Dietary bioavailability of cadmium presented to the gastropod Peringia ulvae as quantum dots and in ionic form.
For quantum dots (QDs) synthesized in solvents that are immiscible in water, dietary, rather than aqueous, exposure is expected to be the primary route of uptake. The estuarine snail Peringia ulvae was presented with mats of simulated detritus spiked with oleic acid capped cadmium sulfide (CdS; 3.1 ± 0.4 nm) or cadmium selenide (CdSe; 4.2 ± 0.8 nm) nanoparticles, synthesized using a microfluidics method, or Cd(2+) (added as Cd[NO3 ]2 ) as a control. A biodynamic modeling approach was used to quantify parameters that describe the dietary accumulation of the Cd forms. Ingestion rates decreased across treatments at higher exposure concentrations, indicating a metal-induced stress response related to Cd dose rather than form. Although Cd was bioavailable from both CdS and CdSe QDs, uptake rate constants from diet were significantly lower than that of Cd(2+) (p < 0.05). After 72 h depuration, however, no loss of Cd was observed from snails that had accumulated Cd from either type of QD. In comparison, snails ingesting Cd(2+) -spiked detritus eliminated 39% of their accumulated body burden per day. The almost identical uptake and efflux rates for Cd in both QDs suggest no effect of the chalcogenide conjugates (S or Se). The findings of the present study indicate that the availability of Cd in the form of nanoparticles and its apparent in vivo persistence will lead to bioaccumulation. The implications of this are discussed.
Department of Life Sciences, Natural History Museum, London, United Kingdom.
Farhan R
FR
Khan
Katarina
K
Schmuecking
Siva H
SH
Krishnadasan
Deborah
D
Berhanu
Brian D
BD
Smith
John C
JC
Demello
Philip S
PS
Rainbow
Samuel N
SN
Luoma
Eugenia
E
Valsami-Jones
D000818:Animals; D002104:Cadmium / Q000378:metabolism*; D019187:Cadmium Compounds / Q000378:metabolism*; D002413:Cations, Divalent; D005502:Food; D020387:Food Chain; D008954:Models, Biological; D045663:Quantum Dots / Q000378:metabolism*; D018036:Selenium Compounds / Q000378:metabolism*; D012908:Snails / Q000378:metabolism*; D013440:Sulfides / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D019187:Cadmium Compounds; D002413:Cations, Divalent; D018036:Selenium Compounds; D013440:Sulfides; D014874:Water Pollutants, Chemical; D002104:Cadmium; C034939:cadmium sulfide; C058667:cadmium selenide
Biodynamic modeling; CdS and CdSe nanoparticles; Dietary bioavailability; Ingestion rates; Microfluidics