Carbon sequestration of black locust forests in the Yellow River Delta region,China

The Yellow River Delta region in China is a land area of 1,200,000 ha with rich natural resources. Adverse environmental conditions, such as low rainfall and high salinity, promote the dominance of black locust trees for afforestation. With the increase of CO₂ in the atmosphere, this forest and others throughout the world have become valued for their ability to sequester and store carbon. Forests store carbon in aboveground biomass (i.e. trees), belowground biomass (i.e. roots), soils and standing litter crop (i.e. forest floor and coarse woody debris). There are well-developed methods to sample forest ecosystems, including tree inventories that are used to quantify carbon in aboveground tree biomass. Such inventories are used to estimate the types of roundwood products removed from the forest during harvesting. Based on standard plot inventories and stem analyses, carbon sequestration estimates of trees were 222.41 t ha^?1 for the Yellow River Delta region accounted for 67.12% of the whole forest. Similarly, carbon storage by herbaceous matter and soil was 0.50 and 50.34 t ha^?1, respectively. The results suggest that carbon sequestration in the forest ecosystem was performed by most of the forest, which plays an increasingly important role in sequestering carbon as the stand grows.     

Carbon sequestration potential of Rhizophora mucronata and Avicennia marina as influenced by age, season, growth and sediment characteristics in southeast coast of India

This work analysed the carbon sequestration potential in two species of mangroves (Rhizophora mucronata and Avicennia marina) along with their growth, biomass, sediment characteristics for four seasons of the year 2009–2010, in planted stands of different age (1–17.5 years) in the Vellar-Coleroon estuarine complex, India. The mangroves were recorded to store significant amount of biomass. Avicennia marina performed better to display 75 % higher rate of carbon sequestration than that in Rhizophora mucronata. This could be attributed to growth efficiency and high biomass production. For instance, Avicennia marina exhibited 2.7 fold higher girth, 24 % higher net canopy photosynthesis, 2 fold aboveground biomass (AGB), 40 % more belowground biomass (BGB) and 77.3 % higher total biomass, than R. mucronata did. Seasonally the rate of carbon sequestration was 7.3 fold higher in post-monsoon, 3.4 fold in monsoon, 73 % more in summer than that in pre-monsoon. The rate of carbon sequestration was positively correlated with age of planted site, tree height, tree diameter, net canopy photosynthesis, AGB, BGB, total biomass, carbon stock, growth efficiency, AGB/tree height tree girth, leaf area index, silt content (p?<?0.01). The carbon sequestration was negatively corrected with soil temperature and clay content (p?<?0.05). Mangroves were found to be a productive system and important sink of carbon in the tropical coastal zone, but increasing soil temperature due to global warming would have a negative impact on carbon sequestration potential of the mangroves.     

Soil characteristics and their potential thresholds associated with <Emphasis Type="Italic">Scirpus mariqueter</Emphasis> distribution on a reclaimed wetland coast

We studied various soil characteristics associated with Scirpus mariqueter growth and spatial heterogeneity in the Shanghai Nanhui Dongtan wetlands. In September and October 2015, 12 soil characteristics (soil organic carbon, total phosphorus, total nitrogen, nitrate, nitrite, ammonia, orthophosphate, pH, moisture content, particle size, salinity, and tidal elevation) were analyzed from 101 soil samples. The key factors affecting S. mariqueter spatial distribution were determined using canonical correspondence analysis and curve-fitting analysis. Results showed that vegetation indices of height, cover, density, and biomass were positively correlated (P?<?0.05) with tidal flat elevation. S. mariqueter was mainly distributed at tidal flat elevations of 2.0–3.4 m. Plant coverage and density were positively correlated (P?<?0.05) with total nitrogen and soil salinity. Based on the curve-fitting and independent samples t-test analyses, thresholds of total nitrogen, conductivity, and tidal flat elevation of soil were 0.5475 g/kg, 0.8368 μS/cm, and 2.75 m, respectively. This study provides critical data for future coastal wetland remediation worldwide.     

