Levels, distribution, and health risks of polycyclic aromatic hydrocarbons in four freshwater edible fish species from the Beijing market

Polycyclic aromatic hydrocarbons distribution in fish tissues and human health risk assessment on consumption of four fish species collected from Lagos Lagoon, Nigeria

Lagos Lagoon is a very popular lagoon in Lagos state that receives effluents from neighboring industries. These effluents tend to increase the level of contaminants in the lagoon, thereby creating more stressors for aquatic animals. Determination of polycyclic aromatic hydrocarbons (PAHs) in four commonly consumed fish species from the lagoon and the prediction of possible health risks associated with their consumption were performed in this study. Various levels of PAH were detected in the fish tissues with the highest total concentration of PAH in Sarothoredon melanotheron. High concentrations of benzo(a)pyrene were noticed in Sarothoredon melanotheron and Ethmalosa fimbriata, and their values were above the guideline value of 0.002 μg/g. The dietary daily intake (DDI) value in S. melanotheron 82.00 ×10-5 μg/g/day was highest. Carcinogenic toxic equivalents (TEQ) showed that consumption of S. melanotheron had higher potential to pose carcinogenic risks, while the excess cancer risk (ECR) index for the PAHs in all the assessed fish species was beyond threshold values indicating potential carcinogenic risk from their consumption. No significant association was found between the concentration of PAHs and the size of the fish. Target hazard quotient (THQ) results suggested absence of potential non-carcinogenic risk if individual PAH in the fish are consumed frequently. The study however established possible carcinogenic human health risk from consumption of the fish obtained from Lagos Lagoon. The study recommends monitoring of contamination and consumption of fish from harvest sites within the study region.

Mechanistic insights into phenanthrene-triggered oxidative stress-associated neurotoxicity, genotoxicity, and behavioral disturbances toward the brandling worm (Eisenia fetida) brain: The need for an ecotoxicological evaluation

In this study, earthworm (Eisenia fetida) brain was chosen as targeted receptors to probe the mechanisms of oxidative stress-related neurotoxicity, genotoxicity, and behavioral disturbances triggered by PHE. Results showed that PHE stress can initiate significant amounts of ROS, thus triggering oxidative stress in E. fetida brain. These effects were accompanied by a significant increase of damage to macromolecules DNA and lipids, resulting in severe oxidative effects. PHE exposure can induce AChE inhibition by ROS-induced injury and the accumulation of excess ACh at the nicotinic post-synaptic membrane, thus inducing aggravated neurological dysfunction and neurotoxicity of E. fetida through an oxidative stress pathway. Moreover, the burrowing behavior of earthworms was disturbed by oxidative stress-induced neurotoxicity after exposure to PHE. Furthermore, the abnormal mRNA expression profiles of oxidative stress- and neurotoxicity-related genes in worm brain were induced by PHE stress. The IBR results suggested that E. fetida brain was suffered more serious damage caused by PHE under higher doses and long-term exposure. Taken together, PHE exposure can trigger oxidative stress-mediated neurotoxicity and genotoxicity in worm brain and behavioral disorder through ROS-induced damage. This study is of great significance to evaluate the harmful effects of PHE and its mechanisms on soil ecological health.

Assessment of Total Petroleum Hydrocarbon Contamination of the Red Sea with Endemic Fish from Jeddah (Saudi Arabia) as Bioindicator of Aquatic Environmental Pollution

The aim of this study was to determine whether endemic coral fish commonly consumed by Jeddah residents could serve as bioindicators of oil contamination. In addition, we planned to investigate the relationship between amino acid changes and hydrocarbon concentrations in fish tissue. The composition of amino acids was analyzed using high-pressure liquid chromatography with precolumn derivatization. An analytical study of the polycyclic aromatic hydrocarbons and total petroleum hydrocarbons was conducted by combining gas chromatography with gas chromatography/mass spectrometry. Multivariate statistical analysis was applied using Statgraphics software to determine the impact of the polycyclic aromatic hydrocarbons and total petroleum hydrocarbons on the amino acid profile of three species of fish. In addition, the bioconcentration factor was estimated in the studied species and was used to validate the results obtained from the multivariate analysis. Based on the results of the study, the sum of polycyclic aromatic hydrocarbons with two cycles, and with five to six cycles, is in reverse order in Plectropomus pessuliferus with respect to Epinephelus tauvina and Cephalopholis argus. The factor analysis showed high factor scores for aspartic acid, glutamic acid, tyrosine, chrysene, and total petroleum hydrocarbons, and for lipids and benzo(g,h,i)perylene, which could be explained by bioaccumulation. It was concluded that the high proportions of glutamic acid (8.32–11.10%) and aspartic acid (6.06–8.27%) in the muscles of the studied species are a sign of contamination with petroleum hydrocarbons. The incremental lifetime cancer risk values for the three endemic fish exceeded the limit value (>10−5), indicating a high potential cancer risk for the Saudi population.

