The simultaneous determination of silicic, boric and carbonic acids in natural water via ion-exclusion chromatography with a charged aerosol detector

The simple and simultaneous determination of silicic, boric and carbonic acids was made using ion-exclusion chromatography (IEC) and a Corona™ charged aerosol detector (C-CAD). Silicic and boric acids were separated by the column packed with a weakly acidic cation-exchange resin in H+-form and ultra-pure water eluent, and the detector responses were improved by the addition of acetonitrile to eluent. Under the optimized conditions, the simultaneous determination of weak inorganic acids, except for carbonic acid, was successfully performed. When the conversion column packed with a strong acidic cation-exchange resin in Na+- or K+-form was inserted between the separation column and the detector, weak inorganic acids including carbonic acid could be detected by the C-CAD. The calibration curves were linear in the range of 0.5–10 mg·L−1 as Si for silicic acid (r2 = 0.996), 10–100 mg·L−1 as B for boric acid (r2 = 0.998) and 1.3–21 mg·L−1 as C for carbonic acid (r2 = 0.993). The detection limits based on three times the standard deviation were 0.03 mg·L−1 as Si for silicic acid, 0.40 mg·L−1 as B for boric acid and 0.08 mg·L−1 as C for carbonic acid. This method was applicable to river, hot spring and drinking water

Utilization of Ion-Exclusion Chromatography for Water Quality Monitoring in a Suburban River in Jakarta, Indonesia

We evaluated the use of ion-exclusion chromatographic systems for analyzing the behavior of inorganic ions (e.g., bicarbonate, sulfate, chloride, nitrate, phosphate, dissolved silicate, sodium, ammonium, potassium, magnesium, and calcium ions) in a suburban river located in Jakarta, Indonesia. Carbonate, phosphate, and silicate ion concentrations were determined using ion-exclusion chromatography (IEC) on a weakly acidic cation-exchange resin column (WCX) in the H+-form with water eluent. Other ions were identified by ion-exclusion/cation-exchange chromatography (IEC/CEC) on a WCX column with tartaric acid eluent. The use of IEC systems for water quality monitoring was advantageous for the following reasons: (1) the concentrations of analyte ions, except NO3− and silicate ions, increased from upstream to downstream; and (2) the speciation of inorganic nitrogen ions could be analyzed by single injection into the IEC/CEC. The IEC approach provided beneficial information for the construction of sewage treatment facilities in our study area. Results showed that (1) the analyte concentrations for samples obtained in the downstream area were higher than those in the upstream area owing to contamination by domestic sewage; (2) the concentrations of NO3− and NH4+ correlated with the concentration of dissolved oxygen; and (3) bicarbonate concentrations increased downstream, likely due to respiration of bacteria and dissolution of concrete under low-oxygen conditions. - See more at: http://www.mdpi.com/2073-4441/6/7/1945/htm#sthash.Kc46oQ6g.dpu

Phytotoxicities of fluoranthene and phenanthrene deposited on needle surfaces of the evergreen conifer, Japanese red pine (Pinus densiflora Sieb. et. Zucc).

Polycyclic aromatic hydrocarbons (PAHs) have been widely studied with respect to their carcinogenic and mutagenic effects on animals and human cells. Phenanthrene (PHE) and fluoranthene (FLU) effects on the needle photosynthetic traits of two-year-old Japanese red pine (Pinus densiflora Sieb. et. Zucc) seedlings were investigated. Three months after fumigation of foliage with solutions containing these PAHs (10 μM each), FLU had negative effects on net photosynthesis at near-saturating irradiance, stomatal conductance, initial chlorophyll fluorescence, and the contents of total chlorophyll, magnesium, and ribulose 1,5-bisphosphate carboxylase (rubisco) of current-year needles. PHE had similar negative effects to FLU but in lesser magnitude. The effects of the PAHs were mitigated by the addition of an OH-radical scavenger (mannitol) into the PAHs solutions. PAHs deposited on the surface of pine needles may induce the generation of reactive oxygen species in the photosynthetic apparatus, a manner closely resembling the action of the herbicide paraquat. Capsule: Fluoranthene and phenanthrene caused negative effects on the needles of Japanese red pine

Cause of decade’s stagnation of plant communities through16-years successional trajectory toward fens at a created wetland in northern Japan

Hiraoka is the created wetland that was constructed in 2000 in an urban park in Sapporo City. We introduced fen and bog plants and monitored the hydrochemical conditions and species assemblage composition four times during the 16 years after construction (YAC). The species richness indices of total, exotics, and annuals resembled those of the target fens within 11 YAC, but the species assemblages did not match the target fens even after 16 YAC, showing that species richness is a less effective way to measure success. The 0.1 m high artificial hummocks enhanced species richness 1.3 to 1.4 times more than the surrounding hollows and increased variety within species assemblages (although these hummocks collapsed before16 YAC). Water level from ground surface (WL) were stable at around 0.00 to +0.05 m, except during several-days floods, when a maximum WL of +0.4 to +0.5 m. Hydrological conditions were, therefore, similar to those natural fens nearby. Mean pH values (min and max) decreased from 6.9 (5.5–9.3) in 1 YAC to 6.2 (5.7–6.9) in 16 YAC and approached those of natural fens. The mean electrical conductivity (166–196 μS cm^ ) and concentrations of major minerals (Ca^, Mg^, and K^+) were consistently higher than those of Japanese fens, but dissolved phosphorus (0.00–0.04 mg l^) and nitrogen (0.12–0.48 mg l^) were lower. The trajectory of species assemblages quickly approached the target fen at least 5 YAC, but then changed between 5 and 11 YAC, before stagnating. Since mineral content in Hiraoka was near the lower limit of calcareous rich-fens, abundant minerals would be less effective in changing the species assemblage compositions. Due to the dominance of eight initially introduced fen species, the trajectory turned in a different direction. Species assemblages stagnated between initial and target communities before 16 YAC, since the five fen dominants introduced at 8 to 9 YAC had not yet dominated. Accordingly, initial introductions, including species combinations of target fen, can shorten the time required to achieve natural fens. At 16 YAC, large emerged macrophytes did not dominate and did not competitively exclude fen species, probably because the water was oligotrophic and the wetland design did not include open water