Highest PAH Concentrations Research Articles

Contamination levels and spatial distributions of heavy metals and PAHs in surface sediment of Imam Khomeini Port, Persian Gulf, Iran

Imam Khomeini Port (IKP) is the largest Iranian commercial port. Because of many petrochemical industries and urban areas are located around this port and also having heavy ship traffic, concentrations of PAHs, mercury and other heavy metals were measured as the first time in surface sediment of the jetties. The highest concentrations of PAHs, Hg, Cu, Pb and Fe were recorded at Site 1, located in the vicinity of the petrochemical industrial zone, where ships are repaired. The highest concentration of Zn was found at Site 4, which is the jetty for loading mineral materials. The comparison between measured values in this study and some sediment quality guidelines indicated that the concentrations of mercury and PAHs are much higher than other studies. Also, the ratios of PAHs in the stations showed a mixture of both of pyrolytic and petrogenic sources with a dominance of pyrolytic sources.

Effects of environmental pollution in caged mussels (Mytilus galloprovincialis)

Biological effects of environmental pollution, mainly related to presence of PAHs, were assessed in mussels Mytilus galloprovincialis caged in Priolo, an anthropogenically-impacted area, and Vendicari, a reference site, both located along the eastern coastline of Sicily (Italy). PAHs concentration and histopathological changes were measured in digestive gland tissues. Expression of cytochrome P4504Y1 (CYP4Y1) and glutathione S-transferase (GST), indicative of xenobiotic detoxification, and activity of catalase (CAT) as oxidative stress index, were evaluated.The results show a direct correlation between the high concentrations of PAHs in digestive glands of mussels from Priolo and the significantly altered activity of phase I (P < 0.001) and phase II (P < 0.0001) biotransformation enzymes, along with increased levels of CAT activity (P < 0.05). These findings show the enhancement of the detoxification and antioxidant defense systems. The mussel caging approach and selected biomarkers demonstrated to be reliable for the assessment of environmental pollution effects on aquatic organisms.

Multi-Year PAH Behaviours in Atmospheric Particulates According to Land-Use Type

The present study assessed the multi-year behaviours of high molecular-weight PAHs (four or more benzene ring) (benzo(a)anthracene, benzo(a)pyrene (BaP), benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, and indeno(1,2,3-cd)pyrene) that are associated with airborne particulates in five areas of three cities (Seoul, Ulsan, and Gwangyang) and one rural area (Taeahn), utilizing four-year monitoring data. The order of the mean PAH concentrations was as follows (in descending order) residential-commercial complex (Seoul), traffic junction (Seoul), petrochemical plant (Ulsan), iron and steel plant (Gwangyang), and background area (Taeahn). With a few exceptions, individual congeners exhibited a concentration pattern similar to that of the total PAHs. The high PAH concentrations in the residential-commercial complex and traffic junction are likely attributable to the heavy traffic in Seoul, South Korea’s capital. The inter-annual and seasonal modulations of PAHs were different for each area type, due to differences in land use. It is suggested that neither total PAHs nor BaP alone seem sufficient to index carcinogenicity associated with exposure to these substances. In most cases, the three meteorological parameters (relative humidity, temperature, and wind speed) exhibited a negative correlation with PAH concentrations, although only a few cases demonstrated a statistical significance at p < 0.05.

Pulmonary inflammation and tissue damage in the mouse lung after exposure to PM samples from biomass heating appliances of old and modern technologies

