Methods and kits for determining sediment and pore water toxicity with dormant and developing zooplankton and other species having a dormant life stage
Inventors
Assignees
University of North Carolina at Wilmington
Publication Number
US-11714076-B2
Publication Date
2023-08-01
Expiration Date
2036-06-02
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Abstract
Methods for determining the toxicity of fresh-water and marine sediments and sediment pore water containing indigenous or introduced toxicants from each as a one-time analysis and/or for analysis over a period of time are provided. The present disclosure further provides kits assembled for the afore-mentioned determination. The methods and kits can be used for analyzing sediment and pore water samples from, among other locations, all environments where species having a dormant life stage may exist including, for example, natural zooplankton.
Core Innovation
The invention provides methods and kits for determining the toxicity of indigenous or introduced toxicants in fresh-water and marine sediments, sediment pore water, and terrestrial samples. The approach allows for both one-time analysis and analysis over a period of time. It specifically makes use of embryos from zooplankton or other species having a dormant life stage, which are mixed with sediment or pore water samples under anoxic or special conditions to induce or maintain dormancy, followed by hatching and observation for developmental deformities, emergence issues, or mortality.
Existing methods for evaluating sediment and pore water toxicity have used active or developing invertebrates, but these tests face limitations in duration due to physiological needs of the organisms, and there has been no known method for assessing the effects on dormant invertebrates over extended timeframes. The methods disclosed enable direct observation of development, emergence, hatching, and deformity endpoints using dormant embryos, which can be maintained under controlled conditions for prolonged exposures. This addresses a critical need identified by regulatory agencies for chronic toxicity testing of bottom sediments and pore water.
The invention further supplies kits constructed for carrying out these processes, including combinations of dormant zooplankton or similar embryos, dry salt packages for preparing hatching media, incubation containers to induce or maintain dormancy, and materials like sieves, sucrose or other osmolyte solutions, and vessels suitable for embryo separation and observation. The methodology accommodates the analysis of both sediment and pore water samples from diverse environments where dormant life stages occur.
Claims Coverage
The patent includes one independent claim detailing five main inventive features.
Method for determining sediment toxicity using dormant embryos
A method is disclosed in which a sediment sample (including fresh water sediment, marine sediment, terrestrial soil, or sediment pore water) is collected and mixed with a plurality of dormant embryos of at least one species having a dormant life stage. The embryos are mixed in an incubation container under conditions that induce or maintain dormancy.
Separation of dormant embryos from sediment via osmolytic solution
The method specifies separating the dormant embryos from the sediment sample by mixing the sediment with an osmolytic solution in the incubation container. This enables subsequent evaluation of emergence, hatching, development, and mortality of the embryos.
Toxicity determination based on lifecycle deviations
The determination of the presence of a toxicant is based on observing one or more deviations from the normal lifecycle of the species involved. This includes a simultaneous evaluation of emergence, hatching, developmental deformity, mortality, altered developmental rate, and altered developmental timing with respect to hatching and emergence.
Applicability to a broad range of sample types and species
The method applies to fresh water, marine, and terrestrial samples or sediment pore water. It allows for the selection of various species having a dormant life stage, including but not limited to zooplankton and Artemia species.
Capability for repeated testing over predetermined periods
The method can be carried out multiple times over a predefined period, supporting both single and long-term monitoring of sediment toxicity.
The inventive features collectively enable a comprehensive method of testing sediment and pore water toxicity using dormant embryos, with specific steps for mixing, separation, and multi-faceted observation, applicable over varying timeframes and a range of sample types.
Stated Advantages
Provides a method for determining the chronic toxicity of sediments and pore waters using species with dormant life stages, overcoming limitations in duration faced by previous methods using active invertebrates.
Enables evaluation of developmental deformities, mortality, and lifecycle disruptions in dormant species over extended periods.
Permits analysis in all environments where species with dormant stages exist, including natural and introduced zooplankton.
Documented Applications
Analyzing sediment and pore water samples from environments containing species with dormant life stages, including fresh-water, marine, and terrestrial environments.
Primary or secondary school demonstrations of sediment toxicity assessment where centrifuge alternatives (like salad spinners) are used for embryo separation.
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