Butyltins in water, biofilm, animals and sediments of the west coast of India

Biofilm, fish, oyster, mussel, clam, surface seawater, suspended particulate matter (SPM), and sediment samples were collected from marine and/or estuarine waters of the west coast of India. These samples were analysed for butyltin derivatives such as dibutyltin (DBT) and tributyltin (TBT). The concentrations DBT plus TBT varied between 2.4 and 8.3, 163 and 363 ng/l, 5 and 2853 ng/g dry wt in the SPM, seawater and sediment samples, respectively, of the Marmugao harbour. The values of DBT plus TBT ranged between 0.60 and 29, 123 and 242 ng/l and 1.4 and 65 ng/g dry wt in SPM, water and sediment samples, respectively, collected from the Mandovi estuary. In the Dona Paula Bay the DBT plus TBT varied from 10 to 89 ng/l in surface seawater, and TBT from 10 to 513 ng/g in biofilm samples. For the coastal sediment samples the concentration of DBT plus TBT ranged between 36 and 133 ng/g dry wt of sediment. For the animal samples the DBT plus TBT ranged between 58 and 825 ng/g dry wt of the tissue. Mussel tissues contained the highest amount of DBT plus TBT (825 ng/g dry wt tissue), whereas highest TBT concentration was recorded in the oyster (732 ng/g dry wt). TBT was generally the most abundant butyltin compound in most of the samples suggesting fresh inputs and/or less degradation of TBT. A wide range of the observed butyltin concentrations suggests the presence of localized areas of contamination. Leaching of tributyltin-containing antifouling paints from the ocean going ships, fishing and recreational boats, barges, and the inputs of TBT from the Goa shipyard and dry dock facility situated in the harbour are the probable sources of the DBT and TBT in the samples of the west coast of India. Higher levels of TBT were observed in biofilm relative to that in the surrounding seawater. When fed on TBT contaminated biofilm of the diatom Navicula subinflata, butyltin concentrations in the clam Paphia malabarica increased over the period of feeding suggesting the importance of biofilm in the transfer of butyltins to higher group of organisms.     

Concentrations of organotin compounds in sediment and clams collected from coastal areas in Vietnam

Levels of butyltin (BT) and phenyltin (PT) compounds were determined in sediments and clam Meretrix spp. collected from north and central coastal areas in Vietnam. Concentrations of TBT in sediments ranged from 0.89 to 34 ng g(-1) dry wt and those in clams ranged from 1.4 to 56 ng g(-1) wet wt. The levels of TBT in sediments and clams from Vietnam were within limits reported from other countries. Further, the TBT level in clams was lower than the tolerable average residue level (TARL) estimated based on tolerable daily intake (TDI). Trace amounts of PTs were also found in both sediment and clam samples. In sediments from north and central Vietnam, the concentrations of TBT were highest in the order of Hue (28 ng g(-1) dry wt), Cua Luc (15 ng g(-1) dry wt), Sam Son (6.3 ng g(-1) dry wt), and Tra Co (5.5 ng g(-1) dry wt). Among the clams from north and central Vietnam, the levels of TBT in clams from Cua Luc were dramatically high at 47 ng g(-1) wet wt. TBT formed the principal butyltin species in sediment at all sites studied. The ratios of TBT in sediment were higher among BT compounds at all study sites. Of total BTs, TBT was the dominant species in clams from almost all sites studied. In spatial distribution, TPT showed a pattern similar to TBT, suggesting the use of TPT as an antifouling paint. The partition coefficient between sediment and calms was calculated. The partition coefficients of TBT and TPT were 2.01 (0.56-5.5) and 9.23 (3.1-20), respectively. These results show that sediment-bound TBT is a source of contamination to clams in addition to dissolved TBT.     