Nitrogen limitation in the coastal heath at Anholt,Denmark

The purpose of the study was to investigate, whether the coastal grey dune vegetation at Anholt, Denmark, is limited by nitrogen or phosphorus. The island Anholt (22,37 km²) is situated in the centre of Kattegat A two factor fertilization experiment with nitrogen as NH₄NO₃ (N-addition) and phosphorus as KH₂PO₄ (P-addition) was carried out in the coastal grey dune vegetation of Anholt. The N-addition corresponded to 40 kg N ha^?1 year^?1 and the P-addition to 7 kg P ha^?1 year^?1 The experiment included N-, P-, N + P-addition and control. Lichens (genera: mainly Cladonia, Stereocaulon, Cetraria, Hypogymnia) and bryophytes (genera: Polytrichum, Racomitrium) cover most of the surface. Only two plant species, Corynephorus canescens and Empetrum nigrum, constitute nearly all vascular plant cover and biomass of this calcium poor coastal heath community. Corynephorus and Empetrum increased their cover significantly following N and N + P addition. No effect was observed by P addition alone. N limitation of this coastal heath vegetation remote from agricultural and industrial activities was evident. The effect on the plant species of the single application was short-lived. After two-three years of enhanced cover, the Corynephorus and Empetrum cover had returned to their level before the experiment. The lichen vegetation, however, changed more permanently, and after 12 years the subplots with N + P addition was dominated by rich growth of Cladina and Cetraria species. The results are discussed in relation to anthropogenic nitrogen deposition and conservation of this high priority ecosystem.     

Field evaluation of intensive compost application on Cd fractionation and phytoavailability in a mining-contaminated soil

A field experiment was conducted to investigate the effect of chicken manure compost on the fractionation of cadmium (Cd), soil biological properties and Cd uptake by wheat in a soil affected by mining activities in Hubei province, China. Compost was applied at five levels (0, 27, 54, 108, 216 t ha^?1), and winter wheat (Triticum aestivum L.) was chosen as an indicator plant. Results showed that the application of compost increased soil pH and the content of total phosphorus and organic matter. Soil biological properties such as microbial biomass carbon, invertase, protease, urease and catalase activities were significantly enhanced by 0.24–3.47 times after compost application. Sequential extraction indicated that compost amendments decreased the acid-extractable Cd by 8.2–37.6 %, while increased the reducible and oxidisable Cd by 9.2–39.5 and 8.2–60.4 %, respectively. The addition of 27–54 t ha^?1 compost reduced Cd content in wheat stems and seeds by 69.6–75.0 % and 10.3–18.4 %, respectively. However, only 25.5–26.5 % reductions in Cd content in wheat stems were observed in 108–216 t ha^?1 compost amendments, and no significant decrease was detected for seeds. This study suggests that although compost is a suitable organic amendment to improve soil fertility and biological activities, the addition of compost should be moderated by an appropriate rate to optimize the use of compost for the reclamation of metal-contaminated soils at field scale.     

Aboveground biomass and carbon stock are related with soil humidity in a mangrove at the Piraquê-Açu River,Southeastern Brazil

In Brazil, few studies have been conducted about the assimilation of carbon and biomass accumulation in mangroves despite its great role as a carbon sink. In this sense, this study aimed to estimate the aboveground biomass (AGB) and carbon stocked by mangrove species in a stretch along the Piraquê-Açu River in southeastern Brazil, and to verify their relation with some soil parameters. For such, the height and diameter of all trees inside six plots of 100 m² were measured and used to quantify AGB through an allometric equation, and soil samples were collected to calculate granulometry, humidity, time of infiltration and permeability. Multiple regressions were used to identify relations between AGB and soil parameters. A total of 296 trees were found in the area and the AGB and carbon assimilated were 2.92 t ha^?1 and 1.46 t ha^?1, respectively. Laguncularia racemosa was the most abundant species and contributed with 61% of these values. Only a positive relation between AGB/carbon of L. racemosa and soil humidity was found, probably due to the substrate characteristics which contain a large concentration of silt/clay, and may store more water and do not yet provide firmness to the roots. By comparison, this mangrove had a low amount of AGB and carbon stocked and has yet to develop structurally. Along with other ecological functions and its associated ecosystem services such as supplying food for the local community, these features highlight the importance to conserve the studied mangrove and the interlinked coastal ecosystems.     

Impacts of vineyard area dynamics on soil erosion in a Mediterranean catchment (1950-2011)

The Mediterranean basin has undergone widespread land cover change. Urbanization of coastal areas, land abandonment of steeper slopes, and agricultural intensification in alluvial plains are recurrent themes. The objective of this study was to examine how vineyard land cover changes have affected agricultural soil erosion in a 50 year period (1950–2011). The study area covers a 235 km² catchment located near the Gulf of St Tropez. Aerial photographs were used to map land cover in 1950, 1982, 2003 and 2011, and the RUSLE soil erosion model was run to estimate soil erosion.

