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Definitions of Common Terms Used in the
Shipping/Antifoulant and Toxicology Industries
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Ablative:
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To remove or dissipate by melting, vaporization, erosion, etc.
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Ablative Paint:
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A rosin-based paint in which the film is dissolved at a slow rate in sea water after immersion, exposing a biocide (e.g., copper compound) which is released after dissolution and diffusion from the film. Although the thickness of the film of these types depletes over time, the paint film does not show smoothing characteristics in-service on ships.
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Absorption:
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The uptake of substances by an organism across membranes (e.g., cell wall, gill, intestine).
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Active Zone:
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The thickness of paint (e.g., 20 �m) exposed to water for leaching, also called the leached layer.
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Acute Exposure:
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One dose or multiple doses of a stimulus occurring within a short time period (e.g., 96 hours or less for aquatic life; less than 14 days for human health).
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Adsorption:
- The gathering of a compound on a surface in a condensed layer.
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Aerobic:
- An organisms requiring the presence of oxygen for life.
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Anaerobic:
- The absence of oxygen for life.
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Antifoulant:
- Coatings applied to the portion of a hull below the waterline to discourage marine animals and plants that would otherwise adhere to it.
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Bioaccumulation:
- Chemical taken up by an aquatic organism directly from water and food, including sediment.
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Bioavailability:
- The degree to which a substance becomes available to the target tissue after administration or exposure.
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Biocide:
- Active substance, intend to destroy, deter, render harmless, prevent the action of, or otherwise exert a controlling effect on, any harmful organism by chemical or biological means (e.g., pesticide, herbicide, algaecide, or fungicide).
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Bioconcentration:
- The process whereby there is a net accumulation of a chemical directly from water into aquatic organisms resulting from direct uptake from the water, but not food.
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Biodegradation:
- Decomposition of a substance via biological means (e.g., microorganisms).
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Biomagnification:
- The process by which the tissue concentration of a bioaccumulated chemical increases as it passes up the food chain through at least two trophic levels (minimum of three involved).
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Biomarker:
- A sublethal physiological, biochemical, or histological response to exposure.
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Biomonitoring or (biological
monitoring):
- Use of living organisms as "sensors" in water/sediment quality surveillance and compliance to detect changes in the environment.
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Biota:
- The total of all living things (plants [flora] and animals [fauna]) in a designated area.
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Booster biocides:
- An industry term for biocides targeting individual types of fouling organisms (e.g., algae, slime) added to paint formulations.
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Carcinogenic:
- Causing or promoting cancer.
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Chambering:
- Abnormalities found on the shells of certain species of oysters (i.e., Crassostrea gigas) consisting of wafer-like chambers with the formation of an interlamellar jelly.
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Chronic Exposure:
- Multiple exposures occurring over an extended period of time (e.g., > 3 months) or a significant fraction of an animal�s or human�s lifetime.
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Copolymer:
- A polymer derived from more than one species of monomer (groups of molecules which can undergo polymerization to the essential structure of a macromolecule.
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Depurate:
- The process in which organisms free themselves of impurities via excretion, diffusion, and/or detoxification.
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Desorption:
- Removal of a substance from the surface of a particle or organism.
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Detection Limit:
- The lowest amount of substance that can be distinguished from the noise of an analytical instrument or method for a "clean" sample of a particular matrix.
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Dissociation:
- A reversible decomposition of a complex substance into simpler constituents by physical conditions, as when salts gradually decomposes into ions or when tributyltin oxide decomposes into tributyltin ion.
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Dry-docking:
- The process of docking a ship to be drained and lifting it to make all parts of the hull accessible for repairs and/or painting.
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Dry-docking
Interval:
- The elapsed or scheduled time between dry-dockings of a ship.
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Exposure:
- Contact of an organism with a chemical or physical agent. Exposure is quantified as the amount of the agent available at the exchange boundaries of the organism (e.g., skin, gills, lungs, or gut) that is available for absorption.
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Exposure Pathway:
- The course a chemical or physical agent takes from a source to an exposed organism. An exposure pathway describes a unique mechanism by which an individual or population is exposed to chemicals or physical agents at or originating from a site.
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Food Chain:
- The transfer of food, energy, and certain chemicals when one organism is eaten by another.
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Fouling:
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With respect to ships, the growth of shell, tissue, and microorganisms on immersed surfaces such as ship hulls. This may include organisms such as bryoza, tubeworms, tunicates, microorganisms, algae, barnacles, and mussels.
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Free-association:
- A type of antifouling paint in which the biocide is not chemically bound and leaches freely from the paint. The initial release is rapid and uncontrolled and declines steadily from the paint such that the antifouling performance of the paint diminishes with time.
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Hazard Quotient or
PEC/PNEC:
- Hazard Quotient (HQ) is the ratio of the estimated level of chemical exposure of an organism to the level at which adverse effects would be expected.
The predicted environmental concentration (PEC) is a term used to define the exposure level.
The predicted no-effect concentration (PNEC) is the concentration below which adverse effects on one or more species of concern are not expected.
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Hydrolysis:
- Chemical decomposition where by a compound is split into other compounds by reacting with water.
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Hydrophilic:
- Literally water loving, a compound that readily dissolves in water.
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Imposex:
- The masculinization of certain species of female snails via formation of a penis and vas deferens.
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In-Water Surveys:
- Underwater inspections of a ship�s hull performed by divers in place of dry-docking surveys for ships with resistant paint. These surveys are performed to satisfy classification society (e.g., Lloyd�s Maritime) requirements and extend the periods between dry-docking periods.
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Leaching rate:
- The rate at which a biocide is released from an antifouling paint into the water (e.g., 4 �g of biocide per square centimeter of hull per day).
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Metabolize:
- The change in an organism�s metabolism by which a substance is biochemically modified to make energy.
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Number of Vessels vs.
Surface Area:
- Two statistics sometimes used to characterize the portions of the world fleet using different antifouling methods; number of vessels provides a simpler statistic, whereas hull surface area provides a more accurate depiction of the volumes of different antifouling paints in use.
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Photodegradation:
- A process in which a substance is decomposed by light.
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Photosynthetic:
- The process by which plants synthesize organic chemicals from sunlight.
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Reference Dose:
- The amount of a substance that is likely to be without appreciable risk of deleterious effects to an organism during a lifetime.
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Repainting:
- The reapplication of antifouling paint to a ship�s hull.
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Residues:
- The matter remaining after evaporation, combustion, etc.
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Risk Assessment:
- The likelihood of adverse effects arising from exposure.
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Safety Factors:
- A mathematical expression of uncertainty applied to toxicological effects data used to ensure protection of human and wildlife populations from that which cannot be defined with sufficient precision.
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Sediment:
- Matter that settles to the bottom of a river, stream, or the ocean.
Self-Polishing Copolymer
Paints (SPC):
- Paints consisting of copolymers designed to be smoothed via erosion of their surface as the vessel moves through the water, continually exposing smooth, fresh paint.
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Silicone SPC:
- New paint types based on polymers with alkylsilane groups.
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Volatile Organic
Compounds (VOC):
- Organic chemicals used in industrial solvents (e.g., acetone) used in paint application that have tended to evaporate readily. Many of these compounds are associated with carcinogenic and chronic toxicity.
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Water Quality
Criteria:
- The concentration of a substance that will protect an organism, a community of species, or a prescribed water use from adverse effects of safety.
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