Cadmium would certainly be a concern, lead and arsenic, depending on the contaminants in the metal that end up in the kidneys. Bioavailability and absorption would be higher than for ingested sources. Altho the main body of research has been on tubule damage, there are indications that these metals may also cause glomerular damage at lower levels in people with diabetes and other causes of renal inflammation. You might look in the tobacco literature for heavy metal contaminants as well to explore the transport and lodging of metals in the kidney from inhaled sources.

Metal fumes like cadmium is associated with decreased absorbance of creatinine level in the body, thus excretory creatinine becomes higher. The nephrotic damage induced by various metals like lead, cadmium, mercury becomes inefficient to reabsorb creatinine. Here are some link you can search them out:

Falck, F. Y., Fine, L. J., Smith, R. G., McClatchey, K. D., Annesley, T., England, B. and Schork, A. M. (1983), Occupational cadmium exposure and renal status. Am. J. Ind. Med., 4: 541–549. doi: 10.1002/ajim.4700040408

http://onlinelibrary.wiley.com/doi/10.1002/ajim.4700040408/abstract

Message from Gunnar Nordberg, Department of Public Health and Clinical Medicine, Umea University, Sweden: Concerning the question whether exposure to metal fumes can cause changes in creatinine, please understand that short term exposure to high concentrations (1mg/m3) of cadmium in air in the form of cadmium fumes will cause serious lung toxicity. Longer lerm exposures to lower concentrations will give rise to lung and kidney toxicity. Both the glomerular and tubular function of the kidney will be affected. For those who suffer glomerular damage creatinine clearence will be decreased and less creatinine will be excreted in urine. Serum creatinine will increase. It is, however possible to get predominantly tubular damage with little influence on serum creatinine. For further information please see.

Nordberg GF et al. Chapter 23 Cadmium in Handbook on the Toxicology of Metals, 3rd Edition Elsevier/Academic Press 2007

If exposure to metal fume is associated with a hot, humid environment then increased creatinine excretion could be an indication of dehydration rather than or as well as health effects.