Organic geochemistry of sediments from the continental margin off southern New England, U.S.A.--Part II. Lipids

Assessing Metallic Pollution Using Taxonomic Diversity of Offshore Meiobenthic Copepods

The Gulf of Gabès, located on the south-east Tunisian coast, is an important maritime area, with great influence on the local economy and human welfare. The aim of the current study was to assess the response of meiobenthic copepod populations from this gulf to anthropogenic disturbances. Nine sampling sites, situated along the shores of the gulf were surveyed seasonally from winter of 2004 to autumn of 2005. Interestingly, this biotope has one of the highest semi-diurnal tides in the Mediterranean Sea. Despite the fact that the data being presented here are not that new, such a high maximum amplitude of tides reaching 2 m makes any information available on animals with diurnal dispersal cycles such as copepods extremely precious. Furthermore, the lack of knowledge on these crustaceans is obvious and lags behind that of numerous other meiobenthic taxa and planktonic calanoids. Actually, most publications do not reach the species level and are limited to determining densities. This is mainly due to the modest size of harpacticoids, and the lack of qualified taxonomic experts and global taxonomic databases. Sediment samples were analyzed for fluorine, carbohydrates and trace metals (i.e., Fe, Zn and Cd) content. A pollution index, based on the eigenvalues of the main ordination axis of a Principal Component Analysis, was applied. The highest values of chemicals were detected at the sites situated near an industrial complex, along with significant variations among seasons. The copepod community comprised 38 species, including five species new to science. Species richness, density and biomass of copepod communities varied among sites and seasons. These community-based indices were also analyzed separately for each season with conditional autoregressive models, revealing a significant negative response with the level of pollution. However, the results of partial Mantel tests showed positive correlations between species richness and pollution level, after controlling for the effect of geographic proximity in-between pairs of sites (winter: r = 0.927, p < 0.0001; spring: r = 0.935, p < 0.0001; summer: r = 0.918, p < 0.0001; autumn: r = 0.937, p < 0.0001). The overall pattern was that nearby sites were characterized by similar pollution levels and inhabited by similar species of copepods. Moreover, the copepod communities were significantly influenced by pollutants, mainly by trace metals. The results of the current survey emphasize the usefulness of meiobenthic copepods in biomonitoring programs not only for the gulf of Gabès, but also for other coastal areas from the Mediterranean Sea region.

Historical changes in trace metals and hydrocarbons in nearshore sediments, Alaskan Beaufort Sea, prior and subsequent to petroleum-related industrial development: part II. Hydrocarbons

Composition and concentration of hydrocarbons (normal and isoprenoid alkanes, triterpenoids, steranes, and PAHs) in nearshore surface sediments from Elson Lagoon (EL), Colville Delta-Prudhoe Bay (CDPB) and Beaufort Lagoon (BL), Alaskan Beaufort Sea, were assessed for spatio-temporal variability. Principal component analysis of the molecules/biomarkers concentrations delineated CDPB and BL samples into two groups, and cluster analysis identified three station groups in CDPB. Overall there was no geographic distribution pattern in the groups. The diversities between groups and individual samples are attributed to differences in n-alkanes and PAHs contents, which are influenced predominantly by sediment granulometry and sitespecific fluvial input. The predominant hydrocarbon source is biogenic, mainly terrigenous, with hardly any contribution from natural oil seeps, oil drill effluents and/or refined crude. The terrigenous source is corroborated by δ(13)C, δ(15)N, and OC/N of sediment organic matter. Time interval (1976-1977, 1984 and 1997) changes in hydrocarbon compositions and concentrations in CDPB are not significant.

Organic matter compounds as source indicators and tracers for marine pollution in a western Mediterranean coastal zone

INTRODUCTION

Complex organic compounds found in oil and sediments linked with a particular source (such as algae, bacteria or vascular plants) are defined as biomarkers and are useful dating indicators in organic geochemistry.

METHODS AND RESULTS

This paper presents the composition of the organic matter (OM) on marine surface sediments from a degraded Tunisian coast analysed by pyrolysis and gas chromatography-mass spectrometry (GC-MS). High total OM contents (0.3-4.2%) were detected with high levels of saturated linear hydrocarbons. The aliphatic lipids had contributed with up to 11.7% of the total OM, and their distribution had consisted of resolved compounds (n-alkanes and fatty acid (FAs)) and an unresolved complex mixture. Hydrocarbons, primarily n-alkanes, were ranged from 368 to 3,886 μg g(-1). The FAs (674-2,568 μg g(-1)) were dominated by derived primary production, and the short chain FAs (C16 and C18) were the most abundant throughout. The ubiquitous presence of petroleum contamination, mainly from offshore oil exploration, discharge of pollutants from rivers, shipping activities and atmospheric deposition was found in all samples. The Gabès littoral seems to be quite to very polluted near the industrial zone of Ghannouch. The C/H ratio (generally around 5.9), the thermal analysis and GC-MS of n-alkanes and FAs showed that the OM in the studied area was composed of anthropogenic/petrogenic, marine and continental sources.

