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This study reports the transport characteristics of the pharmaceutical compounds carboplatin and cisplatin, and their respective derivatives, in saturated sand and soil columns. Pharmaceuticals are recognized as emerging pollutants of soil and water resources, but studies of the transport characteristics of organometallic pharmaceuticals in soil-water environments are rare. A recent study of oxaliplatin transport in natural soil raises the question of whether or not its behavior is representative of all Pt-based pharmaceuticals behavior in soil-water systems. To address this question, transport behaviors of carboplatin and cisplatin species were studied individually in packed sand columns under unamended conditions, and in packed soil columns under unamended and acetate-amended conditions. In contrast to oxaliplatin, carboplatin species exhibited very low affinity to both sand and soil surfaces: the retention of injected carboplatin was 3% and6% for sand and soil, respectively. The affinity to soil was practically the same under the different redox conditions. The affinity of carboplatin to sand and soil surfaces was much smaller than the reported oxaliplatin affinity and the values reported in the literature. Cisplatin exhibited transport behavior similar to that of oxaliplatin in soil, including mild sensitivity to redox conditions (e.g., higher retention under acetate-amended conditions), overall exhibiting retention of 64-70% of the injected species. However, cisplatin also exhibited a similar retention in sand (retention of 45-53%), unlike the cases of carboplatin and oxaliplatin. The results indicate that similarly structured pharmaceuticals can exhibit very different transport characteristic in natural soil-water environments, and should therefore be studied and assessed individually.

This study reports the transport characteristics of the organometallic anticancer compound oxaliplatin and its derivatives in natural soil-water environments. Although pharmaceuticals and their derivatives have for many years been detected in water resources, and linked to toxicological impacts on ecological systems, their transport in soil and groundwater is not fully understood. Specifically, studies that describe transport of organometallic pharmaceuticals in porous media are rare, and the transport characteristics of platinum complexes have received little attention. Oxaliplatin transport was studied in sand, as a function of two added natural chelators (citrate and humic acid), and in soil, under four continuously monitored, environmentally-relevant redox conditions: oxic, nitrate reducing, iron reducing and methanogenic. In sand, oxaliplatin species retention was about 7%, and affected only mildly by added citrate, and by humic acid under buffered pH. Transport with unbuffered humic acid was affected significantly by pH variations, and exhibited strong retention at pH

We have adapted the X-ray diffraction technique of measuring crystal lattice parameters as a function of sample orientation in order to investigate the Poisson ratio (ν) of thin films of Ce 0.8 Gd 0.2 O 1.9 with different degrees of in-plane compressive strain. Since Gd-doped ceria is mechanically inelastic, the unstrained lattice constant is not well-defined. Therefore in order to determine the Poisson ratio, more than one strain state of the same sample must be characterized. We have accomplished this with a home-built, diffractometer-compatible sample-bender. Using this device, we find that the Poisson ratio of as-deposited thin films of Gd-doped ceria is a decreasing function of the in-plane compressive strain. At total strain ≈ −0.9 %, ν is > 0.45, indicating that the material tends to preserve volume. Increase of the in-plane strain to ≈ −2 % produces a monotonic decrease in the Poisson ratio to ~0.2. Such low values are indicative of reduced volume. We explain this behavior by noting earlier results from our group suggesting that, at temperatures below 200 °C and at low strain values, Ce 0.8 Gd 0.2 O 1.9 responds to non-isotropic mechanical stress by reorienting the locally distorted CeCe-VO –O7 units. At higher strain values this mechanism is apparently no longer effective. Measurement of the Poisson ratio of inelastic thin films by this technique is straightforward and not diffractometer-dependent. It therefore represents a practical method for ceramic thin film characterization.