This paper presents a novel research direction in the field of sensor data management. It concerns transactional support in heterogeneous large scale sensor systems. Besides well-known continuous queries on sensor data, system management queries should be supported in these systems. Indeed, with increasing capacity and diversity of sensors, new applications which require complex read-only and update queries are likely to appear. Those applications will require challenging properties such as ACID properties. This paper discusses the relevance of ACID properties in sensor data management context. It then focuses on the isolation property and proposes a concurrency control mechanism to support concurrent execution of continuous queries and update transactions on sensor properties.