Earthquakes today

Current and latest world earthquakes breaking news, activity and articles today


Geological news

Elevated Lead Levels Found in Songbirds in Southeast Missouri



Elevated Lead Levels Found in Songbirds in Southeast Missouri

The report is available online.

BELTSVILLE, M.D.  – About half of ground-feeding songbirds collected from a historic lead mining district in southeast Missouri contained toxic levels of lead in their blood and internal organs, according to a new U.S. Geological Survey study.  Elevated lead levels were also found in soils and earthworms in the lead district sites examined, which included the “Missouri Mines” in the Old Lead Belt; “Washington State Park,” on the Big River floodplain; and the “Viburnum Trend,” within Mark Twain National Forest. 

Tested birds had lead concentrations exceeding those of reference birds by factors of 8 in blood, 13 in liver, and 23 in kidney samples. Soils in the study exceeded background levels for lead nearly 40 fold, for zinc 8 fold, and for cadmium 25 fold.

Southeast Missouri contains the world’s largest deposit of the lead mineral galena.  The area has a long history of lead mining and smelting.  Lead has been mined in the region since 1721. Previous studies have measured elevated lead in floodplain soils, stream sediments, fish, invertebrates, amphibians, other birds and wildlife in the area.  Lead has been released from the erosion of tailings, mine waste, smelting, and dust. Periodic flooding has also transported lead in the environment.

Cadmium levels in birds from the mining study sites were several times those in reference birds, but concentrations of zinc were not elevated more than those in the reference birds.  

Ground-feeding songbirds were selected for the study because they were more likely to be exposed to lead than songbirds feeding in shrubs or in the forest canopy.  Cardinals, robins, blue jays, and eastern towhees were among the birds tested.  

USGS completed this study at the request of the U. S. Fish and Wildlife Service as part of a natural resource damage assessment by the U.S. Department of the Interior to investigate whether wildlife might be adversely affected by exposure to lead contaminated soil.  

Lead poisoning in birds can cause abnormal muscular function, kidney and liver failure, decreased fertility, and anemia. Songbirds poisoned by lead, however, generally do not show lesions.  The exposure to lead is detected by chemically testing tissues or by measuring suppressed enzyme levels.  

The study, “Toxic exposure of songbirds to lead in the Southeast Missouri Lead Mining District,” is available in the journal Archives of Environmental Contamination and Toxicology.

USGS Newsroom



More information

Parameter Value Description
Magnitude mb The magnitude for the event.
Longitude ° East Decimal degrees longitude. Negative values for western longitudes.
Latitude ° North Decimal degrees latitude. Negative values for southern latitudes.
Depth km Depth of the event in kilometers.
Place Textual description of named geographic region near to the event. This may be a city name, or a Flinn-Engdahl Region name.
Time 1970-01-01 00:00:00 Time when the event occurred. UTC/GMT
Updated 1970-01-01 00:00:00 Time when the event was most recently updated. UTC/GMT
Timezone offset Timezone offset from UTC in minutes at the event epicenter.
Felt The total number of felt reports
CDI The maximum reported intensity for the event.
MMI The maximum estimated instrumental intensity for the event.
Alert Level The alert level from the PAGER earthquake impact scale. Green, Yellow, Orange or Red.
Review Status Indicates whether the event has been reviewed by a human.
Tsunami This flag is set to "1" for large events in oceanic regions and "0" otherwise. The existence or value of this flag does not indicate if a tsunami actually did or will exist.
SIG A number describing how significant the event is. Larger numbers indicate a more significant event.
Network The ID of a data contributor. Identifies the network considered to be the preferred source of information for this event.
Sources A comma-separated list of network contributors.
Number of Stations Used The total number of Number of seismic stations which reported P- and S-arrival times for this earthquake.
Horizontal Distance Horizontal distance from the epicenter to the nearest station (in degrees).
Root Mean Square sec The root-mean-square (RMS) travel time residual, in sec, using all weights.
Azimuthal Gap The largest azimuthal gap between azimuthally adjacent stations (in degrees).
Magnitude Type The method or algorithm used to calculate the preferred magnitude for the event.
Event Type Type of seismic event.
Event ID Id of event.
Event Code An identifying code assigned by, and unique from, the corresponding source for the event.
Event IDS A comma-separated list of event ids that are associated to an event.

Leave a Reply