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Aquaculture activities in southern Chile demand floating devices to produce electricity powered by diesel generators. It has been recently proposed to replace this fuel with propane. However, little is known about the behaviour and possible environmental impacts of an accidental release of propane underwater. In this study we evaluated the impact of water temperature and salinity on the saturation and further release of propane under controlled laboratory experiments. Results showed that under extreme environmentally relevant scenarios (high and low temperature and salinity), propane saturated the water more quickly. However, while it is important to consider that saturation times can be similar (∼2 h), the magnitudes of propane dissolved can be different. Experiments showed that cold waters (5 °C) propane is dissolved twice than warm waters (20 °C). Residence time was more affected by water temperature and almost independent of water salinity. Propane may take at least 2 days to be released from waters (around 90% of the initial amount dissolved under laboratory conditions). Additionally, we evaluated the impact on dissolved oxygen displacement and the embryotoxicity of the dissolved fraction by using Zebrafish Embryo Toxicity Assay. Results showed that dissolved oxygen was quickly removed. However, the levels of dissolved oxygen were promptly recovered in the studied systems. We also observed that propane can generate genotoxic effects (3–10% mortality), but after 2 days the system can be almost free of propane and the effects may become much lower. Comparatively with the literature, propane showed to be less toxic than diesel and it is a viable and less environmentally hazardous replacement for diesel.

Fine particulate matter in the atmosphere, especially the fraction less than 2.5 µm in diameter (PM2.5), arises from several sources. Assessing the relative contributions from each source may be modeled through a mixing method, where the chemical signatures of known sources are mixed in a variety of proportions to provide the best explanation of the measured data. Alternatively, unmixing models determine what the chemical composition of the end members must have been in order to produce the observations. This study uses three different unmixing models with both a synthetic and a real-life (environmentally measured) alkane dataset from PM2.5 collected in five locations in Chile. Polytopic vector analysis (PVA), positive matrix factorization (PMF), and UNMIX modeling were used with ∼300 samples collected across 18 months. Using the synthetic data, both PVA and PMF were able to satisfactorily reconstruct the initial sources and their contribution to the samples, with PMF marginally more accurate than...

Airborne particulate matter (PM2.5) are known environmental cotaminants. Nevertheless, it is not only the size of particulate matter that influences human health, but also its chemical composition. The chemical composition of the PAH suite in PM2.5 may be indicative of the source materials, typically combustion products. In this study, particulate matter (PM2.5) was collected using portable air samplers during all of 2013 and 2014 at five locations of the Los Rios Region, Valdivia, Chile. The quantity of PM2.5 collected was measured using gravimetric methods. Solvent extracts were analyzed for associated PAHs by means of GC-MS techniques. The concentrations of PM2.5 for all locations ranged from 2.8 to 386 µg/m3 for the autumn/winter periods and from 1.1 to 315 µg/m3 for the spring/summer periods. The mean concentrations of PM2.5 ranged from 11.9 to 112 µg/m3 in summer for all sites. The concentrations of PAHs for all locations ranged from 2.8 to 115 ng/m3 for the autumn/winter periods and from 0....

Fatty alcohol-based surfactants are widely used in detergents and personal care products; they are typically disposed of down-the-drain and are degraded or removed during wastewater treatment. Analytical data had shown concentration and profile differences between regions of the United States. Market sales data were purchased relevant to the sampling dates. In combination with analysis of the fatty alcohol profiles in the top selling products, the influent profiles were reconstructed and compared to the whole U.S. sales data. The per capita usage rate for fatty alcohols through these 4000+ top selling products was 4.9 g per day, with 88% arising from liquid laundry detergents and hand dish detergents. This extrapolates to a national usage of 185,000 tonnes per year. There were significant differences in the purchasing habits of the inhabitants across the four regions sampled, although this had minimal impact on the fatty alcohol profile which was dominated by the C12 moiety. The U.S. market was also dominated by petrochemically-sourced chemicals. This market forensics approach using purchased sales data was able to extend our knowledge of the fate of these chemicals without a major (expensive) sampling and analytical campaign.

The formation of trihalomethanes (THMs) during water disinfection is related to several parameters such as water temperature, free chlorine and availability of dissolved organic matter. This paper compares and quantifies the THMs in drinking water from Concepcion city in the Bio Bio Region of central Chile, during summer of 2007 and autumn–winter 2008. THM concentrations in the source water were low (0.001–0.023 μg L−1). The concentration ranges in summer sampling period for the drinking water were 9.7–111.6, 0.1–1.0 and 0.9–25.5 μg L−1 for chloroform (CHCl3), and dibromochloromethane (CHClBr2) and bromodichloromethane (CHCl2Br), respectively; and 5.4–182.0, 0.1–0.9, 0.9–35.2 μg L−1 respectively for the autumn–winter sampling period. Bromoform was not detected in any sample. There were significant correlations between the THMs concentration and residence time of the water into the network, distance from the treatment plant and an inverse correlation to free chlorine and UV absorbance. In this system, temperature was not a major factor in the THM concentrations at the point of use although lower overall concentrations were measured in summer. The Additive Toxicity Index Value (0.07–1.4) for winter samples indicated that the Chilean Norm was exceeded at the more distant water utilisation points, where the residence time in the system was >600 minutes. This was not the case in summer as utilisation rates were greater reducing the residence times. Dichloromethane (DCM) was also detected at elevated concentrations in the water supply and exceeded the Chilean Norm (20 μg L−1) at all points in the system, up to 12 times, and may pose more of a health risk than the THMs.