Current levels of ambient air fine particulate matter (PM2.5) are associated with mortality and morbidity in urban populations worldwide. In residential areas wood combustion is one of the main sources of PM2.5 emissions, especially during wintertime. However, the adverse health effects of particulate emissions from the modern heating appliances and fuels are poorly known. In this study, health related toxicological properties of PM1 emissions from five modern and two old technology appliances were examined. The PM1 samples were collected by using a Dekati® Gravimetric Impactor (DGI). The collected samples were weighed and extracted with methanol for chemical and toxicological analyses. Healthy C57BL/6J mice were intratracheally exposed to a single dose of 1, 3, 10 or 15mg/kg of the particulate samples for 4, 18 or 24h. Thereafter, the lungs were lavaged and bronchoalveolar lavage fluid (BALF) was assayed for indicators of inflammation, cytotoxicity and genotoxicity. Lungs of 24h exposed mice were collected for inspection of pulmonary tissue damage. There were substantial differences in the combustion qualities of old and modern technology appliances. Modern technology appliances had the lowest PM1 (mg/MJ) emissions, but they induced the highest inflammatory, cytotoxic and genotoxic activities. In contrast, old technology appliances had clearly the highest PM1 (mg/MJ) emissions, but their effect in the mouse lungs were the lowest. Increased inflammatory activity was associated with ash related components of the emissions, whereas high PAH concentrations were correlating with the smallest detected responses, possibly due to their immunosuppressive effect.

PAH concentrations in the moss species Hylocomium splendens (Hedw.) B.S.G. and Pleurozium schreberi (Brid.) Mitt. from the Kielce area (south-central Poland)

Forty eight samples of mosses Hylocomium splendens and Pleurozium schreberi from the Kielce area (south-central Poland) were analyzed for seventeen polycyclic aromatic hydrocarbons. The PAH concentrations varied from 558.00 μg/kg (ppb) to 4457.00 μg/kg in H. splendens and from 643.00 to 3086.00 μg/kg in P. schreberi. In both moss species phenanthrene (75.00–732.00 μg/kg), fluoranthene (101.00–577.00 μg/kg) and pyrene (68.00–568.00 μg/kg) predominated, but H. splendens accumulated more PAHs than P. schreberi at eighteen different sites. The highest PAH concentrations were noted at sites located close to the housing estates (sites 1–10) and potential emission sources (e.g. heat and power generating plant “Kielce S.A.”) (sites 19–21). The moss samples displayed the diverse ring sequence, but the most prevalent was four>five>three>six. The diagnostic ratios (three+four ring/total PAHs, Flu/Py, Phen/Ant, Phen/Phen+Ant, Flu/Flu+Py, IndPy/IndPy+BghiPe and BaA/BaA+Chr) indicated that coal and petroleum combustion was a principal PAH source in the study area.

A source mixing model to apportion PAHs from coal tar and asphalt binders in street pavements and urban aquatic sediments

Present-day and more than 30 years old road and footpath pavements from Auckland, New Zealand were analysed for PAHs to test the hypothesis that coal tar based pavement binders contribute to unusually high PAH concentrations in adjacent stream and estuarine sediments. Total PAH (∑ 28PAH) concentrations in the dichloromethane-soluble fraction (“binder”), comprising 5–10% of pavement mass, were as high as 200 000 mg kg −1 (10 000 mg kg −1 in binder + aggregate). Older and deeper pavement layers were strongly pyrogenic, whereas pavement layers from recently sealed roads had a more petrogenic composition and more than 1000 times lower ∑ 28PAH concentrations. Source identification analysis using three PAH isomer ratio pairs (benz(a)anthracene/(benz(a)anthracene + chrysene); benzo(a)pyrene/(benzo(a)pyrene + benzo(e)pyrene); and indeno(1,2,3-cd)pyrene/(indeno(1,2,3-cd)pyrene + benzo(g,h,i)perylene) revealed low PAH (bitumen) pavements to have consistently lower isomer ratios than high PAH (coal tar) samples. Moreover, pavement data for one isomer ratio (e.g. benzo(a)pyrene/(benzo(a)pyrene + benzo(e)pyrene) were highly correlated with those of another isomer ratio (e.g. benz(a)anthracene/(benz(a)anthracene + chrysene) and were bounded at their lower and higher extremes by the characteristics of pure bitumen and coal tar, respectively, suggesting that PAH composition of a given pavement sample could be accounted for by conservative mixing between coal tar and bitumen as source materials. A concentration-weighted mixing model, with coal tar and bitumen as source materials, explained more than 80% of the variance in isomer ratios and enveloped the entire PAH compositional and concentration range encountered. PAH composition and concentrations in adjacent stream sediments (> 15 mg kg −1 dry weight) were consistent with diluted coal tar material as a principal PAH source. Due to the very high PAH concentrations of coal tar, a coal tar content of as little as 0.01% of total sediment mass can account for more than 90% of PAH concentrations in adjacent stream sediments.

