Palladium – A review of exposure and effects to human health

Kielhorn, Janet; Melber, Christine; Keller, Detlef; Mangelsdorf, Inge

doi:10.1078/1438-4639-00180

Cited by 397 publications

(188 citation statements)

References 89 publications

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“…-Other exposure pathways such as inhalation of palladium released by emission from the automotive exhaust emission control catalysts or in some regions from pollution caused by mining should be considered (Kielhorn et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

Scientific Opinion on the safety evaluation of the active substances, sodium borohydride and palladium acetate for use in active food contact materials

Flavourings¹

2012

EFS2

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This scientific opinion of EFSA deals with the risk assessment of sodium borohydride (CAS No 16940-66-2 and FCM substance No 981), and palladium acetate , reduced to palladium FCM substance No 993) in the plastic during the manufacturing process, when used in combination as an oxygen absorbing system in food contact materials. The CEF Panel considers that palladium is non genotoxic and a low exposure to palladium resulting from a concentration up to 0.05 mg/kg food is not of toxicological concern.In addition, the CEF Panel used the tolerable upper intake level (UL) of 0.16 mg boron/kg bw per day equivalent to 10 mg boron/person per day in adults established by the EFSA NDA Panel in 2004, instead of the previously derived TDI of 0.1 mg boron/kg bw (SCF, 2001a).Migration of palladium into food was not detectable (detection limit = 0.0005 mg/kg) while the migration of boron into food was up to 0.09 mg/kg. Based on the default assumption for food contact materials that an adult may consume daily up to 1 kg of food in contact with food contact materials containing boron, the migration of 0.09 mg/kg food The CEF Panel considered that a low exposure to palladium resulting from a concentration up to 0.05 mg/kg food is not of toxicological concern. In migration tests in various food simulants, there was no detectable migration of palladium (detection limit = 0.0005 mg/kg). In migration tests in various food simulants, the migration of boron from the use of sodium borohydride was up to 0.09 mg/kg. Samples tested were composed of two polymer layers, boron being in the layer not in direct contact with food simulant as it is the intended use of the substance.Based on the default assumption for food contact materials that an adult may consume daily up to 1 kg of food in contact with food contact materials containing boron, the migration of 0.09 mg/kg food would correspond to an intake of 0.09 mg boron/adult/day which is 111 times lower that the UL set by the NDA.The CEF Panel after having considered the above-mentioned data concluded that there is no safety concern for the consumer from the intended use of sodium borohydride and of palladium acetate and its reduction product, palladium, in oxygen absorbing systems in active food contact materials.The sodium borohydride should only be used behind a plastic layer to prevent direct contact with the packaged food and the palladium species should also be behind a barrier layer or should be incorporated into the plastic of the primary packaging material in order to minimise direct contact of palladium with the food and thereby keep its migration within acceptable levels.The Commission may wish to take note of the different sources of exposure to boron and palladium, other than FCM, if setting a restriction for these substances. 4 Commission Regulation (EC) No 450

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Section: Discussionmentioning

confidence: 99%

Scientific Opinion on the safety evaluation of the active substances, sodium borohydride and palladium acetate for use in active food contact materials

Flavourings¹

2012

EFS2

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“…Pd is mostly used for catalytic converters in auto mobiles [44], but can also be found in electronic devices such as computers, mobile phones, multi-layer ceramic capacitors, component plating, low voltage electrical contacts, and televisions [45]. The metal can also be used in dentistry [46], hydrogen purification, chemical applications, medicine, groundwater treatment, and fuel cells.…”

Section: Palladium Propertiesmentioning

confidence: 99%

Characterization of amorphous and crystalline silicon nanoclusters in ultra thin silica layers

Thøgersen

Mayandi

Finstad

et al. 2008

Journal of Applied Physics

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The nucleation and structure of silicon nanocrystals formed by different preparation conditions and silicon concentration (28 -70 area %) have been studied using Transmission Electron Microscopy (TEM), Energy Filtered TEM (EFTEM) and Secondary Ion Mass Spectroscopy (SIMS). The nanocrystals were formed after heat treatment at high temperature of a sputtered 10 nm thick silicon rich oxide on 3 nm SiO2 layer made by Rapid Thermal Oxidation (RTO) of silicon. Nanocrystals precipitate when the excess silicon concentration exceeds 50 area %. Below this percentage amorphous silicon nanoclusters were found. In-situ heat treatment of the samples in the TEM showed that the crystallization requires a temperature above 800 o C. The nanocrystals precipitate in a 4 nm band, 5 nm from the Si substrate and 4 nm from the SiO2 sample surface. The silicon nucleates where the excess Si concentration is the highest. The top surface has less excess Si due to reaction with oxygen from the ambient during annealing. The SiO2-RTO layer is more Si rich due to Si diffusion from the SiO2-Si layer into RTO. Twinning and stacking faults were found in nanocrystals with 4-10 nm in diameter. These types of defects may have large effects upon the usability of the material in electronic devices. Both single and double twin boundaries have been found in the nanocrystals by high resolution transmission electron microscopy (HRTEM). Image simulations were carried out in order to obtain more information about the defects and nanocrystals. The stacking faults are extrinsic and located in the twin boundaries.

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“…Palladium (Pd) catalysts have been reported to be effective in hydrogenation due to their low toxicity, ability to work under moderate conditions and also because their performance can be altered by combination with other materials (Kielhorna et al, 2002;Polshettiwara et al, 2009). For example, the modifi-cation of a monometallic palladium catalyst using a small quantity of other metals can change its attributes (Belkacemi et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Optimization of Pd-B/γ-Al2O3 catalyst preparation for palm oil hydrogenation by response surface methodology (RSM)

Alshaibani

Yaakob

Alsobaai

et al. 2014

Braz. J. Chem. Eng.

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-Response surface methodology was used to design and evaluate the experimental variables for Pd-B/γ-Al 2 O 3 catalyst preparation. The catalyst was prepared by impregnation and chemical reduction. Thirteen different samples of the catalyst were prepared at different KOH concentrations and annealed at various temperatures, before applying them in palm oil hydrogenation. Hydrogenation was performed on a 0.12% Pd-B/γ-Al 2 O 3 catalyst at a temperature of 393 K, hydrogen pressure of 500 kPa and agitation of 500 rpm for 1 h. The iodine value (IV) and trans fatty acids (TFAs) content responses were measured for each hydrogenated palm oil sample. The predicted models were verified for both responses and found to be statistically adequate. An optimization study was performed on the catalyst preparation variables for minimizing both IV and TFAs content. The Pd-B/γ-Al 2 O 3 prepared under optimized conditions exhibited 47% higher conversion and 22% lower trans-isomerization selectivity than Escat 1241 commercial catalyst. The Pd-B/γ-Al 2 O 3 catalyst preparation variables have a noticeable effect on palm oil hydrogenation conversion and trans-isomerization selectivity.

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Palladium – A review of exposure and effects to human health

Cited by 397 publications

References 89 publications

Scientific Opinion on the safety evaluation of the active substances, sodium borohydride and palladium acetate for use in active food contact materials

Scientific Opinion on the safety evaluation of the active substances, sodium borohydride and palladium acetate for use in active food contact materials

Characterization of amorphous and crystalline silicon nanoclusters in ultra thin silica layers

Optimization of Pd-B/γ-Al2O3 catalyst preparation for palm oil hydrogenation by response surface methodology (RSM)

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