RMP News Volume 4 Issue 2

RMP NewsVolume 4, Issue 2

Contents

San Leandro Bay

Bivalve Study Field Methods

Norcal SETAC

Nonpoint Sources of Pollution

Review Implementation

Around Town

Correction to Organophosphate article

Staff Profile: Gabriele Marek

Calendar

Announcements

Sediment Investigation in San Leandro Bay

By Ted Daum, SFEI

Introduction

The San Francisco Bay Regional Water Quality Control Board (Regional Board) has authorized SFEI to conduct a sediment chemistry investigation in San Leandro Bay. The Port of Oakland is funding this effort, with money earmarked in lieu of a fine levied by the Regional Board. 

The shallow embayment of San Leandro Bay is formed by the confluence of East Creek, Damon Creek, Elmhurst Channel, San Leandro Creek Channel, which are freshwater, and Oakland and San Leandro Bay Channels, which are tidal (see map page 3). These watersheds encompass areas of gently sloping commercial, residential and industrial land. 

Sediment contamination in San Leandro Bay by trace metals, PCBs, PAHs, and various synthetic biocides has been documented through a number of short-term and continuing studies, including the Bay Protection and Toxic Cleanup Program (BPTCP), the Regional Board, and various localized surveys and site assessments. Sources of current and historical contamination appear to include metal plating industries, auto industries, lead processing, stormwater runoff, atmospheric deposition, and pesticide discharges from residential sources. 

There are a number of possible avenues of contaminant transport into San Leandro Bay. One possibility is tidal action from Oakland Inner Harbor, as tidal flow occurs primarily through this channel as opposed to the San Leandro Bay channel. In this scenario pollutants would be expected to disperse in a homogeneous fashion in this shallow, windblown embayment. Other potential sources of contaminant transport are the canals described above which drain into San Leandro Bay. In fact, the highest concentrations measured for many trace element and organic contaminants at the BPTCP sites were at the mouths of East Creek, and San Leandro and Elmhurst Channels. This would seem to point to these channels as the main sources of many pollutants. However, there is only one control site in the open portion of San Leandro Bay for comparison. Little sediment chemistry information is available for the main shipping channels where the sediment deposition rates are the highest, and gradient sampling to discern potential sources has not been undertaken....