Final answer:
The product for hydraulic systems in plants where zinc is an environmental concern is a zinc-free hydraulic fluid.
Step-by-step explanation:
The product for hydraulic systems in plants where zinc is an environmental concern is a zinc-free hydraulic fluid. These hydraulic fluids are specifically formulated to minimize or eliminate the use of zinc compounds, which can be harmful to the environment. Instead, they use alternative additives and base oils that offer similar performance without the environmental risks associated with zinc.