Phosphate, 3 - 10 nmol, in 1 dm3 of natural-water samples was quantitatively collected along with 10 micromol of Fe(III) ion onto a silica-gel collector in the pH range of 5.4 - 6.2. The amount of Fe(III) ion needed was limited to such a low level that the Pyrocatechol Violet method could be applied without removing the Fe(III) ion, providing a superior determination method for phosphate. Surfa...

A novel on-line oxidation method of ultra-trace Cr(III) dissolved in natural water has been developed using a flow electrolysis cell. This method was successfully applied to the determination of the total Cr concentration by flow injection-solid phase spectrophotometry using diphenylcarbazide as a coloring agent. With the applied potential of 1.35 V (vs. Ag/AgCl) and the flow rate of 0.80 cm(3)...

Background: Synthetic coagulants commonly used for water treatment are associated with undesirable properties, such as inefficacy and toxicity in addition to being expensive. Natural coagulants are considered safe and economical alternatives for developing countries where the plants are abundantly available. Methods: The phytochemical composition and safety of water samples treated with Mang...

Background: Due to the potential public health effects of releases of uranium to the environment, isotopic determination and measurement of this radionuclide in environmental samples is very important. Achieving this goal, monitoring programs for this radionuclide seems necessary to be applied in many countries. Materials and Methods: The uranium was separated from the water samples using anion...

Groundwater and seepage samples were collected from both the natural and building-modified slopes in the highly urbanized spaces of the Mid-Levels area, Hong Kong. Groundwater in the natural slopes, although retaining some signatures from rainwater, is enriched in major cations such as Na, K, Ca and Mg and some anions such as HCO3 and SO4. Clearly, water-rock interactions, such as weathering of...

A novel fractionation method, based on both particle size and settling characteristics, was employed to examine metal distributions among five fractions. In-stream and stormwater runoff samples were collected from four land use types: highway, urban, agricultural (storm event and irrigation), and natural. Highway samples contained the highest dissolved concentrations for most metals, and freshw...

OBJECTIVES Fluoride levels in the public water supplies of 40 Brazilian cities were analyzed and classified on the basis of risk/benefit balance. MATERIAL AND METHODS Samples were collected monthly over a seven-year period from three sites for each water supply source. The samples were analyzed in duplicate in the laboratory of the Center for Research in Public Health - UNESP using an ion ana...

A novel electroanalytical procedure is proposed for the determination of the triflumizole in formulation, soil and natural water samples using differential pulse polarography (DPP). Triflumizole exhibited a single well-defined cathodic peak over the pH range of 1.0-9.0 in Britton-Robinson (B-R) buffers. The peak potentials were shifted to more negative values upon increasing the pH and a plot o...