Behavioral and hypothalamic transcriptome analyses reveal sex-specific responses to phenanthrene exposure in the fathead minnow (Pimephales promelas)

Environmental concentrations of the polycyclic aromatic hydrocarbon phenanthrene can become elevated with petroleum processing, industrial activities, and urban run-off into waterbodies. However, mechanisms related to its neurotoxicity in fish are not fully described. Here, we exposed adult fathead minnows (FHM) to an average measured concentration of 202 μg phenanthrene/L over a 47-d period. Behaviors of male and female FHM were assessed using a novel aquarium test. Phenanthrene exposed females displayed equilibrium loss, while phenanthrene exposed males spent less time in the aquarium bottom, suggesting phenanthrene reduced anxiety-related behavior. To elucidate putative mechanisms underlying behaviors, we determined the hypothalamic transcriptome profile, a critical integration centre for the regulation of behaviors. There were 1075 hypothalamic transcripts differentially expressed between males and females (sex-specific) while 15 transcripts were phenanthrene-specific. Thus, sex of the animal was more pervasive at influencing the transcriptome compared to phenanthrene and this may partially explain the divergent behavioral responses between sexes. Transcripts altered by phenanthrene included palmitoylated 3 membrane protein, plectin 1,ATP synthase membrane subunit c, and mitochondrial ribosomal protein S11. Gene set enrichment analysis revealed less than 5% of the gene networks perturbed by phenanthrene were shared between males and females, thus phenanthrene altered the hypothalamic transcriptome in a sex-specific manner. Gene networks shared between both sexes and associated with phenanthrene-induced neurotoxicity included processes related to mitochondrial respiratory chain dysfunction, epinephrine/norepinephrine release, and glutamate biosynthesis pathways. Such energy deficits and neurotransmitter disruptions are hypothesized to lead to behavioral deficits in fish. This study provides mechanistic insights into phenanthrene-induced neurotoxicity and how it may relate to changes in fish behaviors.

Polycyclic aromatic hydrocarbons in 30 river ecosystems, Taiwan: Sources, and ecological and human health risks

Polycyclic aromatic hydrocarbons (PAHs) are diverse contaminants of global concern because of their ubiquity, toxicity, and carcinogenicity to many organisms, including humans. This study determines the distribution and sources of PAHs in sediments and fish from 30 major rivers in Taiwan, and the risks these PAHs pose to river ecosystems and human health. The total concentrations of 26 PAHs in sediments and fish were 0.016-7.44 mg/kg dw and 0.096-5.51 mg/kg ww, respectively. The PAH composition in sediments differed from that in fish, indicating that sediments may not be the major contributor of PAHs to fish. The accumulation of different PAH compounds in fish was species-specific, depending on the lipid content, living pattern, and trophic level of each fish species, and on the level of environmental contamination. The diagnostic ratios revealed that PAHs in the sediment primarily originated from pyrogenic sources, with some contribution from petrogenic sources. The contribution of each source varied with the sampling site and season. Several water and air quality variables were found to significantly correlate with PAH concentration in sediments and fish, suggesting that PAHs were mainly derived from wastewater discharge and combustion emissions. The 95th percentile risk quotient values suggested that PAHs in sediment from six rivers pose high ecotoxicological risks. The toxic equivalents of benzo[a]pyrene for 16 PAHs in fish were 12-108 μg/kg dw. A human risk assessment using the 95th percentile values of hazard quotient, hazard index, and margin of exposure revealed that the consumption of contaminated fish muscle poses no remarkable risk to human health. However, the 95th percentile carcinogenic risk values indicated that benzo[a]pyrene concentrations in some fish muscles may pose a carcinogenic risk. Benzo[a]pyrene risk management measures are, therefore, necessary.

