Marine Pollution: The Future Challenge Is to Link Human and Wildlife Studies. (Guest Editorial)
Jenssen, Bjorn Munro, Environmental Health Perspectives
The rapid population growth and enormous urban and coastal development in many of the world's coastal regions have caused considerable concern that anthropogenic pollution may reduce biodiversity and productivity of marine ecosystems, resulting in reduction and depletion of human marine food resources. In addition, natural environments are important for recreation, and consequently for human health and welfare, and there is now increased awareness that nature has its own intrinsic value. Pollution reduces the aesthetic value and perhaps also the intrinsic value of the marine environment, whether the pollution is visual (such as oil pollution and plastic debris) or invisible (such as chemical compounds).
Another main reason for concern about marine pollution is related to the direct effects of pollution on human health. Because many pollutants accumulate in marine organisms, humans are exposed to pollutants when they consume food from polluted areas. Several studies have documented that human populations that consume large amounts of marine food have high burdens of persistent organic pollutants (POPs), such as dioxins, furans, polychlorinated biphenyls (PCBs), and some heavy metals. There has been a particular focus on indigenous people who consume large amounts of marine food, including blubber products of marine mammals (Dewailly et al. 1999).
Because construction of treatment facilities for sewage is unlikely to catch up with increasing human activities, especially in developing countries, eutrophication and hypoxia will be a persistent problem. Also, exposure of marine organisms to increasing concentrations of human bacteria may pose a threat to coastal ecosystems. High levels of natural and synthetic compounds with estrogenic properties in sewage effluents have been linked to feminization of fish. There is also concern about other chemicals with endocrine-disrupting properties. One example is the marine antifouling paint ingredient tributyltin, which has been shown to cause imposex in gastropods, to affect coastal and estuarine molluscs populations, and to cause reduction of species diversity in marine estuarine benthic and epibenthic invertebrate communities (Matthiessen and Law 2002). Until now, most studies concerned with the effects of marine pollution have focused on biochemical and physiologic effects. In the future, studies should address the effects of pollution on behavioral traits that can potentially alter biodiversity and ecosystem functioning. Examples of such ecologically significant behavioral traits are antipredator behavior, reproductive behavior, parental behavior, and feeding success (Wibe 2003).
Recent reports have documented dose relationships between mercury, dioxins, furans, and PCBs and several reproductive, cognitive, and neurologic factors in humans. Obviously, there is a clear need to pursue such studies, and there is a particular need to identify possible confounding factors. Breast-feeding and the quality of the home environment are examples of identified confounding factors that may modify and actually counteract harmful effects of POPs (Jacobson and Jacobson 2002; Walkowiak et al. 2001).
Many marine mammals are highly dependent on well-developed cognitive abilities and must have a normal behavior to survive. The selection against cognitive and neurologic dysfunction or retardation is most likely much more significant in wildlife than in humans. Thus, there is also a great need for wildlife studies that focus on the effects of marine pollution on cognitive abilities and related neurologic effects, and it is of great interest how such effects can affect biodiversity and ecosystem functioning.
The harmful effects of many POPs on human and environmental health have been recognized, and in 2000, an international ban was implemented on the 12 most noxious POPs, the so-called "dirty dozen" (Kaiser and Enserink 2000). During the last two decades, the concentrations of many pollutants in marine biota have declined. …