Environmental Engineering Reference
In-Depth Information
ENPs may induce cytotoxicity by arresting the cell cycle and the mitotic phases.
In contrast, exposures to ENPs may cause upregulation of the p53 tumor suppressor
geneandtoDNArepairproteins.Wanetal.( 2012 ) showed that ENPs can induce
DNA damage and cell death via up-regulation of phosphorylated p53, histone
H2AX(Ęł-H2AX)andviaanataxiatelangiectasiamutant(ATM).
7
Summary
Recent developments in nanotechnology have facilitated the synthesis of novel
engineered nanoparticles (ENPs) that possess new and different physicochemical
properties. These ENPs have been extensively used in various commercial sectors
to achieve both social and economic benefits. However, the increasing production
and consumption of ENPs by many different industries has raised concerns about
their possible release and accumulation in the environment. Released ENPs may
either remain suspended in the atmosphere for several years or may accumulate and
eventually be modified into other substances. Settled nanoparticles can be easily
washed away during rains, and therefore may easily enter the food chain via water
andsoil.Thus,ENPscancontaminateair,waterandsoilandcansubsequentlypose
adverseriskstothehealthofdifferentorganisms.
Studies to date indicate that ENP transport to and within the ecosystem depend
ontheirchemicalandphysicalproperties(viz.,size,shapeandsolubility).Therefore,
the ENPs display variable behavior in the environment because of their individual
properties that affect their tendency for adsorption, absorption, diffusional and col-
loidal interaction. The transport of ENPs also influences their fate and chemical
transformation in ecosystems. The adsorption, absorption and colloidal interaction
of ENPs affect their capacity to be degraded or transformed, whereas the tendency
of ENPs to agglomerate fosters their sedimentation. How widely ENPs are trans-
ported and their environmental fate influence how toxic they may become to envi-
ronmental organisms. One barrier to fully understanding how ENPs are transformed
intheenvironmentandhowbesttocharacterizetheirtoxicity,isrelatedtothenature
of their ultrafine structure. Experiments with different animals, plants, and cell lines
haverevealedthatENPsinducetoxicityviaseveralcellularpathwaysthatislinked
tothesize,shape,surfacearea,agglomerationstate,andsurfacechargeoftheENP
involved. Future research is needed to elucidate the mechanisms by which nanopar-
ticles act to induce their toxic effects after they reach various ecosystems. Moreover,
workisneededtodevelopaholisticapproachforbetterunderstandingtheeffects
that ENPs produce at the cellular and genetic level.
Acknowledgement Authors are thankful to CSIR-NEERI and Department of Science and
Technology,GovernmentofIndiaforprovidingopportunityandfundstoworkinthisarea.
Search WWH ::




Custom Search