Ian D. Brindle

Identification and screening analysis of halogenated norbornene flame retardants in the Laurentian Great Lakes: Dechloranes 602, 603, and 604.

Dechlorane (Dec) 602, Dechlorane (Dec) 603, Dechlorane (Dec) 604, and Dechlorane Plus (DP) are flame retardant substitutes for mirex. Dec 602, 603, and 604 were detected in sediment and fish from the Laurentian Great Lakes. Lake Ontario surface sediments had the highest concentrations of Dec 602 and 604 at 6.0 and 4.0 ng/g dry weight, respectively. Temporal analysis of a Lake Ontario sediment core indicates that Dec 602 and 604 trends are similar to DP peaking in the early 1980s. Lake trout and whitefish from Lake Ontario also had the highest concentrations of Dec 602 and 604 at 34 and 1.2 ng/g lipid. Concentrations of Dec 602 were higher than those of DP in all fish samples, indicating that Dec 602 is likely more bioavailable and/or more readily bioaccumulates than DP. Spatial trends for Dec 602 and 604 in sediment and fish indicate that manufacturing plants along the Niagara River upstream of Lake Ontario were important sources of Dec 602 and 604 to the Great Lakes, while Dec 603 in the Great Lakes is likely from atmospheric deposition. The findings of this first report of Dec 602, 603, and 604 in the Laurentian Great Lakes basin suggests further investigation of halogenated norbornene flame retardants in the environment is merited.

Reduction of interferences in the determination of germanium by hydride generation and atomic emission spectrometry

Abstract Effects of interferences and methods for the reduction of interferences in the determination of germanium were studied. Simultaneous signal enhancement and reduction of interference were achieved using l -cysteine, l -cystine, penicillamine and thioglycerol. Amino acids such as glycine and alanine showed some capacity to reduce interferences, but this was both different in mechanism from, and inferior to, the reagents mentioned above. Histidine, on the other hand, proved to be superior to l -cysteine in its ability to reduce interferences from high levels of nickel. Sodium citrate, sodium oxalate, thiourea and thiosemicarbazide also reduced interferences to some extent. Mechanisms are proposed to explain reduction of interferences and enhancement of signals by the thiol-containing compounds and to explain the behaviour of amino acids as interference-reducing reagents.

Historic trends of dechloranes 602, 603, 604, dechlorane plus and other norbornene derivatives and their bioaccumulation potential in lake ontario.

Temporal trends and seasonal variation of Dechloranes (Dec) 602, 603, 604, and Chlordene Plus (CP) in Niagara River suspended sediment, a Lake Ontario sediment core, and Lake Ontario lake trout were investigated, with Mirex and Dechlorane Plus (DP) included for comparison. Temporal concentration trends were generally consistent in each of the media for all compounds with the lowest concentrations observed in or after the late 1990s. In Niagara River suspended sediments, all compounds showed seasonal variation over a year with distinct profiles observed. The relative concentration patterns observed were total DP > Mirex > Dec 602 and Dec 604 > Dec 603 > CP in suspended sediments and sediment cores, whereas Mirex was highest in lake trout, followed by Dec 602 and DP. Dec 602 concentrations were 50 to 380 times greater than those of DP in lake trout, indicating Dec 602 has a greater bioaccumulation potential. The estimated biota-sediment accumulation factor (BSAF) for Dec 602 was much greater than for DP in Lake Ontario, and was greater than those calculated for PBDEs, indicating that assessment of some dechlorane compounds is merited if use is ongoing or planned.

Liquid chromatography-atmospheric pressure photoionization tandem mass spectrometry for analysis of 36 halogenated flame retardants in fish.

A comprehensive, sensitive and high-throughput liquid chromatography-atmospheric pressure photoionization tandem mass spectrometry (LC-APPI-MS/MS) method has been developed for analysis of 36 halogenated flame retardants (HFRs). Under the optimized LC conditions, all of the HFRs eluted from the LC column within 14min, while maintaining good chromatographic separation for the isomers. Introduction of the pre-heated dopant to the APPI source decreased the background noise fivefold, which enhanced sensitivity. An empirical equation was proposed to describe the relation between the ion intensity and dopant flow. The excellent on-column instrument detection limits averaged 4.7pg, which was similar to the sensitivity offered by gas chromatography-high-resolution mass spectrometry (GC-HRMS). This method was used to analyze a series of fish samples. Good agreement was found between the results for PBDEs from LC-APPI-MS/MS and GC-HRMS.

A new continuous hydride generator for the determination of arsenic, Antimony and tin by hybride generation atomic absorption spectrometry

Abstract A new continuous hybride generator is described. Its characteristics are compared with a conventional hybride generator for the determination of arsenic, antimony and tin by using flame atomic absorption spectrometry. This simple hybride generator combines hybride production and gas-liquid separation in one unit, obviating the use of a separate mixing/reaction coil and gas-liquid separator. Radioactive tracer studies show that a hybride generation efficiency of over 95% is achieved with the new hybride generator and that approximately 90% of monomethylarsonic acid (MMA) is converted to its hybride (methylarsine) within the first 10 s of the hybride generation reaction. Compared to a conventional hybride generator, an improved signal-to-noise ratio is achieved and comparable or less interference from transition metal ions is observed. Cysteine (1% in the sample solution) is effective in reducing interferences during the hybride generation processes. In the presence of cysteine, 10–1000 fold higher amounts of Ni2+, Co2+ and Cu2+ are tolerated in the determination of arsenic, antimony and tin. Cysteine also enhances the signals of arsenic, antimony and tin by 60, 200 and 40%, respectively. Reaction conditions were optimized by using both the simplex optimization method and one-factor-at-a-time method and results are in good agreement.

