Effects Of Cadmium Pollution On Human Health In A Region Of Guangdong Province

Cadmium (Cd) has been recognized as a toxic element that is ubiquitous in the envi-ronment. Since the notorious Itai-Itai disease broke out in Japan due to severe Cd pollu-tion, researchers had begun to pay close attention to the health outcome of Cd pollution. According to numerous previous studies, health effects maybe occurred and kidney is believed to be particularly susceptible to Cd toxicity, especially under the long-term exposure. Therefore, conducting studies in typical cadmium polluted areas of our coun-try, understanding the pollution condition of environment and population is crucial for preventing the breaking-out of Itai-Itai disease in China. And we should modify our ex-isting policies, propose proper standards to protect population health based on the study of benchmark dose.We conducted a study in a typical cadmium polluted area of Guangdong province, collecting seven species samples (total number of 607 samples) and recruiting inhabit-ants (total number of 872 inhabitants) for this investigation. We used Urinary Cadmium (UCd) as an indicator of internal Cd body burden. Urinary N-acetyl-β-D-glucosaminidase (UNAG) and P-2-microglobulin (Uβ2MG) were consid-ered as renal effect markers. We used hybrid method to estimate the benchmark dose of UCd.1. Concentration of samples:Samples collected from this region are showing a certain percentage of exceeding the reference level and the ratio is 15%-37%. The mean values of samples were significant lower than the national standard. However, the excessive condition showed that the environmental cadmium pollution had changed the local ecological environment. Taking the food with exceeding cadmium may cause dietary cadmium exposure risk.2. Cadmium exposure in population:The mean values of urinary cadmium were sig-nificantly lower than the national standard (P< 0.05), but there were different per-centages of exceeding the reference level. The results showed that, there was no statistical difference of UCd levels in different ages (P> 0.05) and the UCd mean values of woman were significantly lower than that of man. There was significant linear correlation between UCd and UNAG/Uβ2MG. UCd levels indeed affected the concentrations of renal effect markers. Results showed that, it would cause renal dysfunction under long-term cadmium exposure.3. Estimation of Benchmark Dose Lower Confidence Limit (BMDL) of UCd: BMDL10 of UCd for UNAG was 0.90 μg/g (Creatinine, Cr) in men and 1.14 μg/g Cr in women. Using Uβ2MG as the renal effect marker, BMDL10 of UCd was 2.23 μg/g Cr and 0.98 μg/g Cr in men and women, respectively. These results were lower than the existing standard 5 μg/g Cr, may due to different calculation methods, UCd levels, length of exposure and dietary habits. For safety reason, it is acceptable to lower the existing standard to protect population health.