ABSTRACT
As the production, use, and disposal of nanotechnologies continues to grow, so too is the presence of particulate matter in the nanoscale such as nanomaterials (NMs) or nanoparticles (NPs) in the environment. These two terms cannot necessarily be used interchangeably and so in this review the term NM will be used preferentially since it is more wide ranging, with the term NP used when quoting specific studies. The unique characteristics of NMs including size, shape, composition and structure determines the route and rate at which they will enter the environment; however aquatic systems, particularly the benthic environment, are anticipated to be the ultimate sink for the majority of nano-wastes. The fate of NMs in aquatic systems is dependent on processes of aggregation, agglomeration and deposition, which in turn, are dependent on NM-specific characteristics, hydrodynamic conditions and abiotic factors such as pH, temperature, organic matter content and ionic strength. Where conditions favour deposition, aquatic sediments will receive an influx of NMs. Despite being identified as likely recipients of nano-wastes, studies investigating the ecotoxicological effects upon benthic organisms are severely lacking in comparison with aquatic exposures using pelagic species. Given the uncertainty of NM toxicity and the ecological importance of sediments, understanding potential interactions between the two is of great interest and importance. Within this chapter, a review of NM fate, behaviour and effects in sedimentary systems will be discussed alongside methods for analysing NMs in sediments and the extent and mode through which they exert toxicity towards key benthic species.