Workplace Environment and Personal Exposure of PM and PAHs to Workers in Natural Rubber Sheet Factories Contaminated by Wood Burning Smoke

The workplace environment in factories producing ribbed smoked sheet rubber (RSS), the interiors which are heavily contaminated by wood burning smoke, was evaluated with a focus on the concentration of suspended particulates and particle-bound PAHs as well as workers' exposure in the breathing zone during the period January, 2006-February, 2008 in Thailand. Seasonal changes in particulate and PAH concentrations are discussed in relation to the amount of RSS produced, wind direction, ventilation type and the geometry of the factory building. The concentration of particulate matter in the workplace was shown to increase nearly linearly with RSS production while being influenced by the wind direction to the open sides of the building and wind speed. Particulate concentrations in the workplace and in the worker’s breathing zone were lower than those for other common occupational exposure limits. However, rather high PAH concentrations of 97.4 ± 129 ng/m^3 and 142 ± 184 ng/m^3 were found in the workplace and in the breathing zone, respectively. BaPTEQ concentrations in the workplace ranging from 21.4 to 91.0 ng/m^3 were similar to those in a sinter plant. The workers' exposure to PAHs was similar to that in a sinter plant, a metal recycling plant, a paving bitumen manufacturing plant and a carbon black manufacturing plant. The mass fraction of PAHs in particles in the RSS factory was as high as 0.30 BaP(subscript TEQ) ng/μg, much higher than that in a carbon black plant (0.004–0.01 BaP(subscript TEQ) ng/μg). The results reported herein suggest that the workers in the RSS factory have a somewhat high health risk from exposure to PAHs. Natural ventilation by the addition of roof turbines was insufficient in terms of reducing PAHs levels in the workplace although a roof ridge vent was functional and had a positive effect.

Winter fine particulate matter from Milan induces morphological and functional alterations in human pulmonary epithelial cells (A549)

Samples of PM(2.5) were gravimetrically collected during the winter 2005/2006 in the urban area of Milan (North Italy). Samples were chemically characterized and the particles were detached from filters to determine their cytotoxic effects on the A549 cell line. Based on the potential toxicological relevance of its components, Milan winter PM(2.5) contained high concentrations of pro-oxidant transition metals and PAHs, while re-suspended particles showed a relatively high frequency of dimensional classes ranging from 40 nm to 300 nm. A549 cells exposed to particle suspensions showed a concentration-dependent decrease in viability, starting from 10 microg/cm(2). Phagocytosis of particles by A549 cells and particle aggregates were morphologically characterized and seemed to depend on both particle concentration and exposure time, with the majority of particles being engulfed in membrane-bound vacuoles after 24h of exposure. The ability of ultrafine particles to penetrate and spread throughout the cells was also verified. Cell membrane lysis and mitochondrial ultrastructural disruption appeared to be the main modifications induced by PM(2.5) on A549 cells. Concomitantly to the adverse effects observed in terms of cell mortality and ultrastructural lesions, a significant intracellular production of reactive oxygen species (ROS) was observed, suggesting that the cytotoxicity, exerted by the winter PM(2.5) in Milan, derived also from its oxidative potential, probably associated with particle-adsorbed metals and PAHs.

Use of biomarkers to assess the welfare of the edible clam, Ruditapes philippinarum: may it be a tool for proving areas of origin?