Between 1950 and 2011, vineyard went from about 2,426 ha to 1,561 ha. Mean soil erosion increased as vineyard slopes became steeper (11.8 T ha^?1, 13.2 T ha^?1, 14.4 T ha^?1 and 13.5 T ha^?1 for 1950, 1982, 2003 and 2011). Total erosion decreased after 1982: 28,621 T y^?1 in 1950, 29,030 T y^?1 in 1982, 22,848 T y^?1 in 2003, and 21,074 T y^?1 in 2011. Total soil loss in 2011 is about 75% of values in 1950–1982, so impacts on water pollution and channel dredging have evolved positively over time.     

Diffusive boundary layers and photosynthesis of the epilithic algal community of coral reefs

The effects of mass transfer resistance due to the presence of a diffusive boundary layer on the photosynthesis of the epilithic algal community (EAC) of a coral reef were studied. Photosynthesis and respiration of the EAC of dead coral surfaces were investigated for samples from two locations: the Gulf of Aqaba, Eilat (Israel), and One Tree Reef on the Great Barrier Reef (Australia). Microsensors were used to measure O₂ and pH at the EAC surface and above. Oxygen profiles in the light and dark indicated a diffusive boundary layer (DBL) thickness of 180–590 μm under moderate flow (~0.08 m s^?1) and >2,000 μm under quasi-stagnant conditions. Under light saturation the oxygen concentration at the EAC surface rose within a few minutes to 200–550% air saturation levels under moderate flow and to 600–700% under quasi-stagnant conditions. High maximal rates of net photosynthesis of 8–25 mmol O₂ m^?2 h^?1 were calculated from measured O₂ concentration gradients, and dark respiration was 1.3–3.3 mmol O₂ m^?2 h^?1. From light–dark shifts, the maximal rates of gross photosynthesis at the EAC surface were calculated to be 16.5 nmol O₂ cm^?3 s^?1. Irradiance at the onset of saturation of photosynthesis, E _k, was <100 µmol photons m^?2 s^?1, indicating that the EAC is a shade-adapted community. The pH increased from 8.2 in the bulk seawater to 8.9 at the EAC surface, suggesting that very little carbon in the form of CO₂ occurs at the EAC surface. Thus the major source of dissolved inorganic carbon (DIC) must be in the form of HCO₃ ^?. Estimates of DIC fluxes across the DBL indicate that, throughout most of the daytime under in situ conditions, DIC is likely to be a major limiting factor for photosynthesis and therefore also for primary production and growth of the EAC.     

Duckweed: an effective tool for phyto-remediation

Effective wastewater treatment through conventional methods that rely on heavy aeration are expensive to install and operate. Duckweed is capable of recovering or extracting nutrients or pollutants and is an excellent candidate for bio-remediation of wastewaters. Such plants grow very fast, utilizing wastewater nutrients and also yield cost effective protein-rich biomass as a by-product. Duckweeds being tiny surface-floating plants are easy to harvest and have an appreciable amount of protein (15%–45% dry mass basis) and a lower fiber (7%–14% dry mass basis) content. Besides nutrient extraction, duckweeds has been found to reduce total suspended solids, biochemical oxygen demand (BOD), and chemical oxygen demand in wastewater significantly. Depending on the initial concentrations of nutrients, duckweed-covered systems can remove nitrate (NO₃^?) at daily rates of 120–590 mg NO₃^? m^?2 (73%–97% of initial concentration) and phosphate (PO₄^?) at 14–74 mg PO₄^? m^?2 (63%–99% of initial concentration). Removal efficiencies within 3 days of 96% and 99% have been reported for BOD and ammonia (NH₃). Besides several genera of duckweeds (Spirodela, Lemna, Wolffia), other surface-floating aquatic plants like water hyacinth (Eichhornia) are well known for their phyto-remediation qualities.     

Isolation and characterisation of a carbofuran degrading Burkholderia sp. PCL3 from carbofuran-phytoremediated rhizosphere soil

A bacterial strain capable of degrading carbofuran as the sole carbon source was isolated from carbofuran-phytoremediated rhizosphere soil of rice. A 16S rRNA study identified the strain as Burkholderia sp. (isolate PCL3). Free cells of isolate PCL3 possessed inhibitory-type degradation kinetics with a q _max of 0.087 day^?1 and S _m of 248.76 mg·L^?1. Immobilised PCL3 on corncob and sugarcane bagasse possessed Monod-type degradation kinetics with a q _max of 0.124 and 0.098 day^?1, respectively. The optimal pH and temperature with the highest degradation rate coefficient of carbofuran were pH 7.5 and 35 °C, respectively.     

