Partitioning of Cs-137 Between Sediment and Water From the Black Sea

As part of a joint USA/USSR Environmental Agreement to determine the distribution and concentration of Chernobyl radioactivity in the northwest Black Sea area, the sediment from eight stations was collected and analyzed to assess the ability of this material to adsorb radiocaesium. Batch tests were conducted in which Cs-137 tracer was added to mixtures of sediment and bottom water, with contact solutions ranging from 85 Bq ml^-1 to 1,760 Bq ml^-1. This work was done in an argon atmosphere at 9.5°C, which is the average temperature of the sediment. Isotherms were linear for all cores and distribution ratios (R_D) calculated from the slopes of the isotherms ranged from 660 to 1,660 ml g^-1. These isotherms fit a simplified Freundlich isotherm. Correlations of R_D to a number of sediment parameters describing texture and mineralogy were determined. A close relationship was observed between R_D for caesium and the percentage of illite contained in the samples.     

Activity and metabolism of larval Atlantic cod (Gadus morhua) from Scotian Shelf and Newfoundland source populations

Patterns of activity and metabolism were investigated in larval Atlantic cod (Gadus morhua L.) between December 1991 and July 1992: (1) throughout larval development; (2) between two genetically discrete populations (Scotian Shelf and Newfoundland) and (3) as a function of two different culture temperatures. During the yolk-sac stage (0 to 5 d post-hatch), changes in swimming speed were not related to mass-specific metabolic rates; no portion of the mass-specific oxygen consumption could be explained by changes in activity. In the mixed feeding stage (6 to 14 d posthatch), there was a tendency for oxygen consumption to be related to changes in swimming speed. In the exogenous feeding stage (>14 d post-hatch), oxygen consumption significantly increased with swimming speed. These ontogenetic patterns of activity and metabolism were the same for larvae from the Scotian Shelf and Newfoundland populations. However, over the entire larval life and among ontogenetic stages, the metabolic cost of activity (mass-specific O₂ consumption/swimming speed) of Scotian Shelf larvae was significantly higher than that of Newfoundland larvae. When cod larvae, that had developed at 5°C, were acutely exposed to 10°C, Scotian Shelf larvae had a higher intrinsic cost of activity than Newfoundland larvae, over the entire larval life. During the exogenous feeding stage, the mean metabolic cost of activity for Newfoundland larvae raised at 10°C and tested at 10°C was significantly higher and more variable than that of larvae raised at lower temperatures. However, the metabolic cost of activity of larvae raised and tested at 10°C was not significantly different between source populations. Together these findings suggest that differences in swimming energetics reflect changing energy requirements for activity among ontogenetic stages, and reflect adaptation to regional environments among genetically discrete populations.     

Vertical fluxes and ecological significance of organic materials during the phytoplankton bloom during austral summer in Breid Bay,Antarctica

A mooring system consisting of an in situ fluorometer at a depth of 50 m and a time-series sediment trap at a depth of 110 m was deployed at the sediment trap site (70°11.536'S; 24°18.679'E; water depth: 300 m) in Breid Bay, Antarctica in austral summer from 28 December 1985 to 13 February 1986. Sinking particles, consisting of diatoms (mainly Thalassiosira antarctica), were analyzed for organic materials, stable carbon and nitrogen isotopes. Vertical fluxes of organic carbon and nitrogen were determined to be within the ranges of 12.3 to 116 mg C m^-2 d^-1 and 1.79 to 15.4 mg N m^-2 d^-1, respectively, with maxima in the middle of January 1986, after which time the organic carbon and nitrogen fluxes tended to decrease with a steep gradient. High values of ¹³C were found in the organic matter of the sinking particles collected before the middle of January, indicating that the organic matter was derived from the diatoms in the logarithmic phase of their growth. Increased abundance of glucose was found in the water-extractable carbohydrate, which was one of the sinking particles collected in the middle of January. This fact clearly indicated that the diatoms were no longer in the growth phase but rather in the stationary phase, because reserved glucan as well as various cellular organic materials were reportedly accumulated within the algal cells in the stationary phase. Fifteen species of protein amino acids with trace amounts of -alanine, -aminobutyric acid and ornithine were found in the sinking particles upon acid hydrolysis, but the amino acid composition of these samples had not been affected much by biological agents. The essential amino acid index was calculated for the sinking particles collected in the course of the sediment trap experiment. The indices obtained indicated that the sinking particles collected in Breid Bay were more ecologically significant than the sinking and suspended particles from deep waters.     

