The study presented here searched for the level of taxonomic resolution required to detect the effects of low-level chronic pollution on estuarine meiobenthic communities. Meiofauna from two sites, with special attention to harpacticoid copepods, was analysed at different taxonomic levels of aggregation using uni- and multivariate methods. Adaptation processes that could buffer biodiversity disruptions were also considered through the analysis of fitness-related and tolerance traits in the harpacticoid copepod Paronychocamptus nanus. Results showed that uni- and multivariate analyses could be inadequate when assessing subtle anthropogenic contamination. Instead, the assessment of inter-population differences in tolerance to the main source of stress rises as a required procedure if potential effects of this type of contamination are being investigated. Specifically, a 96 h acute toxicity test performed with populations from the affected site appears as a faster and reliable general tool to assess impacts of low-level chronic pollution in estuaries.

To elucidate tidally related variations of hydrophobic organic contaminant (HOC) bioavailability and the impact of these contaminants on estuarine ecosystems, both PCB and PAH concentrations were investigated in the dissolved phase and in the suspended particulate material (SPM) of the Seine Estuary. Both PAH and PCB highest levels were observed in surface and bottom water when SPM remobilizations were maximum, in relation to higher speed currents. In parallel, acetylcholinesterase (AChE) and glutathione-S-transferase (GST) activities were investigated in the copepod Eurytemora affinis. Significant decreasing AChE levels were measured during the tidal cycle and between surface and bottom copepods related to salinity and to HOC concentration variations. Significant increasing GST levels were also observed when HOC concentrations in the water column were the highest. This study underlined the need to standardize sampling procedures for biomonitoring studies in order to avoid interfering factors that could modify biomarker responses to chemical exposure. Variations of contamination of E. affinis and enzymatic responses have been studied over a tide cycle in view to improve the use of this copepod for biomonitoring.

A solid-phase microextration-based sampling method was employed to determine the concentrations of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its metabolites, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (DDE) and 1-chloro-2,2-bis(p-chlorophenyl)ethene (DDMU), in two estuarine bays, Daya Bay and Hailing Bay, of South China. Six DDT components including p,p'-DDT, o,p'-DDD, p,p'-DDD, o,p'-DDE, p,p'-DDE, and p,p'-DDMU were detected in Hailing Bay, while only p,p'-DDD was found in Daya Bay. p,p'-DDD was the most abundant DDT component in both bays, sharply different from the previous finding in the water column of the Palos Verdes Shelf, California, USA that p,p'-DDE was prevalent. In addition, the occurrence of p,p'-DDMU (with a range of 0.047-0.21 ng/L in Hailing Bay) has not been reported around the globe, and its presence in our study region appeared to stem from dehydrochlorination of p,p'-DDD, favored under aerobic conditions, but further investigations are clearly needed to confirm the mechanism for generation of DDMU in estuarine environments. DDT and its metabolites, particularly p,p'-DDMU, are detected in the water column of two estuarine bays in South China using a SPME-based sampler.

The presence of triclosan, a widely-used antibacterial chemical, is currently unknown in higher trophic-level species such as marine mammals. Blood plasma collected from wild bottlenose dolphins (Tursiops truncatus) in Charleston, SC (CHS) (n = 13) and Indian River Lagoon, FL (IRL) (n = 13) in 2005 was analyzed for triclosan. Plasma concentrations in CHS dolphins ranged from 0.12 to 0.27 ng/g wet weight (mean 0.18 ng/g), with 31% of the sampled individuals having detectable triclosan. The mean IRL dolphin plasma concentrations were 0.072 ng/g wet weight (range 0.025-0.11 ng/g); 23% of the samples having detectable triclosan. In the CHS area, triclosan effluent values from two WWTP were both 190 ng/L and primary influents were 2800 ng/L and 3400 ng/L. Triclosan values in CHS estuarine surface water samples averaged 7.5 ng/L (n = 18) ranging from 4.9 to 14 ng/L. This is the first study to report bioaccumulation of anthropogenic triclosan in a marine mammal highlighting the need for further monitoring and assessment. Triclosan in bottlenose dolphin plasma and their environment.

The objective of this study was to investigate the influence of salinity on the effectiveness of surfactants in the remediation of sediments contaminated with phenanthrene (PHE). This is an example of a more general application of surfactants in removing hydrophobic organic compounds (HOCs) from contaminated soil/sediment in saline environments via in-situ enhanced sorption or ex-situ soil washing. Salinity effects on surfactant micelle formation and PHE partitioning into solution surfactant micelles and sorbed surfactant were investigated. The critical micelle concentration of surfactants decreased, and PHE partition between surfactant micelles and water increased with increasing salinity. Carbon-normalized partition coefficients (Kss) of PHE onto the sorbed cationic surfactant increased significantly with increasing salinity, which illustrates a more pronounced immobilization of PHE by cationic surfactant in a saline system. Reduction of PHE sorption by anionic surfactant was more pronounced in the saline system, indicating that the anionic surfactant has a higher soil washing effectiveness in saline systems. The effectiveness of surfactant-enhanced remediation technology was promoted when applying it in estuarine environment with a higher salinity.