Seasonal variations in physicochemical characteristics and cyanobacterial diversity of a lake in Northern India

Physicochemical analyses and cyanobacterial diversity of Ramgarh Lake water were performed at five sampling sites during winter, summer, and monsoon seasons. Higher load of solids, carbon, and nutrients were persistent throughout the analysis that indicates the conversion of lake from oligotrophic to eutrophic nature. High nutrients load enhanced cyanobacterial biomass, while low nutrients load produced relatively less biomass. The physicochemical parameters of water samples revealed minimum 2.9 mg L^?1 dissolved oxygen (DO) at site-1 during summer, while maximum (5.6 mg L^?1) at site-4 in monsoon season. Maximum biochemical oxygen demand (BOD) (40 mg L^?1) and chemical oxygen demand (COD) (126 mg L^?1) were recorded at site-1 during summer, whereas minimum BOD (18 mg L^?1) and COD (52 mg L^?1) were evident at site-3 in monsoon season. Minimum concentration of nitrate (0.72 mg L^?1) was recorded at site-3 in summer, whereas maximum 2.7 mg L^?1 was present at site-5 in winter season. The phosphate concentration was maximum (0.52 mg L^?1) at site-5 in summer, and minimum (0.18 mg L^?1) was observed at site-4 in monsoon season. Cyanobacterial diversity was higher during all the seasons, and dominated by the species of Microcystis at all the five sampling sites.     

Carbon emission associated with respiration and calcification of nine gastropod species from the intertidal rocky shore of Western Europe

Intertidal rocky shores are characterized by vertical zonation that results from the interplay between environmental conditions, organism physiology, and species interactions. Metabolism of intertidal organisms is highly variable between species and it changes with vertical position along the intertidal gradient. The present study aimed to quantify the carbon metabolism of nine intertidal rocky shore gastropods, in order to clarify their respective roles in carbon production during emersion and immersion. The influences of monthly temperature variation and tidal level were tested for each species. Analyses were performed in the laboratory using the infrared gas analyzer method for measuring aerial respiration rates, and the dissolved inorganic carbon and total alkalinity technique for measuring aquatic respiration rate and calcification. Hourly carbon fluxes were calculated for the mean annual temperature of 13 °C measured in both air and underwater in the study area. Respiration rates were similar for emersion (8–25 μmol CO₂ g AFDW^?1 h^?1) and immersion (10–23 μmol DIC g AFDW^?1 h^?1). For all species, underwater respiration fluxes were more influenced by monthly temperature variation than by air fluxes, probably as an adaptation to the rapid changes occurring during emersion. Calcification was an important factor influencing annual carbon fluxes for all studied species; every species showed different calcification rates according to its size and position on the intertidal zone. Annual carbon emissions were calculated using the mean immersion/emersion time of each species. Intertidal gastropod carbon emission was primarily influenced by body biomass and their vertical position within the intertidal zone.     

The Influence of Varying Algal Biomass On Contaminant Exposure in Benthic-Planktonic Mesocosms: Copper (Ii)

Abstract

A series of mesocosms was exposed to a suite of light treatments and nutrient enrichment in order to generate algal communities of varying biomass. the influence of this biomass on the speciation of copper (II) was studied. Distribution coefficients ( _Kd,Lkg?1) were relatively high (log _Kd = 5 to 7), indicative of robust trace metal sequestration, and were likely controlled by the particulate organic carbon content (foc). Differences in _Kd over time and among treatments were significant, as was the relationship between _Kd and foc. Fluorescence quenching was used to determine binding capacities ( _Lt , M) and their associated binding constants ( _Kcond ,M^?1) in order to model the solid phase copper speciation. the _Kcond ranged between 2.1 and 5.2 × 10¹²M^?1, indicating a very strong copper-ligand complex, and was higher in mesocosms that received more light. the light _Lt increased over time, dramatically after the nutrient enrichment, but did not vary systematically among light treatments. _Lt ranged from 7.2 × 10? 7 to 4.9 × 10? 5 M. the large magnitudes of _Kd , _Kcond and _Lt ensured that greater than 97% of total copper in the mesocosms was complexed by organic matter. the total copper concentration ([Cu]_T, M) needed to reach a target dissolved copper concentration of 10^?12.5 M (pCu = 12.5) was determined for each mesocosm over time. [Cu]_T was between 8.02 × 10^?5 and 3.41 × 10^?2 M, and increased over time. the [Cu]_T normalized to the target pCu (Effective Dose Ratio, EDR) increased directly with increases in algal biomass, indicating a direct link between system productivity and copper exposure. Approximately 45% of the variance in EDR was explained by variance in total biomass, while the residual variance in EDR was due likely to differences in the strengths of particle associations and magnitude of binding capacities.     