Nutrient regeneration by zooplankton during a red tide off Peru,with notes on biomass and species composition of zooplankton

During March and April 1976, a red tide, dominated by the dinoflagellate Gymnodinium splendens Lebour, developed in the vicinity of 15°06'S and 75°31'W off Peru. At the height of the bloom, the euphotic zone was 6 m deep and the chlorophyll a at the surface was 48 g l^-1. A daily collection of zooplankton at 09.00 hrs showed large fluctuations of biomass, from 0.2 to 3.84 g dry weight m^-2 in a water column of 120m. Copepodids and nauplii dominated the collections. During a period of reduced wind, the adult copepods were a mixture of the species characteristic of the coastal upwelling system and the neritic species associated with more northerly, tropical waters. Nitrogen regeneration by the zooplankton varied with the development of the bloom, the type of zooplankton dominating the experiment, and biomass fluctuations, but never accounted for more than 25% of the nitrogen uptake by phytoplankton.     

Effects of suspended sediments on egg production of the calanoid copepod Acartia tonsa

The estuarine copepod Acartia tonsa was collected on several occasions between 4 April and 14 August 1985 from Terrebonne Bay, Louisiana (29°08N; 90°36W) and the effects in its diet of suspended sediments, collected from the same area, were measured at five different concentrations of sediment (100 to 1 000 ppm) and six phytoplankton concentrations (500 to 13 000 cells ml^-1 Thalassiosira weissflogii). Egg production rate was used as an index of diet quality. At low phytoplankton concentrations (500 cells ml^-1), and at intermediate phytoplankton concentrations (2 000 cells ml^-1) for previously starved copepods, egg production was reduced by up to 40% at a sediment concentration of 250 ppm and further reduced at higher sediment concentrations. At higher food concentrations (4 000 to 13 000 cells ml^-1), suspended sediment had no effect on egg production rates at sediment concentrations up to 500 ppm. Rates were reduced only at the highest sediment concentration of 1 000 ppm. Under most natural conditions, suspended sediment would not significantly affect egg production rates in A. tonsa.     

Distribution of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, dioxin-like polychlorinated biphenyl and polycyclic aromatic hydrocarbons in the sediment of Temsah lake, Suez Canal, Egypt

Lake Temsah is one of the main wetlands in the Suez Canal region, and the main source for fish for the area. The lake is the end-point of several wastewater effluents. In the present study, residues of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyl (PCB) and polycyclic aromatic hydrocarbons (PAH) were monitored in the sediment of the lake. Samples were collected from six different sampling stations around the lake using a box-corer sampler, then kept frozen. Samples were extracted and cleaned up before residue determination was conducted using an HRGC/HRMS. An HP 6890 plus gas chromatograph was coupled to a Micromass Autospec Ultima mass spectrometer operating in EI mode at 35 eV and with a resolution of 10.000 (5% valley). PCDDs and PCDFs were detected in all sediment samples collected from various sampling stations. Results showed some progressive increase in PCDDs concentrations relevant to increase in chlorination. In the PCDD group of congeners, 1, 2, 3, 4, 6, 7, 8, 9 octa-CDD had the highest detected concentrations in all samples, while 2, 3, 7, 8 tetra-CDD showed the lowest concentrations. The World Health Organization toxicity equivalents ranged from 0.387 to 11.20 ng kg^-1 d.w. For PCDD homologues, hexa-CDD was the most dominant homologue in all sediment samples analysed. Regarding dioxin-like PCBs, results showed that IUPAC No. 118 congener, 2, 3, 4, 4, 5, pentachlorobiphenyl was the most concentrated of all detected congeners, with concentrations ranging between 0.039 and 43.201 µg kg^-1. For polycyclic aromatic hydrocarbons, benzo(b+k+j)fluoranthene had the highest concentrations in almost all sampling stations. However, fluorene was the smallest detected concentration in almost all stations. This result would indicate that PAH contamination of the lake seems to be coming from one main source in all sampling stations. The present work is the first record of PCCDs, PCCFs, and dioxin-like PCBs in the Temsah lake. The concentrations of the contaminants monitored in this study, especially those of PAHs, are rather alarming. Efforts should be made to stop point sources that contaminate the lake.     