The use of biomarkers as early-warning signals to assess the impact of pollutants and other environmental stressors in coastal habitats has been internationally recognized as a useful tool in marine coastal monitoring. We propose a similar approach to verify the welfare of edible shellfish, Ruditapes philippinarum, thus exploiting its possible application as an effective tool to verify the origin of fishing/aquaculture products. A selected battery of biomarkers was chosen and applied to organisms from two different habitats in the Lagoon of Venice (a farming site and a natural area where fishing is currently banned, because of pollution problems) and from a local market. Biological responses were evaluated physiologically (survival in air test and condition index), behaviourally (reburrowing rate), and histochemically (quantification of neutral lipids and lipofuscin). Micropollutants (heavy metals, PCBs, and PAHs) were also determined in the soft tissues. Results indicated clams from the farming site were in the best condition with regard to both chemical and biological measurements. In contrast, the market sample contained the highest concentrations of PAHs. PCBs and heavy metals varied slightly and quite irregularly among the three samples. The worst values of the biomarkers were observed for clams collected at the polluted site, where, in particular, the lowest physiological and behavioural indexes and the highest accumulation of lipofuscin in the digestive tissue were recorded.

PAH desorption from river floodplain soils using supercritical fluid extraction

Sequential supercritical fluid extraction (SFE) was performed in order to estimate desorption of PAHs from river floodplain soils which contain coal and coal-derived particles. Original soils, soils' light fractions (rho<2 g cm(-3)), and <63 microm fractions were studied for PAHs' desorption kinetics. Desorption data were successfully described using a two-site model. Desorption rate constants were one order of magnitude lower than those of "slow" and "very slow" desorption rates from other studies. This suggests very slow and extremely slow desorption. Estimated time scales releasing 99% of total extractable contaminants ranged from decades for 2-4-ring PAHs and hundreds of years for 5-6-ring PAHs. We demonstrate that, despite high soil PAH concentrations which are due to coal and coal-derived particles, the general environmental risk is reduced by the very slow and extremely slow desorption rates.

DNA strand breaks in grass shrimp embryos exposed to highway runoff sediments and sediments with coal fly ash

Embryo production was reduced in female grass shrimp exposed to sediments with added coal fly ash and to sediments collected from an estuarine station containing high PAH concentrations due to its proximity to a highway storm drain. Grass shrimp embryos exposed to pore water from the high PAH and high metal sediments showed both reduced hatching and increases in DNA strand breaks (comet assay). Sediments with added coal fly ash had high concentrations of vanadium and selenium which may have contributed to effects similar to those observed with sediments with high PAH. The embryo pore water bioassay (hatching/DNA strand breaks) gave results comparable to those observed for reproduction effects (reduced embryo production/embryo hatching) with female grass shrimp exposed to whole sediment.

Characterization and distribution of PAHs in surface sediments of Daliao River, China

The concentrations of 16 priority pollutant PAHs in the samples of Daliao River were analyzed by a method based on Soxhlet extraction, solid-phase extraction clean-up and high performance liquid chromatography-programmable fluorescence/ultra violet detection. The total concentrations of PAHs in Daliao River ranged from 267.9 ng/g to 9,212 ng/g. The highest concentration of PAHs was 9,212 ng/g at the Station 24 (Anshan Railroad Bridge), and the lowest 267.9 ng/g at the Station 19 (Estuary). Compared with the total concentrations of PAHs of rivers in other parts of the world, the degree of contamination of Daliao River by PAHs was moderate to high. Specific compounds or groups of PAHs have been used as molecular markers to differentiate petrogenic and pyrogenic origin. The results showed that the main sources of PAHs in Daliao River were pyrolytic inputs such as combustion of coal, wood and petrogenic chemicals. The data was also compared by mean of two guideline values, an effects range-low (ER-L) and effects range-medium (ER-M), to assess the potential biological effects of the sediment adsorbed PAHs. It showed that the PAHs in some sites of Daliao River would exert adverse biological effects.

Petroleum contamination impact on macrobenthic communities under the influence of an oil refinery: Integrating chemical and biological multivariate data

