ETH Zurich, Institute of Environmental Engineering, 8093 Zurich, Switzerland.
Environ Sci Technol. 2010 Dec 15;44(24):9364-9. doi: 10.1021/es102260c. Epub 2010 Nov 11.
To date the impact of thermal emissions has not been addressed in life cycle assessment despite the narrow thermal tolerance of most aquatic species. A method to derive characterization factors for the impact of cooling water discharges on aquatic ecosystems was developed which uses space and time explicit integration of fate and effects of water temperature changes. The fate factor is calculated with a 1-dimensional steady-state model and reflects the residence time of heat emissions in the river. The effect factor specifies the loss of species diversity per unit of temperature increase and is based on a species sensitivity distribution of temperature tolerance intervals for various aquatic species. As an example, time explicit characterization factors were calculated for the cooling water discharge of a nuclear power plant in Switzerland, quantifying the impact on aquatic ecosystems of the rivers Aare and Rhine. The relative importance of the impact of these cooling water discharges was compared with other impacts in life cycle assessment. We found that thermal emissions are relevant for aquatic ecosystems compared to other stressors, such as chemicals and nutrients. For the case of nuclear electricity investigated, thermal emissions contribute between 3% and over 90% to Ecosystem Quality damage.
迄今为止，尽管大多数水生生物对温度的耐受范围很窄，但生命周期评估并未考虑热排放的影响。本文开发了一种方法，用于推导冷却水排放对水生生态系统影响的特征化因子，该方法利用了水温变化的归宿和影响的时空显式综合。归宿因子通过一维稳态模型进行计算，反映了热排放在河流中的停留时间。影响因子则指定了单位温度升高导致的物种多样性损失，其基于各种水生生物的温度耐受区间的物种敏感性分布。作为示例，针对瑞士一座核电站的冷却水排放，计算了时间显式特征化因子，量化了对阿尔河和莱茵河等河流中水生生态系统的影响。还比较了这些冷却水排放与生命周期评估中其他影响因素的相对重要性。结果发现，与化学品和营养物等其他压力因素相比，热排放对水生生态系统更为相关。在所研究的核电案例中，热排放对生态系统质量损害的贡献在 3%到 90%以上不等。
