Triclosan (TCS) and triclocarbon (TCC), two chemicals that are used in anti-bacterial soaps and deodorants, have been identified in estuary sediment samples that date back to the 1960s, according to a recent study published in the journal Environmental Science and Technology. The researchers, led by Todd R Miller from the John Hopkins Bloomberg School of Public Health, believe that this persistence is worrying especially as the levels of the chemicals measured could be harmful to certain aquatic organisms. Compounds found in estuary sediment samples The team took sediment samples from tributaries of Chesapeake Bay in Maryland and Jamaica Bay, New Jersey, both of which receive large quantities of outflows from waste water treatment plants. Sediment samples were dated using radioisotope dating, which allowed the team to investigate the degradation of the chemicals over time. Samples containing TCS and TCC from the Jamaica Bay site were found to date from the 1950s and 60s according to the study, illustrating that the chemicals are able to persist in aquatic environments for up to forty years. According to the report TCC is more persistent than TCS although it is the least commonly used of the two ingredients. Effect of compounds on organisms is unknown Although the scientists expressed concern over these results they said more information is needed to identify the toxicity of these chemicals in aquatic ecosystems. Firstly it is unknown how sediment concentration values of these chemicals relate to exposure levels for aquatic organisms. The scientists did estimate the potential pore water concentrations (the concentration in water in between sediment particles) as part of the study stating that they exceeded or approached values that may cause harm to certain aquatic organisms however more research is needed to accurately judge the actual threat posed by such compounds. Chemicals under repeated attack This is not the first time the chemicals have attracted criticism. A similar report was published late last year by the UK's Royal Society of Chemistry stating that current waste water systems are not designed to treat these chemicals which then remain in the system. The Environmental Working Group went a step further last year when they argued that improving waste water treatment systems was economically unviable therefore calling for a ban on the use of these chemicals in personal care products. Triclosan and triclocarbon both fall into a family of chemicals that have been dubbed 'gender benders' as they have been shown in laboratory and animal studies to affect the hormone system. However studies documenting any detrimental effects on humans are lacking.