Effects of temperature on morphological landmarks critical to growth and survival in larval Atlantic cod (Gadus morhua)

The morphology and function of structures important to energy acquisition were studied from spawning to the stage of transformation of larva to pelagic juvenile in Atlantic cod, Gadus morhua L., from December 1991 to July 1992. Fertilized eggs produced by adult fish from two genetically discrete populations (Newfoundland and Scotian Shelf) were raised under similar conditions in the laboratory at temperatures of 5 and 10°C. Subsamples of larvae were removed from cultures daily for 10 d, and then less frequently, and fixed for light microscopy and scanning electron microscopy. Nine functional morphological landmarks important to feeding, respiration and locomotion were chosen from observation of 280 ind. These landmarks defined 12 major developmental stages, from hatching to the pelagic juvenile stage. One of the feeding landmarks, intestinal stage, varied as a function of age and size and the variance in development was higher at 10°C than at 5°C; Newfoundland larvae developed more complex intestines than did Scotian Shelf larvae. In addition, Newfoundland larvae had significantly higher growth rates than those of Scotian Shelf larvae. Despite the higher growth rates and greater structural complexity of the intestine in Newfoundland larvae, the rate of yolk utilization was not significantly different between Newfoundland and Scotian Shelf larvae. Staging of respiratory landmarks showed that the gill arches were probably used preferentially in feeding while respiration was cutaneous. The gills, operculum and gill rakers developed late in larval life and accompanied the transition from cutaneous to branchial respiration. In the yolk-sac period, development of feeding and respiratory structures may be largely genetically controlled. During exogenous feeding, extrinsic factors also become important, as shown by the size and age-independent variation in intestinal development of larval cod raised at different temperatures.     

Origin and Distribution of Suspended Organic Matter As Inferred From Carbon Isotope Composition in A Mediterranean Semi-Enclosed Marine System

The origin and distribution of suspended organic matter, the trophic features and the stable carbon isotopic composition of particulate organic carbon (POC) were studied monthly in a Western Mediterranean semi-enclosed basin. Sampling stations were selected as a function of wind-exposure and the degree of vegetation cover and then compared with an adjacent unvegetated site. the predominant vegetation was seagrass (Posidonia oceanica and Cymodocea nodosa) and Caulerpa prolifera. Water samples were analyzed for total suspended matter (inorganic and organic fractions), photosynthetic pigments (chlorophyll-a and phaeopigments), dissolved organic carbon, particulate organic carbon and their isotopic composition. Temperature and salinity were also measured at the same sampling sites within range of Mediterranean limits. the suspended organic matter concentration was 1.77 ± 1.55 mg l^-1; the chlorophyll-a concentration was low (0.35 ± 0.24 μg l^-1); the disolved organic carbon concentration was 2,140 ± 2,010 μg l^-1; the particulate organic carbon concentration was 212 ± 106 μg l^-1 and the isotopic composition was 18.77 ± 2.51%_°. There were significant temporal differences except for phaeopigments, POC and its POC isotopic composition, and there were no spatial differences other than for δ¹³C. This picture highlighted a general seasonal trend and trophical features similar to adjacent sea.

