evaluate relevant macroinvertebrate MeHg and THg data sets collected from New York State streams, lakes, and ponds by others, and shall compile appropriate data into the analysis data set for comparison with the findings from analysis of the USGS-collected data.
Task 2.Data Analysis
The USGS shall calculate the ratios of MeHg to THg for each macroinvertebrate sample, and shall calculate statistics (mean, median, standard deviation, minimum, maximum) for each macroinvertebrate taxon. The USGS shall statistically and graphically examine ratios to document taxonomic, trophic, spatial, and temporal variation in observed ratios for the New York State data set. The USGS shall analyze nitrogen stable isotope data in order to incorporate estimates of trophic position to incorporate or control for variation in trophic level within and among taxa in the analysis of MeHg:THg ratios. The USGS shall statistically and graphically compare MeHg:THg patterns for New York State with patterns shown by the same taxa from other states, in order to assess the geographic 'robustness' of MeHg:THg ratios observed in New York State.
Task 3.Manuscript Preparation
The USGS shall interpret findings from the above analyses and shall summarize these findings and interpretations in a manuscript for submission to a scientific journal for peer review.
Project Location by County
Fulton
County, NY, Hamilton County, NY, Herkimer County, NY , Saratoga County, NY, Warren County, NY,
Washington County, NY, Schenectady County, NY, Rensselaer County, NY, Albany County, NY, Greene County, NY, Ulster County, NY, Columbia County, NY, Dutchess County, NY, Putnam County, NY, Westchester County, NY Orange County, NY, New York County, NY, Bronx County, NY
- Source: USGS Sciencebase (id: 55e0afa8e4b05561fa1eef65)