Final answer:
A nurse investigating environmental health problems due to contaminated groundwater is practicing community-oriented nursing, focusing on population-level concerns and strategies.
Step-by-step explanation:
The nurse who is investigating environmental health problems caused by contaminated groundwater is engaging in community-oriented practice. This type of practice often involves assessing environmental risks, identifying health concerns at the population level, and implementing strategies to address these concerns on a larger scale, which may include education, policy advocacy, or intersectoral collaboration. It is different from community-based practice, which focuses more directly on individual or family health needs within the context of the community.