Tributyltin distribution and producing androgenic activity in water,sediment, and fish muscle

This study investigated the concentrations of Tributyltin (TBT) in water, sediment, and fish muscle samples taken from Kaohsiung Harbor and Kaoping River estuary, Taiwan. TBT concentrations in water and sediment samples ranged from less than 18.5 to 34.1 ng Sn L^?1 and from 2.44 to 29.7 ng Sn g^?1 weight per weight (w/w), respectively. Concentrations in the TBT‐contaminated fish muscle samples ranged from 10.8 to 79.6 ng Sn g^?1 w/w. The TBT concentrations in fish muscle were higher than those in water and sediment samples. The fish muscle/water TBT bioconcentration factor (BCF) ranged from 590 to 3363 L kg^?1. Additionally, the water samples were assessed for androgenic activity with an MCF7‐AR1 human breast cancer cell line. The androgenic activity ranged from 0.94 to 3.1 ng‐dihydrotestosterone per litre water (ng‐DHT L^?1). Higher concentrations of TBT in water and sediment samples occurred in the dry season, but the androgenic activity had higher values in the rainy season.     

Experimental effects of tributyltin (TBT) contaminated sediment on a range of meiobenthic communities

Microcosm experiments have been carried out with whole natural meiobenthic communities to look at the effects of TBT sediment contamination on the community structure of the dominant nematode component of the meiobenthos. TBT has a high affinity for aquatic sediments, yet this is the first study of the effects of this contaminant in sediment on natural benthic communities. Three communities were studied from contrasting locations in south-west England: the intertidal of the Lynher estuary (muddy sediment) and the Exe estuary (sandy sediment) and the subtidal (50m depth) at Rame Head off Plymouth (muddy sand). Fresh sediment with natural meiobenthic communities was incubated for 2 months with TBT-contaminated sediment (three dose levels) in bottles. Nematodes were identified and enumerated and subjected to multivariate data analysis. The sandy Exe estuary fauna was significantly affected by TBT-contaminated sediment at all three doses (0.3, 0.6 and 0.9 microg g(-1) dry wt (as Sn) sediment), whereas the offshore fauna from Rame Head was significantly affected only at the highest dose. The muddy Lynher estuary meiofauna was affected (somewhat peculiarly) at the medium dose level only. Meiobenthic nematodes may not be as sensitive to TBT-contaminated sediment as other infaunal benthos but exhibited responses to levels of contamination still persisting in some UK estuaries and harbours. Comparing the effects of TBT with those of copper and zinc in the same laboratory experiments, our observations suggest that the relative impact of TBT on meiobenthic community structure is not as great as these contaminants in marine sediments. Although there are very few observations of TBT toxicity in sediment, it appears that TBT is toxic at much lower concentrations in seawater (ppb) than it is in sediment (ppm).     

Concentration of butyltin species in sediments associated with shipyard activity

Tributyltin (TBT) and dibutyltin (DBT) were analyzed in sediment samples collected from intertidal locations in Portland and Boothbay Harbor, Maine (USA) in 1990 and 1992. Surface sediment TBT concentrations ranged from 24 to 12 400 ng gm(-1) (dry wt basis). Sediments with the highest TBT concentrations were associated with shipyard hull washing/refinishing activities. Analysis of different layers in core samples found that butyltin concentrations decreased with depth at the Boothbay site and remained relatively constant with depth at the Portland site. Elutriate analysis showed that soluble TBT was released from a heavily contaminated sediment. The resulting TBT seawater concentration 1400 ng liter(-1) was < 0.03% of reported seawater solubilities of TBT and was only 0.14% of the total TBT in the sediment sample. This suggests that the TBT in the sediments analyzed is in a bound matrix form, such as paint particles, that releases the biocide slowly. The results indicate that there is a potential for future release of TBT from the resuspension of fine sediments at certain locations in Maine.     

