PAHs contamination in edible gastropods from north Patagonian harbor areas.

PAHs are persistent pollutants released into the environment by fossil fuels burning and leak during petroleum operations. Associated with suspended particles upon entering marine ecosystem are accumulated by benthic fauna. Human exposure occurs mainly from ingestion such as gastropods consumption. The objective was to determine PAHs in sediments and in the marine gastropod Buccinanops globulosus in sites with different maritime and urban influences. In sampling sites located 20 km from the harbor, PAHs were non-detected; while in harbor gastropods, the level of PAH4 was exceeded according to international normative. Level of dibenzo[a,h]anthracene in sediments was between the ISQG and PEL. Since these are the first results of PAHs in edible gastropods in South America, we concluded that PAHs can be dangerous for consumers according to ingestion frequency. Integrative studies are necessary to evaluate the interaction among pollutants in maritime areas and the incidence in human health due to shellfish consumption.

Fate of petroleum hydrocarbons in bioturbated pristine sediments from Caleta Valdés (Patagonia Argentina): An ex situ bioassay.

Petroleum can pollute pristine shorelines as a consequence of accidental spills or chronic leaks. In this study, the fate of petroleum hydrocarbons in soft pristine sediment of Caleta Valdés (Argentina) subject to ex situ simulated oil pollution was assessed. Sedimentary columns were exposed to medium and high concentrations of Escalante Crude Oil (ECO) and incubated in the laboratory during 30 days. Levels of aliphatic hydrocarbons at different depths of the sedimentary column were determined by gas chromatography. Oil penetration was limited to the first three centimetres in both treatments, and under this depth, hydrocarbons were clearly biogenic (terrestrial plants) as in the whole sedimentary column of the control assay. Bioturbation by macrobenthic infauna was strongly impacted by oil pollution which resulted in reduced sediment oxygenation and low burial of petroleum hydrocarbons. This may partly explain the limited hydrocarbon biodegradation observed, as indicated by the relatively high values of the ratios nC17/pristane, nC18/phytane, and total resolved aliphatic hydrocarbons/unresolved complex mixture. Correspondingly, at the end of the experiment the most probable number of hydrocarbon-degrading bacteria reached ~ 103 MPN g-1 dry weight. These values were lower than those found in chronically polluted coastal sediments, reflecting a low activity level of the oil-degrading community. The results highlight the low attenuation capacities of Caleta Valdés pristine sediments to recover its original characteristics in a short time period if an oil spill occurs. In this work, we present a novel and integrative tool to evaluate the fate of petroleum hydrocarbons and their potential damage on pristine sediments.

Organochlorine pesticides and PCBs in Southern Right Whales (Eubalaena australis) breeding at Península Valdés, Argentina.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were assessed in blubber from 35 dead Southern Right Whales (SRW - Eubalaena australis) stranded at Península Valdés, Argentina. The life cycle includes a feeding period in high productivity areas of the South West Atlantic and a reproductive period in coastal template waters of Argentina. Organochlorine pesticides showed higher concentrations (22.6±13.8 ng·g(-1)ww) than PCBs (7.5±10 ng·g(-1)ww). Among pesticides, HCHs, DDTs, endosulfans, dieldrin, chlordans, heptachlor epoxide, and trans-nonachlor were detected. p,p'-DDE and p,p'-DDT were present in 69% and 26% of samples, respectively. p,p'-DDT/p,p'-DDE ratio showed low values (<0.33) as a result of aged DDT inputs. However, the occurrence of only p,p'-DDT in some samples suggests a recent pesticide input. α-HCH/γ-HCH ratio (

Nutritive and xenobiotic compounds in the alien algae Undaria pinnatifida from Argentine Patagonia.

Seaweeds have been used as food since ancient times. The edible brown algae Undaria pinnatifida is native to northeast Asia; however, in 1992, the first specimens in Patagonian environments were found and, since then, have rapidly expanded. The main object of this study was to determine, for the first time in Argentina, the nutritive composition and concentrations of trace elements and hydrocarbons in these alien algae and evaluate their usefulness as food. Sexually mature U. pinnatifida samples were collected at 10-m depth in the Nuevo and San José gulfs. The first site is influenced by activities from Puerto Madryn city, and the latter place was considered as the control. Protein, dietary fiber, and mineral concentrations were similar in both gulfs and in the same order as in eastern countries. Crude protein, indigestible fiber, and calcium and magnesium concentrations were greatest in blade; lipid concentration was greatest in sporophyll; and sodium and potassium concentrations were greatest in midrib. Amino acids showed the greatest concentrations in blades, and these were greater than those reported in kelp from Japan. Cadmium (Cd), arsenic, mercury, and hydrocarbons were detected, but only Cd showed concentrations that could be a risk for consumption. In Argentina, maximum acceptable levels of these contaminants in seaweeds are not established.

Biodegradation pattern of hydrocarbons from a fuel oil-type complex residue by an emulsifier-producing microbial consortium.

The biodegradation of a hazardous waste (bilge waste), a fuel oil-type complex residue from normal ship operations, was studied in a batch bioreactor using a microbial consortium in seawater medium. Experiments with initial concentrations of 0.18 and 0.53% (v/v) of bilge waste were carried out. In order to study the biodegradation kinetics, the mass of n-alkanes, resolved hydrocarbons and unresolved complex mixture (UCM) hydrocarbons were assessed by gas chromatography (GC). Emulsification was detected in both experiments, possibly linked to the n-alkanes depletion, with differences in emulsification start times and extents according to the initial hydrocarbon concentration. Both facts influenced the hydrocarbon biodegradation kinetics. A sequential biodegradation of n-alkanes and UMC was found for the higher hydrocarbon content. Being the former growth associated, while UCM biodegradation was a non-growing process showing enzymatic-type biodegradation kinetics. For the lower hydrocarbon concentration, simultaneous biodegradation of n-alkanes and UMC were found before emulsification. Nevertheless, certain UCM biodegradation was observed after the medium emulsification. According to the observed kinetics, three main types of hydrocarbons (n-alkanes, biodegradable UCM and recalcitrant UCM) were found adequate to represent the multicomponent substrate (bilge waste) for future modelling of the biodegradation process.

