Pyrethroids, a synthesized compound modeled after the naturally occurring pyrethrins found in pyrethrum flowers, include a long list of extremely effective pest control substances that have substituted more hazardous and understood compounds. Pyrethroids are much less toxic to birds and mammals than their pesticide predecessors, yet are extremely lethal to aquatic invertebrates and fish species at levels on the magnitude of parts per trillion. Although pyrethroids are hydrophobic, resulting in very low water solubility, they readily bind to organic compounds in soils, sediments, or particulate matter which can be transferred to coastal areas during rain, irrigation, or erosion events. Pyrethroids are fairly persistent in the environment and can accumulate in the sediments to toxic levels.