The occurrence of airborne particulate matter has been flagged as "of concern" in several megacities, especially in Asia. Selected Chilean regions have similar problems as wood burning is the major source of heating in homes. This concern has led to mitigation measures restricting the burning of wood at periods when the particulate matter smaller than 2.5 μm (PM2.5) concentrations are predicted to be high. This work investigates the linkage between indoor and outdoor particle concentrations, determines their source through the polyaromatic hydrocarbon (PAH) signature and investigates the efficacy of the current management practice of burning restrictions. The PM2.5 fraction was collected at 12 different properties with coincident indoor and outdoor sampling using a low-volume active sampler for 24 hours. Indoor concentrations of PM2.5 ranged from 6 to 194 μg m(-3) with a mean of 72 μg m(-3) and corresponding outdoor concentrations ranged from 5 to 367 μg m(-3) with a mean of 85 μg m(-3) over the winter periods of 2014 and 2015; the Chilean national permitted maximum in outdoor air is 50 μg m(-3) in 24 hours. Higher concentrations were measured when the outdoor air temperature was lower. The PAHs were analysed on the PM2.5 fraction; the indoor concentrations ranged from 2 to 291 ng m(-3) with a mean of 51 ng m(-3) compared to an outdoor concentration between 3 and 365 ng m(-3) with a mean of 71 ng m(-3). Multivariate statistical analysis of the PAH profiles using principal components analysis (PCA) and polytopic vector analysis (PVA) identified wood burning, static and mobile diesel emissions and kerosene combustion as the major contributors to the particulate matter. When converted to toxicity equivalents (BaP-TEQ), the highest toxicity arising from PAHs in the indoor air was associated with a property that used a "leaky" combined wood stove and heater and also used a wood-fired brazier for local heating. In outdoor air, there was a relationship between the housing density and the BaP-TEQ, such that denser housing had higher BaP-TEQ values. The restrictions in wood burning on selected days may have had a measureable effect on the PM2.5 concentrations in that region but the effects were small and only present for the day of the restriction.

Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzo-p-furans (PCDF) are widely distributed in the environment. The diverse production processes that form these compounds lead to a range of chemical signatures although weathering may cause changes to these signature over time and with increasing distance from their origin. Chemical signatures in sediments based on 17 PCDD/Fs were developed in Concepcion, a Chilean city in the middle of a complex hydrological system which contains several small urban freshwater bodies and the River Bio-Bio. The region has numerous industrial and domestic activities that may contribute PCDD/Fs to the environment. Sediments from urban lakes had higher concentrations of dioxins and furans (mean = 941 ng·kg− 1) than either a remote lake (335 ng·kg− 1) located 32 km from the city or marine samples (mean = 124 ng·kg− 1). Up to 85% of the compounds present in all sediment samples could be explained by the chemical signature associated with airborne particulates leaving only 15–30% of the chemical signature potentially arising from other sources. The remote lake had higher proportions of the less-chlorinated compounds compared to the urban samples.

There are many approaches to the investigation of oil spills, but many share the same purpose of identifying the source of the oil and determining how much oil came from the spill versus other potential sources. This chapter outlines a few of the established multivariate methods that may assist with such aims. Principal components analysis (PCA) is useful for aggregating both samples that have similar compositions and compounds that are behaving similarly in the environment, but on its own, it does not quantify how much of any one source is present in a sample. Other approaches such as polytopic vector analysis (PVA) are particularly good at this although as with any such statistical tool, knowledge of the chemistry and the environment is necessary to achieve a sensible resolution. These methods are compared to traditional univariate or bivariate methods of determining the changes in oil chemistry over time and additionally highlight the problem of multiple oils at different stages of degradation.

