The ecological risk assessment (ERA) of polycyclic aromatic hydrocarbons (PAHs) is imperative due to their ubiquity and biological effects in aquatic organisms. We evaluated the seasonal levels and ERA of 16 priority PAHs in surface water, sediment and fish from four (4) anthropogenic-impacted zones of the Lagos lagoon, Nigeria. PAHs were analysed using GC-FID and standard guidelines were utilized for the ERA. Also, we developed a sediment to water-PAHs ratio and ranking of PAHs for the ERA. The dominant fish species were Sarotherodon melanotheron (Black-Jawed Tilapia), Gerres melanopterus (Gerres), Liza falcipinnis (Sicklefin Mullet) and Pseudotolithus elongatus (Bobo Croaker) at Ilaje, Iddo, Atlas cove and Apapa zones respectively. The range of sum PAHs was 195–1006 μg L⁻¹, 302–1290 μg kg⁻¹ and 8.80–26.1 μg kg⁻¹ in surface water, sediment and fish species respectively. Naphthalene was dominant in the surface water and sediment samples while 3-ring to 4-ring PAHs were predominant in fish species across the zones and seasons. The sediment to water-PAHs ratio was greater than 1 for sum PAHs and significantly higher (p < 0.05) in the wet season for specific PAHs across the zones and seasons. On the basis of the sediment PAHs level, Apapa zone was highly polluted with frequent biological effects while the other zones were moderately polluted with occasional biological effects across the zones and seasons. Fish species from all zones were minimally contaminated in both seasons except S. melanotheron which was not contaminated. The specific PAHs identified as ecological risk factors in the lagoon and ranking based on 50–75% recurrence in the ERA were; naphthalene, acenaphthene > acenaphthylene, fluorene, pyrene and benzo[a]anthracene. We recommend that the specific PAHs identified should form the basis for the establishment of environmental quality standards for individual PAHs in coastal waters based on the UN sustainable development goal 14 (life below water).

Microplastics and fibres occur in high concentrations along urban coastlines, but the occurrence of microplastic ingestion by fishes in these areas requires further investigation. Herein, the ingestion of debris (i.e., synthetic and natural fibres and synthetic fragments of various polymer types) by three benthic-foraging fish species Acanthopagrus australis (yellowfin bream), Mugil cephalus (sea mullet) and Gerres subfasciatus (silverbiddy) in Sydney Harbour, Australia has been quantified and chemically speciated by vibrational spectroscopy to identify the polymer type. Ingested debris were quantified using gut content analysis, and identified using attenuated total reflectance Fourier transform infrared (ATR-FTIR) and Raman microspectroscopies in combination with principal component analysis (PCA). The occurrence of debris ingestion at the time of sampling ranged from 21 to 64% for the three species, and the debris number ranged from 0.2 to 4.6 items per fish for the different species, with ∼53% of debris being microplastic. There was a significant difference in the amount of debris ingested among species; however, there was no difference among species when debris counts were standardised to fish weight or gut content weight, indicating that these species ingest a similar concentration of debris relative to their ingestion rate of other material. ATR-FTIR microspectroscopy successfully identified 72% of debris. Raman spectroscopy contributed an additional 1% of successful identification. In addition, PCA was used to non-subjectively classify the ATR-FTIR spectra resulting in the identification of an additional 9% of the debris. The most common microplastics found were polyester (PET), acrylic-polyester blend, and rayon (semi-synthetic) fibres. The potential of using Raman microspectroscopy for debris identification was investigated and provided additional information about the nature of the debris as well as the presence of specific dyes (and hence potential toxicity).

Previous studies have shown that accumulation of perfluoroalkyl acids (PFAAs) in the tissues of aquatic species is highly variable. Movement and migration patterns in these species represent an important consideration when evaluating contaminant accumulation in exposed biota, and may have a large influence on the risk profiles for migratory seafood species. In this study, relationships between PFAA concentrations in muscle and liver tissue, and recent fish migration history (inferred from metals profiles in fish otoliths, otherwise known as otolith chemistry) were evaluated in Sea Mullet (Mugil cephalus). A greater number of PFAAs, and higher concentrations, were found in liver compared to muscle tissue. Perfluorooctane sulfonate (PFOS) was present in highest concentrations in both muscle and liver tissues, and there was strong correlation in concentrations between these two tissues. PFOS was found to decrease and increase alongside recent strontium and barium concentrations (respectively) in the otolith, suggesting higher concentrations of PFAAs in fish recently exposed to comparatively lower salinity environments. This study highlights how otolith chemistry can be employed to examine links between contaminant concentrations in fish, and their recent migration history. This approach shows promise for studying contaminant residues in mobile seafood species within the natural environment.

Microplastics are a global concern, and yet, Philippine studies about it are still wanting. This study investigated microplastic ingestion among detritus-feeding mullet versus the herbivorous rabbitfish, and between freshwater and marine fishes. The first part aimed to compare microplastics in fishes’ guts differing in feeding guilds, individual sizes, and body weights. The second part compared MPs in fishes’ guts and their surrounding waters. Part one revealed that herbivores (58.57%) ingested more MPs than their detritivore-counterparts (30.0%). Pearson correlation, averaging 0.06, suggests a weak correlation between fish weight and MPs amount for both species. Part two showed marine fishes (66.0%) ingested more MPs than its freshwater counterparts (45.0%). A very weak correlation was observed between fish weight and amount of MPs ingested. Fish along the estuary ingested more MPs than those in other stations. No significant differences (p = 0.23) between the MPs in the water samples from each sampling stations was found.