Spatial differences in δ¹³C showed that the source of suspended organic matter was different between stations as that between sources and wind-hydrodynamic constraints. In     

Bathymetric distribution of chaetognaths in the South Eastern Pacific Ocean

The bathymetric distribution of chaetognath fauna observed at planktonic stations in the South Eastern Pacific Ocean during three different expeditions, is presented quantitatively. The material from the cruises IFOP-01 (October–December, 1964) and IFOP-04 (November–December, 1965) was collected by vertical closing net, at regular intervals, from 2000 and 1000 m depth, respectively; the R.V. A. Bruun Cruise 13 data include vertical samples at usual depth intervals from 3000 m (see Table 12), Isaac-Kidd Midwater Trawl (IKMT) and surface collections. They allowed us to identify, for the first time, the meso and bathypelagic species of this region and to extend the longitudinal distribution of the epipelagic species, which had been previously limited to the coastal areas. Among the epiplanktonic species, it was shown that two, Sagitta serratodentata and S. bipunctata, do not penetrate into the Peru Coastal Current region, where the endemic S. bierri is to be found extending westwards to the west boundary of the Peru Coastal Current, and that both mesopelagic species, previously reported for the epipelagic level of this area, S. decipiens and Eukrohnia hamata, inhabit the upper mesopelagic level in the oceanic region, but also rise to the epipelagic level near the coast, where upwellings do occur. The lower mesopelagic levels (500 to 1000 m) are occupied by E. fowleri and S. macrocephala, this latter species being reported for the first time in the South Eastern Pacific Ocean. The other mesopelagic species, S. zetesios and S. bathypelagica, also found for the first time in this region, were not found in large enough numbers to obtain a correct view of their stratification. Eukrohnia bathyantarctica, described for the Southern Ocean and previously reported only in the bathypelagic levels of the Gulf of Mexico and Caribbean Sea, was found at only bathypelagic levels. The faunistic data from the R.V. A. Bruun Cruise 13, were compared with the corresponding hydrographical profiles.     

Removal of toxic chromium(VI) from aqueous solution by activated carbon using Casuarina equisetifolia

Highly activated carbon from the seed husk of Casuarina Casuarinas equisetifolia, a worldwide famous plant, have been prepared and tested for the removal of toxic Cr(VI) from its aqueous solution. The adsorbent was investigated for influences of initial chromium concentration (75, 100, 125, and 150 mg l^-1), pH, contact time, and quantity of carbon on removal of Cr(VI) from aqueous solution at room temperature (25±2 °C). The adsorption kinetic of Cr(VI) was studied, and the rates of sorption were found to conform to pseudo-second-order kinetics with a good correlation (R²≥0.99). The Langmuir and Freundlich models fit the isotherm data well. Furthermore, the Gibbs free energy was obtained for each system and was found to be-5.29 kJ mol^-1 for removal of Cr(IV). The negative value of Δ G° indicates the feasibility and spontaneous nature of adsorption. The results indicate that acidic pH (1.05) supported the adsorption of Cr(IV) on activated carbon. The maximum adsorption capacity of Cr(VI) on activated carbon was about 172.4 mg g^-1 at pH 1.05.     

Heavy-metal adsorption by non-living biomass

The adsorption of some heavy metals onto the walls of harvested, washed, and dried non-living biomass cells of different Pseudomonas strains was studied at optimum experimental conditions using a simplified single component system. The Langmuir adsorption model was found to be a suitable approach to describe the system via multi-step processes. Isotherms measured at 30.0°C and pH 5.5 with [M]_total = 10-100 mM for tight, reversible Cr⁶⁺(aq), Ni²⁺(aq), Cu²⁺(aq) and Cd²⁺(aq) binding by the cell walls of the investigated biomass fit the Langmuir model and give the pH-independent stoichiometric site capacities ν_i and equilibrium constants K_i for metal binding at specific biomass sites i = A, B, C, and D. Tight binding sites A, B, and D of the non-living biomass are occupied by Cr^VI, sites A and C by Ni^II, sites A and D by Cd^II, and only site B by Cu^II. It is concluded that ν_i is a stoichiometric parameter that is independent of the magnitude of K_i for binding site i and that the studied heavy metals selectively and tightly bind at different biomass sites.     

