RISK TO ORGANISMS FROM MERCURY
There is an abundance of field data on levels of mercury in a variety of organisms and tissues, and there are a number of studies that demonstrate the effects of mercury on laboratory animals, but few studies examine the relationship between the two. Thus it is often difficult to determine the ecological relevance of mercury levels found in nature, or to predict the ecological consequences of current levels. We have reviewed the levels in tissues that are correlated with adverse effects in birds from laboratory studies, and compare these levels with those found in birds in the wild to provide a method of interpretation for values in avian populations. Laboratory studies indicate that mercury levels of 1 ppm in the blood and eggs, and 5 to 40 ppm in the feathers of birds, produce adverse effects in some bird species, including impaired reproduction. We reported egg levels in birds that range as high as 3.8 ppm, and feather levels that range as high as * ppm, although means are much lower. The levels in eggs of some wild birds are within the range known to affect embryo and chick mortality, lower hatchability and decreased chick weight; all parameters that would reduce reproductive success. Species with high egg levels include Forster's tern (Sterna forsteri) and black skimmer (Rynchops niger) from the New York Bight and black-crowned night heron (Nycticorax nycticorax) and cormorant (Phalacrocorax auritus) from Minnesota. Levels in feathers of some wild birds are within the range associated with reduced hatchability of female's eggs, behavioral abnormalities of adults, and sterility. Species with dangerously elevated mercury levels in feathers include several species from the New York Bight including terns, herons and egrets, as well as gannets (Morus serrator) from New Zealand, Sooty terns (Sterna fuscata) from Puerto Rico, Cattle egrets (Bubulcus ibis) from Egypt.
This research over the years has been funded by NIH, NIEHS, EPA, NJDEP, CRESP, and the U.S. Fish & Wildlife Service.
 |
New York Academy of Sciences Harbor
Consortium Releases Letter on Mercury, Fish Advisories 2003 |
 |
Mercury Levels in N.J. Tuna Excessive 2005 |
 |
toxic birds |
 |
Pregnant Women Should Avoid Eating Predatory Fish |
 |
What Fish You Buy Is Key To Avoiding Mercury |
|
|
Profile: FDA finds tuna has more mercury than previously thought, gives guidelines for eating fish to get maximum benefits, minimum exposure to mercury |
