Lead Pollution: Records in Southern California Coastal Sediments

Abstract

The present anthropogenic lead fluxes into sediments from the Santa Monica, San Pedro, and Santa Barbara basins of Southern California are, respectively, 0.9, 1.7, and 2.1 micrograms of lead per square centimeter of sea bottom per year; the natural (prepollution) rates for these three basins were, respectively, 0.24, 0.26, and 1.0 microgram of lead per square centimeter per year. Studies of isotopic composition indicate that lead pollutants in coastal sediments are derived mainly from the combustion of lead additives in gasoline.

Pyrogenic Remobilization of Historic Industrial Lead Depositions

“…4 Atmospheric depositions of those and other industrial lead aerosols markedly increased lead concentrations of sediments in Southern California. 5,6 For example, Chow et al 7 reported that subsequent to the introduction of leaded gasoline, lead fluxes into sediments increased from 1.0 to 2.1 μg/cm 2 /year in the Santa Barbara Basin, 0.26 to 1.7 μg/cm 2 /year in the San Pedro Basin and 0.24 μg/cm 2 /year to 0.9 μg/cm 2 /year in the Santa Monica Basin. Similarly, Harris and Davidson 8 reported that the average (mean ( SD, Standard Deviation) soil lead concentration in Southern California (Los Angeles and suburbs) increased from a 1919À1933 value of 16 ( 0.5 to 79 ( 23 μg/g between 1967 and 1970.…”

Record of lead pollution in sediments of the Tokyo Bay, Japan.

“…The lead accumulation rates in the table are in good agreement with MATSUMOTO (1979) and SUGISAKI (1979) even they used a corer of a diameter narrower than this work. The value is rather high compared with the total flux of 1-3µg/cm2/y in the Southern California basin (CHow et al, 1973). The reasons why it is so high are that the Tokyo Bay is surrounded by the heavily industrialized coast line and that the Bay enters the land so deeply and the exit is so narrow in contrast to its area (^ 1,000km2) that the lead would be deposited rapidly in the Bay as described before.…”

“…CHOW et al (1973) reported the lead profiles in the South ern California basin sediments and clarified the lead pollution status in that area. They esti mated the anthropogenic lead input rate to be about 1 to 2µg/cm2/y in 1972.…”

Natural and anthropogenic lead in sediments of the Rotorua lakes, New Zealand

“…Historically, the natural airborne lead fraction has been insignificant compared with supply from catchments (Bindler et al, 2001). With increasing anthropogenic additions of lead to the natural environment it has been possible to distinguish anthropogenic sources in disparate environments such as the Arctic (Sturges and Barrie, 1989), Pacific Ocean atmosphere (Settle and Patterson,1982), Antarctic and Greenland ice (Murozumi et al, 1969;Rosman et al, 1993;Hong et al, 1994), peat bogs (Shotyk et al, 1998), Alantic and Pacific Ocean corals (Shen and Boyle, 1987), coastal marine sediments (Chow et al, 1973;Veron et al, 1987) and lake sediments (Edgington and Robbins, 1976;Graney et al, 1995;Monna et al, 1999;Renberg et al, 2002). In these studies, isotopic ratios and/or changes in concentrations of lead have been used to infer a variety of different sources.…”