Aquatic biota including fish, shrimp and bivalves were collected from the Yellow River Delta (YRD), China to investigate the levels, composition profile and dietary exposure of polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) and dechlorane plus (DP). The concentrations of PBDEs, DBDPE and DP in the organisms ranged from 5.3 to 149, not detected (nd) - 49, and 0.5–29 ng/g lipid weight, respectively. Higher levels of PBDEs and DP were found in mullet (Liza haematocheila).PBDEs were the major pollutants and BDE 209 was the predominant congener of PBDEs suggesting the great production and application of deca-BDE in YRD. The average fₐₙₜᵢ values for different species were similar to or a little lower than that of the commercial DP, suggesting syn-DP might be selectively accumulated by the organisms. The estimated daily intake values of HFRs suggested consuming fish was the main pathway for the exposure of halogenated flame retardants.

Dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), 2,3,5,6-tetrabromo-p-xylene (pTBX) and pentabromotoluene (PBT) were measured in baby croaker (Collichthys lucidus) and mullet (Osteomugil ophuyseni) collected in 2005 and 2013 from the Pearl River Estuary. DDTs, HCHs, PCBs, and PBDEs were detected in two fish species at concentrations of 150–8100, 1.4–120, 22–560, 2.2–280ng/g lipid wt., respectively. The levels of these chemicals were significantly lower in 2013 than in 2005. The compositions for DDTs, HCHs, and PBDEs in 2013 differed from those in 2005, indicating source changes between the two sampling periods. DP, pTBX and PBT were detected at concentrations of ND–130ng/g lipid wt. No clear temporal trends were found for these contaminants. Overall, these results indicated the effectiveness of regulations and source controls in substantively reducing inputs of these contaminants to the Pearl River Estuary.

Mercury and PCBs are used by non-governmental organizations and federal agencies to inform seafood safety recommendations. Pollution dynamics suggest recommendations on the national scale may be too large to be accurate. We tested softshell and hardshell blue crab, white and pink shrimp, oysters, clams, spot, and mullet from fishers in each of the three North Carolina fishery districts. We measured mercury using EPA method 7473 and PCBs using a commercially available ELISA kit. Over 97% of samples were below the Environmental Protection Agency levels of concern for both mercury and PCBs. Mercury and PCBs have different spatial dynamics, but both differ significantly by water body, suggesting that seafood safety recommendations should occur by water body instead of at the national scale. This finding supports previous research suggesting that differences in water chemistry, terrestrial influence, and flushing time in a particular water body control the contaminant load in locally resident species.

Two species of fishes (n=52; tilapia and mullet) from industrialized and urbanized areas of Okinawa Island (Manko-Noha river, Hija river and Shikaza river) and from a remote area of Ishigaki Island (Anparu mudflat), Japan were collected between August 2005 and July 2006, and analyzed for five organochlorine compounds (OCs), viz., DDTs, PCBs, CHLs, HCHs and HCB. Concentrations and the contamination patterns of OCs in fishes varied between locations. Considerable residue levels of OCs, especially CHLs and DDTs were found in both fishes from the main Okinawa Island. These levels were relatively higher than the reported values for seafood from Japanese coasts, indicating that even now pollution sources of these contaminants still exist in this region. On the other hand, lower concentrations of OCs were detected in fishes from Ishigaki Island waters than those of other Japanese coastal waters, suggesting that this region is less contaminated by OC contaminants.

Perfluorinated alkyl compounds (PFCs) including perfluorooctane sulphonate (PFOS) and perfluorooctanoate (PFOA) were measured in environmental samples collected from around Homebush Bay, an urban/industrial area in the upper reaches of Sydney Harbour and Parramatta River estuary. Water, surface sediment, Sea Mullet (Mugil cephalus), Sydney Rock Oyster (Saccostrea commercialis) and eggs of two bird species; White Ibis (Threskiornis molucca), and Silver Gull (Larus novaehollandiae) were analysed. In most samples PFOS was the dominant PFC. Geometric mean PFOS concentrations were 33ng/gww (wet weight) in gull eggs, 34ng/gww in ibis eggs, and 1.8ng/gww and 66ng/gww in Sea Mullet muscle and liver, respectively. In sediment the PFOS geometric mean was 1.5ng/g, in water average PFOS and PFOA concentrations ranged from 7.5 to 21ng/L and 4.2 to 6.4ng/L, respectively. In oysters perfluorododecanoic acid was most abundant, with a geometric mean of 2.5ng/gww.

We investigated levels of the pollutant tributyltin (TBT) in blood of pufferfishes (six species), Japanese sea perch, red sea bream, Japanese common goby, Japanese flounder, rockfish, conger eel, and sea mullet collected off the coast of northern Kyushu, Japan. We found considerable levels of TBT (1.4–190ng/mL) accumulated in the blood of these fish. Blood TBT concentrations were 1.3–22.5times liver concentrations and 4.9–78times muscle concentrations, except in conger eel and mullet. We detected TBT (16–111ng/mL-blood) in the plasma of the fine-patterned puffer (Takifugupoecilonotus) year-round, without any apparent seasonal trend. These results suggest that fish inhabiting coastal areas of Kyushu, Japan, continue to be contaminated with TBT.