Methyl bromide in surface drinking waters: Gas-chromatographic determination by the headspace technique

A sensitive method for the gas-chromatographic determination of methy bromide in surface drinking waters is reported. The analytical principle is based on the conversion of methyl bromide into methyl iodide by reaction with sodium iodide. Reaction parameters (amount of sodium iodide added, temperature, reaction time and salinity) are reported to provide a simple, precise and sensitive analytical method with a CH₃Br detection threshold of approx. 5 × 10⁻³μgl⁻¹.     

Weak and strong acids in the surface waters of the tovdal region in S. Norway

The concentrations of weak and strong acids in surface waters of the Tovdal region of southern Norway were measured during a spring snow-melt period. The determinations were made by the pH titration method due to Gran. The strong acid concentrations in Tovdal river water varied between 3 and 11 μeq 1⁻¹, while the weak acid concentrations were between 62 and 106 μeq 1⁻¹ and the contribution of the weak acids to the hydrogen ion concentration ranged between 10 and 60%. The pH of the river water varied from 4.9 to 5.0 and in the absence of excess strong acid, the weak acids would have produced a pH of 5.2–5.3. The concentration of weak acids and their contribution to the hydrogen ion concentration were least during the period of most rapid thaw.No direct evidence of the nature of the weak acids was obtained, but routine chemical analysis data suggested that inorganic species derived from aluminium and silicon accounted for 40–60 μeq 1⁻¹, while 20–50 μeq 1⁻¹ were attributable to humic and fulvic acids. The titration characteristics of the weak acids could be approximated closely by a polybasic acid with a first ionization constant in the range 10⁻⁶ to 5 × 10⁻⁷ and less well defined weaker ionizations.Measurements on old snow containing coniferous tree litter and on melt water from a rocky barren contained weak acid concentrations comparable to the riverwater, indicating that only slight contact with vegetable matter or the ground is required to obtain significant concentrations of weak acids.     

Distribution of halomethanes in potable waters of Kuwait

The distribution of bromine containing trihalomethanes in the water distribution system of Kuwait has been studied. Total halomethanes in the drinking water averaged 25.6 ± 9.1 μg l⁻¹ with a maximum of 50.5 μg l⁻¹. Average concentrations (μg l⁻¹) of individual compounds were: CHBr₃, 13.6 ± 4.6; CHBr₂Cl, 8.8 ± 3.7; CHCl₂Br, 3.3 ± 1.5. Water from roof top storage tanks contained significantly less halomethanes than that from underground reservoirs.     

Heavy metals in animals of Lake Balaton

Hg, Cd, Cu, Pb, Zn, Fe and Mn concentrations were measured in Chironomidae larvae, Crustacea plankton, as well as in various organs of mussels and fishes collected from the open water area of Lake Balaton. The values were comparatively low. However, there were significant differences in the metal concentrations of species and tissue.Most Cd was found in the gill of Unio pictorum L., most Pb, Zn and Mn in the gill of Anodonta cygnea L., most Cu in Crustacea plankton and in the liver of Abramis brama L., and most Hg and Fe in Chironomidae larvae. Low concentrations occurred in fishes, the lowest in the flesh of Stizostedion lucioperca L.Accumulation of metals in organs as compared with their concentration in the lake water was in the range of 3.4 × 10²−2.6 × 10³ for Hg; 7.0 × 10²−6.8 × 10³ for Cd; 3.3 × 10²−9.7 × 10³ for Cu; 6.9 × 10²−8.1 × 10³ for Zn; 1.5 × 10³−2.4 × 10⁴ for Pb; 3.5 × 10²−3.1 × 10⁴ for Fe; and 5.0 × 10¹−3.5 × 10⁵ for Mn.     