Estimation and validation of biomass of a mountainous agroecosystem by means of sampling,spectral data and QuickBird satellite image

Biomass estimation in agroecosystems (AESs) is important to understand their role in carbon exchange for a sustainable environment. We used field spectra and sampled biomass of an AES including cultivated and abandoned croplands to develop a simple biomass estimation model. The digital number (DN) of a QuickBird (QB) satellite image was converted to a reflectance factor using the dark object subtraction method and the spectral reflectance of asphalt. The relationship between the reflectance factor of field-based spectra and the QB image obtained in early July 2007 was insignificant in the blue (R ² = 0.15) and green (R ² = 0.18) bands but was significant (p < 0.05) in the red (R ² = 0.57) and near-infrared (NIR, R ² = 0.45) bands in the AES. Better correlations were obtained between field-based and QB-based vegetation indices (VIs). The best correlations were obtained with the normalized difference vegetation index (NDVI) (R ² = 0.97, p < 0.001) and the ratio vegetation index (RVI) (R ² = 0.99, p < 0.001). Biomass was significantly correlated with both field-based NDVI and RVI (R ² = 0.79 and 0.72, respectively, p < 0.001). Although RVI saturated at higher biomass densities (>600 g m^?2), NDVI showed a linear relationship. Other field-based VIs showed poorer correlations with biomass. The model was evaluated by incorporating it into high-resolution QB images to obtain the observed biomass. The relationship between field-estimated and QB-observed biomass appeared to be a one-to-one linear relationship (R ² = 0.79). Thus, models using field spectra and sampled biomass can be applied to QB images for remote estimation of biomass in an AES.     

Effects of zinc stress on growth and antioxidant enzyme responses of Kandelia obovata seedlings

This study evaluated the tolerance and accumulation potential in the mangrove Kandelia obovata under moderate and high levels of external Zn. A greenhouse experiment was conducted to investigate the effects of a range of external Zn concentrations (0–400 mg L^?1) on the growth of this species by counting the lateral root number and measuring the root length, leaf area, and total dry biomass. We also determined the Zn accumulation in plant tissues. K. obovata survived with external Zn concentrations of up to 400 mg L^?1, although the excess metal resulted in a biomass reduction of 34%. A significant increase in antioxidant enzyme activities occurred in roots of plants under high-level Zn stress, suggesting that K. obovata seedlings could tolerate up to 200 mg L^?1 zinc treatment.     

Combination system of full-scale constructed wetlands and wetland paddy fields to remove nitrogen and phosphorus from rural unregulated non-point sources

Constructed wetlands (CWs) have been used effectively to remove nitrogen (N) and phosphorus (P) from non-point sources. Effluents of some CWs were, however, still with high N and P concentrations and remained to be pollution sources. Widely distributed paddy fields can be exploited to alleviate this concern. We were the first to investigate a combination system of three-level CWs with wetland paddy fields in a full scale to remove N and P from rural unregulated non-point sources. The removal efficiencies (REs) of CWs reached 57.3 % (37.4–75.1 %) for N and 76.3 % (62.0–98.4 %) for P. The CWs retained about 1,278 kg N ha^?1 year^?1 and 121 kg P ha^?1 year^?1. There was a notable seasonal change in REs of N and P, and the REs were different in different processing components of CWs. The removal rates of wetland paddy fields adopt “zero-drainage” water management according to local rainfall forecast and physiological water demand of crop growth reached 93.2 kg N ha^?1 year^?1 and 5.4 kg P ha^?1 year^?1. The rice season had higher potential in removing N and P than that in the wheat season. The whole combined system (0.56 ha CWs and 5.5 ha wetland paddy fields) removed 1,790 kg N year^?1 and 151 kg P year^?1, which were higher than those from CWs functioned alone. However, another 4.7-ha paddy fields were needed to fully remove the N and P in the effluents of CWs. The combination of CWs and paddy fields proved to be a more efficient nutrient removal system.     