Dechloranes 602, 603, 604, Dechlorane Plus, and Chlordene Plus, a newly detected analogue, in tributary sediments of the Laurentian Great Lakes.

A chlorinated compound (Chlordene Plus, CP), structurally related to Dechloranes (Dec) 602, 603, 604, and Dechlorane Plus (DP), was identified, and concentrations and spatial trends of Dec 602, 603, 604, CP, and DP in tributary sediments of the Laurentian Great Lakes are reported. The dechloranes were widely detected with their concentrations varying considerably across the Great Lakes basin. Spatial trends of Dec 602, 604, and DP in Canadian tributary sediments were similar to that of BDE 209, which suggested these flame retardant chemicals in tributaries were associated with industrial and urban areas. The highest concentrations of Dec 602, 604, and DP observed in tributaries of the Niagara River confirmed that past or ongoing manufacturing of these compounds at plants along the river were important sources to Lake Ontario. Dec 603 was detected in technical products of aldrin and dieldrin, and its spatial trend was consistent with historic pesticide usage. Similarly, CP was detected in technical products of chlordene and chlordane, and it was found in higher concentrations in sediments near urban areas, possibly related to past chlordane use in home termite control.

Evidence of Teratogens in Sediments of the Niagara River Watershed as Reflected by Chironomid (Diptera: Chironomidae) Deformities

Chironomids from two locations in an IJC “Area of Concern” in the Niagara River watershed and from one site in Lake Huron were sampled and classified as either normal or abnormal based on their menta (“teeth”) deformities. The two Niagara River sites were the Kings Bridge reference site and the Kane Dock coal tar contaminated area. The latter site was immediately downstream of an abrasives company located about 800 m downstream of the Kings Bridge reference site. Among the 739 chironomids sampled from the Kings Bridge reference site, 3.1% (23) possessed menta with deformities. This deformity frequency was similar to the 2.8% deformity frequency observed in a clean water site in Lake Huron. Chironomids removed from the coal tar contaminated site displayed a deformity frequency of 14%. The dominant invertebrate in the coal tar (PAH) contaminated sediments was the midge (Chironomus anthracinus), a non-biting fly larva referred to as a blood worm. Thus there was a significantly higher frequency of menta deformities downstream of the abrasives manufacturers discharge than at the Kings Bridge reference site (Students “t” test, P < 0.05). The chironomids at the contaminated site were themselves contaminated with elevated levels of fifteen different PAHs. The PAH levels in the bodies of the deformed chironomids were higher than the levels in the undeformed chironomids collected at the same site. When over 200 chironomids with an average deformity frequency of 7.7% were taken from the PAH contaminated site and placed in clean (PAH uncontaminated) sediments taken from the Kings Bridge Park reference site, the resulting F1 generation displayed a mentum deformity frequency of 4%. These rearing experiments indicated that few, if any, of the observed C. anthracinus menta deformities were passed on to the next generation.

A new sample introduction system for atomic spectrometry combining vapour generation and nebulization capacities

The Multimode Sample Introduction System™ (MSIS™, patent pending), a system that combines the benefits of nebulization and vapour generation in a single device, is described. MSIS™ delivers detection limits 10- (for Te at 238.578 nm) to 90-fold (for Sb at 217.582 nm) lower than conventional nebulization for a variety of elements that can be transformed into volatile species by reduction of aqueous ions, in the appropriate oxidation state, with tetrahydroborate(III). The device provides similar sensitivities and significantly improves precision compared with a frit-based gas–liquid separator for hydride-forming elements. In addition, the device minimizes the transfer of solution from the vapour generation process to the excitation source but retains similar efficiency of mass transfer when used for conventional nebulization. MSIS™ can be operated as either a vapour generator or as a conventional spray chamber, separately or simultaneously, while retaining the sensitivity and detection limits of both modes of sample introduction.

Combined generator/separator for continuous hydride generation: application to on-line pre-reduction of arsenic(V) and determination of arsenic in water by atomic emission spectrometry

A continuous hydride generator is described which incorporates a combined generator/separator. The low acid concentrations necessary in the tetrahydroborate(III)—L-cystein mediated determination of most hydride-forming elements require that the gas is purged from solution. As the hydride transfer reaction is so rapid, this allows both the hydride-forming reaction and the stripping reaction to take place in the same vessel. The system has been further modified to allow on-line pre-reduction of arsenic(V) to arsenic(III) by L-cysteine. Detection limits for arsenic, germanium and selenium are 4, 0.3 and 8 ng ml–1, respectively, at a sample flow rate of 15 ml min–1. Application of the system to the determination of arsenic in water is described. Concentrations of arsenic in several Ontario waters were found to be in the range 7–600 ng ml–1, Interferences from nickel and palladium, two of the most strongly interfering elements in the continuous hydride generation process, are diminished to a greater extent with the system described here than with the conventional high acid continuous system.

Combined generator/separator. Part 2. Stibine generation combined with flow injection for the determination of antimony in metal samples by atomic emission spectrometry

Application of a new continuous hydride generator to the determination of antimony in metals by flow injection is described. A modified hydride generator/gas–liquid separator has been designed. The detection limit for antimony is 7.5 ng cm–3 for a 0.5 cm3 sample. For solutions containing 200 ng cm–3 of antimony, the relative standard deviation is 0.9%. Reduction of antimony(V) to antimony(III) is effected by off-line pre-reduction with L-cysteine. L-Cysteine also accelerates the tetrahydroborate(III) reaction and reduces interferences from transition elements and, with the exception of selenium, other hydride-forming elements. Results are reported for the determination of antimony in iron and copper samples.