The concentration and signature of n-alkanes (n-C10 to n-C33) and 18 PAHs were determined in air filters across a year period (2010) in an urban area of the city of Valdivia, Chile. Filter samples were extracted using sohxlet apparatus and analyzed by GC-MS techniques. Concentrations of total hydrocarbons ranged from 45–352 ng.m−3 and total PAHs ranged from 2.93–78.01 ng.m−3. Concentrations of hydrocarbons during the summer were high (288–352 ng.m-3) and reduced when the autumn began (45–79 ng.m−3) to then increase almost linearly to the next summer. The drop in concentration was attributed in part to the significant reduction of traffic when summer ends as tourists leave the city (about 9–15% of the total cars circulating). Results from the chemometric technique of Polytopic Vector Analysis (PVA) indicated three main sources for the alkanes: biogenic (terrestrial plants), signatures of oil combustion, and an unconfirmed source which is thought to come from non specific organic matter degradation. Total P...

Advances in analytical chemistry have led to numerous low-level observations of consumer product ingredients in environmental media. A “market forensics” approach complementary to a typical sampling and analysis campaign is described using readily available product formulation and market sales data to estimate the “down-the-drain” load to a wastewater treatment facility. A case study for common cleaning product ingredients is provided for a site in the USA. A regional per capita daily use rate was derived (0.33 g/ person/day) and applied to the residents resulting in an estimated daily influent load (2 kg). A single product type, liquid laundry detergent, was found to contribute 69% of the load alone.

Experiments with microcosms of sand corresponding to high, mid and low intertidal area were contaminated with crude oil and treated with biosolvent. Two treatments were done. The first (treatment 1) treating the sand 5 days before the event of contamination and the second (treatment 2) treated immediately after the contamination. The degradation of total TPH after 90 days ranged from 44 to 78%. However, the first 10 days were very important in terms of degradation and it slowed down significantly until 90 days. The degradation rate for light fractions in treatment 1 was slightly slower than treatment 2. On the other hand, for heavier fractions the degradation rate of heavier fractions in treatment 1 was at least twice as faster than treatment 2. Implicating that pre-treating the samples with biosolvent some days before the event of contamination may accelerate the degradation process of heavier fraction that are more difficult to degrade. The biosolvent used was degraded in a range from 55 to 100% showing that the biosolvent employed was biodegradable.

The permafrost is under considerable pressure at the moment. Global temperature increases are leading to changes in the whole global ecosystem but the Polar Regions appear to be bearing the brunt o...

Formation of trihalomethanes (THMs) during water disinfection has been related to several health problems, although the magnitude of these effects is under discussion. This paper quantifies the THMs in drinking water from the Bio-Bio Region of central Chile, the first since the modification of the national reference value (Nch 409/05) to include maximal values for THMs. THMs were quantified using a solid phase micro-extraction (SPME) method and GC-MS. The concentration ranges were 9.7-111.6, 0.1-1.0 and 0.9-25.5 μg/L for chloroform (CHCl 3 ), and dibromochloromethane (CHClBr 2 ) and bromodichloromethane (CHCl 2 Br), respectively. Bromoform was not detected in any sample. There were good correlations (R 2 =0.91-0.98, P< 0.001) between the THMs and the residence time of the water, the distance from the treatment plant and an inverse correlation to free chlorine in the water. The Additive Toxicity Index Value (0.07-1.00) showed that all samples were within the Chilean reference value for THMs in drinking water. However, several values were close to exceeding the maximum permitted concentration (200, 100, 100 and 60 μg/L for CHCl 3 , CHBr 3 , CHClBr 2 and CHCl 2 Br, respectively), which may occur when the water demand is low and thus residence times are longer.

Analyses of trace metals in benthic sediments from selected fjords and channels between 41 degrees 30' and 46 degrees 50'S, 75 degrees -72.3 degrees W were made after the CIMAR 1 Fjords expedition co-ordinated by CONA-Chile in 1995; the metals analyzed include Ba, Cd, Co, Cr, Cu, Ni, Pb, Sr, V and Zn. The objective of this study was to establish baseline values for these metals and to compare them with similar studies made in comparable, but geographically distinct, environments. Box core samples were collected at 35 stations and metal analysis was by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) using the MESS-2 reference standard. The ranked abundance by metal was Ba >> Sr >> V > Zn > Cr > Cu approximately Ni approximately Pb > Co >> Cd; these metals were not homogenous across the region and coefficients of variation were >10%. There were distinct groupings by metal and geographical area including the fjords, basins and channels. Depth profiles of the metal concentrations also varied spatially, e.g. Guafo, Laguna San Rafael, Moraleda, Corcovado, Quitralco, and Jacaf were predominantly homogeneous with depth profiles indicative of pristine systems experiencing few human impacts. In contrast, Aysen, Cupquelan and Puyuguapi Fjords had higher concentrations towards the surface, indicating elevated inputs in recent years. No major differences in metal content of the sediments were observed when compared with values from comparable natural systems in the northern hemisphere. Principal component analysis (PCA) grouped several seemingly isolated locations as having the same metal signature and indicated the pattern of dispersion across the region.