Butyltin compounds in sediment and fish from the Polish Coast of the Baltic Sea

Concentrations of mono- (MBT), di- (DBT), and tri-(TBT) butyltin compounds were measured in eggs, liver, and muscle of nine species of fish from four regions of the Baltic Sea - the Firth of Vistula, the Gulf of Gdańsk, Puck Bay, and the mouth of the Vistula River. The overall concentration ranges among all the fish sampled from the four sites were: < 7 to 79 ng/g for MBT, 6 to 1100 ng/g for DBT, 7 to 3600 ng/g for TBT, and 16 to 4800 ng/g for total BTs, on a wet wt basis. The highest concentration of total BTs was found in herring liver from the Firth of Vistula (4800 ng/g, wet wt) and in roach muscle from Puck Bay (3300 ng/g, wet wt), while the least concentration was found in burbot eggs and liver from the Vistula River (39 and 32 ng/g, wet wt, respectively). TBT was the major form of BTs present in most samples analyzed. Sediment samples collected from shipyards in the Gulf of Gdańsk contained butyltin concentrations ranging from 1.2 to 46 μg/g (dry wt) for MBT, 2.0 to 42 μg/g for DBT, and 2.6 to 40 μg/g for TBT. As with the fish, the majority of the BTs in sediment were present as TBT, which suggested recent exposure of the aquatic environment of the region to TBT.     

Contamination of butyltin and phenyltin compounds in the marine environment of Otsuchi Bay, Japan

Butyltin (BT) and phenyltin (PT) compounds were measured in seawater, sediment, and biological samples collected from coastal areas of Otsuchi Bay, Japan. Tributyltin (TBT) compounds in seawater, sediment, plankton, mussels, scallops and fish were in the range of 0.008-0.074 microg liter(-1), 0.01-0.64 mg (kg dry wt)(-1), 0.24-9.8 mg (kg dry wt)(-1), 0.04-0.18 mg (kg wet wt)(-1), 0.10-0.13 mg (kg wet wt)(-1) and 0.01-0.02 mg (kg wet wt)(-1), respectively. Trace amount of PTs were found in seawater. The highest concentrations of TBT and triphenyltin (TPT) were found near a shipyard. Triorganotin compounds were more dominant than their metabolites. A positive correlation was observed between the concentrations of TBT and TPT in the mussels. Concentrations of TBT and TPT in mussels were high in the upper intertidal zone, and decreased toward the water.     

Spatial and temporal variations and possible sources of dichlorodiphenyltrichloroethane (DDT) and its metabolites in rivers in Tianjin, China

Water, suspended solid (SS) and sediment samples were collected from nine water courses in Tianjin, China and analyzed for dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including o,p'-,p,p'-DDT, DDD and DDE). The average DDX concentrations in water, SS and sediment were 59+/-30 ng l(-1), 2690+/-1940 ng g(-1)dry wt. and 340+/-930 ng g(-1)dry wt., respectively. Due to the termination of the extensive agricultural application and industrial manufacture, DDXs in river sediment decreased by one order of magnitude since 1970's and low DDT fractions in these sediments were observed. Still, DDXs in the sediments near the outlets of the major manufacturers remained relatively high attributed to the historic input. DDXs in sediment were also positively correlated with organic matter content. Spatial distributions of DDXs in SS and water was different from that in sediment. For SS, a negative correlation between DDX concentration and SS content indicated a dilution effect in many rivers. Dissolved organic carbon content was the major factor affecting DDX concentrations in water phase. Wastewater discharged from dicofol manufacturers and likely illegal agricultural application were the primary reasons causing high DDT (DDE+DDD) ratios in SS and water.     

Contamination of butyltin compounds in Malaysian marine environments

Concentration of butyltin compounds (BTs), including tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) and total tin (SigmaSn) were determined in green mussel (Perna viridis), 10 species of muscle fish and sediment from coastal waters of Malaysia. BTs were detected in all these samples ranging from 3.6 to 900 ng/g wet wt., 3.6 to 210 ng/g wet wt., and 18 to 1400 ng/g dry wt. for mussels, fish and sediments, respectively. The concentrations of BTs in several locations of this study were comparable with the reported values from some developed countries and highest among Asian developing nations. Considerable concentration of BTs in several locations might have ecotoxicological consequences and may cause concern to human health. The parent compound TBT was found to be highest than those of its degradation compounds, DBT and MBT, suggesting recent input of TBT to the Malaysian marine environment. Significant positive correlation (Spearman rank correlation: r2=0.82, P<0.0001) was found between BTs and SigmaSn, implying considerable anthropogenic input of butyltin compounds to total tin contamination levels. Enormous boating activities may be a major source of BTs in this country, although aquaculture activities may not be ignored.     