Preliminary studies on the leaching of some trace metals from kitchen faucets

Preliminary studies were carried out on the leaching of copper, zinc, chromium, cadmium and lead from eight kitchen faucets by samples of raw, filtered and distributed Ottawa water, a sample of well water and deionized water containing 2 mg l⁻¹ aqueous fulvic acid. Leaching was effected by allowing the test solutions to stand in the inverted faucets for two successive 24-h periods. Concentrations of the metals found in the leachates were copper: first leaching, 0.12–28.0 mg l⁻¹, second leaching, 0.08-3.54 mg l⁻¹; zinc: first leaching, 0.13-10.25 mg l⁻¹, second leaching, 0.06-2.85 mg l⁻¹; chromium: first leaching, < 1.0 × 10⁻³ − 0.395 mg l⁻¹, second leaching, < 1.0 × 10⁻³−0.032 mg l⁻¹; cadmium: first leaching, < 0.05 × 10⁻³−0.01 mg l⁻¹, second leaching, < 0.05 × 10⁻³−4 × 10⁻³ mg l⁻¹; and lead: first leaching, < 0.2−110.0 mg l⁻¹, second leaching, < 0.2−82.0 mg l⁻¹. The faucets containing lead-soldered copper joints released high concentrations of lead, particularly in the case of leaching with the aqueous fulvic acid solution. Under the conditions of the present investigations it is indicated that in some cases the concentrations of metals leached could lead to intakes in excess of the maximum permissible limits for these metals. However, further investigations will be required to determine the possible contribution of these faucets to metal intake under normal usage.     

Mercury fluxes in a natural forested Amazonian catchment (Serra do Navio, Amapá State, Brazil)

Mercury (Hg total) fluxes were calculated for rainwater, throughfall and stream water in a small catchment located in the northeastern region of the Brazilian Amazon (Serra do Navio, Amapá State), whose upper part is covered by a natural rainforest and lower part was altered due to deforestation and activities related to manganese mining. The catchment area is 200 km from the nearest gold mining (garimpo). Minimum and maximum Hg concentrations were measured monthly from October 1996 to September 1997 and were 3.5–23.4 ng l⁻¹ for rainwater, 16.5–82.7 ng l⁻¹ for throughfall (March–August 1997) and 1.2–6.1 and 4.2–18.8 ng l⁻¹ for stream water, in natural and disturbed areas, respectively. In the natural area, the inputs were 18.2 μg m⁻² year⁻¹ in rainwater and 72 μg m⁻² year⁻¹ in throughfall. This enrichment was attributed to dry deposition. The stream output of 2.9 μg m⁻² year⁻¹ indicates that Hg is being recycled within the forest as other chemical species or is being retained by the soil system, as confirmed by the cumulative Hg burden in the 0–10 cm surface layer, which was 36 480 μg m⁻². When the disturbed area of the catchment was included, the stream output was 9.3 μg m⁻², clearly indicating the impact of the deforestation of the lower part of the basin on the release of mercury. The Hg burden in the disturbed area was 7560 μg m⁻² for the 0–10 cm surface layer.     

Complexation analysis of fresh waters by equilibrium diafiltration

Equilibrium ultrafiltration has been employed to determine the extent of Cu, Ni, Co, Fe, Mn and Zu chelation in oxic waters from mineralized terrains. Concentrations of Cu, Ni and Co were determined in different organic fractions separated by various Amicon ultrafilters. Titrations of fresh water samples with metal ions were made, and “free” metal concentration measured by equilibrium diafiltration. Experiments were made at concentrations and pH at which metals and ligands occur in natural waters. Conditional stability functions ranged from 10^6.72 at pH 6.5 to 10^7.07 at pH 7.6 for Ni and 10^6.85 at pH 6.8 to 10^6.97 at pH 7.6 for Co. At low metal concentrations (8 × 10⁻⁷ M) only one complexing class of major importance for natural water environments was observed. The order of metal complexing ability was found to be Cu > Ni > Co > Zn > Mn with Cu showing a preference towards the higher MW organic fractions.     

Sorption and accumulation of cadmium in the sediment of the Tama River

Cadmium contents in the water and the sediment samples collected from the Tama River and several branches were measured. Cadmium (above 0.005mgl⁻¹) was detected in only four of the water samples, while the sediment samples showed cadmium content of 1.0–9.8 μg g⁻¹ dry sediment. Cadmium concentration in the sediments of the main stream was correlated against ignition loss of the samples and it was found that 1 g of ignition loss (organic matter) corresponded to 35 μg of cadmium.The batch adsorption experiment in the laboratory using an aqueous solution of cadmium for 14 sediment samples with a higher concentration of cadmium indicated that the amount adsorbed by the sediment is highly dependent on the ignition loss. The amount adsorbed on unit mass of ignition loss q_IL could be correlated by a Freundlich-type equilibrium relation as where C is the equilibrium concentration in the aqueous phase ranging between 7 × 10⁻³ and 10 mg l⁻¹, while k_IL and n are equilibrium constants.The adsorption rate measurement showed that the intraparticle diffusion coefficient of cadmium in the sediment was about 1.1 × 10⁻⁶ cm²s⁻¹, which is of a reasonable order of magnitude assuming the pore diffusion mechanism inside the particle.The results suggest that suspended solid particles of high organic content in flowing water contribute significantly to the transport of cadmium along the river.     