Surface seawater samples were collected in the Irish Sea and Liverpool Bay area from the R.V. Prince Madog during the period of 25–31 of March 2006. VOCs were purged with nitrogen, pre-concentrated on a SPME fibre and analysed immediately on a GC–MS. Target compounds quantified were halogenated (0.2–1400 ng L −1 ), BTEXs and mono-aromatics (1.5–2900 ng L −1 ), aliphatic hydrocarbons and others (0.6–15,800 ng L −1 ). Day and night sampling was performed at a single station and suggested that factors such as sunlight and tide affect the presence of many of these compounds. Sample variability was high due to the variable weather conditions at the station. Poor correlations were found between marine phytopigments and selected VOCs. Principal component analysis (PCA) analysis showed that chlorinated compounds such as 1,2-dichloroethane, 1,1,1-trichloroethane, trichloroethene, tetrachloroethene and carbon tetrachloride, predominantly from anthropogenic sources, originated from the River Mersey. Other brominated and iodinated compounds quantified were more likely to be from biogenic sources including novel marine compounds such as 2-chloropropane, 1-bromoethane and 1-chlorobutane.

The spatial and temporal variation of phytoplankton pigments in the western part of Ria Formosa, Portugal, was investigated between September 2000 and July 2002. Sampling stations included the ocean boundary (Ancao inlet) and two different landward boundary situations: 1) the shallow westernmost “blind end” of the lagoon (Ponte) and 2) near a main sewage outlet (Ramalhete). Nutrient concentrations were higher during the first year of sampling but were lower than those recorded in previous studies. This decrease in the concentration of nutrients was possibly the result of the 1997 relocation of the Ancao inlet, which allowed better water circulation in the lagoon. Throughout this study, concentrations of chlorophyll a determined by high-performance liquid chromatography were consistently low. Inter-annual variability in the pattern of chlorophyll a concentration was observed in the form of a bimodal peak (spring/summer and autumn) between September 2000 and June 2001 and more uniform concentrations from Se...

The concentrations of 16 individual polycyclic aromatic hydrocarbons (PAHs) were measured in sediments from eight locations in the Ria Formosa Lagoon (Portugal) between January and August 1995. Total PAH concentrations were higher in January than in the other months and were related to the higher sedimentary organic carbon content in the winter. The distribution pattern of the individual PAHs was generally dominated by the 4-aromatic ring PAHs, followed by the 2 + 3-aromatic ring PAHs. Fluoranthene, pyrene, and acenaphthene were the most abundant individual PAHs. Principal components analysis revealed that PAHs in the Ria Formosa Lagoon vary by season rather than location. This variation was related to changes in the source term. In the winter, PAH sources were mainly of pyrolytic origin, probably transported by road runoff. In the other months, and especially in the summer, the most important PAH source was related to boat traffic in the Ria Formosa. Source assessment was also conducted using partial lea...

In an environmental forensic context, statistics can lend considerable support to evidence presented to a court and assist in the interpretation of data. However, the use of statistical methods must be conducted with utmost rigor and be applied only where relevant and necessary. Statistics for the sake of statistics or the wrong statistics may lead to doubt being raised and imply deception. It has also been suggested that a well-planned and executed analytical program should not need statistics to prove a point; this suggestion may be true when simple comparisons are all that is required, but when examining complex environmental situations, statistical methods might be the only ones that can identify the underlying truth. There are several types of statistics, but this article concentrates on some of the multivariate statistical methods that can assist in the identification of the source. This article is not designed to be a comprehensive study of any one method or of any one case but an overview of the m...

Seasonal variation of antioxidant enzymes activities (superoxide dismutase, catalase, and glutathione peroxidases) and lipid peroxidation (LPO) were studied in the clam Ruditapes decussatus in relation to body burdens of polycyclic aromatic hydrocarbons (PAHs). Clams were sampled in eight sites from the Ria Formosa lagoon. PAH concentrations were seasonally rather than spatially dependent, being higher in summer (August). Antioxidant enzymes activities and LPO levels in the clam digestive gland were also seasonally dependent. Antioxidant enzymes presented distinct seasonal variations: Mit SOD (superoxide dismutase activity measured in the mitochondrial fraction) was induced in the summer and down-regulated in winter and spring, while Cyt SOD activity (measured in the cytosolic fraction) was highest in autumn and lower in the summer. Neither Mit nor Cyt SOD were related to the clam PAH body burden, suggesting that cells are using other antioxidant systems to eliminate oxyradicals. Catalase (CAT), however, was induced in spring and down-regulated in summer, the inverse of the PAH concentrations in clam tissues. CAT induction in spring appears to be related to the excess of oxyradicals arising from the metabolic activity associated with the reproductive cycle. Conversely, the decrease in CAT activity in the summer may be related to the high water temperatures reached in the Ria Formosa (up to 30 °C). Glutathione peroxidases (total fraction - T-GPx and dependent on selenium - Se-GPx) presented a similar seasonal pattern, and were negatively related to PAH concentrations, which may indicate a precarious state of the clams, associated with PAH toxicity. Similarly, LPO was also inversely correlated to the PAH concentrations indicating that increases in PAH concentrations were not causing membrane oxidative damage in R. decussatus digestive gland. The results suggest that antioxidant enzymes in R. decussatus digestive gland are strongly affected by seasonal factors stressing the need of other experiments to clarify the PAHs effect on this clam species. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 203–221, 2007.

