Toxicity of platinum, palladium and rhodium to Daphnia magna in single and binary metal exposure experiments.

Title Toxicity of platinum, palladium and rhodium to Daphnia magna in single and binary metal exposure experiments.
Authors S. Zimmermann; C. Wolff; B. Sures
Journal Environ Pollut
DOI 10.1016/j.envpol.2017.02.016
Abstract

Mainly due to automobile traffic, but also due to other sources, the platinum group elements (PGE) platinum (Pt), palladium (Pd) and rhodium (Rh) are introduced into aquatic biotopes where they accumulate in sediments of lakes and rivers. However, the toxicity of these noble metals to aquatic organisms is not well understood and especially toxicity studies under standardized condition are lacking. Thus, the toxicity of Pt, Pd and Rh to Daphnia magna was tested in single metal exposure experiments according to OECD guideline 202. Immobility and lethality was recorded after 24 h and 48 h of exposure and EC50 and LC50, respectively, were determined. As the nominal exposure concentration of Pd differed significantly from the quantified concentration, the control of the real exposure concentration by chemical analysis is mandatory, especially for Pd. The toxicity decreased in the order Pd > Pt ? Rh with e.g. LC50(48 h) values of 14 ?g/L for Pd, 157 ?g/L for Pt and 56,800 ?g/L for Rh. The exposure period had a clear effect on the toxicity of Pt, Pd and Rh. For Pt and Rh the endpoint immobility was more sensitive than the endpoint lethality whereas Pd toxicity was similar for both endpoints. The Hill slopes, which are a measure for the steepness of the concentration-response curves, showed no significant discrepancies between the different metals. The binary metal exposure to Pt and Pd revealed a more-than-additive, i.e. a synergistic toxicity using the toxic unit approach. The present study is a start to understand the toxicity of interacting PGE. The modes of action behind the synergistic effect are unclear.

Citation S. Zimmermann; C. Wolff; B. Sures.Toxicity of platinum, palladium and rhodium to Daphnia magna in single and binary metal exposure experiments.. Environ Pollut. 2017;224:368376. doi:10.1016/j.envpol.2017.02.016

Related Elements

Rhodium

See more Rhodium products. Rhodium (atomic symbol: Rh, atomic number: 45) is a Block D, Group 9, Period 5 element with an atomic weight of 102.90550. Rhodium Bohr ModelThe number of electrons in each of Rhodium's shells is [2, 8, 18, 16, 1] and its electron configuration is [Kr] 4d8 5s1. The rhodium atom has a radius of 134 pm and a Van der Waals radius of 195 pm. Rhodium was discovered and first isolated by William Wollaston in 1804. In its elemental form, rhodium has a silvery white metallic appearance. Elemental RhodiumRhodium is a member of the platinum group of metals. It has a higher melting point than platinum, but a lower density. Rhodium is found in ores mixed with other metals such as palladium, silver, platinum, and gold. Rhodium is primarily used as the catalyst in the three-way catalytic converters of automobiles it is also highly valued in jewelry. The name Rhodium originates from the Greek word 'Rhodon,' which means rose.

Palladium

Palladium Bohr ModelSee more Palladium products. Palladium (atomic symbol: Pd, atomic number: 46) is a Block D, Group 10, Period 5 element with an atomic weight of 106.42. The number of electrons in each of palladium's shells is 2, 8, 18, 18 and its electron configuration is [Kr] 4d10. The palladium atom has a radius of 137 pm and a Van der Waals radius of 202 pm. In its elemental form, palladium has a silvery white appearance. Palladium is a member of the platinum group of metals (along with platinum, rhodium, ruthenium, iridium and osmium). Elemental PalladiumPalladium has the lowest melting point and is the least dense of the group. Palladium can be found as a free metal and alloyed with other platinum-group metals. Nickel-copper deposits are the main commercial source of palladium. Palladium was discovered and first isolated by William Hyde Wollaston in 1803. Its name is derived from the asteroid Pallas.

Platinum

See more Platinum products. Platinum (atomic symbol: Pt, atomic number: 78) is a Block D, Group 10, Period 6 element with an atomic weight of 195.084. The number of electrons in each of platinum's shells is [2, 8, 18, 32, 17, 1] and its electron configuration is [Xe] 4f14 5d9 6s1. The platinum atom has a radius of 139 pm and a Van der Waals radius of 175 pm. Platinum Bohr ModelElemental PlatinumPlatinum was discovered and first isolated by Antonio de Ulloa in 1735. It is one of the rarest elements in the earth's crust, occurring at a concentration of only 0.005 ppm. Platinum is found uncombined as a free element and alloyed with iridium as platiniridium. In its elemental form, platinum has a grayish white appearance. It is highly resistant to corrosion: the metal does not oxidize in air at any temperature. It is generally non-reactive, even at high temperatures. The origin of the name "platinum" comes from the Spanish word platina, meaning silver.