Metal Concentration in Oyster, Crassostrea Gigas, and Sediment in Ann-Ping Mariculture Ground, Taiwan

This study was to assess the metal contamination in oyster tissue grown in the Ann-ping mariculture ground in Taiwan. the information generated from this work also revealed general metal pollution problem for Taiwan's oyster farmers. Oysters, Crassostrea gigas, and surficial sediments collected from ten locations in Ann-ping mariculture ground in Taiwan for metals concentration (Cu, Zn, Pd, Cd, Fe and Mn) were performed. Analytical results indicated that the yearly averaged oyster copper concentrations (μg g^-1, wet weight) in oyster soft parts from Ann-ping increased from 21.3±4.1 in 1993; 24.1±6.8 in 1994; 36.8±11.9 in 1995 to 43.9±23.1 μg g^-1, wet weight, in the 1996 raising season. the mean oyster copper concentration reached a level of 50 μg g^-1, wet weight, in December 1996. This increasing trend of metal concentration in oyster tissue indicates a potential pollution source which may pose a potential disaster as green oyster incidence, which occurred on the Charting coast in 1986, in Taiwan. Sediment samples in Ann-ping mariculture ground were also collected and examined. the seasonal variation of the copper concentration in surficial sediment from Ann-ping did not show an increasing trend as observed in oyster tissue.     

美国和五大湖双边共同关注区域的白肚燕(双色树燕)雏鸟的有机污染状况

白肚燕,又名双色树燕,栖居于五大湖流域中27个双边共同关注区域(AOCs),从2010年到2014年对其进行了污染物暴露风险评估,以协助管理者和监管者评估五大湖AOCs的污染状况。本文比较了AOCs和附近非AOCs雏鸟体内污染物浓度的差异。AOCs白肚燕雏鸟尸体中多氯联苯(PCB)和多溴联苯醚的含量分别为30%和33%,低于非AOCs的平均浓度。AOCs白肚燕雏鸟胃含物中多环芳烃(PAH)浓度和血浆中全氟化合物浓度分别为67%和64%,也低于非AOCs的平均浓度。但是与已有生殖效应记载的高PCB污染区相比,有些AOCs雏鸟尸体内的PCBs浓度只是存在小幅升高。一些AOCs食物中PAHs的浓度足够高以致引起可测量的生理响应。在AOCs中,全氟化合物全氟辛烷磺酸在血浆中的最高浓度出现在Raisin河(密歇根州,美国;几何平均数330 ng/mL),但远低于预估毒性的参考值(1 700 ng/mL)。之前有研究报道雏鸟胃含物中PAH和PCB的浓度以及尸体中PCBs的含量与沉积物中污染物的含量显著相关,从而可加强白肚燕在评估沉积物污染生物有效性方面的应用。
精选自Thomas W. Custer, Christine M. Custer, Paul M. Dummer, Diana Goldberg, J. Christian Franson, Richard A. Erickson. Organic contamination in tree swallow (Tachycineta bicolor) nestlings at United States and binational Great Lakes areas of concern. Environmental Toxicology and Chemistry: Volume 36, Issue 3, pages 735–748, July 2017. DOI: 10.1002/etc.3598
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3598/full
     

Mercury in surface waters of a macrotidal urban estuary (River Adour, south-west France)

Surface waters were collected in the River Adour estuary (south-western France) during different sampling periods from 1998 to 2001 in order to investigate the phase distribution and speciation of methylmercury (MeHg⁺). Although a high variability is observed, significant higher average concentrations of total MeHg⁺ (dissolved and particulate) are measured during the warm seasons, at 4.40±8.18 pM and 3.90±1.87 pM for July 1998 and September 1999, compared with the winter seasons, with concentrations at 0.99±2.85 pM and 1.00±1.75 pM for February 1998 and February 2001, respectively (one-tailed t-test, P=0.01). The seasonal variations are explained with enhanced bacterial activity during summer and sedimentation/resuspension phenomena. Additionally, signi-ficant longitudinal variations of the MeHg⁺ concentrations are observed. The highest levels in both dissolved and particulate fractions are found within the downstream urban estuarine area. This can be explained by the high methylation potential of the sediments, but direct anthropogenic inputs of MeHg⁺ from specific discharge points cannot be neglected. Biogeochemical factors like phytoplankton biomass and salinity also show a relationship with MeHg⁺ partitioning in the surface waters of the Adour estuary.     