Statistical methods form the basis of many environmental forensic investigations. These techniques can bring clarity to complex data and assist in the identification of the environmental history of samples and locations. However, treating the methods as a black box without appreciation of the method itself and its limitations can lead to erroneous interpretations. This chapter outlines some of the major methods used in multivariate statistical analyses from the standpoint of the end user; it highlights how data should be presented, transformed, and ultimately presented. Three major methods are used in this chapter: PCA, PLS, and PVA. In summary, data should be converted to proportions to remove the concentration effects, transformed to their log10 values if needed, the presence of zero should be considered—especially why they are zero in the first place—and finally how the user can interpret the results needs to be considered.

Fats, oils and greases (FOGs) in wastewater create problems including the production of foul odours, the blockage of sewer lines and may interfere with the proper operation of sewage treatment works. Removal of FOG from wastewater is thus critically important to ensure that wastewater is disposed of efficiently and economically. In this study, the ability of commercial microbial supplements to degrade fat/oil under laboratory conditions was investigated. One of the multi-species supplements examined was capable of significantly enhancing the degradation of several fats and oils by 37–62%, in contrast to all of the single-species supplements which had no significant effect. The multi-species supplement showed no preferential cleavage or degradation of fatty acids in a range of FOGs, whilst wastewater-associated bacteria preferentially degraded octadecatrienoic acid (18:3ω3) and octadecadienoic acid (18:2ω6). A semi-solid, sticky material, likely to cause blockages in pipework and sewer lines formed when the oil was incubated in the presence of wastewater bacteria. The sticky material was enriched in saturated and mono-unsaturated fatty acids and depleted in polyunsaturated fatty acids relative to the original oil, most likely reflecting preferential fatty acid usage by the bacteria. The production of this semi-solid material by the wastewater bacteria was significantly reduced by the presence of the multi-species product, indicating that commercial supplements have the potential to minimize FOG accumulation and blockages in grease traps and sewer lines as well as enhancing FOG degradation.

The presence of the radionuclide 99 Tc in the marine environment is of concern to environmental scientists because of its conservative nature and high concentration factor in commercially valuable species. The brown seaweed Ascophyllum nodosum (Linnaeus) Le Jolis was used to biomonitor the spatial distribution of 99 Tc around the Welsh coast, an area relatively unstudied with respect to this isotope. Over the course of a year an inverse relationship was observed between the 99 Tc concentration in A. nodosum samples and approximate straight-line distance from Sellafield. These data show that detectable levels of a Sellafield derived radionuclide are reaching the Welsh coast despite the overall northward movement of the Sellafield plume.

There has been much controversy regarding the origins of the natural polycyclic aromatic hydrocarbon (PAH) and chemical biomarker background in Prince William Sound (PWS), Alaska, site of the 1989 Exxon Valdez oil spill. Different authors have attributed the sources to various proportions of coal, natural seep oil, shales, and stream sediments. The different probable bioavailabilities of hydrocarbons from these various sources can affect environmental damage assessments from the spill. This study compares two different approaches to source apportionment with the same data (136 PAHs and biomarkers) and investigate whether increasing the number of coal source samples from one to six increases coal attributions. The constrained least-squares (CLS) source allocation method that fits concentrations meets geologic and chemical constraints better than partial least-squares (PLS) which predicts variance. The field data set was expanded to include coal samples reported by others, and CLS fits confirm earlier findings of low coal contributions to PWS.

The Ria Formosa is a meso-tidal coastal lagoon experiencing enhanced nutrient concentrations. Assessment of sediment–seawater interaction is essential if nutrient dynamics and the risk of eutrophication are to be fully understood. Pore water concentrations of dissolved inorganic and organic phosphorus, ammonium, nitrate and nitrite were determined in cores from six sites. Changes in nutrients concentrations were measured in intertidal pools on sand and mud between tides. Dissolved inorganic phosphorus (DIP) concentrations (~200 µmol l−1) and effluxes (123 ± 14 µmol m−2 h−1) were greater from sand than mud (37 ± 10 µmol m−2 h−1), possibly due to the binding of P with the

Terminal Restriction Fragment Length Polymorphism (T-RFLP) of PCR amplified 16S rRNA genes was used to investigate microbial communities in the sediments of Ria Formosa, Portugal. Five replicates of surface sand sediments were collected at an artificial inlet to the sea, between June 2001 and July 2002. Restriction enzymes Msp1 and Hha1 provided 57 different terminal fragments (T-RFs). The sediments were essentially dominated by the same ribotypes throughout the year, with seasonal shifts attributed to minor ribotypes. Principal component analysis of the T-RFs profile revealed no consistent pattern of temporal variation and no consistent grouping of replicate sediment samples. The results suggest that the small-scale spatial variability outweighs the seasonal variability. Phylogenetic affiliations suggested that the dominant bacteria were representatives of the α-Proteobacteria group.