Tissue distribution, bioaccumulation, and carcinogenic risk of polycyclic aromatic hydrocarbons in aquatic organisms from Lake Chaohu, China

Freshwater products consumed in the diet are among the major sources of exposure of humans to polycyclic aromatic hydrocarbons (PAHs). In this study, eight freshwater organisms and environmental samples were collected from Chaohu Lake, the fifth-largest lake in China. The levels of PAHs in the collected organisms were measured using GC-MS. Tissue distribution characteristics in three fish species were studied. Relationship between residual levels and environment concentrations were analyzed and bioaccumulation effect and influencing factors were identified. Finally, the potential carcinogenic risk of aquatic product intake was estimated. The concentrations of ΣPAHs in aquatic organisms varied from 18.4 to 398 ng/g, with a mean value of 157 ± 125 ng/g. For carp, the highest ΣPAHs level was detected in the brain with concentration of 591 ng/g. For topmouth culter, and bighead fish, the organs with the greatest ΣPAHs concentration were gills (440 ng/g) and muscles (200 ng/g), respectively. Significant correlations were found between the PAH content in environment media including water, SPM, sediment and PAH content in aquatic animals. The calculation of food web magnification factors and risk assessment indicates that although the PAH concentration diluted with the increase of the trophic level, PAHs exposure through the aquatic products intake still poses potential carcinogenic risk. The incremental lifetime cancer risk values were 7.68 × 10^-6 and 4.75 × 10^-6 in urban and rural populations, respectively.

Bioaccumulation and toxic potencies of polycyclic aromatic hydrocarbons in freshwater biota from the Ogbese River, Nigeria

Samples of fish and shellfish (periwinkles, mussel, and snail) collected from the rapidly contaminated Ogbese River, Ondo State, Nigeria, were analyzed for their polycyclic aromatic hydrocarbon (PAH) levels by gas chromatography-mass spectrometry after cleanup using solid-phase extraction. The rank order of concentration of ΣPAHs in fish follows: gills >> eggs >>> muscle. The dry weight concentrations (μg/g) of total PAHs ranged from < 0.001 to 2.06, 0.01 to 18.67, 0.01 to 9.56, and 0.01 to 8.28 in fish muscle, periwinkle, snail, and mussel respectively. Accumulation levels of PAHs in the biota were used to calculate biota-sediment (or porewater) accumulation factors (BSAF (BPwAF)) and bioaccumulation factor (BAF). The lower molecular weight PAHs constitute major components (≥ 87% in each case) of PAH congener profiles. Bioaccumulation was greatest for PAHs with log K_ow values between 5.0 and 5.6. However, the study did not show a good correlation between log K_ow of individual PAH and the corresponding BSAFs/BPwAF for the biota. The study indicates that significantly greater (p < 0.05) BSAFs for ΣPAHs were observed in the three bottom dwellers than in fish muscle which suggests that the sediment-feeding behavior largely affected the extent of PAH bioaccumulation in the aquatic organisms. The calculated potency equivalent concentration (PEC) of total PAHs was above the recommended screening value (SV) in US EPA guidelines, suggesting great concern for human consumption. However, estimated excess cancer risk (ECR) induced by dietary exposure only suggests potential cancer risk. The study suggests urgent remediation of the river to safeguard public health.

Proteome changes in muscles, ganglia, and gills in Corbicula fluminea clams exposed to crude oil: Relationship with behavioural disturbances

The use of online remote control for 24/7 behavioural monitoring can play a key role in estimating the environmental status of aquatic ecosystems. Recording the valve activity of bivalve molluscs is a relevant approach in this context. However, a clear understanding of the underlying disturbances associated with behaviour is a key step. In this work, we studied freshwater Asian clams after exposure to crude oil (measured concentration, 167 ± 28 μg·L^-1) for three days in a semi-natural environment using outdoor artificial streams. Three complementary approaches to assess and explore disturbances were used: behaviour by high frequency non-invasive (HFNI) valvometry, tissue contamination with polycyclic aromatic hydrocarbons (PAH), and proteomic analysis. Two tissues were targeted: the pool adductor muscles - retractor pedal muscle - cerebral and visceral ganglia, which is the effector of any valve movement and the gills, which are on the frontline during contamination. The behavioural response was marked by an increase in valve closure-duration, a decrease in valve opening-amplitude and an increase in valve agitation index during opening periods. There was no significant PAH accumulation in the muscle plus nervous ganglia pool, contrary to the situation in the gills, although the latter remained in the low range of data available in literature. Major proteomic changes included (i) a slowdown in metabolic and/or cellular processes in muscles plus ganglia pool associated with minor toxicological effect and (ii) an increase of metabolic and/or cellular processes in gills associated with a greater toxicological effect. The nature of the proteomic changes is discussed in terms of unequal PAH distribution and allows to propose a set of explanatory mechanisms to associate behaviour to underlying physiological changes following oil exposure. First, the first tissues facing contaminated water are the inhalant siphon, the mantle edge and the gills. The routine nervous activity in the visceral ganglia should be modified by nervous information originating from these tissues. Second, the nervous activity in the visceral ganglia could be modified by its own specific contamination. Third, a decrease in nervous activity of the cerebral ganglia close to the mouth, including some kind of narcosis, could contribute to a decrease in visceral ganglia activity via a decrease or blockage of the downward neuromodulation by the cerebro-visceral connective. This whole set of events can explain the decrease of metabolic activity in the adductor muscles, contribute to initiate the catch mechanism and then deeply modify the valve behaviour.

