The ever increasing production and use of nano-enabled commercial products release the massive amount of engineered nanoparticles (ENPs) in the environment. An increasing number of recent studies have shown the toxic effects of ENPs on different organisms, raising concerns over the nano-pollutants behavior and fate in the various environmental compartments. After the release of ENPs in the environment, ENPs interact with various components of the environment and undergoes dynamic transformation processes. This review focus on ENPs transformations in the various environmental compartments. The transformation processes of ENPs are interrelated to multiple environmental aspects. Physical, chemical and biological processes such as the homo- or hetero-agglomeration, dissolution/sedimentation, adsorption, oxidation, reduction, sulfidation, photochemically and biologically mediated reactions mainly occur in the environment consequently changes the mobility and bioavailability of ENPs. Physico-chemical characteristics of ENPs (particle size, surface area, zeta potential/surface charge, colloidal stability, and core-shell composition) and environmental conditions (pH, ionic strength, organic and inorganic colloids, temperature, etc.) are the most important parameters which regulated the ENPs environmental transformations. Meanwhile, in the environment, organisms encountered multiple transformed ENPs rather than the pristine nanomaterials due to their interactions with various environmental materials and other pollutants. Thus it is the utmost importance to study the behavior of transformed ENPs to understand their environmental fate, bioavailability, and mode of toxicity.

纳米级商业产品的不断增长的生产和使用在环境中释放出大量的工程纳米颗粒（ENP）。越来越多的最新研究表明，ENP对不同生物的毒性作用，引起人们对各种环境隔室中纳米污染物行为和命运的担忧。在环境中释放ENP之后，ENP与环境的各个组成部分进行交互并经历动态转换过程。这篇综述着重于各种环境部分的ENPs转化。ENP的转化过程与多个环境方面相关。物理，化学和生物过程，例如均聚或异聚，溶解/沉淀，吸附，氧化，还原，硫化，光化学和生物介导的反应主要发生在环境中，因此改变了ENP的迁移率和生物利用度。ENP的物理化学特征（粒径，表面积，ζ电势/表面电荷，胶体稳定性和核壳组成）和环境条件（pH，离子强度，有机和无机胶体，温度，等）是调节ENP环境转变的最重要参数。同时，在环境中，生物由于与各种环境材料和其他污染物的相互作用而遇到了多种转化的ENP，而不是原始的纳米材料。因此，研究转化的ENP的行为以了解其环境命运，生物利用度和毒性模式至关重要。