CONCLUSIONS

Our study represents an innovative approach to assessing environmental pollution. The evaluation of organic matter by examination of sterols, alkanes and fatty acids allows the identification of source, both anthropogenic and natural.

Trace organic contaminants and their sources in surface sediments of Santa Monica Bay, California, USA

Spatial distribution of selected contaminants in the surface sediments of Santa Monica Bay (SMB), California was investigated. Sediments were analyzed for DDTs (DDT and metabolites), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), linear alkylbenzenes (LABs) and coprostanol. Effluent samples from the Hyperion Treatment Plant (HTP), which discharges treated municipal wastewater effluents into SMB, were also analyzed. The inter-correlation in the distribution trends of contaminants was examined. The concentrations of contaminants were interpolated in a geographic information system to visualize their spatial distribution in the Bay. Inventories of the contaminants were also estimated. The concentrations of coprostanol, LABs and PCBs are very high only in the vicinity of the sewage outfall whereas PAHs and DDTs occur widespread in the Bay. The poor correlation of DDTs with LABs, PAHs or coprostanol content confirms the historic origin of DDTs and their absence in the contemporary wastewaters. Moderate correlation of DDTs with PCBs implies historic deposits as a major origin of PCBs. There are hot spots of DDTs at water depths of 60 and 100m and the inventory of DDTs in Bay sediments is insignificant compared to that estimated in the Palos Verdes Shelf which extends from the southern edge of Redondo Canyon around Palos Verdes Peninsula. The concentration of toxic contaminants was examined according to published sediment quality guidelines. About 20 stations contain p, p'-DDE and/or total DDTs above ERM and, PCBs between ERL and ERM indicating potential for adverse biological effects.

Investigation of natural and anthropogenic hydrocarbon inputs in sediments using geochemical markers. II. Sao Sebastião, SP--Brazil

The São Sebastião Channel, NE São Paulo State, Brazil, is an area of environmental interest of that state not only because of the tourism, but also because of the presence of the most important oil terminal of Brazil, the PETROBRAS Maritime Terminal (DTCS). Sediment samples were collected at 15 sites in the channel, extracted and analyzed by GC/FID and GC/MS for composition and levels of the following organic geochemical markers: aliphatic hydrocarbons (normal and isoprenoid alkanes), petroleum biomarkers, linear alkylbenzenes (LABs) and polycyclic aromatic hydrocarbons (PAHs). The total concentrations varied from 0.04 to 8.53 micorg g(-1) for aliphatics, from 51.1 to 422.0 ng g(-1) for petroleum biomarkers, from 12.6 to 27.7 ng g(-1) for LABs and from 20.4 to 200.3 ng g(-1) for PAHs. The PETROBRAS Maritime Terminal (DTCS), Sao Sebastião Harbor and sewage outfalls along the area had clear influences on the geochemical marker concentrations, especially at locales in the central and north parts of the channel.

Lipid composition of suspended particulate matter (SPM) in a southeastern blackwater stream

Suspended particulate matter (SPM) was collected seasonally for 1 yr at third- and fifth-order sites in a blackwater stream on the coastal plain in South Carolina. Fatty acids with carbon chain lengths from C(12)-C(32) were the most abundant component among the lipid classes examined with total concentrations varying from 8.5 to 60.2 microgL(-1). Unsaturated fatty acids predominated while significant concentrations of the even-chained saturated components C(24)-C(30) derived from cuticular plant waxes were also found. Concentrations of aliphatic alcohols, with carbon chain lengths between C(16) and C(30), ranged from 0.52 to 2.73 microgL(-1) and was dominated by the higher molecular weight compounds (C(22)-C(30)) derived primarily from cuticular plant waxes. Total hydrocarbon concentrations ranged from 0.35 to 5.66 microgL(-1) and showed no discernible trends with time or consistent difference between sites. The hydrocarbon assemblage observed indicates that these components are entirely of biogenic origin with no detectable anthropogenic contribution. The ratios of unsaturated to saturated fatty acids and cuticular to noncuticular fatty acids and alcohols at both stream locations indicate that the organic detritus associated with SPM collected during November and January is of more recent origin and less processed than that collected in the spring and summer months. Lipid concentrations at the third-order site generally had higher and more variable concentrations of the lipid classes compared with the fifth-order site. The ratio of saturated to unsaturated fatty acids was higher at the third-order site indicating that the organic fraction of SPM at this site was of more recent origin and less decomposed. The ratios of cuticular to noncuticular fatty acids and alcohols support this conclusion. These results indicate an export of particulate lipids of higher carbon resource quality from upstream to lower stream reaches.