Petroleum contamination impact on macrobenthic communities in the northeast portion of Todos os Santos Bay was assessed combining in multivariate analyses, chemical parameters such as aliphatic and polycyclic aromatic hydrocarbon indices and concentration ratios with benthic ecological parameters. Sediment samples were taken in August 2000 with a 0.05 m 2 van Veen grab at 28 sampling locations. The predominance of n-alkanes with more than 24 carbons, together with CPI values close to one, and the fact that most of the stations showed UCM/resolved aliphatic hydrocarbons ratios (UCM:R) higher than two, indicated a high degree of anthropogenic contribution, the presence of terrestrial plant detritus, petroleum products and evidence of chronic oil pollution. The indices used to determine the origin of PAH indicated the occurrence of a petrogenic contribution. A pyrolytic contribution constituted mainly by fossil fuel combustion derived PAH was also observed. The results of the stepwise multiple regression analysis performed with chemical data and benthic ecological descriptors demonstrated that not only total PAH concentrations but also specific concentration ratios or indices such as ≥C24:<C24, An/178 and Fl/Fl + Py, are determining the structure of benthic communities within the study area. According to the BIO-ENV results petroleum related variables seemed to have a main influence on macrofauna community structure. The PCA ordination performed with the chemical data resulted in the formation of three groups of stations. The decrease in macrofauna density, number of species and diversity from groups III to I seemed to be related to the occurrence of high aliphatic hydrocarbon and PAH concentrations associated with fine sediments. Our results showed that macrobenthic communities in the northeast portion of Todos os Santos Bay are subjected to the impact of chronic oil pollution as was reflected by the reduction in the number of species and diversity. These results emphasise the importance to combine in multivariate approaches not only total hydrocarbon concentrations but also indices, isomer pair ratios and specific compound concentrations with biological data to improve the assessment of anthropogenic impact on marine ecosystems.

An assessment of an oil spill in Gladstone, Australia – Impacts on intertidal areas at one month post-spill

In January 2006, 25 tonnes of heavy fuel oil spilled into the Port of Gladstone in Queensland, Australia, from the breached hull of a bulk carrier ship. Over the following days, approximately 18 tonnes of the oil was recovered, however a certain amount of oil was deposited in the intertidal areas of Port Curtis leaving a highly visible, viscous residue. The objectives of this research were to assess the immediate impacts on the intertidal habitat and to gain baseline information for future comparative assessments. Sediment PAH and metal concentrations, mangrove communities and intertidal macroinvertebrates were assessed within one month post-spill at oil-impacted sites; adjacent sites which were not visibly impacted; and reference sites which were located outside the recorded distribution of the oil spill. Highest PAH concentrations were found at the impacted sites, with concentrations of some PAHs exceeding Australian and New Zealand Sediment Quality Guidelines ( ANZECC/ARMCANZ, 2000). These sites contained very few or no crab holes in the high intertidal area, indicating a low crab density in comparison to reference sites. Little immediate impact was evident on the mangrove and macrobenthic communities, however future surveys may show evidence of longer-term impacts on these communities.

The influence of Sarcocornia fruticosa on retention of PAHs in salt marsh sediments (Sado estuary, Portugal)

Depth concentration profiles of PAHs, organic carbon and dissolved oxygen in non-colonised sediments and sediments colonised by Sarcocornia fruticosa from Mitrena salt marsh (Sado, Portugal) were determined in November 2004 and April 2005. Belowground biomass and PAH levels in below and aboveground material were also determined. In both periods, colonised sediments were oxygenated until 15-cm, rich in organic carbon (max 4.4%) and presented much higher PAH concentrations (max. 7.1 μg g −1) than non-colonised sediments (max. 0.55 μg g −1). Rooting sediments contained the highest PAH concentrations. The five- and six-ring compounds accounted to 50–75% of the total PAHs in colonised sediments, while only to 30% in non-colonised sediments. The elevated concentrations of PAHs in colonised sediments may be attributed to the transfer of dissolved PAH compounds towards the roots as plant uptake water and subsequent sequestration onto organically rich particles. A phase-partitioning mechanism probably explains the higher retention of the heavier PAHs. In addition oxygenated conditions of the rooting sediments favour the degradation of the lighter PAHs and explain the elevated proportion of the heavier compounds. Below and aboveground materials presented lower PAH concentrations (0.18–0.38 μg g −1) than colonised sediments. Only 3- and 4-PAHs were quantified in aboveground material, reflecting either preferential translocation of lighter compounds from roots or atmospheric deposition.