Photosynthetic and growth responses of Japanese sasabamo (Potamogeton wrightii Morong) under different photoperiods and nutrient conditions

Controlled laboratory experiments were conducted to examine how photosynthesis and growth occur in Potamogeton wrightii Morong under different photoperiods and nutrient conditions. The experiment was based on a 3×2 factorial design with three photoperiods (16, 12 and 8 h) of 200 μE · m^?2·s^?1 irradiance and two nutrient conditions, high (90 μmol N · L^?1·d^?1 and 9 μmol P · L^?1·d^?1) and low (30 μmol N L^?1·d^?1 and 3 μmol P · L^?1·d^?1). After 14, 28, 56 and 70 days of growth, plants were harvested to determine net photosynthesis rate and various growth parameters. Above- and below-ground biomass were investigated on days 56 and 70 only. Plants under low nutrient conditions had greater leaf area, more chlorophyll a, a higher rate of net photosynthesis and accumulated more above- and below-ground biomass than plants in the high nutrient condition. Plants with an 8 h photoperiod in the low nutrient condition had a significantly higher rate of net photosynthesis, whereas 8 h photoperiod plants in the high nutrient condition had a lower rate of net photosynthesis and their photosynthetic capacity collapsed on day 70. We conclude that P. wrightii has the photosynthetic plasticity to overcome the effects of a shorter photoperiod under a tolerable nutrient state.     

The pollution characteristics of PM<Subscript>2.5</Subscript> and correlation analysis with meteorological parameters in Xinxiang during the Shanghai Cooperation Organization Prime Ministers’ Meeting

The pollution characteristics of PM_2.5 and correlation analysis with meteorological parameters in Xinxiang during the Shanghai Cooperation Organization Prime Ministers’ Meeting were investigated. During the whole meeting, nine PM_2.5 samples were collected at a suburban site of Xinxiang, and the average concentration of PM_2.5 was 122.28 μg m^?3. NO₃ ^?, NH₄ ⁺, SO₄ ^2? accounted for 56.8% of the total water-soluble ions. In addition, with an exception of Cl^?, all of water-soluble ions decreased during the meeting. Total concentrations of crustal elements ranged from 6.53 to 185.86 μg m^?3, with an average concentration of 52.51 μg m^?3, which accounted for 82.5% of total elements. The concentrations of organic carbon and elemental carbon were 7.71 and 1.52 μg m^?3, respectively, lower than those before and after the meeting. It is indicated that during the meeting, limiting motor vehicles is to reduce exhaust emissions, delay heating is to reduce the fossil fuel combustion, and other measures are to reduce the concentration of PM_2.5. The directly dispersing by mixing layerheight increase and the indirectly reducing the formation of secondary aerosol by low relative humidity, andthese are the only two key removing mechanisms of PM_2.5 in Xinxiang during the meeting.     

Determination of persistent organic pollutants in sediment and fish of the western coast of Alexandria,Egypt

Persistent organic pollutants (POPs) were recorded in sediment and fish samples collected from the western coast of Alexandria. Total hydrocarbons (aliphatic+PAHs ) in sediment ranged from 683.8 to 34670.1 ng g ^?1 with an average of 9286.9 ng g ^?1. The sum of C16–C34 of aliphatic fractions was<4000?ng g;^?1, indicating the presence of a fresh petroleum source. For all sediments, the anthracene/phenanthrene ratio was>0.1, suggesting the dominance of a pyrolytic source. Total aliphatics in different fish species ranged from 253 to 11?132 ng g;^?1, while total PAHs ranged from 3862 to 35?746 ng g;^?1 wet weight. Benzo[a]pyrene was the most dominant PAH fraction ranged from 1902.7 to 32 905.5 with an average of 9464.5?ng g;^?1 wet weight in all fish species. Concentrations of polychlorinated biphenyls (PCBs) ranged from 0.79 to 64.9?ng g;^?1 with an average 12.14?ng g;^?1 wet weight. The concentrations of organochlorines in fish species (Euthynnus alleferatus, Scomberomorus commerson, Sphyraena Sphyraena, Diplodus vulgaris, and Alepes djedaba) decreased following the order: PCBs>DDTs>HCHs>total cyclodienes. Concentrations of DDTs in fish tissues ranged from 4.89 to 36.37 ng g^?1 with an average of 16.4?ng g;^?1 wet weight. The concentrations of total HCHs ranged from 0.3 to 65.7?ng g;^?1 with an average of 16.35?ng g;^?1. The present study indicates: (1) fresh petroleum input where Pr/Ph>1; (2) PAHs in sediment<4000 ng g ^?1; (3) BaP concentration exceeded the permissible levels in Alepes djedaba species; (4) DDTs in sediment were below the effective range low level; (5) PCBs>effective range low and相似文献