Bioconcentration of vanadium in American flagfish over one reproductive cycle

Flagfish (Jordanetta floridae Goode and Bean) were exposed to constant concentrations of vanadium (V) in the water from age 10 days to maturity, and second-generation fish were continued in the same concentrations to age 30 days. Residues of vanadium were directly related to exposure concentrations but bioconcentration factors were inversely related to them. Both residues and bioconcentration factors increased with exposure time up to 70 days, after which they remained stable to the end of exposure at 96 days. Residues and bioconcentration factors did not differ significantly between first- and second-generation fish, nor between males and females.Adults accumulated 21–29 μg V g⁻¹ (whole body dry weight) during exposure to 0.48 or 1.50 mg V 1⁻¹. These residues were significantly higher than values of 15–17.5, 4.4–4.8, and 0.27–0.54 μg V 1⁻¹, found after exposure to 0.17, 0.041 mg V 1⁻¹, and control conditions, respectively. Residues for these two lowest concentrations and control were significantly different from each other.Bioconcentration factors were 2.0–28 × two or three orders of magnitude lower than the factors for cadmium and zinc in the same species of fish, as determined by other investigators. The bioconcentration factors appeared, in fact, to be at the low end of the range found for metals, and danger to fish from bioaccumulation of vanadium was accordingly judged to be low.     

Chlorophenols in surface waters of the Netherlands (1976–1977)

In this paper an analytical method is described for the capillary gas chromatographic determination, after derivatization, of 19 individual chlorophenols in surface water. The minimum detectable amounts are for monochlorophenols 2 μg l⁻¹, for dichlorophenols 0.05 μg l⁻¹, for trichlorophenols 0.02 μg l⁻¹ and for tetra- and pentachlorophenols 0.01 μg l⁻¹. The results of a monitoring program in the river Rhine and other Dutch surface waters with respect to these compounds are presented. The results cover the period January 1976–December 1977. 2,6-Dichlorophenol, 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol and pentachlorophenol had the highest frequencies of occurrence in the river Rhine and its tributaries. Pentachlorophenol was found in the highest concentrations (up to 11 μg l⁻¹).     

Particulate and dissolved trace metals in Lake Ontario

Particulate metal concentrations in the nearshore waters of Lake Ontario have been determined to be 690 ng l⁻¹ for Cu; 40 ng l⁻¹ for Cd; 180 ng l⁻¹ for Ni; 1690 ng l⁻¹ for Zn; 2100 ng l⁻¹ for Mn; and 700 μg l⁻¹ for Fe. These values are considerably higher than the particulate metal concentrations in the offshore waters: 130, 8, 34, 230, 110, 260 and 9000 ng l⁻¹ for Cu, Cd, Ni, Zn, Pb, Mn and Fe respectively. In general, 50–80% of the Cu, 10–40% of the Ni, 20–60% of the Cd and >60% of the Pb in the lake water were bound to the suspended particulates. From the standing crop of the particulate metals and the estimated rates of their deposition on the lake bottom, the residence times of the particulate metals in the lake water column have been estimated to be about 0.5 yr. on the average. The suggestion is made that particulate organic matter may be an important vehicle for metal transport to the Lake Ontario sediments.     

Determination of ozone in water by the indigo method

The concentration of aqueous ozone can best be determined by the decolorization of indigo trisulfonate (600 nm, pH below 4) whenever the ozone cannot be measured directly by its u.v. absorption. The method is stoichiometric and extremely fast. The change of absorbance vs ozone added is −2.0 ± 0.1 × 10⁴ M⁻¹ cm⁻¹ and is independent of the concentration of aqueous ozone in the range 0.005–30 mg 1⁻¹. The precision of the analysis is 2% or 3 μg 1⁻¹ for low concentrations if a spectrophotometer or a good filter instrument is used. Visual methods can be used to measure 0.01 mgl⁻¹ ozone. Secondary oxidants produced by ozone in natural water, including hydrogen peroxide or chlorite, do not interfere; chlorine can be masked. The reagent solution is stable for 3 months. The method is recommended for kinetic measurements, for studies of ozonation processes and for visual field methods.     