Previous work in the Ria Formosa Lagoon has revealed that it is possible to use macrofauna community structure as an indicator of contamination effects. Communities at sites adjacent to sewage outfalls indicated contamination but no pollution gradients were observed. In this study, macrofauna within a sub-section of the earlier work were investigated to determine the extent of mesoscale (10–100 m) variability and new indices of biological community structure. The results were evaluated using univariate (Marine Biotic Index; BI) and multivariate statistical methods (PCA). The computer program Barrier (usually used with genetic data) was also applied to detect “barriers” between spatially referenced samples. PCA identified the most significant factor effecting the distribution of the organisms in the study area to be the mud content of the sediment (% < 63 μm). Communities at sandy sites consisted of suspension feeders and detrital browsers, whilst communities at muddy sites were composed mainly of deposit ...

Polychlorinated biphenyl (PCB) congener concentrations and organic matter content were determined in 84 samples of suspended and settled sediments collected from six different locations in the Ria Formosa lagoon (Portugal). Total PCB (tPCB) concentrations were higher in the suspended matter (1.00–39.80 ng g–1 dw) than in the sediments (0.10–2.10 ng g–1 dw) and, in general, the same was true for the organic matter. Partial least squares (PLS) analysis using the suspended sediments as signatures indicated that they better explained the settled sediment pattern compared to the reverse. This suggests a suspended sediment source outside the lagoon as source of these PCBs. PLS analysis also indicated that Aroclor 1242 best explained the congener pattern in the sediments, but lower fits were obtained for the suspended matter. The tri- and tetra-chlorinated biphenyls were the most abundant congeners (about 60% of tPCB), followed by the hexa- (20%), penta- (11%) and hepta + octa-chlorobiphenyls (9%). The principal congener differences between the suspended and settled sediments were for the smaller tri- and tetrachlorinated biphenyls, which were preferentially accumulated in the settled sediments. In contrast, congener 49 was significantly more abundant in the suspended phase and may be formed through the anaerobic UV degradation pathway either in suspension or on the surface of strongly anoxic sediments at low tide.

Dimethylsulphide (DMS) is a trace sulphur gas found in most atmospheric and surface water samples, which is derived from dimethylsulphonioproprionate (DMSP). Although it has been extensively studie...

A series of laboratory experiments were carried out to test the potential of vegetable oil biodiesel for the cleaning of oiled shorelines. In batch experiments, biodiesel was shown to have a considerable capacity to dissolve crude oil, which appears to be dependent on the type of biodiesel used. Pure vegetable oil biodiesels (rapeseed and soybean) were significantly more effective in the cleanup of oiled sands (up to 96%) than recycled waste cooking oil biodiesel (70%). In microcosm and mesocosm experiments, oiled sediments were sprayed with biodiesel and subjected to simulated tides. Microcosm experiments revealed that, of those tested, the highest ratio of biodiesel to crude oil, had the highest effectiveness for cleaning fine sands, with ratios of 2:1 (biodiesel:crude oil) giving the best results. In the mesocosm experiments a ratio 1:1 of soybean biodiesel to crude oil removed 80% of the oil in cobbles and fine sands, 50% in coarse sand and 30% in gravel. Most of the oil was removed with the surface water, with only a small amount being flushed through the sediments. Particle size and pore size were important determinants in the cleanup and mobility of crude oil in the sediments in these static systems. It is expected that the biodiesel effectiveness should improve in the natural environment particularly in exposed beaches with strong wave action. However, more laboratory and field trials are required to confirm the operational use of biodiesel as a shoreline cleaner.

The distribution of metal contaminants between different size fractions of marine sediments is well known. However, the use ofsize normalization techniques may alter the ability or usefulness in identifying potential sources in complex environments. In areassessment of metal data from the shelf area of Sydney, Australia, the mud and sand fractions were investigated separately by PCAand PLS methodologies. The analyses were able to produce clear distinctions between industrial/urban sources when based on a suite ofmetalsratherthanindividual(single-element)concentrations.SignatureanalysisbyPLSwithcopper,lead,zinc,manganese,chromium,cobalt, nickel, and cadmium demonstrated the dispersion of the fine-grained contaminated material to the south in the East AustralianCurrent. However, due to the commonality between many of the metals, a subset of four metals was used to define the signature. Thissignificantly improved separation, showing clear plumes extending ∼30 km from the source rivers.Keywords: PCA, PLS, Sydney, Newcastle, size fractionated, sediment, metals