Biodegradation of bilge waste from Patagonia with an indigenous microbial community.

Oily residues that are generated in normal ship operation are considered hazardous wastes. A biodegradation assay with autochthonous microbiota of Bilge Waste Oily Phase (BWOP) was performed in a bioreactor under controlled conditions. Petroleum, diesel oil, and PAH degraders were isolated from bilge wastes. These bacteria belong to the genus Pseudomonas and are closely related to Pseudomonas stutzeri as shown by 16S rDNA phylogenetic analysis. The indigenous microbial community of the bilge waste was capable of biodegrading the BWOP (1% v/v) with biodegradation efficiencies of 70% for hexane extractable material (HEM), 68% for total hydrocarbons (TH) and 90% for total aromatics hydrocarbons (TA) in 14 days. Solid phase microextraction (SPME) was successfully applied to evaluate hydrocarbon evaporation in a control experiment and demonstrated a mass balance closure of 88%. The SPME and biodegradation results give useful information to improve and scale up the process for BWOP treatment.

Natural and anthropogenic hydrocarbons in sediments from the Chubut River (Patagonia, Argentina).

In March of 2001 a study was carried out to evaluate hydrocarbon levels in the lower course of the Chubut River. The study included 12 sample stations along the river from San Cristóbal Bridge to the confluence with the sea, in a 25 km straight-line extension in a urbanized area. In the first 11 stations, resolved aliphatic (RAli) hydrocarbons presented low values, between 0.07 and 0.96 microg/g dry weight (dw); the unresolved complex mixture (UCM) between 0.42 and 2.72 microg/g dw, and the total aliphatic (TAli) hydrocarbons between 0.55 and 3.07 microg/g dw. In the last station, at the mouth of Chubut river, these values increased to 460, 284, and 741 microg/g dw for RAli, UCM and TAli, respectively. The n-alkanes distribution indices and the compositional parameters suggested a predominantly biogenic origin in eleven stations, and a predominantly anthropogenic origin in the last station, with the highest hydrocarbon values. It is possible to conclude that the stations with low hydrocarbon values and biogenic origin predominance would constitute the baseline of aliphatic hydrocarbons for river sediments at this zone. The station with the highest hydrocarbon concentration and predominantly anthropic origin was related to the presence of Rawson city's port, where its activities (harbor and fishing vessels) generate hydrocarbon wastes unrelated to the river base profile in the study zone. Offshore, but within the river influence, there is an important fishing area of Argentine Red and Patagonian shrimps (Pleoticus muelleri and Artemesia longinaris, respectively).

Microbial characterization and hydrocarbon biodegradation potential of natural bilge waste microflora.

Shipping operations produce oily wastes that must be managed properly to avoid environmental pollution. The aim of this study was to characterize microorganisms occurring in ship bilge wastes placed in open lagoons and, particularly, to assess their potential to degrade polycyclic aromatic hydrocarbons (PAHs). A first-order kinetic was suitable for describing hydrocarbon biodegradation after 17 days of treatment. The calculated rate constants were 0.0668 and 0.0513 day(-1) with a corresponding half-life of 10.3 and 13.5 days for the aliphatic and aromatic hydrocarbon fractions, respectively. At day 17, PAH removal percentages were: acenaphtylene 100, fluorene 95.2, phenanthrene 93.6, anthracene 70.3, and pyrene 71.5. Methyl phenanthrene removals were lower than that of their parent compound (3-methyl phenanthrene 83.6, 2-methyl phenanthrene 80.8, 1-methyl phenanthrene 77.3, 9-methyl phenanthrene 75.1, and 2,7-dimethyl phenanthrene 76.6). Neither pure cultures nor the microbial community from these wastes showed extracellular biosurfactant production suggesting that the addition of an exogenously produced biosurfactant may be important in enhancing hydrocarbon bioavailability and biodegradation. DNA analysis of bilge waste samples revealed a ubiquitous distribution of the nahAc genotype in the dump pools. Although almost all of the isolates grew on naphthalene as sole carbon source, only some of them yielded nahAc amplification under the experimental conditions used. The variety of PAHs in bilge wastes could support bacteria with multiple degradation pathways and a diversity of catabolic genes divergent from the classical nah-like type.

Enhancement of hydrocarbon waste biodegradation by addition of a biosurfactant from Bacillus subtilis O9.

A non-sterile biosurfactant preparation (surfactin) was obtained from a 24-h culture of Bacillus subtilis O9 grown on sucrose and used to study its effect on the biodegradation of hydrocarbon wastes by an indigenous microbial community at the Erlenmeyer-flask scale. Crude biosurfactant was added to the cultures to obtain concentrations above and below the critical micelle concentration (CMC). Lower concentration affected neither biodegradation nor microbial growth. Higher concentration gave higher cell concentrations. Biodegradation of aliphatic hydrocarbons increased from 20.9 to 35.5% and in the case of aromatic hydrocarbons from nil to 41%, compared to the culture without biosurfactant. The enhancement effect of biosurfactant addition was more noticeable in the case of long chain alkanes. Pristane and phytane isoprenoids were degraded to the same extent as n-C17 and n-C18 alkanes and, consequently, no decrease in the ratios n-C17/pri and n-C18/phy was observed. Rapid production of surfactin crude preparation could make it practical for bioremediation of ship bilge wastes.