In Bangladesh, arsenic contamination of groundwater becomes a serious threat to human health. In a series of survey conducted in the northwest Bangladesh, we have examined the infantile exposure to arsenic in a periurban community. A high correlation was found between arsenic concentrations of urine ([As]u) in children and those in their mothers. The arsenic concentrations in breast milk ranged between non-detectable level to 38 ng/mL, which was much higher than ever reported from arsenic-contaminated population, suggesting that exposure via breast milk may also be important for infants in this area. Chemical speciation of urinary arsenic with HPLC-ICP-MS revealed that there might be a suppression of the second step methylation in highly exposed individual, although this point needs to be further confirmed with larger sample size. Current mitigation technologies for arsenic-polluted groundwater in Bangladesh and West Bengal, India were reviewed and their arsenic removal performances were evaluated by chemical analysis (IC/ICP/MS method). Performance of some groundwater treatment plants and instruments was lower than expected and did not satisfy the drinking water standard of 50mg/L in Bangladesh. Improvements of the current arsenic mitigation technologies in respect to their structure, and other technical concerns were discussed.