Recent research suggests anthropogenic disturbance may disproportionately advantage non-indigenous species (NIS), aiding their establishment within impacted environments. This study used novel laboratory- and field-based toxicity testing to determine whether non-indigenous and native bryozoans (common within marine epibenthic communities worldwide) displayed differential tolerance to the common marine pollutant copper (Cu). In laboratory assays on adult colonies, NIS showed remarkable tolerance to Cu, with strong post-exposure recovery and growth. In contrast, native species displayed negative growth and reduced feeding efficiency across most exposure levels. Field transplant experiments supported laboratory findings, with NIS growing faster under Cu conditions. In field-based larval assays, NIS showed strong recruitment and growth in the presence of Cu relative to the native species. We suggest that strong selective pressures exerted by the toxic antifouling paints used on transport vectors (vessels), combined with metal contamination in estuarine environments, may result in metal tolerant NIS advantaged by anthropogenically modified selection regimes.

We evaluated mercury (Hg) in five waterbird species representing three foraging guilds in San Francisco Bay, CA. Fish-eating birds (Forster's and Caspian terns) had the highest Hg concentrations in thier tissues, but concentrations in an invertebrate-foraging shorebird (black-necked stilt) were also elevated. Foraging habitat was important for Hg exposure as illustrated by within-guild differences, where species more associated with marshes and salt ponds had higher concentrations than those more associated with open-bay and tidal mudflats. Importantly, Hg concentrations increased with time spent in the estuary. Surf scoter concentrations tripled over six months, whereas Forster's terns showed an up to 5-fold increase between estuary arrival and breeding. Breeding waterbirds were at elevated risk of Hg-induced reproductive impairment, particularly Forster's terns, in which 48% of breeding birds were at high risk due to their Hg levels. Our results highlight the importance of habitat and exposure timing, in addition to trophic position, on waterbird Hg bioaccumulation and risk. The influence of foraging habitat, trophic position, and exposure timing on mercury bioaccumulation and risk to reproduction is evaluated in three waterbird guilds.

Ninety-six riverine runoff samples collected at eight major outlets in the Pearl River Delta (PRD), South China, during 2005-2006 were analyzed for 17 brominated diphenyl ether (BDE) congeners (defined as Σ17PBDE). Fourteen and 15 congeners were detected, respectively, in the dissolved and particulate phases. These data were further used to elucidate the partitioning behavior of BDE congeners in riverine runoff. Several related fate processes, i.e. air-water exchange, dry and wet deposition, degradation, and sedimentation, within the Pearl River Estuary (PRE), were examined to estimate the inputs of Σ10PBDE (sum of the target BDE congeners, BDE-28, -47, -66, -85, -99, -100, -138, -153, -154, and -183) and BDE-209 from the PRD to the coastal ocean based on mass balance considerations. The results showed that annual outflows of Σ10PBDE and BDE-209 were estimated at 126 and 940 kg/year, respectively from the PRE to coastal ocean. Besides sedimentation and degradation, the majority of Σ10PBDE and BDE-209 discharged into the PRE via riverine runoff was transported to the coastal ocean. Fate of polybrominated diphenyl ethers in the environment the Pearl River Estuary, South China.

Comprehensive survey of major rivers in the Tokyo metropolitan area was conducted for clarifying the emission sources of perfluorooctane sulfonate (PFOS) in Tokyo. PFOS was found at all sampling sites at concentrations ranging from 0.5 to 58 ng L⁻¹; in addition to this, it was also indicated that unknown PFOS emission sources are present in the midstream of the Tama River basin. The relationship between PFOS and perfluorooctanoic acid (PFOA) was constant at a ratio of 10:3 (PFOS/PFOA) throughout the Tama River basin. The sum of daily load amounts of PFOS from Tokyo's major rivers to Tokyo Bay reached 215 g day⁻¹. This value corresponds to 12.8 μg day⁻¹ per person using the sum of wastewater treatment district populations. In contrast, an estimation of PFOS contribution of domestic wastewater was also attempted, and the contribution was 1.6 μg day⁻¹ per person. We took samples up trunk sewers in the Tama River and finally found at the highest PFOS concentration (58,000 ng L⁻¹) from one of the wastewater of the electronic parts manufacturing facilities.

An experiment was set up to assess the factors affecting metal mobility in five wetland soils of the Scheldt estuary at different sampling depths when subjecting the soils to various water table levels. Pore water metal concentrations were monitored for 10 months at four sampling depths (10, 30, 60 and 90 cm) upon adjusting the water table level to 0, 40 and 80 cm below the surface of the soils. Nickel (Ni) release is facilitated by reductive conditions. These reductive conditions mainly occur below the water table. The fate of chromium (Cr) under reductive conditions seems to be promoted by the presence of dissolved organic matter. However, Cr fate seems to be inconsistent between the soils, as it is affected by a series of counteracting mechanisms. Copper (Cu), zinc (Zn) and especially cadmium (Cd) are all primarily released above the water table under high salinity conditions. These elements are also released below or just above the water table when organic matter is being decomposed, resulting in calcium (Ca), manganese (Mn), Ni and/or iron (Fe) release upon CO₂ accumulation and Fe/Mn oxide reduction, without being accompanied by sulphide production. Their mobility is low under reducing conditions, i.e. in the presence of sulphides, whereas the complexation by soluble organic matter especially seems to promote Cu mobility.