In the 1980s, the migration of chemical waste into the soil at the Solvay plant in Tavaux (Jura) caused long-term contamination of the groundwater. The contamination, monitored by a piezometric network, extends across nine municipalities, four of which are inhabited directly in the affected area. Health risk assessment calculations indicate a low level of risk, but one that is nevertheless higher than the benchmarks typically accepted in France if the groundwater is used as drinking water over several years. Health consequences could include skin and liver damage. A mortality study did not show an excess risk for this population. However, both the risk assessment and the mortality studies have limitations: lack of toxicological data for certain products, uncertainties regarding the effects of mixtures, and an epidemiological study based solely on mortality and a small population. Consequently, the question raised in the referral regarding the advisability of implementing epidemiological surveillance is difficult to address. Collective health monitoring in the form of an epidemiological study would not be appropriate due to the too small number of people to be monitored. Individual health monitoring would offer no benefit compared to standard patient care. Indeed: - measuring the level of biological contamination in these individuals would not provide additional information to determine the actual extent of exposure (already known through water consumption habits) or to define a medical course of action (independent of the contamination level); - systematic screening would offer only a hypothetical benefit (no reliable, validated tests) and significant logistical challenges in its implementation (participation, anxiety caused). However, raising awareness among the physicians involved in these individuals’ standard care pathways would ensure that this environmental exposure is properly integrated into their overall health management. (R.A.)