Oil fields are a source of heavy metal pollution, but few studies have evaluated its impact on the intake of these contaminants through milk, an important food especially for children. From February 2015 to 2016, 118 samples of raw cow's milk, 14 of fodder and 8 of water in Southwest Iran were collected from farms close to oil fields or related industries. Lead (Pb) and cadmium (Cd) levels were evaluated by graphite furnace atomic absorption spectrometry. Mean±SE in milk and fodder were 47.0±3.9 and 54.0±6.9μg/kg for Pb, and 4.7±1.0 and 3.5±1.3μg/kg for Cd. No Pb or Cd was detected in water. Most milk samples (82.2%) for Pb were above the permissible limits (20μg/kg). Exposure to Pb and Cd from milk consumption was calculated in two scenarios: mean and maximum exposure for the age range of 2-90years. The intake of an average Iranian adult (25years, 60kg b. w., 0.14kg milk/day) would be 6.6μg Pb and 0.66μg Cd/day (WI of 46.2 and 4.6μg, respectively), well below the risk values proposed by some international organizations, even in the maximum exposure scenario. However, Pb exposure for infants and toddlers may be closer to the risk values, since milk and milk products could be the main contributor to Cd and Pb, and small children consume 2-3 times more food than adults relative to their body weight. The risk of Pb and Cd exposure through milk close to oil fields should be considered and a monitoring plan for these contaminants is strongly recommended.
The present study expanded the magnetic pH‐dependent, and nucleolin receptor‐targeted nano‐drug delivery system consists of synthesized superparamagnetic iron oxide nanoparticles (SPIONs) and poly N‐isopropyl acrylamide (PNIPAM) with aptamer AS1411 to deliver the erlotinib (ERL) to prostate cancer (PC) cells. Their properties were characterized using different techniques. The encapsulation efficiency (EE) and drug loading (DL) were found to be about 34% and 85%, respectively. The characterization studies disclosed that formulated SPION‐PNIPAM/ERL@AS1411 nanoparticles (NPs) were spherical with an average particle size of 97.8 nm, polydispersity index (PDI) of 0.03, and the zeta potential of −2 mV. The flow cytometry and cell viability assay results disclosed that SPION‐PNIPAM/ERL@AS1411 NPs operated cancer cell death via the pH‐sensitive release of ERL. The conjugation of the AS1411 modified the cellular uptake of ERL as proved by cellular sensing fluorescence. Therefore, the present study revealed that the SPION‐PNIPAM/ERL@AS1411 NPs improved the treatment effect of ERL in PC via the nucleolin‐targeted drug release.
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