Seasonal variation in the composition and concentration of butyltin compounds in marine fish of Taiwan

For the first time, strong evidence is presented to demonstrate that the accumulations of butyltin compounds (BTs) exhibit seasonal variations with respect to their compositions and concentrations in marine fishes. Measurements were made on the benthic ponyfish Leiogenathus splendens and lizardfish Trachinocephalus myops inhabiting the west coast of Taiwan. In the whole body samples of the ponyfish, BT concentrations ranged from 236 to 2501 ng/g wet wt, with those in winter considerably higher than in the other seasons (p < 0.05 ). In a similar vein, proportions of mono- (MBT), di- (DBT) and tributyltin (TBT) differed significantly (p < 0.001) depending upon the season, with TBT (75 and 50%) dominant in winter and spring and DBT (37 and 57%) and MBT (42 and 24%) dominant in summer and autumn, respectively. In the lizardfish, the concentrations of BTs were one to two orders of magnitude higher in the liver than in the muscle, i.e. 3058-11,473 vs. 36-159 ng/g wet wt, respectively. Concentrations of MBT, DBT and TBT in the muscle ranged, respectively, from 5 to 14, 8 to 35 and 23 to 110 ng/g wet wt, with the major compound being TBT (57-69%) in all seasons. However, in the liver, DBT concentrations, ranging from 992 to 7797 ng/g wet wt, differed seasonally with a descending order of autumn>summer>spring (p < 0.05). Meanwhile, TBT (41%) was predominant in spring, whereas DBT (50 and 68%) was most heavily concentrated in summer and autumn (p < 0.001). Seasonally mediated physiological changes, such as dilution due to growth and metabolic compensation, may play important roles in forming different BT accumulation patterns among seasons and organisms.     

Organotin concentrations in three intertidal neogastropods from the coastal waters of Taiwan

This study was aimed to determine organotin concentrations in the muricids Thais clavigera, Thais tuberosa and Morula granulata on an island wide scale and to find an adequate bioindicator species for long-term monitoring purpose. Samples were collected from the coast of Taiwan and vicinity islands with organotin analysis by graphite furnace atomic absorption spectrophotometry. Because triphenyltin (TPT) could not be discriminated from tributyltin (TBT) by the extraction method, organotins were measured as TBT + TPT and total hexane extractable organotins. Severity of imposex in the muricid population samples expressed as relative penis size (RPS) indices were calculated and compared to determine a suitable bioindicator species. In T. clavigera, T. tuberosa and M. granulata, TBT + TPT were 17-157, 1-44 and 117-1343 ng Sn g(-1) dry wt, respectively. And total organotins varied in the range of 181 to 1125, 23 to 44 and 229 to 1402 ng Sn g(-1) dry wt, respectively. A positive correlation was found between TBT + TPT and total organotins in M. granulata (TBT + TPT = Total organotins x 1.01-110.79; R2=0.97; p<0.001). At the site of Dapaisha, total organotins in M. granulata was 10 times higher than in T. tuberosa (i.e. 242 versus 23 ng Sn g(-1) dry wt). No signs of imposex were found in T. tuberosa (a single site in two subsequent years) and in M. granulata (seven collection sites). The degree of imposex (RPS) of T. clavigera varied from 0.2 to 38.1%. The RPS indices from fishing harbors were not higher than from rocky shores and oyster culture sites. No correlation was found between RPS indices and concentrations of TBT + TPT or total organotins. M. granulata seemed to be insensitive to organotin pollution although organotins were also detected. Our results indicate that organotin pollution is wide spread in coastal waters of Taiwan and pollutants at least include butyltins and phenyltins. As a bioindicator species, T. clavigera is more appropriate than T. tuberosa and M. granulata to monitor organotin contamination.     

