Cu Isotopic Composition in Surface Environments and in Biological Systems: A Critical Review

Abstract

Copper (Cu) is a transition metal and an essential micronutrient for organisms, but also one of the most widespread toxic inorganic contaminants at very high content. The research on Cu isotopes has grown rapidly in the last decade. Hitherto, a large number of studies have been published on the theoretical fractionation mechanisms, experimental data and natural variations of Cu isotopes in variable environments and ecosystems. These studies reported a large variation of δ65Cu (−16.49 to +20.04‰) in terrestrial samples and showed that Cu isotopes could be fractionated by various biogeochemical processes to different extent. Several papers have previously reviewed the coupling of Cu and Zn isotope systematics, and we give here a tentative review of the recent publications only on Cu isotopesin variable surface repositories, animals and human beings, with a goal to attract much attention to research on Cu (and other metals) behaviors in the environment and biological systems.

Multi-isotope signatures (Cu, Zn, Pb) of different particle sizes in road-deposited sediments: a case study from industrial area

“…Variation of Cu isotopic composition (~ 1.05‰) was greater than Zn isotopic composition (~ 0.37‰) in this study. In case of Cu isotopes, there were large variations in low temperature environments (~ 5.86‰) and various natural materials (~ 36.53‰) (Wang et al 2017). Redox reaction, adsorption, complexation with organic matters/ minerals, and biological process can affect the Cu isotopic composition, and heavy Cu isotope was readily oxidized and preferentially released into solution (Rodríguez et al 2015;Lv et al 2016;Wang et al 2017).…”

“…In case of Cu isotopes, there were large variations in low temperature environments (~ 5.86‰) and various natural materials (~ 36.53‰) (Wang et al 2017). Redox reaction, adsorption, complexation with organic matters/ minerals, and biological process can affect the Cu isotopic composition, and heavy Cu isotope was readily oxidized and preferentially released into solution (Rodríguez et al 2015;Lv et al 2016;Wang et al 2017). The difference in the Cu isotopic composition (δ 65 Cu max -δ 65 Cu min ) was ~ 0.80‰ for 125-250 µm and ~ 0.16‰ for 63-125 µm particles, with the fine particles having a narrow range of isotopic variation among the sampling sites.…”

Differences in Copper Isotope Fractionation Between Mussels (Regulators) and Oysters (Hyperaccumulators): Insights from a Ten-Year Biomonitoring Study

“…17,[54][55][56][57][58][59][60] Overall, Cu (II) displays low coordination, and tends to favor heavy isotopes, in contrast to the reduced form Cu(I) with high coordination numbers which is enriched in the light isotope. 61,62 Ab initio calculations show that the heavy Cu isotope is preferentially bound to O-donor ligands, followed by N-and S-donor ligands. 6,55,63 By analogy to other organisms, particular isotope range for mussels and oysters can be related to species-specific physiological features on the fractionation of Cu isotopes at the cellular and tissue levels.…”

“…Some δ 65 CuSRM-976 values reported for anthropogenic materials in literature, such as cement (+0.30 to +0.61‰), 10 road dust (+0.08 to +0.25‰), 10 vehicular traffic (+0.46 to +0.59‰), 10 and antifouling paint (+0.54 ±0.03) 70 are characterized by isotope compositions that are heavier than natural average of the Upper Continental Crust (+0.07± 0.10‰), 71,72 than the uncontaminated sedimentary materials from estuaries (−0.04 ± 0.18‰) 73 , and rivers worldwide (−1.02 to +0.09‰). 62 Extending the current Cu isotope bank data for anthropogenic materials and additional investigations on the Cu isotope fractionation in post-depositional processes will help track Cu pollutant sources and bioaccumulation routes in bivalves.…”

A copper isotope investigation of methane cycling in Late Archaean sediments

“…Variability in Δ 33 S-Δ 36 S dynamics have been forwarded as novel proxies that are capable of resolving subtle changes in the chemical composition of the atmosphere (e.g., Claire et al, 2014;Endo et al, 2016). Of relevance here, the broad correlations between low Δ 36 S/Δ 33 S values and extremely negative organic carbon isotope values (𝛿 13 Corg), termed C-S anomalies, have formed the primary evidence for the development of PHEs during the Neoarchaean (Zerkle et al, 2012;Izon et al, 2015;2017).…”