Characteristics and contaminants of the Salton Sea sediments

Abstract

This was the first comprehensive study to evaluate the distribution of sediment types and sediment contaminants throughout the Salton Sea. The sampling effort encompassed the entire Sea plus its three main tributaries, and im luded collection of sediment samples from 73 locations. The agricultural runoff that keeps the Sea alive is loaded with salts, pesticides, selenium, and other metals. Metals and metalloids found at elevated concentrations and of potential ecological concern were cadmium, copper, molybdenum, nickel, zinc, and selenium. The most significant metalloid of concern was selenium, which was limited to the upper 30 cm of sediment. There did not appear to be any strong correlation between the sand, silt, or clay content with the areas of elevated metals and metalloids. Acetone, 2-butanone, and carbon disulfide were also widespread but appeared to be associated with natural biological processes within the sediments. One of the most significant findings of this study was the absence of elevated concentrations of organic chemicals commonly used in agriculture earlier this century, such as dichlorodiphenyltrichloroethane (DDT).