Tributyltin in environmental samples from the Former Derecktor Shipyard, Coddington Cove, Newport RI

Tributyltin (TBT) was detected in all 24 surface sediment (top 2 cm) samples collected from Coddington Cove, Newport, RI. TBT surface sediment concentrations ranged from 32 to 372 ng Sn/g with a mean concentration of 146 ng Sn/g. Analyses of selected core sections detected TBT in at least the top 18 cm at all 7 stations where cores were collected. No consistent TBT concentration trends with depth for these cores suggest mixing is an important process in the sediment column. In one core (station 28), TBT was found in the 76-86 cm section at a concentration of 141 ng Sn/g; thus sediments are a significant sink for TBT. However, sediment mixing processes can enhance releases of bioavailable TBT. Mussels, clams and fish from Coddington Cove contain TBT at concentrations ranging from 9.2 to 977 ng Sn/g. TBT concentrations in lobsters were below the detection limit (<6 ng Sn/g). Based on available screening criteria, TBT concentrations in Coddington Cove sediment is likely to be having an adverse effect on the biota at some locations.     

Horizontal distribution of butyltins in surface sediments from an enclosed bay system, Korea

Tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) compounds were quantitatively determined from surface sediment samples (total 59 stations) covering a whole basin where harbors, shipyards, and aquaculture farms were located. Butyltin compounds were detected from all the stations covering 640 km(2) of an enclosed bay system. TBT concentrations ranged from 4 to 382 ng/g as tin on a dry weight basis, and total butyltin concentrations, from 27 to 1763 ng/g. Horizontal distribution of TBT concentration showed apparent negative gradients from harbors and shipyards, indicating that its contamination was closely related to boating and dry-docking activities. However, TBT concentrations were decreased steeply from source areas. Elevated DBT and MBT levels in creeks imply the possible input of DBT from industrial wastewater. Total butyltin concentrations in sediments are significantly correlated with particulate organic carbon concentration for the subset of stations that are distant from source areas.     

Growth of Plants on TBT-contaminated Harbour Sludge and Effect on TBT Removal (10 pp)

Background Worldwide, large amounts of sediments have to be dredged annually from waterways and harbours. These sediments are sometimes polluted with a variety of toxic compounds. In some countries, including Belgium, the load with the biocide tributyltin (TBT) from ship coatings prohibits the dumping of harbour sludge into the sea. Land-based dumping is a commonly used alternative. Objective This research investigated the feasibility to use land-deposited harbour sludge for plant production. In a field trial, the growth of 38 more or less salt-tolerant plant species on low and high TBT-contaminated sediments was studied. The elimination of TBT from sludge with and without vegetation was compared. The uptake of TBT and its degradation products di- and monobutyltin (DBT and MBT) into harvest products under field conditions was determined. - Experimental Set-up. Sediments dredged in May 2003 from the brackish waters of the port of Antwerp were analysed in the laboratory for soil texture, pH, electroconductivity, sodium, magnesium, potassium, calcium, ammonium, nitrate, total nitrogen, chloride, sulphur and the organotins TBT, DBT and MBT. The sediments were lagooned for one year to dewater, desalinate and improve their structure. Salt-tolerant domestic and wild plants were selected and sown in May 2004. In August 2004, plants were harvested and the produced biomass was determined. Samples were taken from vegetated and non-vegetated top and bottom sediments and from plants growing above soil and analysed for TBT, DBT and MBT. Results The fresh sediments showed a good supply with nutrients and a neutral pH, but were rather saline (EC 14 mS cm-1 of the saturated paste extract). The salinity decreased to 3.7 mS cm-1 during lagoonation. The high and the low contaminated sediment had initially 43 and 1.6 mg TBT kg-1 dry weight, respectively. Besides TBT, several other contaminants were present in the sediments at critical levels. The biomass production of the plant species from the field trial ranged from 0.2 to 13 tons dry mass per hectare. Plants performing excellently were barley, sorghum, rape seed, a clover/grass mix and reed. If at all, a positive influence of TBT on plant growth was seen. TBT was degraded significantly faster (>40%) below barley. The uptake of TBT, DBT and MBT into stem and leaves of reed, grass and clover was very low, but measurable and not related to concentrations in soil. No uptake of TBT or its metabolites into corn of barley was found. Discussion This study confirmed former results: the toxicity of TBT to higher plants is low, and even high levels in soils would not be a hindrance for crop production. The removal of TBT seemed to be increased by both lagooning and plant growth, although the target values for sea dumping in use in certain European countries were not reached. A plausible explanation for the faster degradation of TBT under vegetation is that oxygen is a limiting factor, and plants dewater the soil, thus aerating it. The uptake of the organotins TBT, DBT and MBT into harvest products is probably due to attached soil particles. Conclusions To summarize, barley was the optimal species: it grew very well despite the salinity of the dredged sediments, it had a significantly positive effect on TBT removal; it showed no measurable uptake of TBT or the other butyltins into the harvested product; and it is a cash crop well established in European agriculture. Outlook The amounts of dredged sediments are high, and good soils are becoming increasingly rare. The feasibility of using dredged sediments for non-food production, such as energy crops, should be investigated by a critical risk assessment.     