Polycyclic Aromatic Hydrocarbons in Sediment and Health Risk of Fish, Crab and Shrimp Around Atlas Cove, Nigeria

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are toxic contaminants and pose health risks to humans and the ecosystem due to their persistence in the environment.

OBJECTIVES

This study determined the concentrations of PAHs in sediment, two species of fish (Drepane africana and Pomadasys jubelini), crabs (Callinectes amnicola) and shrimps (Penaeus notialis) around the Atlas Cove jetty, Lagos, Nigeria.

METHODS

Polycyclic aromatic hydrocarbons were extracted from fish, shrimp, and crabs that were purchased from local fishermen. Sediments were collected at five locations impacted by ship movement and cargo offloading around the Atlas Cove jetty during the period of June to August 2016, using standard methods. Potential toxicity of PAHs in the sediments on the surrounding aquatic organisms was assessed. The PAHs were analyzed using gas chromatography-mass spectrometry. Human health risk assessment was calculated from biota using dietary daily intake and carcinogenic potencies of individual PAH concentrations.

RESULTS

A total of 17 PAH congeners were detected in sediment samples and ten were detected in biota samples. Concentrations of total PAHs obtained in sediment and fish samples ranged from 2.15 - 36.46 mg/kg and 11.89 - 71.06 mg/kg, respectively. The total PAHs concentration pattern follow the order of P. notialis > C. amnicola > P. jubelini (whole) > D. africana (whole) > D. africana (fillet) > P. jubelini (fillet) > sediment. Concentrations of total PAHs were higher in whole fish than in fillet samples (muscle) in both fish species. High values of PAHs were recorded in the dietary intake (0.10 - 2.33 mg/kg body weight/day) of the organisms. Toxic equivalent quotient values (0.01 to 0.10 mg/kg) were observed to be higher than the screening values (0.0014 to 0.0599 mg/kg). In the muscle of Drepane africana and Pomadasys jubelini, splitting and atrophy of the muscle bundles were observed.

CONCLUSIONS

The concentrations of PAHs in analyzed sediment and organisms were higher than the maximum permissible limit of the United State Environmental Protection Agency (USEPA). Most of the detected PAHs were of petrogenic origin, which is an indication that anthropogenic activities were influencing PAH concentrations.

COMPETING INTERESTS

The authors declare no competing financial interests.

Bioaccumulation of Polycyclic Aromatic Hydrocarbon (PAH) in a bivalve (Arca senilis- blood cockles) and health risk assessment

Concentration of PAH in bivalves (Arca senilis) and human health risks due to consumption was examined in samples collected from southern Nigeria and analysed using gas chromatography. Mean PAH concentration (ngkg-1) ranged from 12.0 ± 5.0-5500.0 ± 1000 with a significant difference (p < 0.001) while total PAH ranged from 3000.0-16,000.0. Concentrations (ngkg-1) of PAH4 varied from 250 to 15268.0 while concentrations of PAH8 ranged from 542.0 to 15620.7 with significant difference (p < 0.001). Diagnostic ratios for PAH source distinction suggested mixture of petrogenic and pyrogenic sources. Dietary daily intake-DDI (ng/kg/day) of individual PAHs ranged from 1.04 to 9.86 while DDI for PAH4 and PAH8 were 340.8 and 379.8 respectively. Carcinogenic potencies (ngkg-1) varied from 0.012 to 900.0 for individual PAH while carcinogenic toxic equivalent (TEQs) values were 1916.2, 572.49 and 1914.4 for total PAH, PAH4 and PAH8 respectively. The Excess cancer risk (ECR) for individual PAHs, PAH4 and PAH8 were all <10-6. DDI and ECR values obtained were below USEPA threshold concentration/limits indicating minimal health risk concerns while PAH4 and PAH8 concentrations were also below the EU regulatory limits (30 μg kg-1) for PAH4. The margin of exposures were above the 10,000 critical limit proposed by EFSA while incremental life cancer risk (ILCR) value (10-5 - 10-9) also suggests low potential health risk for consumers of the sea food. The screening value (SV) was 0.095 but lower than observed TEQs values indicating potential health concerns. The study concluded that consumers of bivalves (Arca senilis) in southern Nigeria generally have minimal health risk concern via consumption but regular monitoring is required to detect changes.

