Predicting the bioaccumulation of polyaromatic hydrocarbons and polychlorinated biphenyls in benthic animals in sediments.

There were two main objectives in this study. The first was to compare the accuracy of different prediction methods for the chemical concentrations of polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the organism, based on the measured chemical concentrations existing in sediment dry matter or pore water. The predicted tissue concentrations were compared to the measured ones after 28-day laboratory test using oligochaeta worms (Lumbriculus variegatus). The second objective was to compare the bioaccumulation of PAHs and PCBs in the laboratory test with the in situ bioaccumulation of these compounds. Using the traditional organic carbon-water partitioning model, tissue concentrations were greatly overestimated, based on the concentrations in the sediment dry matter. Use of an additional correction factor for black carbon with a two-carbon model, significantly improved the bioaccumulation predictions, thus confirming that black carbon was important in binding the chemicals and reducing their accumulation. The predicted PAH tissue concentrations were, however, high compared to the observed values. The chemical concentrations were most accurately predicted from their freely dissolved pore water concentrations, determined using equilibrium passive sampling. The patterns of PCB and PAH accumulation in sediments for laboratory-exposed L. variegatus were similar to those in field-collected Lumbriculidae worms. Field-collected benthic invertebrates and L. variegatus accumulated less PAHs than PCBs with similar lipophilicity. The biota to sediment accumulation factors of PAHs tended to decrease with increasing sediment organic carbon normalized concentrations. The presented data yields bioconcentration factors (BCF) describing the chemical water-lipid partition, which were found to be higher than the octanol-water partition coefficients, but on a similar level with BCFs drawn from relevant literature. In conclusion, using the two-carbon model method, or the measured freely dissolved pore water concentrations method is recommended for predicting the bioaccumulation of PAHs and PCBs.

Determination of (mono-, di- and) tributyltin in sediments. Analytical methods.

Methods for the reliable determination of butyltin compounds in sediments are required for both national and international marine monitoring programmes. This evaluation of current commonly used approaches to the analysis identifies critical aspects of extraction, derivatisation, clean-up, separation, standardisation and detection with the objective of improving the analytical capabilities both of experienced laboratories and of those addressing the problems for the first time.

Semi-xylenol orange and its purification by high-pressure liquid chromatography.

By Mannich condensation of o-Cresol Red, iminodiacetic acid and formaldehyde, Semi-Xylenol Orange (SXO) has been prepared in a 10-hr batch-procedure with a yield of about 30%. From the crude product SXO has been isolated by reversed-phase HPLC with perchloric acid-acetone mixtures as the mobile phase and C(18)-bonded silica as the stationary phase. The SXO fraction was freed from accompanying perchloric acid by a second separation on the same column, with water as eluent. After elution with acetone, the SXO was crystallized by evaporation.

Simple and fast solvent extraction system for selective and quantitative isolation of adrenaline, noradrenaline and dopamine from plasma and urine.

A very simple solvent extraction system for the selective and quantitative isolation of adrenaline, noradrenaline and dopamine from plasma and urine is described. The extraction system makes use of the complex formation, in alkaline medium, between diphenylborate and the diol group in the catecholamines in combination with ion-pair formation. The influence of various parameters on the distribution coefficient was investigated by analysis of the liquid phases by high-performance liquid chromatography with electro-chemical detection. From these results the optimal extraction conditions can be selected. With hexane + 1% n-octanol containing 0.25% (w/v) of tetraoctylammonium bromide as extraction solvent, the catecholamines can be quantitatively isolated from plasma and urine at pH 8.6 in the presence of 0.1% (w/v) of diphenylborate. For urine the recovery was 101.5 + 1.9% for adrenaline, 100.6 +/- 2.0% for noradrenaline and 99.9 +/- 1.5% for dopamine. For plasma the recoveries were, respectively, 101.8 +/- 3.3%, 100.5 +/- 2.6% and 92.9 +/- 3.5%. The recovery of dihydroxybenzylamine, included in the study as internal standard, was determined to be 96.3 +/- 1.6% for urine and 89.9 +/- 2.7% for plasma. The applicability of the developed extraction system as clean-up and concentration step for the analysis of catecholamines in plasma and urine by high-performance liquid chromatography with electrochemical detection is demonstrated.