Diffuse sources groundwater pollution

Dijfuse sources are highly dynamic, spread out pollution sources and their magnitude is closely related to meteorological factors such as precipitation. Major diffuse sources under this definition include surface runoff (load from atmospheric deposition), groundwater, erosion (load from eroded material), diffuse loads of paved urban areas (atmospheric deposition, traffic, corrosion) including combined sewer overflows, since these events occur discontinuously over time and are closely related to precipitation (it has to be pointed out that emissions from urban areas are also partly involved in the point source term, so these discharges are not constant in reahty). Both point and diffuse sources contribute to the total contaminant load of rivers. 

Indirect emissions are caused by atmospheric degradation of precursor compounds. Atmospheric degradation of precursors is likely the major source of pollution in remote areas [30, 31]. Municipal WWTP effluents and infiltration of urban runoff and leaching piping [6, 32] are probably the major source of diffuse pollution to rivers and groundwater aquifers. 

Pollutants can enter through direct dumping, piped outflow, and channeled waste streams as localized point sources, or as diffuse nonpoint sources they can enter rivers, lakes, streams, and groundwater through runoff and soil percolation. Nonpoint sources are considered to be major contributors to air, water, and soil pollution which include runoff from paved streets and parking lots, agricultural lots, soil erosion from logging, atmospheric deposition of acidic or toxic air pollutants (Table 1). The source is particularly... 

Abstract In the last decade, it became increasingly evident that the fuel oxygenate methyl tertiary butyl ether (MTBE) is nearly ubiquitous in the worldwide environment. The detection frequency of MTBE rivals other volatile organic compounds (VOCs) that have been produced and used for a much longer period of time. Its mere presence in water bodies used as drinking water reservoirs (rivers, lakes, or groundwater tables) has aroused concern about its potential sources, persistence, or possible adverse effects (aesthetic or toxic implications) for end-users and aquatic life. The purpose of this chapter is to provide an updated overview of the current environmental concentrations, the occurrence of the pollutant in the different aquatic compartments, the relevance of diffuse and point sources, and the different alternatives for remediation of MTBE contaminated sites. 

To the best of our knowledge, the leaching of surface runoff and from sewer pipes has not been studied in Europe. One Japanese paper reports on the contamination of groundwater in the city of Tokyo [6]. PFHpA, PFOA, PFNA and PFOS were present in the following concentrations ranges <0.1-20, 0.47-60, 0.1-94 ng/L and 0.28-133 ng/L, respectively. Surface runoff, wastewater leaching from sewer pipes, and in one sample infiltrating river water appeared to be the sources of the contaminations. This could be denoted as diffuse urban pollution. 

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