Laura Ortiz

Predicting single and mixture toxicity of petrogenic polycyclic aromatic hydrocarbons to the copepod Oithona davisae

In the present study, the acute toxicity of 10 polycyclic aromatic hydrocarbons (PAHs) associated with the Prestige fuel oil spill (Spain, 2002) were evaluated, either as single substances or in mixtures, in adults of the copepod Oithona davisae. All but dimethylphenanthrene had negative effects on O. davisae survival at concentrations below their water solubility, with 48-h median lethal concentrations for naphthalene and pyrene of 56.1 and 0.8 micromol/L, respectively, making these the least and most toxic compounds. Polycyclic aromatic hydrocarbons had narcotic effects on copepods, as evidenced by the lack of motility at lower concentrations than those causing death. Naphthalene showed the greatest narcotic effects, and phenanthrene showed minor effects. Acute toxicity of the tested PAHs was inversely related (r2 = 0.9) with their octanol-water partition coefficient, thereby confirming the validity of the baseline quantitative structure-activity regression models for predicting the toxicity of PAH compounds in copepod species. When supplied in mixtures, the toxic effect of PAHs was additive. These results indicate that the many PAHs in an oil spill can be considered unambiguous baseline toxicants (class 1) acting additively as nonpolar narcotics in copepods; hence, their individual and combined toxicity can be predicted using their octanol-water partition coefficient.

Determination of linear alkylbenzensulfonates in aqueous matrices by ion-pair solid-phase microextraction–in-port derivatization–gas chromatography–mass spectrometry

Trace determination (low ng/ml) of linear alkylbenzensulfonates (LASs) in water was achieved by solid-phase microextraction (SPME) of ion-pairs formed with tetrabutylammonium. This ion-pairing reagent served two purposes. First, it allowed the extraction of LAS with the polydimethylsiloxane fiber by counterion association and second, the derivatization of the formed LAS ion pairs in the GC injection port at 300 degrees C to form the corresponding sulfonated butyl esters. The methodology developed allows the isomer specific determination of LAS at low detection limits (0.16-0.8 ng/ml), depending on the alkyl chain lengths of LASs with RSDs of 10-12%. Furthermore, the developed methodology was applied to urban wastewater and sea water and compared with a solid-phase extraction (SPE) method (e.g. C18 and strong anion-exchange sorbent) to obtain concordant values for urban wastewater. Moreover, the developed SPME methodology overcame the procedural blank and matrix-dependent recoveries found in the SPE methodologies at low LAS concentrations.

Accumulation trends of petroleum hydrocarbons in commercial shellfish from the Galician coast (NW Spain) affected by the Prestige oil spill

Aliphatic and aromatic hydrocarbons were determined in three species of commercial shellfish, namely razor shells (Ensis arcuatus and Ensis siliqua), goose barnacle (Pollicipes cornucopia) and sea urchin (Paracentrotus lividus), living in different habitats and exhibiting different feeding behaviors. The samples were collected monthly, from January 2003 to October 2004, in three stations of the Galicia coast (NW Spain), following the Prestige oil spill, with the aim of assessing their response to the spill and, therefore, their suitability for monitoring purposes. The aliphatic fractions were mostly dominated by biogenic hydrocarbons, reflecting the diet composition of the organisms and their low metabolic capacity. The presence of oil was assessed by the determination of chemical markers. The analysis of the aromatic fractions revealed the occurrence of 3-6 ring parent and alkylated PAHs, consistent with a mixed petrogenic-pyrolytic origin, with the common feature of the predominance of chrysene in all samples collected after the spill. However, the distributions exhibited both temporal and interspecies variations. The PAH concentrations (Sigma13) increased significantly after the spill and decreased 6-7 months later close to background levels for the region. One year after the accident, the median values were: 58 microg/kg for razor shells, 26 microg/kg for barnacles, and 25 microg/kg for sea urchins. The temporal evolution of the PAH concentrations along the survey period was used to estimate loss rates for bioavailable PAHs in barnacles and sea urchins after the spill. Half-life values were in the order of 30 and 60 d, respectively. The results of the study demonstrate that barnacles can be suitable species for oil spill monitoring.