Exposure to Polycyclic Aromatic Hydrocarbons through Consumption of Edible Marine Species in Catalonia, Spain

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs; naphthalene, acenaphtylene, acenaphtene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-c,d]pyrene, dibenzo[a,h]anthracene, and benzo[g,h,i]perylene) were determined by gas chromatography–mass spectrometry in samples of 14 edible marine species (sardine, tuna, anchovy, mackerel, swordfish, salmon, hake, red mullet, sole, cuttlefish, squid, clam, mussel, and shrimp) collected in March and April 2005. These species are widely consumed by the population of Catalonia, Spain. PAH intake was also estimated for eight age and sex groups of this population. Mussel, clam, and shrimp had the highest PAH concentrations (22.4, 21.5, and 15.9 ng/g of fresh weight, respectively). In contrast, sole (2.5 ng/g of fresh weight) and cuttlefish and squid (both 3.0 ng/g of fresh weight) had the lowest mean concentrations. The highest PAH intake was found in women and girls (5.3 and 5.2 ng/kg/day, respectively), but female adolescents and female seniors had the lowest PAH intakes (3.3 ng/kg/day in both groups). The intake of benzo[a]pyrene and six other PAHs that are probably human carcinogens through consumption of these marine species would be associated with 0.27/106 increase in the risk of development of cancer over a 70-year life span.

Integrated biomarker response index as a useful tool for environmental assessment evaluated using transplanted mussels

Mytilus galloprovincialis mussels from a clean area were transplanted from 2003 to 2005 to several stations in the Bay of Cannes (North-Western Mediterranean Sea) including a site considered as reference, for 1 month at the end of spring (May). Several biomarkers (AChE, GST and CAT activities, TBARS and MT concentrations) were measured in the transplanted organisms. The concentrations of metals (Cd, Cu and Zn) were determined in the transplanted mussels, PAH and PCB analyses were performed in the mussels caged in 2004. The integrated biomarker response (IBR) was calculated; pollutant concentrations in mussels were displayed as star plots and compared to IBR star plots. Visualization was thus possible between sites for comparison with exposure conditions. Results demonstrated that the mussels from the Old harbour site (VP) are characterized by elevated copper and PCB concentrations, those from Canto harbour (PC) presented high PCB contents and those from the mouth of the Siagne River (ES) high PAH concentrations compared to the animals transplanted in the reference site (IL). In 2003, there was a visual correlation between the copper gradient measured in the transplanted mussels and the IBR variation. In 2004, the agreement between the copper gradient and the PCB gradient measured in the caged mussels and the IBR variation was good whereas the PAH gradient did not seem to contribute to the IBR demonstrating that the chosen biomarkers did not respond to PAHs. In 2005, IBR showed that other contaminants, not measured might be present in VP, PC and ES compared to the reference station (IL).

Spatial distribution of PAHs in a contaminated valley in Southeast China

A survey was conducted on the accumulation and spatial distribution of PAHs in surface soils under different land use patterns in a valley in the Yangtze Delta region with an area of 10 km(2) containing 15 small copper- and zinc-smelting furnaces. Sixty-five topsoil (0-20 cm) samples were collected and 16 PAHs were determined. The average amount of all the 16 PAHs ranged from 0 to 530 microg kg(-1) (oven dry basis), with a mean concentration of 33.2 microg kg(-1). Benzo[a]pyrene and indeno[1, 2, 3, -cd]pyrene were the two main PAHs present at high concentrations, while pyrene and fluorene had very low concentrations. PAH concentrations were higher in uncultivated than in cultivated soils, and areas of woods and shrubbery had the lowest soil PAH contents. The average PAH-homologue concentrations ranked as follows: 5-rings >> 3-rings, 4-rings > 6-rings >2-rings. Much higher concentrations of PAHs were found in the southern part of the sampling area, perhaps due to deposition of airborne particles by the southeasterly winds in winter and spring. We conclude that the small smelting furnaces were the dominant source of PAHs that accumulated in the soils and the southeasterly winds led to the spatial distribution of PAHs in the topsoils. Land vegetation cover and soil utilization patterns also affected the accumulation and distribution of soil PAHs.

