Heavy Metal Levels in Terns and Black Skimmers
This is the first of three chapters on metals in Barnegat Bay waterbirds, and this introduction serves for all three chapters. Scientists, environmentalists, managers, public policy makers, and the public are increasingly concerned about contaminants, such as lead and mercury, in the environment. They want reliable, relevant, understandable, cost-effective methods of understanding trends in pollution within their communities. And they want these indicators to be of interest to the public to gain support. Birds are iconic, conspicuous, and interesting to the general public. Some bird species have been used in many different places, over long periods, to track organic and metal contaminants. Heavy metals are released to the environment by mining, milling, manufacturing, combustion, and recycling. Metals occur in air emissions and water effluents of farms, factories, and cities. They are part of fuel cycles and manufacturing cycles. Once released to the environment, they can be transported in the atmosphere or in rivers. Each of the metals has a complex chemistry depending on its ionization potential, its electromotive potential, and its likelihood of forming soluble versus insoluble salts as well as its affinity for sulfur, selenium, and organic complexes. In general, metals are ubiquitous and are present in the food webs of estuarine and coastal ecosystems (see Chapter 8).