In-situ partitioning of butyltin compounds in estuarine sediments

The in-situ solid/pore-water partitioning of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) was determined for an estuarine sediment profile collected from a commercial marina. Total butyltin levels exceeded sediment quality guideline values, and were 220-8750 microg/kg for TBT, 150-5450 microg/kg for DBT and 130-4250 microg/kg for MBT. Pore-water butyltin concentrations ranged from 0.05 to 2.35 microg/l for TBT, 0.07-3.25 microg/l for DBT, and 0.05-0.53 microg/l for MBT. The partitioning of butyltin compounds between the sediment solid-phase and pore-water was described by an organic carbon normalised distribution ratio (D(OC)). The observed D(OC) values were similar for TBT, DBT and MBT, and were 10(5)-10(6) l/kg. Values for the Butyltin Degradation Index (BDI) were larger than 1 at depths greater than 10 cm below the sediment/water-column interface. This indicates that substantial TBT degradation has occurred in the sediments, and suggests that natural attenuation may be a viable sediment remediation strategy.     

Butyltin compounds in sediment and molluscs from the shipping strait between Denmark and Sweden

The distribution of tributyltin (TBT) contamination in the subtidal zone of the waters between Denmark and Sweden was investigated in relation to major international shipping lanes. Sediment and different benthic molluscs were sampled in transects along and perpendicularly to the shipping lanes in the Sound (?resund) and the Kattegat/Skagerrak region. The samples were analysed for TBT and its degradation products, dibutyltin (DBT) and monobutyltin (MBT), using GC-PFPD. In sediments, the TBT concentration ranged from <1 to 19 ng g(-1) dry weight (dw) with a strong correlation between the TBT concentration and the organic fraction in sediment (r(2)=0.90) in the samples collected in the Sound, where the highest concentrations were found. This relationship was not observed in the samples from the Kattegat because the TBT concentration in most sediment samples was below the limit of detection. In the molluscs, TBT and its degradation products were detected in all samples from the entire area with concentrations ranging from 8.1 ng g(-1) dw in Buccinum undatum to 1316 ng g(-1) dw in Nuculana pernula. The deposit-feeding bivalve N. pernula was found to have a particularly high accumulation potential for TBT. In addition, a strong correlation between TBT concentrations in sediment and N. pernula was found. Therefore this species seems to be an ideal organism for monitoring sediment contamination. The TBT concentration in N. pernula was found to decrease gradually along the shipping lanes from the Sound, through the Kattegat and into the Skagerrak.     

Tributyltin distribution in the coastal environment of Peninsular Malaysia

The occurrence of tributyltin (TBT) is reported in the coastal waters of a few selected sites in Peninsular Malaysia. Water, bivalves and sediment samples collected were analysed specifically for TBT using sensitive analytical methods which involved a solvent extraction procedure with appropriate clean-up followed by graphite furnace atomic absorption spectrometric measurements. The levels of TBT in the seawater in unexposed areas were found in the range from <3.4 to 20 ng litre(-1) as compared to coastal areas with high boat and ship activities where TBT levels in seawater were generally above 30 ng litre(-1), with the highest level found at 281.8 ng litre(-1). TBT levels in the tissues of random cockle and soft-shell clam samples from local markets were found in the range from <0.5 to 3.7 ng g(-1) wet weight. The levels of TBT found in green mussel samples both from the market (23.5 ng g(-1) wet weight) and those from a mussel farm (14.2 ng g(-1) wet weight) indicate slight accumulation of TBT. In sediments, TBT levels were found ranging from <0.7 ng g(-1) dry weight in unexposed coastal sites to as high as 216.5 ng g(-1) dry weight for a site within a port area.     