Combined use of calcium salts and polymeric aluminium hydroxide for defluoridation of waste waters

The combined use of calcium salt and polymeric aluminium hydroxide, P, for treatment of fluoridated waste water has been described. In the proposed method of treatment the calcium ions acts as the precipitant and polymeric aluminium hydroxide as the coagulant. At low fluoride concentrations (2 × 10⁻³ M) the precipitation reaction of calcium fluoride is a slow process. The residual fluoride concentrations found experimentally approached the theoretically predicted values only at high calcium concentrations (| F | _t/ | Ca | _I molar ratio = 0.24) and for long equilibration times. The addition of calcium fluoride seeds (approx. 20 mg 1⁻¹) accelerated the precipitation process and the results obtained for the residual fluoride concentrations were close to the theoretically calculated ones regardless of the calcium ion concentration used. Under these conditions fine CaF₂ precipitate with poor settleability was formed. The addition of small amounts of polymeric aluminium hydroxide, P, (F/Al molar ratio = 10) greatly facilitates the settleability of the precipitate. The advantage of using P over alum for the removal of fluoride is that less concentration of the former is required and the reproducibility of the results are good. The effect of sulphate on the precipitation of calcium fluoride has been also studied. Tests with fluoride containing waste water collected from aluminium industry showed that fluoride can be effectively removed.     

The simultaneous determination of arsenic, antimony, bismuth, selenium and tellurium in waters by an inductively coupled plasma/volatile hydride method

A method using inductively coupled plasma spectrometry (ICP) and hydride generation is used to determine As, Sb, Bi, Se and Te simultaneously in both treated and natural waters. Two methods are described, direct analysis and a coprecipitation preconcentration method. Precision (RSD) was less than 10% for solutions of 1 μg l⁻¹ by using the preconcentration method. Recoveries of a wide range of analyte concentrations (0.1–50μg l⁻¹) for sea-water and internal supply water were excellent. Routine application of the method to waters from the rivers Hayle and Gannel, Cornwall are also reported.A time delay experiment was conducted to investigate the stability of the analytes in acidic solution. It was found that all the analytes in an ionic form were stable for up to 8 days.     

Environmental chemistry of copper in Lake Monona, Wisconsin

Lake Monona, located at Madison, Wisconsin, received over 1.5 × 10⁶ pounds of copper sulfate in the past 50 yr to control excessive algal growth. Dissolved copper on Lake Monona epilimnion is inversely related to pH which indicates possible control of dissolved copper by basic copper carbonate. Concentrations as high as about 4 μg Cu l⁻¹ were found in Lake Monona epilimnion, which also contains 3.3 me l⁻¹ (milliequivalents per liter) of alkalinity, mostly bicarbonate. Concentrations of dissolved copper were consistently lower (0.3 μg Cu l⁻¹) in the hypolimnion. Sulfide probably controls dissolved copper in the hypolimnion during anoxic conditions because of sulfide insolubility. Particulate copper concentrations of about 3 μg l⁻¹ increased slightly with depth. The highest concentrations of copper in Lake Monona sediments (650 mg kg⁻¹) were found approximately 60 cm below the current sediment surface. Surface sediments of Lake Monona contained approximately 250 mg Cu kg⁻¹ sediment dry weight.     

Survey of volatile halogenated organics (VHO) in Italy: Levels of VHO in drinking waters, surface waters and swimming pools

A survey undertaken in Italy (Emilia-Romagna region) has shown that Volatile Halogenated Organics (VHO) are present in many water samples; analysis has been performed by static head-space gas chromatographic technique.In drinking water samples low levels of pollution have become evident before any treatment, while after chlorination with sodium hypochlorite, or chlorine as a gas, VHO have appeared, almost exclusively as trihalomethanes (THM), sometimes at fairly high levels (max = 41.8 μg l⁻¹).Surface water samples have been collected every other month in one year, and have shown different levels of contamination; in most cases VHO (mainly chlorinated solvents) appeared just as traces, seldom at high concentration (max = 263 μg l⁻¹).Swimming pool samples have shown the high levels of contamination (max = 177.4 μg l⁻¹), mainly due to THM, as a consequence of chlorination with sodium hypochlorite.As a matter of fact, it has become evident that VHO pollution is wide-spread in every kind of water; while contamination of surface waters can only involve environmental and aquatic life, contamination especially of drinking waters, and also of swimming pool waters must be controlled as it can directly act on human health.     

