Grantee Research Project Results
2000 Progress Report: Early Signs & Determinants of Biotoxins (Microcystins) in Lakes
EPA Grant Number: R827407Title: Early Signs & Determinants of Biotoxins (Microcystins) in Lakes
Investigators: Sasner, John J. , Haney, James F. , Schloss, Jeff , Ikawa, Miyoshi
Current Investigators: Sasner, John J. , Haney, James F. , Ikawa, Miyoshi
Institution: University of New Hampshire
EPA Project Officer: Hahn, Intaek
Project Period: August 16, 1999 through August 15, 2000 (Extended to February 15, 2001)
Project Period Covered by this Report: August 16, 1999 through August 15, 2000
Project Amount: $149,941
RFA: Futures: Detecting the Early Signals (1999) RFA Text | Recipients Lists
Research Category: Water , Sustainable and Healthy Communities , Land and Waste Management , Aquatic Ecosystems , Ecological Indicators/Assessment/Restoration
Objective:
Although blooms of cyanobacteria (Microcystis) and the production of the potent hepatotoxins called microcystins (MCs) are often related to nutrient enrichment in lakes around the world, they also occur in relatively clean lakes in New Hampshire with low nutrient concentrations. The objectives focus on detecting early signals of MC toxicity in all lakes regardless of trophic status. Since many MC-producing cyanobacteria (aka blue-green algae) overwinter in benthic sediments, our hypothesis is that the spring levels of MC in lake sediments may be useful early signs, or predictors, of potential toxin levels in the water column during the summer seasons when physical and chemical conditions favor population growth in the plankton. The goal is to compare benthic Microcystis populations and MC levels in the spring season with subsequent levels in the lake water and plankton during the summer growing season, when harmful levels of biotoxins may compromise the safe use of lake water for drinking and recreational purposes.Progress Summary:
We performed extensive sampling of the sediments and the water column in 30 NH lakes of varied sizes, locations, and trophic status during the spring-early summer and late-summer-early-fall periods. The data include field limnological parameters (temperature, dissolved oxygen, conductivity, pH, redox, turbidity, Chlorophyll a), laboratory nutrient analyses (Fe, NO3, total nitrogen, total phosphorus), and Enzyme-Linked Immunosorbent Assay (ELISA) measurements for MC levels in benthic sediments, lake water, phyto- and zooplankton. Although analyses of our extensive database is in progress, we have already determined that MCs are detectable in lakes in all regions of NH representing all trophic conditions, from heavily polluted to pristine mountain lakes. Overall in 1999, MC concentrations in lake surface sediments (0-2 cm depth) from spring samples were more than an order of magnitude greater (average 340 and maximum 2694 ng MC/L) than those found in the water column (average 15 and maximum 114 ng MC/L). This supports our hypothesis that benthic sampling could be a sensitive method of detecting and predicting MC in lake water. We are presently analyzing data to determine whether MC levels in sediments also can be useful predictors of seasonal nuisance blooms and potential health problems as described by the safety guidelines of the World Health Organization (1 µg MC/L). It is particularly noteworthy that nutrient enrichment alone does not account for the high levels of biotoxins (MCs) found in certain lakes, or for the unexpected occurrence of MCs in very oligotrophic, clear lakes with minimal human disturbance. MCs also were found in different phytoplankton (average 1,577 and maximum 16,228 ng MC/g wet weight) and zooplankton (average 330 and maximum 8980 ng MC/g wet weight). In addition to the potential threat to public health through drinking water and recreational uses of lakes, there is a need to evaluate the impact of MCs in the aquatic food chain on lake productivity and biodiversity.Future Activities:
We presently are evaluating the role of physical features of the lakes, such as basin depth, sediment toxin levels, watershed development and use, and the composition of the lake's food web. We are attempting to design, construct and test an efficient and easy-to-use sediment surface sampler that can provide material for ELISA analyses. This is important for making benthic sampling methods available to water quality monitoring programs. The UNH Center for Freshwater Biology (CFB) and the NH Department of Environmental Services (NH DES) will make results from this project available to the scientific community and the public via a cooperative Web site presently under development with support from U.S. EPA to NH DES.Supplemental Keywords:
cyanobacteria, Microcystis, microcystins, freshwater biotoxins, hepatotoxins, benthic sampling, ELISA, trophic status of lakes, blue-green-algal blooms, HABS., RFA, Scientific Discipline, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, Hydrology, Nutrients, Contaminated Sediments, Chemistry, algal blooms, Biology, early warning capabilities, aquatic ecosystem, environmental monitoring, microbial indicators, nutrient supply, nutrient transport, bloom dynamics, marine biotoxins, toxic cyanobacteria, liver cancer, contaminated sediment, nutrient kinetics, algal growth, bioindicator development, biotoxin risk, water quality, nutrient cycling, microcystins, benthic algae, macroalgal populationsRelevant Websites:
http://zoology.unh.edu/faculty/haney/haney.html Exit
http://zoology.unh.edu/faculty/sasner/sasner.html Exit
http://ceinfo.unh.edu/schloss.htm Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.