Arsenic mobility in the arsenic-contaminated Yangzonghai Lake in China

Effect of reductive dissolution of iron (hydr)oxides on arsenic behavior in a water–sediment system: First release, then adsorption

“…The lake is located at an elevation of 1770 m, and has a maximum depth of 30 m and an average depth of 20 m. This lake has a catchment area of 192 km 2 , with an average annual water storage of 5.69 Â 10 8 m 3 . For the Yangzonghai Lake, the average annual water temperature is 18 C. In 2008 the lake experienced an accidental As contamination; because of this, As concentrations peaked at 134 mg L À1 in October of that year (Liu et al, 2014), when all human uses of the lake water ceased. Subsequently, attempts to abate the concentrations of As were attempted by spraying FeCl 3 .…”

“…These efforts decreased the concentration of As below 50 mg L À1 , according to a measurement taken in August 2011. Such Fe salts are well suited for reducing the concentration of As within water bodies, as they form insoluble complex compounds with As that precipitate to the bottom of the lake (Liu et al, 2014). Yangzonghai Lake is a deep lake, with thermal stratification in the summer leading to strong anaerobic conditions at the bottom of the lake (Liu et al, 2014).…”

“…However, some researches showed that iron (hydr)oxides precipitated during sewage sludge flocculation were partially redissolved the acid soil, releasing previously surface adsorbed contaminants (Contin et al, 2015). Yangzonghai Lake, which was contaminated by As and then treated with FeCl 3 (Liu et al, 2014) during September 2009-December 2011, resulting in a large quantity of insoluble complex as As-iron (hydr)oxides in sediment. The changes of redox potentials (Eh) in the overlying water may lead to dissolve of the iron (hydr)oxides, whether the reduction dissolve promotes the adsorption/desorption of As should be investigated further.…”

Watershed-Scale Phosphorus Balance Evaluation Using a Mass Balance Method

“…The water samples from each site were collected at different depths using a water pump (the first at 0.5 m below the surface, then every 1 m down the water column, and the last sample at 0.5 m from the bottom). Due to the lake was polluted by arsenic in 2008 and was treated with a ferric flocculants (FeCl 3 ) from October 2009 to December 2011, see Liu et al [10] in details. The P flux of sedimentation has been accelerated by the remediation of arsenic pollution.…”

“…Has an elevation of 1,769.9 m. The volume of the lake is about 5.69 × 10 8 m 3 [10] and the main soil type is latosol. There are three inflow streams and one channel called Baiyi River outflow from the watershed, but only one outflow river called Tangchi River which is controlled by a sluice gate in the north (Fig.…”