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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....

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.

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...

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...

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 ...

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...

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

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.

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 ...

Following initial experiments presented elsewhere (2IOPS), the bacterial degradation of two vegetable oils was investigated in some detail. the number of aerobic and anaerobic heterotrophic bacteria, oil degrading and sulphate reducing bacteria were quantified during simulated spills on a salt marsh. the sediment fatty acid composition was also studied using GC-MS analysis. Degradation of linseed and sunflower oils was concomitant with an increase in the numbers of aerobic and anaerobic bacteria. Fatty acids analysis revealed preferential degradation of the principal components of the oils (18:3ω3 for linseed oil and 18:2ω6 for sunflower oil). the presence of several isomers of the usual polyunsaturated fatty acids was also detected. the identification of some of these new fatty acids has been carried out. Possible pathways of degradation of these vegetable oils are suggested.

The Ria Formosa lagoon, Portugal, receives organic matter from many natural and anthropogenic sources. This paper presents an overview of the contribution these sources made through the use of lipid biomarkers. Sixty-one surface sediment samples were collected and analysed for a range of lipids. Sewage materials were confined to regions within 2 km of discharge points; phytoplankton biomarkers (sterols and fatty acids) suggest production was greatest in the inner parts of the lagoon that also have greatest inorganic nutrient enrichment; terrestrial organic matter was present in relatively low concentrations as shown by both sterol and fatty alcohols; bacteria were widespread although the Sulphate Reducing Bacteria (SRBs, shown by the presence of 3-OH fatty acids) were located near but not adjacent to sewage discharge points.

A study of the biomarkers associated with human sewage was conducted on the Arade Estuary and its tributaries, the R. de Boina and Odelouca, Southern Portugal. Surface sediment samples were collected at 20 sites in the system and analysed by gas chromatography - mass spectrometry (GC-MS) for sterols and fatty alcohols. The coprostanol/cholesterol ratio indicated substantial sewage contamination in the Boina and in the lower reaches of the Arade Estuary. The lack of epi-coprostanol suggested that this material was essentially untreated. Other sterols (β-sitosterol and brassicasterol) indicate phytoplankton biomass in the middle and upper reaches of the estuary. The fatty alcohols were not correlated with the β-sitosterol, unlike the brassicasterol, and therefore suggest an algal origin for this matter. Organic matter derived from vascular plants (high C22/C16 ratio) was limited to the central portion of the Estuary where a marsh-like community has developed.

Following the wreck of the M.V. Kimya during which 1500 tonnes of sunflower oil was spilled, sandy sediments bound together with sunflower oil were discovered on the beach. These are still present 2½ years later. Sunflower and linseed oil were applied to salt marsh sediments to reproduce potential spills. Cores were taken and the vertical migration and degradation rates determined. Sunflower oil polymerised at the surface after 28 days resulting in the formation of a cap of increased shear strength and reduced permeability to water and oxygen. This contrasts with linseed oil that rapidly percolated to depth without the formation of a polymer. One degradation product formed from linseed oil was possibly 18:2ω3, although this has still to be confirmed. Increased bacterial numbers were observed with both oils. in the event of spill, these results suggest sunflower oil should be removed although linseed oil could be left to natural degradation processes.