pH adjustment in anaerobic digestion

In the pH range 6·0–7·5, the pH in anaerobic processes is controlled by the interaction of the carbonic system and a net strong base. The acid-base state of a digestor can be monitored by only measuring pH and CO₂ partial pressure. Shock doses of strong bases and carbonates causes temporary undersaturated CO₂ conditions and excessively high pH. Bicarbonate dosing leaves the CO₂ solubility equilibrium unchanged. In the absence of a CaCO₃ precipitation inhibiting agent. CaCO₃ solubility limits the pH, and Ca(OH)₂ dosing is unable to raise the pH significantly. Orthophosphates inhibit CaCO₃ precipitation. With [PO₄] > 1·0 × 10⁻³mole·1⁻¹. CaCO₃. precipitation is partially inhibited. Ca(OH)₂ dosing being approximately 45 per cent effective for doses up to 15000 mg 1⁻¹ as CaCO₃. At [PO₄] < 1·0 × 10⁻³moles·1⁻¹ orthophosphates eventually precipitate out during Ca(OH)₂ dosing, thus removing the inhibition mechanism: pH is then limited by the CaCO₃ solubility. Most wastes contain [PO₄] > 2·0 × 10⁻³moles·1⁻¹ making pH adjustment with Ca(OH)₂ possible to a pH of about 7·2 although the dosages will be very high. The pH changes in a process following dosing can be predicted by the graphical representation of the carbonic and net strong base systems.     

The use of uric acid as a method of tracing domestic sewage discharges in riverine, estuarine and coastal water environments

The chemical tracking of sewage effluents discharged into fresh and saline waters presents difficulties, especially in estuaries. The main difficulty is caused by the dissolved constituents being used to monitor the effluent also occurring naturally at similar levels. Uric acid is present at significant levels in untreated sewage and is not normally found in unpolluted waters. Until now no suitable routine method has been available for uric acid estimation in fresh and saline waters at levels normally encountered in the environment. In this paper we describe a recently developed technique using high-performance liquid chromatography which estimates uric acid in both fresh and saline waters in the range 1–10,000 μg l⁻¹ with a precision (2σ) of ±20% at 2 μg l⁻¹, ±4% at 40 μg l⁻¹ and ±2% at 10 mg l⁻¹.     

Electrodeposition of six heavy metals on reticulated vitreous carbon electrode

Six heavy metals, copper, cadmium, chromium, lead, uranium and zinc were deposited on cathodes made of a newly developed form of carbon, Reticulated Vitreous Carbon, in a laboratory scale electrochemical reactor. Different metals varied in the extent of their removal with copper depositing 100% at a flow rate of 0.24 cm min⁻¹ in a single pass while it would require a maximum of 20 passes for 100% chromium deposition at a flow rate of 1.8 cm min⁻¹, initial concentrations for both metals being 50 μmol 1⁻¹.Experiments conducted using 0.5 × 10⁻³ M CuSO₄ in 0.5 M Na₂SO₄ supporting electrolyte resulted in a mass transfer coefficient of the order of 10⁻³ cm s⁻¹ and a current efficiency of 64% for the electrodeposition of copper at a cell voltage of 4.0V. Because of very high porosity, 97%, high specific surface area, up to 66 cm² cm⁻³ for RVC grade 100, and useful electrochemical characteristics, RVC can be advantageously used as electrode material for heavy metal removal from dilute industrial effluents.     

Phthalic acid esters in water

Two phthalic acid esters, di(n-butyl)phthalate and di (2-ethylhexyl)phthalate, were surveyed in the river water, well water and city water of Tokyo metropolice area. In the river water these esters were found in the range of 0·4–6·8 μ gl⁻¹. The concentration was low in the upper reaches of the stream but increased downstream, giving no seasonal variation. The esters were not found in the well water examined. In the household tap water they were contained in the range of 1·2–3·3 μg l⁻¹ while in the raw water of water supply they were contained in the range of 1·9–8·2 μg l⁻¹. Results of jar test revealed that these esters were efficiently removed from water by using activated carbon or aluminium sulphate.