The effects of a simulated spill of sunflower oil in salt marsh sediments were compared with an experiment with linseed oil. Sunflower and linseed oil penetrated the sediments at the same rates but different adsorption of the oils onto sediment particles resulted in the establishment of anaerobic conditions at shallower depths in sediments contaminated with linseed oil than with sunflower oil. The total lipid content of sunflower oil contaminated sediments remained almost stable for 6 months, whilst only 40% of linseed oil remained in the sediment after 2 months. Numbers of culturable heterotrophic bacteria and aerobic oil degrading bacteria in muddy sediment increased rapidly in response to the presence of the oils but bacterial numbers in sandy sediments increased more slowly for sunflower oil. Changes in fatty acid composition indicate similar degradation pathways for both oils but sunflower oil degraded more slowly than linseed oil and thus has the potential for longer lasting effects in marine environments.

In a recent study of the mesotidal Ria Formosa, a coastal lagoon in southern Portugal, water temperature in the channels ranged from 12 °C in winter to 27 °C in summer and salinity from 13 to 36.5, although much higher values were observed in saltpans. Conditions in the Ria Formosa were not homogeneous despite a large tidal exchange of water; the inner channels of the Ria Formosa were brackish in winter but hypersaline in summer. Water in inner areas of lagoon had significantly different temperature and salinity characteristics compared to the inflowing coastal water, both in winter and in summer. Areas with these differences in temperature and salinity were detectable both at low water and at high water neaps. Deterioration of water quality is therefore more probable in these areas. The waters went through a complex heating and cooling cycle in summer with diurnal difference of ∼6 °C and 2 in temperature and salinity, respectively. The lack of freshwater input and high insolation meant the outflowing water of the lagoon was more saline that the inflowing coastal waters. In summer, the temperature controlled density with the least dense waters also being the most saline, whereas in winter salinity was the major density controlling parameter. The effects of these freshwater inputs were localised to the vicinity of the Gilao River. No evidence was found of persistent or widespread temperature or salinity stratification in the Ria Formosa and so this shallow lagoon appears to be vertically well mixed. Vertical mixing does not allow a dense, stagnant, bottom layer of water to form that would aggravate a deterioration of water quality. The net effect of these processes is a parcel of water that moves through the lagoon with minimal dilution and potentially receiving waste discharges.

Partial least squares (PLS) techniques are used in the re-analysis of NOAA hydrocarbon data previously investigated in 4 . New data have been provided for coal and oil signatures and these have been investigated further. The effects of zeros (less than the limit of detection) in the dataset can be overcome by addition of small values at approximately half of this limit; this then enables logarithms to be taken of the entire dataset which greatly improved the usefulness of principal component analysis (PCA). Source samples collected close to each other had different signatures, probably due to their environmental histories which was also seen when aliphatic hydrocarbons were included in the signatures. Key compounds describing each could be seen in Coomans' Plots. Signatures developed from formation oils, riperian oils and coals from the eastern Gulf of Alaska (GoA) provided mean fits to subtidal samples within PWS of 22, 19 and 38% respectively. This suggests mixed and variable sources across the sampling area. The overall conclusion must be a question regarding the partitioning between oil and coal source materials as they look very similar in this particular location.

In a simulated spill in a salt marsh, linseed oil penetrated rapidly into the sediments at a rate of 10 −7 cm 2 s −1 . The oil concentration remained unchanged for the first month after the spill, but 60% of the oil disappeared from the top 30 cm after a further month. The oil adsorbed to and accumulated in the muddy sediments (top 15 cm) leading to decreased sediment permeability, pH, Eh, abundance of plant roots and infauna and to the establishment of anoxic conditions. These changes accompanied transformations in the original fatty acid composition of the linseed oil, mainly associated with a decrease in 18:3ω3, an increase in the other fatty acids and the presence of `new' fatty acids. A rapid increase in the abundance of heterotrophic aerobic and anaerobic bacteria and aerobic oil degrading bacteria, suggested that these micro-organisms degraded the oil. The role of the bacteria in oil degradation was confirmed in laboratory experiments where the fatty acids composition of the linseed oil underwent identical transformations to those obtained in the field. The degradation of linseed oil appears to be a sequential process initiated by aerobic and/or anaerobic bacteria and continued by sulphate reducing bacteria, which were unable to degrade the raw oil.

