The current disease pattern situation and human health risk related to heavy metal exposure * Prevalence of disease symptoms in the study area The results in Table 3.5 show that the prevalence of symptoms / diseases among local people in the study area were in the following order: teeth-jaw-face (84.16%) > infectious (59.70%) > nervous system (49.01%) > digestion (48.22%) > motor system (42.77%) > circulation (41.49%) > dermatology (39.21%) > respiratory system (29.90%) > ENT (29.50%) > eyes (24.55%) > endocrine-metabolism (17.82%) > urinary (7.13%).