Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, KY16 8LB, UK.
Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, KY16 8LB, UK.
Environ Pollut. 2018 Feb;233:407-418. doi: 10.1016/j.envpol.2017.10.074. Epub 2017 Nov 5.
The potential impact of exposure to polychlorinated biphenyls (PCBs) on the health and survival of cetaceans continues to be an issue for conservation and management, yet few quantitative approaches for estimating population level effects have been developed. An individual based model (IBM) for assessing effects on both calf survival and immunity was developed and tested. Three case study species (bottlenose dolphin, humpback whale and killer whale) in four populations were taken as examples and the impact of varying levels of PCB uptake on achievable population growth was assessed. The unique aspect of the model is its ability to evaluate likely effects of immunosuppression in addition to calf survival, enabling consequences of PCB exposure on immune function on all age-classes to be explored. By incorporating quantitative tissue concentration-response functions from laboratory animal model species into an IBM framework, population trajectories were generated. Model outputs included estimated concentrations of PCBs in the blubber of females by age, which were then compared to published empirical data. Achievable population growth rates were more affected by the inclusion of effects of PCBs on immunity than on calf survival, but the magnitude depended on the virulence of any subsequent encounter with a pathogen and the proportion of the population exposed. Since the starting population parameters were from historic studies, which may already be impacted by PCBs, the results should be interpreted on a relative rather than an absolute basis. The framework will assist in providing quantitative risk assessments for populations of concern.
多氯联苯 (PCBs) 暴露对鲸目动物健康和生存的潜在影响仍然是保护和管理的一个问题，但很少有开发用于估计种群水平影响的定量方法。开发并测试了一种用于评估对幼崽存活率和免疫力影响的基于个体的模型 (IBM)。以四个种群中的三种案例研究物种（宽吻海豚、座头鲸和虎鲸）为例，评估了不同水平的 PCB 摄取对可实现种群增长的影响。该模型的独特之处在于它能够评估免疫抑制的可能影响，除了幼崽存活率之外，还能够探索 PCB 暴露对所有年龄组的免疫功能的后果。通过将来自实验室动物模型物种的定量组织浓度-反应函数纳入 IBM 框架，生成了种群轨迹。模型输出包括按年龄计算的女性体内 PCB 浓度，然后将其与已发表的经验数据进行比较。实现的种群增长率受 PCB 对免疫的影响比受幼崽存活率的影响更大，但幅度取决于随后与病原体遭遇的毒力以及暴露人群的比例。由于起始种群参数来自已经受到 PCB 影响的历史研究，因此应根据相对而非绝对基础来解释结果。该框架将有助于为关注的种群提供定量风险评估。
