Field of the Invention
The field of the invention relates to degradable wads associated with shotgun shells often used in and around aquatic environments.
Description of the Related Art
Over one million waterfowl hunters are present in the United States. Sportsmen who hunt waterfowl typically use shotguns. Shotguns are one of the top produced firearms worldwide. For example, the number of new shotguns manufactured in the United States was close to one million in 2011. Moreover, the annual production of shotgun shells is in the billions. Every shotgun shell that is fired will discharge a wad at a substantial distance from the sportsman. This distance prevents recovery and the ejected wad subsequently becomes aquatic debris.
The effect of non-degradable plastic debris is significant. Abandoned shotgun wads can present safety, nuisance, and environmental problems in freshwater and estuarine waters. When a waterfowl hunter fires a shotgun, a non-degradable plastic wad common in shotgun shells is discharged into the adjoining water. The quantity of abandoned shotgun wads in the nation's waters is unknown; however, a shotgun wad is abandoned with every shot fired. Due to the range of shotguns, there is no practical way for sportsmen to recover spent shotgun wads.
Abandoned wads enter the food chain as non-degradable plastic debris. Plastic wads are reported as one of the most common debris items collected during beach cleanups (NOAA. 2012. Guidebook to community beach cleanups). The buoyancy of many plastics causes the debris to float, therefore, plastic wads that do not wash ashore will float on the water's surface. The floating wads can be mistaken for food by waterfowl and other marine species. For example, wads have been found in the stomach contents of ocean foraging birds including the albatross (The Conservation Report. 2009). The consumption of plastic leads to reduced fitness and delayed mortalities of aquatic species.
Abandoned wads also damage sensitive habitats. Over time, the non-degradable plastic wads can break apart, causing massive amounts of non-degradable microplastics to enter the aquatic ecosystem. Currents can deposit the floating wads on distant river banks and coasts, thereby impacting all marine habitats, even habitats where hunting is prohibited. Furthermore, non-degradable plastic components can remain largely intact even after spending years afloat before fracturing into smaller microplastics.
Due to the low-cost, bio-inertness, and longevity, plastic production is likely to continue to increase. Worldwide commodity plastic production has increased by 9% annually from approximately 1.5 million tons in 1950 to 245 million tons in 2008 (Chanprateep. S. 2010. Current trends in biodegradable polyhydroxyalkanoates. Journal of Bioscience and Bioengineering 110(6): 621-632). It is likely that the increase in plastic production mirrors the increase in aquatic debris. Additionally, around half the global population resides within 100 kilometers of a coastline. With coastal populations increasing, the amount of aquatic debris is likely to rise.
Degradable wads are available, for instance, some companies tout paper or cardboard wads. Many sportsmen have turned away from these shotgun shells because paper wads do not perform as well as non-degradable plastic wads. Paper wads compromise the discharge performance of shotguns, leading to less accuracy of the shot.
There remains a need for a high-performance degradable shotgun wad. A modification to shotgun wads to mitigate the impact of aquatic, plastic debris would be a viable and effective option provided: 1) the modified shotgun wad is as functional as non-degradable plastic wads to contain and propel shot; 2) the wad degrades reasonably quickly once it is abandoned in an aquatic environment, and, once degraded, is environmentally benign; and 3) the wad is relatively inexpensive in order to be of practical use. Due in part to the lack of a sufficiently viable alternative, state regulators fail to limit the enormous amount of aquatic debris created by sportsmen each year.
USPTO Backgrounds
USPTO Backgrounds