There has been considerable exchange in the literature regarding the source of the background hydrocarbons in Prince William Sound and the Gulf of Alaska. Page and coworkers suggest oil-based sources while Short and coworkers suggest coal. The multivariate statistical methodology of partial least-squares (PLS) has been used to reassess the percentage contribution of coal, seep oil, shales, and rivers to the hydrocarbon loading in the Gulf of Alaska. Data have kindly been provided by Short (NOAA) and Page (Bowdoin College, for Exxon), and these have been analyzed using selected sites as sources in order to develop signatures. These signatures are based on 40 and 136 compounds, respectively, and include the PAH and terpane/sterane biomarkers in the case of the Exxon data. The principal components describing these sources are then fitted to the data for other sites around the Prince William Sound (PWS) and Gulf of Alaska (GoA) to determine the proportion of the variability described by each source. Using the Exxon data, a mixed source of coal, seep oil, eroding shales, and rivers (1 and 2) sources described approximately 13%, 18%, 24%, 26%, and 20%, respectively, of the variance in PWS and GoA data. The rivers 1 signature was very similar to that of coal, while rivers 2 was more similar to the eroding shales. New coal data (Short, unpublished work) also indicated considerable overlap with the Exxon seep oil. With the NOAA data, spatial plots of the explained variance indicate that the prespill background has a wide range of explained fits. There is considerable overlap in the signatures developed from the data, and Coomans' Plots identify those compounds which are the most diagnostic: for the Exxon seep oil signature, naphthalene and methyl- and dimethylnaphthalene are the best markers, whereas for the NOAA prespill background, Exxon coals and shales are best defined by the larger PAHs such as benzo[ghi]perylene. The evidence suggests mixed sources whose contributions vary significantly across the sampling area.

As part of a project to determine the fate of contaminated milk in the marine environment (Elliott et al ., 2001), the Biochemical Oxygen Demand (BOD) of unprocessed natural milk in sea water was followed in standard BOD bottles and in an open system. The best estimate for the BOD was ¨ 170,000 r mg - l m 1 although measurable effects could still be seen with dilutions up to one in a million. If incubated in the light, simulating summer conditions, the algae produced oxygen and offset some of the loss through bacterial degradation thereby reducing any slump in oxygen. There was also a "nutrient effect" where the presence of milk increased the oxygen production at low concentrations in sea water. In an open system akin to a slick being dispersed, the change in BOD was exponential after an initial activation period. The length of this activation period was greater in more concentrated mixtures of milk and sea water. These results have been utilised in a model to determine the best strategy for disposing of ...

The paper gives an overview of some of the large, shallow, semi-enclosed coastal systems (SECS) in Europe, These SECS are important both from the ecological and the economic perspective (socioecological systems) and provide many valuable ecosystem goods and services. Although some of the systems are transitional waters under theWater Framework Directive, this is not the case for all of the systems. The paper adopts a Driver-Pressure-State-Impact-Response approach to analyse the ecological status, vulnerability and future perspectives of these systems in the context of global change. This work has been supported by: the EUROMEDLAG federation, http://www.euromedlag.eu/lagoonsfederation/; EC 5FP grant agreement 00084 (DITTY), http://www.ecolag.univ-montp2. fr/index.php?option¼com_content&task¼view&lang¼en&id¼226; EC 6FP grant agreement 036992 (SPICOSA),www.spicosa.eu/; the LOICZ project, http://www.loicz.org/. info:eu-repo/semantics/publishedVersion

In many environmental contamination events it is necessary to reconstruct the source term, and differentiate this source from other potential sources and the baseline condition, without the benefit of any analytical data for the source. This has been made possible with methods such as polytopic vector analysis (PVA), and self-organising maps (SOMs). PVA is an unmixing approach that generates a model with an increasing number of end members (sources) that at some stage explain the environmental data; when coupled with SOMs, the underlying factors that control the composition can be seen. The combination of these techniques has enabled the elucidation of the source chemical profile, along with those of the other contributors. In many cases, one end member will be the ubiquitous baseline condition, and this may be a sensible approach to reconstruct the concentration, chemical makeup, and relative contributions of sources to contaminated environments.

Surface sediment samples from 16 sites in San Vicente Bay were analysed for a range of lipid biomarkers and hydrocarbons. Coprostanol and cholesterol were used to indicate regions of sewage contamination: ratios reached 1.1 adjacent to known discharge points. The fatty alcohol data were used to highlight regions of bacterial and terrestrial biomass. The bacterial fatty acid 18:1ω7 co-varied with the odd/even fatty alcohol ratio and the coprostanol/cholesterol ratio confirming the regions of aerobic bacterial activity near the sewage outlets. The fluoranthene/pyrene ratio together with the ratio between the (three or less/four or more) ring aromatics and total concentration of aromatics demonstrate the extent of crude oil and pyrogenic contamination in the sediments. San Vicente Bay was divided into three principal regions on the basis of this analysis: (a) the highly contaminated northern end with strongly reducing sediments and high concentrations of organic matter, (b) the region adjacent to the sewage outlets with associated bacterial biomass, and (c) the remaining central and southern areas relatively unaffected by the northern discharges. Partial Least Squares path modelling suggests the latter region received less than 50% of the material discharged at the northern end of the Bay.