JOURNAL OF PROGRESS ON PROJECT

BIOMAGNIFICATION OF MERCURY
 
Week One
 Before arriving at the Woodrow Wilson Institute, we decided to do a project on biomagnification.  We already were familiar with the concept: certain chemicals accumulate in higher concentration as the level in the food chain increases.  This phenomenon has detrimental effects for organisms that are at the top of the food chain (such as dolphins, humans, and other large animals) because many of the accumulated substances reach toxic levels.

We started to do research on the topic to clarify our understanding before we could narrow down a feasible area of research.  Initially we had in mind that our topic should be one that was directly transferrable to our own locality (Northern California).  We used the World Wide Web and the libraries at Princeton  to find out which chemicals biomagnify and which ecosystems are affected by biomagnification. To make our problem relevant to our own locality, we investigated the wine industry in California for pesticides, fertilizers, and herbicides. Although we discovered a range of substances used in grape production, we didn't find enough information about any single substance to make it a suitable candidate for our study.

At this point we realized that we would not be able to carry out a field study of biomagnification here at Princeton because of the complexity of the problem and the limitations of our resources.  We believe that the modelling process itself is of sufficient complexity to be the focus of our learning and that our reflections on our process will help us to understand how our students might tackle a similar process.  The STELLA modelling process is a powerful tool for understanding the effects of variables on a system.

Armed with a new paradigm for our research, we decided to pursue a well-documented study of biomagnification.  We researched PCBs, dioxin, DDT, and mercury.  Finally,we came upon a study in Southern Florida that had promise because there was so much documentation at their Web site.  This study,  Mercury Studies in the Florida Everglades, is about the effect of mercury contamination in the Everglades and its subsequent effect of biomagnification.  Their study is long-term and extensive.

By the end of the week we had spent many hours researching and discussing the focus of our project.  We had also begun to learn how to use the STELLA system through several days of workshops, and we had engaged in a lot of collaborative problem-solving.  We started to build a conceptual model of the mercury cycling system in the Everglades and gathered numbers from various sources. (See page entitled Links). In this process we have learned that our initial concept of this system was very unsophisticated; we now know that mercury biomagnification is a very complex system with many variables.  Our task is to understand enough about this system to make decisions about which variables to keep constant in order to simplify the model.

Now at the beginning of the second week we have translated our conceptual model into STELLA language.  We have come to a place where we cannot go farther on our project without expert advice.  We will spent the second week seeking this advice and further clarifying our model.