Provided they were non-smokers, lung cancer cases with an environmental exposure leading to daily urinary excretion levels of more than 24 nmol of cadmium could argue that cadmium was the most likely explanation for the cancer. Cadmium exposure maps for the UK are publicly available.
Evidence from:
T Nawrot et al. Lancet Oncol. (2006) Vol.7 p 119 126
“Environmental exposure to cadmium and risk of cancer: a prospective population-based study”
The paper also suggests a synergistic effect with smoking. Blood tests would identify those at significant risk, and would suggest causation in non-smokers.
Further detail: