Fulvic acid binding sites (1.3−70 μM) and EDTA (0.0017−0.18 μM) accounted for organically bound Cu in seven stream samples measured by potentiometric titration. Cu was 84−99% organically bound in filtrates with 200 nM total Cu. Binding of Cu by EDTA was limited by competition from other trace metals. Water hardness was inversely related to properties of dissolved organic carbon (DOC) that enhance fulvic acid binding:  DOC concentration, percentage of DOC that is fulvic acid, and binding sites per fulvic acid carbon. Dissolved trace metals, stabilized by organic binding, occurred at increased concentration in soft water as compared to hard water.

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Knowledge of the characteristics of highway runoff (concentrations and loads of constituents and the physical and chemical processes which produce this runoff) is important for decision makers, planners, and highway engineers to assess and mitigate possible adverse impacts of highway runoff on the Nation's receiving waters. In October 1996, the Federal Highway Administration and the U.S. Geological Survey began the National Highway Runoff Data and Methodology Synthesis to provide a catalog of the pertinent information available; to define the necessary documentation to determine if data are valid (useful for intended purposes), current, and technically supportable; and to evaluate available sources in terms of current and foreseeable information needs.

Concentrations are given in percent (%), parts per million (ppm), and parts per billion (ppb). Street-Dirt Accumulation Rates Street-dirt accumulation rates are given in grams per curb meter per day (g/curb-m/d). Intuitively, accumulation rates should be reported in units of mass per unit area per unit time. Street dirt accumulates along curbs, however, and therefore accumulation rates are reported in units of mass per unit curb length per unit time as has been the practice in other investigations reporting street-dirt accumulation. For example, one kilogram of street dirt accumulated on a street surface that is one kilometer in length over one day would be equal to 0.5 grams per curb meter per day; one kilometer of street has two kilometers of curb length or 2000 curb meters. Abbreviations BMPs best management practices DIW deionized water HEPA high-efficiency particulate air filter ICPES inductively coupled plasma-emission spectroscopy

Riparian wetlands contaminated with Hg from an industrial point source were found to be important sites of production and release of methyl mercury (MeHg) in a 40-km reach of the Sudbury River in eastern Massachusetts. Stream discharge and concentration measurements were used to calculate annual mean loads for total Hg (ΣHg) and MeHg in contaminated river reaches, a reservoir, and a riparian wetland downstream from the industrial source. Budgets based on these loads indicate that the annual mean ΣHg load increased sixfold in a reach receiving flow from the point source, but the annual mean MeHg load did not increase. About 23% of the ΣHg load was removed by sedimentation during flow through the reservoir. Net production of MeHg in the reservoir was similar to that reported elsewhere for lakes receiving Hg from atmospheric deposition only. ΣHg concentrations and loads increased significantly as the river passed through the riparian wetland reach. On the basis of flooded wetland area, net production of MeHg was 15 times greater in the wetland reach than in wetland-associated drainages described in other studies.