Biomonitoring of heavy metals and trace organics using the intertidal mussel Perna viridis in Hong Kong coastal waters

This paper presents the results of a 6-year (1998–2003) survey of trace toxics in the intertidal mussel Perna viridis conducted by the Hong Kong Environmental Protection Department. Concentrations of heavy metals and trace organics were measured in the soft bodies of P. viridis collected from five sites in Hong Kong waters, i.e. Wu Kai Sha (Tolo Harbour), Ma Wan (Northwest), Tsim Sha Tsui (Victoria Harbour), Tai Tam (Hong Kong South) and Lamma Island (Southern Waters) in order to establish the spatial patterns of contaminants in mussels. Among the metals analysed, Cd showed a significant concentration gradient in Hong Kong waters. The levels of Cd in P. viridis were significantly higher at Ma Wan as compared to the other sites studied. Ma Wan also had relatively higher concentrations of Pb. Mn concentrations were particularly prominent at Wu Kai Sha. Significantly higher concentrations of Hg and Cu were recorded at Tai Tam and Tsim Sha Tsui. Tai Tam and Wu Kai Sha had higher levels of V; whereas higher Ni concentrations were recorded at Lamma Island and Tai Tam. No clear spatial patterns for Al, As, Cr, Fe and Zn were observed. Higher concentrations of PAHs in P. viridis were observed around urban centres impacted by sewage discharges (e.g. Tsim Sha Tsui); whereas higher PCB levels were found not only in Tsim Sha Tsui but also in less urbanised areas such as Lamma Island and Tai Tam, suggesting that these may be due to non-sewage related inputs. The study also shows that Northwest and Southern waters are subject to a higher degree of DDT pollution compared with other sites. Of the 17 dioxin compounds analysed, positive data were mostly recorded for two compounds which are of low toxicity (i.e. OCDD and 1,2,3,4,6,7,8-HpCDD) whereas the most toxic congeners (i.e. 2,3,7,8-TCDD and 1,2,3,7,8-PeCDD) were not detected in the 6 years of monitoring. In general, the levels of OCDD in P. viridis were found to be higher in Tai Tam and Lamma Island in Southern Waters of Hong Kong. This study found that the levels of some highly toxic heavy metals (i.e. Cd, Hg and Pb) in the mussel P. viridis did not exceed the recommended limits for shellfish as food in Hong Kong (i.e. Cd: 2.0 ppm; Hg: 0.5 ppm; Pb: 6.0 ppm wet weight). The levels of As and Ni in P. viridis were also well below the action limits set by the US FDA (i.e. As: 86 ppm; Ni: 80 ppm wet weight). DDT and PCB contaminations in P. viridis were below the concentrations of concern. Compared with data obtained in the 1980s, the current levels of DDTs in P. viridis were 4–16 times lower; whereas Pb concentrations recorded in Tsim Sha Tsui have also been lowered significantly. This is mainly related to reduction in local and regional pollution sources in the past 20 years.

A multibiomarker approach to environmental assessment.

Incorporation of ecologically relevant biomarkers into routine environmental management programs has been advocated as a pragmatic means of linking environmental degradation with its causes. Here, suites of biomarkers, devised to measure molecular damage, developmental abnormality and physiological impairment, were combined with chemical analysis to determine exposure to and the effects of pollution at sites within Southampton Water (UK). Test species included a filter feeder, a grazer, and an omnivore to determine the sensitivity of organisms occupying different trophic levels. Linear regression confirmed a significant association between incidence of intersex in Littorina littorea and tributyltin (TBT) concentrations (R2 = 0.954) and between PAH metabolites in Carcinus maenas urine and PAHs in sediments (R2 = 0.754). Principal component analysis revealed a gradient of detrimental impact to biota from the head to the mouth of the estuary, coincident with high sediment concentrations of heavy metals, PAHs, and biocides. Multidimensional scaling identified C. maenas as the organism most sensitive to contamination. Carboxylesterase activity, metallothionein and total haemolymph protein were the most discriminating biomarkers among sites. This holistic approach to environmental assessment is encouraged as it helps to identify the integrated impact of chemical contamination on organisms and to provide a realistic measure of environmental quality.