Sediment nutrient flux in a coastal lake impacted by diverted Mississippi River water

The internal nutrient load from bottom sediment to the water column of a Louisiana Barataria Basin lake (Lake Cataouatche) receiving diverted Mississippi River water was determined. Dissolved reactive phosphorus (DRP), ammonium (NH₄-N) and nitrate (NO₃-N) flux from sediment to water column were measured. The DRP flux averaged-0.22 mg m^-2 d^-1 under aerobic water column conditions, as compared with that 3.29 mg m^-2 d^-1 under anaerobic conditions. The average NH₄-N released under anaerobic conditions (1.42 mg m^-2 d^-1) was significantly greater than rates under aerobic conditions (-0.02 mg m^-2 d^-1), indicating a strong relationship between nutrient flux and oxygen availability in the water column. The average NO₃-N flux was 2.13 mg m^-2 d^-1 under aerobic conditions as compared with-0.24 mg m^-2 d^-1 under anaerobic conditions in the sediment-water column. When the water column maintained under anaerobic conditions was switched to aerobic conditions, the DRP, NH₄-N, and NO₃-N concentrations in overlying water decreased rapidly over a short period of time. The mean annual internal DRP and NH₄-N load from the sediment to the overlying water was estimated to be 69.26 and 29.9 tonnes (Mg) yr^-1 respectively, which represents a significant portion of the total nutrient load to the Lake. Results demonstrate that the internal flux of nutrients from sediments can contribute a significant portion of the total nutrient load to the water column and should be considered in decisions on impact of nutrient in diverted Mississippi River on water quality of Barataria Basin.     

Determination of Microbial Activity in Marine Sediments by Resazurin Reduction

A simple method is presented to evaluate microbial activity in aquatic sediments. The method is based on resazurin reduction by microbial electron transport chains and reduced chemical compounds present in the sample. The addition of m-cresol, which inhibits enzyme activity, allows one to measure microbial metabolism by difference. Small aliquots of sediment (about 1 g FW) are incubated at 20°C with resazurin solution, with and without m-cresol. The sample is then filtered and the unreduced resazurin is measured at 600 nm.

Testing the method with a bacterial suspension gave a resazurin reduction of 89 μg/h/10⁹ cells. In a few marine coastal sediment samples, the resazurin reduction in aerobic conditions was in the range of 0.31 to 219.3 μg/h/g DW, which is equivalent to an oxygen consumption of 0.02 to 15.32 μg/h/g DW.     

Spatial variations in the N2O emissions and denitrification potential of riparian buffer strips in a contaminated urban river

Spatial variations in the N₂O emissions and denitrification potential of riparian buffer strips (RBS) in a polluted river were examined. The river received large pollutant inputs from urban runoff and wastewater discharge, resulting in impaired water quality in the river and downstream reservoir. The potential for nitrogen removal by RBS was evaluated by measuring in situ N₂O emission fluxes in static closed chambers and sediment denitrification potentials with acetylene inhibition techniques. The results showed that N₂O emission fluxes decreased from the upstream (16.39 μg/(m²·h)) to downstream (0.30 μg/(m²·h)) sites and from the water body to upland sites. The trend in decreasing N₂O emission fluxes in the downstream direction was mainly associated with sediment/soil textures (clay loam→sandy soil) and sediment/soil water contents and was also related to the vegetation along the RBS and nutrients in the sediments/soils. The correlation coefficient was highest (r=0.769) between the N₂O emission flux and sediment/soil water content. Sediment/soil denitrification potentials under N-amended and ambient conditions were higher (highest 32.86 mg/(kg·h)) for the upstream sites, which were consistent with in situ N₂O flux rates.     

