THE STATUS OF NONPOINT SOURCE POLLUTION: ITS NATURE, EXTENT AND CONTROL¹

Abstract

Nonpoint source pollution remains as the primary reason for the designation of many of the Nation's streams as “water quality limited.” This means that even with the application of technology‐based effluent limitations on point sources, ambient water quality standards will not be met. This paper explores several of the reasons why nonpoint sources are so difficult to come to grips with. These reasons include: (1) the inability to expand the definition of nonpoint sources to encompass nonengineering attributes, (2) the relatively primitive state of characterizing nonpoint sources, (3) the lack of prior success in conducting programs to study and alleviate nonpoint problems, and (4) an uncertain approach to providing incentives for control practices.

Distribution of phenanthrene between soil and an aqueous phase in the presence of anionic micelle-like amphiphilic polyurethane particles

“…The distribution of phenanthrene between the soil and the aqueous phase in the presence of APU can be described by concentration ratios of phenanthrene in the soil to that in the aqueous phase, as follows [7,8,21,22] …”

A review of the effects of population pressure on watershed management practices in the Lake Victoria Basin

“…Non-point pollution presents problems to resource managers, both from the standpoint of processes involved and procedures to eliminate, or minimize impacts. VIGNON (1985) points out that a major difficulty is understanding and analyzing the mode of conveyance. Other characteristics that challenge the analyst are the intermittent nature and the extent of nonpoint pollution.…”

Synthesis of amphiphilic polyurethane nanonetwork particles and their application for the soil‐washing process

“…Distribution of HOCs between the aqueous phase and soil is largely changed by the addition of surfactant because surfactant molecules enhance the apparent solubility of HOCs in the aqueous phase through the micellar solubilization of HOCs. [17][18][19][20][21][22][23][24][25][26][27] So, this distribution of compounds can be used as an index for evaluating the soil-washing performance of a surfactant. [23][24][25] So, we examined the sorption of phenanthrene in the presence and absence of Triton X-100 and APU particles with different experimental conditions to investigate how the sorption of Triton X-100 or APU particles influenced the sorption of phenanthrene on the aquifer soil.…”

“…As a consequence, sorbed PAHs may act as long-term sources of groundwater contamination, even when groundwater contaminated by HOCs, such as nonaqueous phase liquids, are completely extracted and treated by surfactant-enhanced remediation process. [17][18][19] So, many researchers have used various surfactants to enhance the desorption of sorbed PAHs from soil through the solubilization of sorbed PAHs in surfactant micelles. 20 -27 Surfactant-enhanced desorption and the washing process are only effective when the surfactant dose is greater than its critical micelle concentration (CMC) because most surfactant molecules below their CMC are sorbed onto soil below its CMC, resulting in the enhanced sorption of PAHs from the aqueous phase to the soil surface.…”