Distribution, characterization, and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in Ovia River, Southern Nigeria

The levels and distribution of polycyclic aromatic hydrocarbons (PAHs) in surface water, sediment, and fish (Clarias gariepinus) samples from Ovia River, Southern Nigeria, were evaluated, to assess the contamination profile, dietary intake, and human health risks associated with exposure. Results showed that naphthalene, acenaphthylene, and fluoranthene were the most dominant contaminant in water, sediment, and fish, respectively, with mean concentrations (μg/L) of 3.08, 45.4, and 90.7. Spatial distribution showed high occurrence of PAHs in Ekenwan, the downstream station, for all the matrices. Source identification using multivariate analysis revealed mixed patterns of pyrogenic and petrogenic origins. Estimated daily intake (EDI) of PAHs through fish consumption ranged from 2.18 × 10^-7 to 5.23 × 10^-5 mg/kg/day; values were however lower than the reference dose (RfD) indicating low risk. Estimated values for hazard quotients (HQs) and hazard index (HI) for both non-carcinogenic and carcinogenic risks were below 1 indicating low risk through dietary and non-dietary exposure to water, sediment, and fish from Ovia River. However, estimated HI values for direct ingestion of sediment were above 1, indicating the possibility of non-carcinogenic health risk from exposure. Carcinogenic risk indices also indicated low risk from fish consumption. In spite of the assessed low risk from exposure, continuous monitoring of PAH levels in this water body is imperative to prevent future human health effects.

Distribution, characterization, and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in Ovia River, Southern Nigeria

The levels and distribution of polycyclic aromatic hydrocarbons (PAHs) in surface water, sediment, and fish (Clarias gariepinus) samples from Ovia River, Southern Nigeria, were evaluated, to assess the contamination profile, dietary intake, and human health risks associated with exposure. Results showed that naphthalene, acenaphthylene, and fluoranthene were the most dominant contaminant in water, sediment, and fish, respectively, with mean concentrations (μg/L) of 3.08, 45.4, and 90.7. Spatial distribution showed high occurrence of PAHs in Ekenwan, the downstream station, for all the matrices. Source identification using multivariate analysis revealed mixed patterns of pyrogenic and petrogenic origins. Estimated daily intake (EDI) of PAHs through fish consumption ranged from 2.18 × 10^-7 to 5.23 × 10^-5 mg/kg/day; values were however lower than the reference dose (RfD) indicating low risk. Estimated values for hazard quotients (HQs) and hazard index (HI) for both non-carcinogenic and carcinogenic risks were below 1 indicating low risk through dietary and non-dietary exposure to water, sediment, and fish from Ovia River. However, estimated HI values for direct ingestion of sediment were above 1, indicating the possibility of non-carcinogenic health risk from exposure. Carcinogenic risk indices also indicated low risk from fish consumption. In spite of the assessed low risk from exposure, continuous monitoring of PAH levels in this water body is imperative to prevent future human health effects.

Human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in smoked fish species from markets in Southern Nigeria

Polycyclic Aromatic Hydrocarbons (PAHs) levels in four commonly consumed smoked fish species from markets in Southern Nigeria were assessed to evaluate possible human health risks associated with consumption. Varying levels of PAH congeners were observed in the fish tissues with the highest total concentration of PAHs in Scomber scombrus. High concentrations of benzo(a)pyrene was observed in Clarias gariepinus and Ethmalosa fimbriata with values above the guideline value of 0.05 mg/kg. The Dietary Daily Intake (DDI) value for total PAHs (∑PAHs) was highest for S. scombrus while the DDI value for the total carcinogenic PAHs (∑CPAHs) was highest for E. fimbriata. Carcinogenic human health risk assessment using carcinogenic toxic equivalents (TEQ), indicated that consumption of E. fimbriata has a higher potential to cause carcinogenic risks. TEQ values for all the fish species were however, below the estimated screening value (SV) of 3.556 mg/kg, while the estimated cumulative excess cancer risk (ECR) for E. fimbriata and C. gariepinus and PAH4 index for all the assessed fish species exceeded threshold values indicating potential carcinogenic risk from consumption.