The resume of Journal
Integrated Human Ecological Risk Assessment:
A Case study of Ultraviolet Radiation Effect
On Amphibians, Coral,
Humans and Oceanic Primary Productions


Background

An ultraviolet radiation (UVR) from the Sun is a naturally occurring stressor to most forms of life. The Earth atmospheric ozone layer reduces the amounts of UVR that reaches the Earth surface. The potential for continued depletions of this ozone layer and environmental changes that increase the penetrance of aquatic habitat, both due to humans activities, and the subsequent increase UVR are global environmental concern for both human and ecosystems. Ozone depletions is the primary cause of change of dose of UVR received by aquatic and terrestrial species include humans. Ozone depletion is thinning or eradication in the case of the polar ozone holes of the UVR on blocking ozone layer. This is cause by a chlorofluorocarbons (CFCs) which are regulated by Montreal Protocol on 1987.

The other factor cause altered UVR at the Earth surface are global climate change/global warming and acidification both decrease of the amount of dissolved organic matter (DOM), which in turn increase UVR penetration in to aquatic ecosystems (Schindler et.al,1996). DOM is the primary mechanism for limiting UVR penetration into the water column (protecting aquatic organisms and establishing the lower limit of the photic zone). The climate warming are decreasing the total amount of DOM which is produced by aquatic system as well as the terrestrial system from which it is then transported to aquatic systems. The overall effect of these changes is increased UV irradiance in both terrestrial and aquatic ecosystems. These changes in the relative amount of UVR reaching the various habitats maybe affecting ecosystem and human health but research is only beginning to assess and quantify the effects. An integrated risk assessment provide efficiency on data gathering, analysis, and reporting by enabling risk assessor to use the combined knowledge from many disciplines to evaluate overall risk.

Formulations
Commonalities in stressors source, exposure pathways, and mechanism and damage and repair facilitate development of analogy assessment endpoints and holistic conceptual models. These conceptual models communicate the direct and indirect pathways of the primary (UVR) and secondary (e.g. loss of food source) stressor to relevant biotic components, taking advantage of the full level of current understanding of UVR physics and exposure issues. Although the UVR action spectrum may be dependent on the specific assessment endpoints, knowing the nature and mechanism of the effect in human informs our conceptualizations of possible direct effect of UVR on amphibians, coral and phytoplankton and probably the vice of versa. Problem formulations has identified common data needs to evaluate risk from the direct effect of UVR on a variety of receptor organisms and target system. The integrated assessment benefits substantially from the resource efficiency gained through use of commons models and flux measurement (network) in predicting outcomes, and the enhances insight to possible effects to receptor organism gained through analogy to other species.

Characterization Exposure

The source of UVR radiation and many of the exposure pathways are identical for both human and ecological assessments. The amounts of UVR reaching the specific receptor is affected by a number of process and conditions, include ozone depletions, global change (particularly increased of SST-sea surface temperature and altered cloud cover), aquatic acidification (by alteration of concentration of DOM) and changing the nutrient profiles. The specific factor that will influence the exposure to receptor include:

· location of the receptor cause the angle of sun and altitude influence on intensity and wavelength spectrum of radiations.
· thickness of stratospheric ozone layer as the influenced by natural distributions phenomena and global change (depletion and hole formations)
· natural habitat protections (e.g. shade, water depth)
· physiological/morphological adaptations, character of receptor , e.g. pigment, fur, feather etc
· behavioral adaptations of receptor screen block by human or changes in activity patters by all organism
· water quality and clarity.

Allowing common information on UVR intensity obtained from monitoring networks and tools to be used as the initial measure of the exposure. Models and methods for estimating or measuring dose can also be shared. This offers an efficiency advantage with respect to an integrated assessment approach. The benefits of an integrated approach thus include cost efficiency and minimizations data collections needs.

Character effect
The range of effects of UVR on humans include skin cancer, immunosuppressant, and ocular damage (zigman,1993). Direct effect on amphibians include developmental damage, mortality, and possible imunocompromise (cummints et al.1999), UV radiations has been implicated as a factor in coral bleaching (wellington,1993), also decreased of photosynthetic on aquatic plants (Smith,1980). Several endpoints have commons mechanism of effect and similar biomarkers of effects (e.g. DNA damage), a situation that promotes characterization efficiency by permitting extrapolation of effect across species.

An extrapolation approach to developing action spectra models (wavelength specific exposure response models) maybe possible depending on the similarity in mechanisms and exposure pathways. Recognition of linkages among components of the integrated conceptual model enhances understanding of the indirect effect of UVR exposure that can influence risks to the assessment endpoints in (sometimes) unexpected ways. Similarly, information about the potential effects to same assessment endpoints may suggest previously unexpected effects to other endpoints for which information’s is lacking.

The risk characterization would use for future UV radiation scenarios, action spectra and others exposure-response relationships to characterize direct effect and ecological model to characterize the indirect effect on assessment endpoints is enhanced by using exposure scenarios, models, data shared in common and by drawing analogies among mechanism effect when possible. Causation would be determined through evaluation of combinations of correlative and mechanistic relationships linking UVR to biological effect, with the risk conclusions being further defined and strengthen as multiple lines of evidence about those relationships converge. The overall confidence in risk conclusions would be enhanced as similarities among risk estimates for individual assessment endpoints emerge.

An emphasis on communicating risk of UVR exposure to human health, although necessary to facilitate effective choices about personal protections, has under represented possible adverse effect on ecological systems. The resulting lack of appreciations of ecological risk can hinder identification of risk management priorities. An integrated approach to risk communications would provide consistent, coherent, and simultaneous expressions of risk to all assessment endpoints, thereby facilitating selections among potential mitigations efforts that minimize risk to human and non humans alike, promoting understand of why various risk management actions are taken.

Risk Management
Risk management informed by more holistic understand risk of changing UVR to humans and ecological systems will result in management and personal decisions That is the most effective in optimizing risk mitigation strategies. Integrated risk assessment endpoints in a consistent and coherent manner, allowing relative risks among assessment endpoints to be compared and understood and the trade off inherent in various risk management options to be transparent and recognized. Integrated risk assessment also facilitates a deeper understanding of the dependence human well being on ecological functions and services, thereby aiding in the identification of management approach that optimize risk reduction from both human health and ecological perspectives and avoiding un intended consequences.
In contrast, facilitated behavioral adjustment and personal protection strategies are not possible or feasible for non human receptors. Protection from stratospheric ozone layer seemingly is the principle option for minimizing the risk to ecosystems. Ideally, management decisions directed towards sources reduction (i.e. minimization of ozone stratospheric depletion through control of ODS-ozone depleting substances) would consider the potential for both direct and indirect effect on ecological systems and direct effects on humans simultaneously. In evaluating relationships between source reduction and risk, attention should be paid to alterations in UVR penetration due changing sea surface temperature-SST. DOM content, and acidification and to introduction of photo reactive anthropogenic contaminants in sensitive ecosystems.
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