title: Interactions of metal-based engineered nanoparticles with aquatic higher plants: A review of the state of current knowledge.
abstract: The rising potential for the release of engineered nanoparticles (ENPs) into aquatic environments requires evaluation of risks to protect ecological health. The present review examines knowledge pertaining to the interactions of metal-based ENPs with aquatic higher plants, identifies information gaps, and raises considerations for future research to advance knowledge on the subject. The discussion focuses on ENPs' bioaccessibility; uptake, adsorption, translocation, and bioaccumulation; and toxicity effects on aquatic higher plants. An information deficit surrounds the uptake of ENPs and associated dynamics, because the influence of ENP characteristics and water quality conditions has not been well documented. Dissolution appears to be a key mechanism driving bioaccumulation of ENPs, whereas nanoparticulates often adsorb to plant surfaces with minimal internalization. However, few reports document the internalization of ENPs by plants; thus, the role of nanoparticulates' internalization in bioaccumulation and toxicity remains unclear, requiring further investigation. The toxicities of metal-based ENPs mainly have been associated with dissolution as a predominant mechanism, although nano toxicity has also been reported. To advance knowledge in this domain, future investigations need to integrate the influence of ENP characteristics and water physicochemical parameters, as their interplay determines ENP bioaccessibility and influences their risk to health of aquatic higher plants. Furthermore, harmonization of test protocols is recommended for fast tracking the generation of comparable data. Environ Toxicol Chem 2016;35:1677-1694. © 2016 SETAC.
authors.affiliation: Source Directed Scientific Measures Research Group, Council for Scientific and Industrial Research, Pretoria, South Africa.|Zoology Department, University of Johannesburg, Johannesburg, South Africa.
authors.forename: Melusi
authors.initials: M
authors.lastname: Thwala
authors.affiliation: Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA.|School of Biological Sciences, North-West University, Potchefstroom, South Africa.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Klaine
authors.affiliation: Department of Chemical Engineering, University of Pretoria, Pretoria, South Africa.
authors.forename: Ndeke
authors.initials: N
authors.lastname: Musee
mesh_terms: D000327:Adsorption; D059001:Aquatic Organisms / Q000187:drug effects* / Q000378:metabolism; D054750:Ecotoxicology / Q000379:methods*; D053768:Metal Nanoparticles / Q000032:analysis* / Q000737:chemistry; D010944:Plants / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism
chemical_list: D014874:Water Pollutants, Chemical
keywords: Aquatic plants; Bioaccessibility; Bioaccumulation; Engineered nanoparticles; Nanoecotoxicology