The toxicology and natural occurrence of several recognized geotoxic elements including arsenic, cadmium, chromium, nickel, lead, selenium, uranium, and vanadium is reviewed. The behavior of these elements in the environment and in biological systems is examined. The properties of these eight toxic elements are summarized and presented in a toxicity matrix. The toxicity matrix identifies each of the elements in terms of average crustal abundance, average soil concentration, drinking water standards, irrigation water standards, daily human intake, aquatic toxicity, phytotoxicity, mammalian toxicity, human toxicity, and bioaccumulation factors for fish. Fish are the major aquatic environment contribution to the human diet and bioaccumulation in aquatic ecosystems has been demonstrated to be an important factor in the cycling of elements in aquatic ecosystems. The toxicity matrix is used as a first approximation to rank the geotoxicity of elements for the purpose of focusing future efforts. The ranking from highest to lowest toxicity with respect to the toxicity parameters being discussed is as follows: arsenic, cadmium, lead, selenium, chromium, vanadium, nickel, and uranium.

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "Susie Graves president of Women's Architectural League joins Linda Winesett in admiring the Christmas tree decorated with hot air balloons created by Willie Locke, right."

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "Bob AHnlin shows off his most recent porcelain pottery to Joss Passmore."

Photograph used for a newspaper owned by the Oklahoma Publishing Company. Caption: "OU's Chuck Barnett splits two Sam Houston defenders for a bucket Monday night."

Photograph used for a newspaper owned by the Oklahoma Publishing Company. Caption: "Sondra Bonds, second from left, and Ken Bonds, second from right , welcome guests James L. Hall, Dorothy McGregor and Carol Hall during their annual Christmas brunch for Baptist Hospital board members and donors."

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "Karen Johnston and Mr. and Mrs. Brad Moss admire the Christmas decorations in the Ruffin home."

B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.

B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.

B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.

Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.

Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.

Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.

Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Mark White, regarding a legal question submitted for clarification;The funding of escheat investigations.

Weekly newspaper from Jacksboro, Texas that includes local, state, and national news along with extensive advertising.

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "Charlie Woods and Paula Carr of Newcastle enjoy the wintery holiday decorations in the OTC lobby."

A postcard from Miriam Owen Irwin of the Mosaic Press to Kathryn I. Rickard.

Photograph used for a newspaper owned by the Oklahoma Publishing Company.

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "LeRoy and Margaret Brower question artist Dean Hyde about his shield of suede, feathers and fiber."

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "Fancy and colorful native costumes from the Scandinavian countries worn by Lorene Lockwood, Ruth Anna Johnson and Gudbjorg Price."

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "Bruce and Sally Lenz, left, co-hosted an early holiday open house with Prudy and Gary Mercer, right."

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "Enjoying the entertainment are team ropers Scott Laramore, Colorado; Bobby Harris, Wyoming; George Aros, Arizona; J.D. Yates, Colorado."

Photograph used for a newspaper owned by the Oklahoma Publishing Company. Caption: "Dr. James Perry - CSU Prof. - chairman fact finding committee."

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "Dr. and Mrs. Elmer Ridgeway enjoys Christmas played by Genevieve Winkenbach at a holiday brunch."