Notice of RetractionCharacteristic and Speciation of pH in Shallow Groundwater in the Pearl River Delta

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

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Through testing the pH values of over two thousand groups of groundwater samples from the Pearl River Delta, water acidification was found to be one of the most outstanding groundwater environmental problems in the region. 76.3% of the whole region was covered by the acidic groundwater. The pH value distribution of the groundwater in the region was characterized by obvious regional differences. The groundwater in hilly areas was mainly acidic with the pH values centralized between 5.6 and 6.4; while the groundwater in the plain areas was generally neutral with the pH values between 6.4 and 7.2. The main factors affecting the pH values of the groundwater were acid rains, soils, rivers and seawater tides. In hilly areas, the acid rains had a high infiltration intensity, and the soils had a weak buffering capacity against acid, which played important roles in the low pH values of the groundwater. The increase of pH values of the groundwater was caused by the influences of the thick clay layer in plain areas, the weakened infiltration intensity of acid rains, the frequent water exchanges between rivers and groundwater as well as the invasion of salty tides and seawater into the groundwater.