Aliphatic Hydrocarbons Distribution in Sediment Cores of Select Creeks in Delta State,Nigeria

The spatial and seasonal changes in the distribution, composition, and concentrations of aliphatic hydrocarbons were investigated in sediment cores of Ubeji, Ifie, and Egbokodo Creeks in the Niger Delta, Nigeria. A total of 222 sediment core samples were collected during the wet season (August 2010) and the dry season (January 2011). The samples were dried, soxhlet extracted, fractionated and analyzed for aliphatic hydrocarbons by using a gas chromatograph with flame ionization detector (GC-FID). The concentrations of aliphatic hydrocarbons ranged from 37 to 286,894 μg/kg (wet season) and from 30 to 11,773 μg/kg (dry season). The concentrations of n-alkanes for a number of stations in this study are comparable to sites with high anthropogenic activities in the Niger Delta. The carbon preference index (CPI) and the pristane/phytane ratios showed that the major source of hydrocarbon pollution in the sediment core was from petrogenic origin.     

Organotins in North Sea brown shrimp (Crangon crangon L.) after implementation of the TBT ban

The organotin (OT) compounds tributyltin (TBT) and triphenyltin (TPhT) are potent biocides that have been used ubiquitously in antifouling paints and pesticides since the mid-1970s. These biocides are extremely toxic to marine life, particularly marine gastropod populations. The European Union therefore took measures to reduce the use of TBT-based antifouling paints on ships and ultimately banned these paints in 2003. Despite sufficient data on OT concentrations in marine gastropods, data are scarce for other species such as the North Sea brown shrimp (Crangon crangon), a dominant crustacean species in North Sea inshore benthic communities. The present study provides the first spatial overview of OT concentrations in North Sea brown shrimp. We have compared these data with historical concentrations in shrimp as well as with sediment concentrations. We have also addressed the effect on the shrimp stock and any human health risks associated with the OT concentrations found. TBT and TPhT in shrimp tail muscle ranged from 4 to 124 and from 1 to 24 μg kg⁻¹ DW, respectively. High levels are accumulated in estuarine areas and are clearly related with sediment concentrations (biota-sediment accumulation factor ∼10). Levels have decreased approximately 10-fold since the ban took effect, coinciding with a recovery of the shrimp stock after 30 years of gradual regression. Furthermore, the OT levels found in brown shrimp no longer present a human health risk.     

Mercury species of sediment and fish in freshwater fish ponds around the Pearl River Delta, PR China: human health risk assessment

This study investigated total mercury (THg) and methylmercury (MeHg) concentrations in five species of freshwater fish and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The concentrations of THg and MeHg in fish pond surface sediments were 33.1-386 ng g(-1) dry wt and 0.18-1.25 ng g(-1) dry wt, respectively. The age of ponds affected the surface sediment MeHg concentration. The vertical distribution of MeHg in sediment cores showed that MeHg concentrations decreased with increasing depth in the top 10 cm. In addition, a significant correlation was observed between %MeHg and DNA from Desulfovibrionacaea or Desulfobulbus (p<0.05) in sediment cores. Concentrations of THg and MeHg in fish muscles ranged from 7.43-76.7 to 5.93-76.1 ng g(-1) wet wt, respectively, with significant linear relationships (r=0.97, p<0.01, n=122) observed between THg and MeHg levels in fish. A significant correlation between THg concentrations in fish (herbivorous: r=0.71, p<0.05, n=7; carnivorous: r=0.77, p<0.05, n=11) and corresponding sediments was also obtained. Risk assessment indicated that the consumption of largemouth bass and mandarin fish would result in higher estimated daily intakes (EDIs) of MeHg than reference dose (RfD) for both adults and children.