Occurrence and distribution of micro- and mesoplastics in the high-latitude nature reserve,northern China

• The first study on micro(meso)plastics (MMPs) in the Liaohe River Reserve is reported. • Diverse MMP were detected in surface water and sediment at all 32 sites. • The abundance of MMPs decreased in the course of the river. • The MMPs abundance in water is significant association with the county population. Microplastics pollution has received growing attention worldwide in recent years. However, data on microplastics in the freshwater environment are still limited, especially in high-latitude nature reserves in Northern China. The first study on microplastic pollution in the Liaohe River Reserve in Northern China is reported here, and mesoplastics were also incorporated. Surface water and sediment samples were collected from 32 sites along the nature reserve. The abundance, type, shape, color, and size of micro- and mesoplastics were measured using density extraction, optical microscopy, and FTIR spectroscopy. The data showed that diverse micro- and mesoplastics were found widespread in the 32 sites, and the average abundance of these plastics was 0.11±0.04 10⁻² items/L in surface water and 62.29±54.30 items/kg in sediment. Moreover, 70% and 66% were smaller than 2000 μm in surface water and sediment, respectively. Fiber accounted for 91.86% in surface water and 43.48% in sediment, indicating that the major source of micro- and mesoplastics in the Liaohe River Reserve may be domestic sewage and aquaculture. A total of 16 and 27 polymers were identified in surface water and sediment, respectively, and mostly consisted of rayon, polyester, polystyrene, and poly(ethylene terephthalate). Moreover, both the risk index and the pollution load index demonstrated a low risk of micro- and mesoplastics in surface water and sediment in the Liaohe River Reserve.     

Microstructure adaptative des radioles deParacentrotus lividus (Echinodermata: Echinoidea) en milieu eutrophisé par des eaux usées

Recent investigations (1984) on the biology and morphometry of populations of the edible sea-urchinParacentrotus lividus (Lamarck) exposed to massive domestic pollution from the Cortiou sewage outlet (Marseille, France), revealed a significant lengthening of sea-urchin spines at sites located at a distance of 500m (Station 0) and 1 200 m (Station 1) from the outlet. At Station 0, spine length (SL) is nearly half as long as the diameter (D) of the test, resulting in a higher SL:D ratio here-0.470 as opposed to 0.360 in unpolluted areas (e.g. Station 3, 5 200 m from the outlet). This spine lengthening appears to be a morphofunctional adaptation, enabling the sea-urchins to adopt sestonophagy in order to benefit better from the plentiful resources of both particulate and dissolved organic matter arising from the outfall; examination of pellets filling the stomachs and guts of the sea-urchins corroborated this. SEM examination revealed that spines of specimens collected at Station 0 are more porous than those from Station 3 and their microarchitecture is better adapted to capturing suspended particulate matter: the ridges are narrower, the grooves wider, and the latter display a dense and more coarsely-meshed network. The axial medulla exhibits true and regularly arranged channels with highly structured walls. The ratio dry wt of spine: dry wt of test revealed thatP. lividus spines from Station 0 (ratio= 1.2) are lighter than those from Station 3 (ratio=1.4), reflecting the more porous microstructure and lighter stereome of the Station 0 sea-urchins. Previous measurements to determine the degree of eutrophication in the area polluted by the Marseilles urban sewage outfall revealed carbon content, as % of total sediment, as high as 36% in newly deposited sediment (100 m from the outlet), 16.7% at Station 0 (500 m) and 2.6% near Station 3 (about 5 200 m). Further experiments using sediment traps indicated that the organic matter tends to accumulate chiefly along the shoreline, whereas the suspended mineral fraction tends to be deposited to the south, i.e., further offshore. Thus, theP. lividus population at Station 0 exhibits a very unusual ecological plasticity, having developed a very efficient adaptative microstructure in order to meet its energy requirements despite the presence of various chemical pollutants.     

Studies of Thermal Transformations of Humic and Fulvic Acids in Soils I. Infrared Spectroscopy and Temperature-Programmed Pyrolysis Mass Spectrometry

Temperature-programmed pyrolysis mass spectrometry and Fourier-transform infrared spectroscopy have been used to monitor structural changes of humic and fulvic acids isolated from soils in China, in the temperature range of 25-550°C. in this work, we found that decarboxylation is obvious as the main reaction with dehydration reaction from 150°C to 400°C, the anhydride can be identified from FT-IR spectra at temperature range from 200°C to 400°C; there are evident changes of the aromatic nucleus of humic and fulvic acids above 400°C, even remaining up to 550°C. Besides, some changes of adsorption water can be distinguished before 200°C, and the mass signal of sulphur dioxide was detected.