Better characterisation of the underwater solar UV environment using a high exposure dosimeter

Abstract

The effect of solar UV radiation (UV) upon the marine ecosystem has been well documented by many previous studies using a wide range of measurement and modeling techniques adapted to an extensive variety of underwater environments such as oceans, lakes, streams and creek beds. From these investigations it has been discovered that UVB radiation (wavelengths running from 280 to 320 nm) has a broad range of negative effects on aquatic biota, while the less energetic UVA radiation (wavelengths running from 320 to 400 nm) has the capability to both repair and damage various types of underwater life. Solar UV radiation also has the potential to cause damage to unprotected humans involved in various aquatic activities such as swimming, snorkeling and diving. The penetration and distribution of the UV field in an underwater environment is primarily dependent upon the water column depth and dissolved organic carbon (DOC) level of the water, and therefore the capability of the UV to cause biological damage is also dependent upon these factors. Various chemical dosimeters have been fabricated and tested to measure the UV underwater, and in turn quantify the relationship between water column depth and DOC levels to the UV field distribution, but have only been able to record UV exposures over short time increments thus limiting the extent of the data. It has now become necessary to build upon this initial research and develop a chemical dosimeter that is capable of measuring long-term SUV exposure in any type of underwater environment. Poly (2,6-dimethyl-1, 4-phenylene oxide) (PPO) has been identified and chosen as a candidate for this objective. This presentation will deliver several preliminary results relating to the development of the PPO dosimeter for use underwater and will discuss the future directions that this research will take.