Physico-chemical characterisation of atmospheric aerosols in a rural area affected by the aznalcollar toxic spill, south-west Spain during the soil reclamation activities

High levels of atmospheric contamination due to the re-suspension of pyrite particles from the mining waste slurry were recorded in the Guadiamar valley (the Guadiamar is a tributary of the Guadalquivir river) after the toxic spill of Aznalcóllar, north of the Doñana Natural Park (SW Spain). Major high-particulate events occurred during the extraction of the pyrite-rich mud layer, which covered an extensive area of the valley downstream of the confluence of the Agrio and Guadiamar rivers. This study deals with the monitoring of the ambient air quality at two stations near the village of Aznalcázar in the central part of the flooded area. Although the Spanish legal limit for atmospheric particles and lead in environmental air were not exceeded, high daily levels of total suspended particles (TSP) and of some elements with an environmental significance (As, Cd, Cu, Mn, Ni, Pb, Sn, Tl and Zn) were recorded at Aznalcázar and in the Guadiamar valley during soil reclamation (July-August 1998). Despite a progressive decrease in TSP levels through September-October 1998, background was higher than the levels for the May-June period. Evolution of levels for most of the elements studied showed a similar trend. The exceptions were copper, which was partially increased by other emission sources such as fumigation activities, and sodium, which remained at relatively constant levels during the study period because of its marine origin. The physico-chemical characterisation of the atmospheric particulates allowed us to determine the major grain size modes of the pyrite related elements and the solubility of the potentially toxic elements, and to identify the major particulate types present in the atmosphere in the area. Secondary and tertiary aromatic amines (i.e. alkyldiphenylamines and phenylcarbazoles, respectively) were identified in the suspended particles and in the vapour phase collected at the same station as the TSP samples. As some of these aromatic amines had been previously identified in the pyrite sludge, it is assumed that fine sludge particles containing aromatic amines were re-suspended in the atmosphere. The highest concentrations of aromatic amines in the particulate phase were recorded in August 1998 during the pyrite slurry extraction in the proximity of the Aznalcázar sampling site. Despite a sharp drop in the suspended particles of the aromatic amine concentrations, a significant concentration was detected in the vapour phase (< 1.2 mm) during autumn, probably because of longer residence time in the atmosphere. Although health hazards associated with the presence of these aromatic amines are unknown, their acute toxicity exceeded that of urban aerosols.

Characterization of organic compounds in soil and water affected by pyrite tailing spillage

Abstract A variety of mono- and di-chlorinated and brominated triphenylamines were identified in the sludge and contaminated soils affected by a toxic waste spill that occurred in the Los Frailes pyrite mine (SW Spain). A negative gradient of aromatic amine concentrations from 29 μg g−1 in the vicinity of the broken dam to 0.14 μg g−1 in contaminated soils collected 30 km to the south in the Guadiamar River valley was observed. Substituted carbazoles (e.g. 9-phenylcarbazole) were also identified as contaminating sludge, soils and the temporarily dammed water at Entremuros and the Guadalquivir River and its tributary, the Guadiamar River. Our results demonstrate that contaminated waters from the pyrite sludge spill reached the Guadalquivir Estuary. However, the more lipophilic compounds, such as the halogenated triphenylamines, were not recorded in water bodies because of their strong adsorption by soils during the weathering process. Conversely, the more hydrophilic benzothiazoles were widespread in surface waters, a finding attributable to their higher solubility than chlorinated aromatic amines. Although the source of the nitrogen organic compounds (NOCs) has not yet been identified, it would seem to be related to the pyrite tail spillage. For example, degradation of technical products used in ore processing or industrial waste dumped in the mine waste collection dam could be the source of these compounds. Given the widespread occurrence of 9-phenylcarbazole in the affected area, this compound is proposed as a specific molecular marker of the Aznalcollar spill. Furthermore, some of the NOCs were identified in the contaminated waters of the Guadiamar and Guadalquivir Rivers, providing evidence that these rivers were affected by the mining spill. Taking into account the field concentrations (water, sludge) and the spill volume, it can be concluded that the budget of aromatic amines is in the range of 27 t — of this, 32.6% was in the aqueous phase and the remaining 67.4% was in the soil.

DETERMINATION OF ORGANOCHLORINE COMPOUNDS IN NEUSTON FROM THE MEDITERRANEAN

Abstract A reliable analytical procedure was developed to determine trace levels of organochlorine compounds in neuston samples. Freeze‐dried samples were extracted by sonication (3 × 15 ml cyclohexane, 15 min) followed by gel permeation chromatography (GPC) and gas chromatography electron capture detection (GC‐ECD) determination. Neuston samples may present great differences in their lipid content, which may become a drawback for the analytical determination of hydrophobic pollutants. In this way, GPC fractionation combined with Florisil® cleanup was successfully used to avoid potential lipidic interferences in the GC‐ECD determination. Organochlorine compounds were determined by GC‐ECD and a standard addition method was performed to evaluate the recoveries of 41 PCB individual congeners (80±20%). The congeners with lower Kow (octanal water partition coeeficient) values showed lower recoveries (54 ± 7%) than the more lipophylic ones (80 ± 7%). The limits of detection ranged from 0.001 to 0.211 ng g−1 of wet samples. The reproducibility of the developed analytical methodology for independent replicates (n = 3) at low pg g−1 levels was quite satisfactory (RSD 18 + 10%).