Distribution of polycyclic aromatic hydrocarbons (PAHs) in rivers and estuaries in Malaysia: a widespread input of petrogenic PAHs

This is the first publication on the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in riverine and coastal sediments in South East Asia where the rapid transfer of land-based pollutants into aquatic environments by heavy rainfall and runoff waters is of great concern. Twenty-nine Malaysian riverine and coastal sediments were analyzed for PAHs (3-7 rings) by gas chromatography mass spectrometry. Total PAHs concentrations in the sediment ranged from 4 to 924 ng/g. Alkylated homologues were abundant for all sediment samples. The ratio of the sum of methylphenanthrenes to phenanthrene (MP/P), an index of petrogenic PAHs contribution, was more than unity for 26 sediment samples and more than 3 for seven samples for urban rivers covering a broad range of locations. The MP/P ratio showed a strong correlation with the total PAHs concentrations, with an r2 value of 0.74. This ratio and all other compositional features indicated that Malaysian urban sediments are heavily impacted by petrogenic PAHs. This finding is in contrast to other studies reported in many industrialized countries where PAHs are mostly of pyrogenic origin. The MP/P ratio was also significantly correlated with higher molecular weight PAHs such as benzo[a]pyrene, suggesting unique PAHs source in Malaysia which contains both petrogenic PAHs and pyrogenic PAHs. PAHs and hopanes fingerprints indicated that used crankcase oil is one of the major contributors of the sedimentary PAHs. Two major routes of inputs to aquatic environments have been identified: (1) spillage and dumping of waste crankcase oil and (2) leakage of crankcase oils from vehicles onto road surfaces, with the subsequent washout by street runoff. N-Cyclohexyl-2-benzothiazolamine (NCBA), a molecular marker of street dust, was detected in the polluted sediments. NCBA and other biomarker profiles confirmed our hypothesis of the input from street dust contained the leaked crankcase oil. The fingerprints excluded crude oil, fresh lubricating oil, asphalt, and tire-particles as major contributors.

Hydrocarbons in surface sediments from the Changjiang (Yangtze River) Estuary, East China Sea

Sedimentary aliphatic (AH) and polycyclic aromatic hydrocarbons (PAHs) were studied in the Changjiang Estuary and the adjacent East China Sea. Total AH ranged from 2.20 to 11.82 microg g(-1) and consisted of n-alkanes and a dominant petroleum-related unresolved complex mixture (UCM). Within the n-alkanes, terrestrial plant wax compounds prevailed at nearly all stations. Of the PAHs, biogenic perylene dominated at stations receiving riverine inputs. Anthropogenic PAHs originating from combustion/pyrolysis processes varied from 17 to 157 ng g(-1), while fossil PAH concentrations ranged from 42 to 187 ng g(-1). Both biogenic and anthropogenic hydrocarbons are primarily derived from riverine discharges and accumulate at shallow-water stations. Distinct phase associations lead, nevertheless, to different sedimentation patterns. Fossil PAHs are enhanced at offshore stations where they are introduced directly by shipping activities. Biomarker fingerprints ascribe their source to Chinese crude oils. The overall levels of anthropogenic hydrocarbons are low compared to relevant areas worldwide and reveal a low/moderate level of hydrocarbon pollution.

Organic geochemistry of sediments from the continental margin off southern New England, U.S.A.--Part I. Amino acids, carbohydrates and lignin

Total organic carbon (TOC), lignin, amino acids, sugars and amino sugars were measured in recent sediments for the continental margin off southern New England. The various organic carbon fractions decreased in concentration with increasing distance from shore. The fraction of the TOC that was accounted for by these major components also decreased with increasing distance from shore. The concentration of lignin indicated that only about 3-5% of the organic carbon in the nearshore sediment was of terrestrial origin. The various fractions were highly correlated, which was consistent with a simple linear mixing model of shelf organic matter with material form the slope and rise and indicated a significant transport of sediment from the continental shelf to the continental slope and rise.