Biota-sediment Accumulation Factors Research Articles

Mercury Levels in Sediment, Water and Selected Organisms Collected in a Coastal Contaminated Environment: The Marano and Grado Lagoon (Northern Adriatic Sea, Italy)

Mercury (Hg) is a global pollutant capable of bioaccumulates/biomagnifies along the trophic chain and posing concerns for organisms and humans. The historical mining in Idrija (NW Slovenia) and the more recent activity of a chlor-alkali plant (CAP) sited in Torviscosa (NE Italy) causes diffuse Hg contamination in the Marano and Grado Lagoon (MGL, northern Adriatic Sea, Italy). Despite the importance of fishing and aquaculture for local inhabitants, knowledge of the Hg content of MGL fish is still scarce and fragmentary. This paper reports the results obtained from the collection of sediments, water, and biota during the implementation of the WFD/2000/60/CE. The solid phase is characterised by high Hg concentrations (up to 7.4 mg kg−1) with a net positive gradient moving eastward, but chemical speciation suggests the prevalence of cinnabar (not mobile) species. The scarce mobility of Hg is attested to by the low concentrations found in surface waters. Hg in fish often exceeds the limit set for commercialization (0.5 mg kg−1 ww), especially in the Grado basin, but its content is variable depending on the size and habits of species. Although there was a significant linear relationship between THg content in sediment and tissues of Chelon auratus, the values of the biota sediment accumulation factor (BSAF), which were always less than one, suggest that the Hg bioavailable for transfer from sediment to biota is low. Additionally, the Target Hazard Quotient (THQ) calculated on C. auratus’s daily consumption showed that adverse effects on human health are out of the question at least for the Marano basin.

Bioaccumulation and trophic transfer of antibiotics in the aquatic and terrestrial food webs of the Yellow River Delta

Antibiotic pollution caused by aquaculture industries is a common problem in the wetland of the Yellow River Delta (YRD). Aquatic and terrestrial food webs coexist and interact in wetlands. However, there are few comparative studies on antibiotics in these two food webs. This study investigated the occurrence, bioaccumulation, and trophic transfer of 19 antibiotics in the aquatic and terrestrial food webs of the YRD, and discussed the effects of physicochemical parameters in different food webs. The total concentrations of antibiotics in aquatic organisms and terrestrial organisms ranged from 11.61 to 63.08 ng/g dry weight (dw) and 4.21–9.11 ng/g dw, respectively. BAF (bioaccumulation factor), BSAFa (biota sediment accumulation factor), and BSAFt (biota soil accumulation factor) were used to explore the bioaccumulation capacity of antibiotics. The calculation results of these three factors showed that fluoroquinolones (FQs) had the highest bioaccumulation capacity. As for the trophic transfer, the total concentrations of antibiotics were biodiluted in the aquatic food web while biomagnified in the terrestrial food web. Physicochemical parameters of the antibiotics showed that log Kow (octanol-water partition coefficient)/log Dow (pH-dependent distribution coefficient) and log Koa (octanol-air partition coefficient) were good predictors for antibiotic bioaccumulation in the aquatic and terrestrial organisms of the YRD, respectively. In addition, the increasing log Dow and log Koa led to a rise of TMF (trophic magnification factor) in the aquatic food web while a decrease of TMF in the terrestrial food web. Overall, these results provide insights into the mechanisms on bioaccumulation and trophic transfer of antibiotics in different food webs.

Biota-Sediment Accumulation Factors for Per- and Polyfluoroalkyl Substances.

Per- and polyfluoroalkyl substances (PFAS) are widely used in commercial products such textiles, firefighting foams, and surface coatings across the globe and some PFAS are known to be bioaccumulative in aquatic species. The ultimate sink for numerous anthropogenic chemicals is the sediments in lakes, rivers, and oceans. To understand the relationship between sediment and aquatic species, a literature search was performed and biota-sediment accumulation factors (BSAFs) data for 17 taxonomic classes were assembled. The carbonyl and sulfonyl PFAS classes were relatively data rich whereas phosphate (no measurements), ether (one chemical), and fluorotelomer (limited number of chemicals) PFAS classes were data poor. Taxonomic classes of Teleostei and Clitellata had the largest BSAFs whereas Magnoliopsida and Bivalvia had the smallest BSAFs, and BSAF values >1 (kg-OC/kg-wet wt) were very rare. Across all studies, median (±standard deviation) whole-body Teleostei BSAFs for perfluorooctane sulfonic acid and perfluorooctanoic acid (kg-OC/kg-wet wt) were 0.0580 (±0.445, n = 60) and 0.00283 (±0.103,24), respectively. Laboratory-measured BSAFs were consistently larger than field-measured BSAFs, that is, 53 of 67 comparisons were larger (80%). Comparing BSAFs across taxonomic classes, 72% of the BSAFs were significantly different (α = 0.05). Comparing BSAFs within a taxonomic class, BSAFs were significantly different for 63% of the taxonomic classes. Elimination kinetics for benthic invertebrates suggests steady-state conditions might be reached in the 28-day uptake portion of a laboratory bioaccumulation test for some test species. The largest data gaps, beyond limited measurements, are understanding the effects of concentration and mixtures on bioaccumulation from sediments, quantifying the difference, if any, in BSAFs between freshwater and brackish/marine ecosystems, and models for predicting BSAFs based on concentrations in sediment. Environ Toxicol Chem 2023;42:277-295. © 2022 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Bioaccumulation and Biota-Sediment Accumulation Factor of Metals and Metalloids in Edible Fish: A Systematic Review in Ethiopian Surface Waters.

Metals and metalloids pollution of Ethiopian surface water is becoming an environmental issue. Bioaccumulation and Biota-Sediment Accumulation Factor (BAF and BSAF) are used to quantify the bioaccumulation of contaminants from water and sediment to biota. The present study aimed to determine the BAF and BSAF of metals and metalloids in different surface waters of Ethiopia. Furthermore, the ecological and human health risks were also examined. Generally, 902 peer-reviewed papers from 2005 to 2022 were searched using search engines. The most common types of edible fish species in studied surface waters of Ethiopia were Oreochromis niloticus, Clarias gariepinus, and Barbus intermedius. The concentration of metals and metalloids were higher in sediment than in water and in carnivorous fish than in herbivorous fish. The BSAF of Se in all fish species was greater than 1. Oreochromis niloticus was a bio-concentrator of As and Se. The dissolved concentration of Cu, Cd, Pb, and Ni were higher compared to the Ethiopian Environmental Protection Authority and the European Union; Organization of Economic and Co-Operation Development environmental water quality standard guidelines for inland surface freshwater bodies. Likewise, in sediment, the concentration of Cu, Pb, Ni, Zn, and Cr were above Tolerable Effect Concentration values and Cd, Ni, and Cr were above Probable Effect Concentration levels when compared to the United States Consensus-Based Sediment Quality Guidelines for freshwater which indicates that these metals may pose risk to aquatic organisms. Consumption of raw water and fish contaminated with the detected metals and metalloids is not associated with any diseases. However, local consumers who live close to each freshwater ecosystem may become more exposed to health risk hazards. The findings of this study will provide baseline information on BAF and BSAF of metals and metalloids in surface waters and will contribute to the effective monitoring of environmental quality.

Bioaccumulation of per- and polyfluoroalkyl substances by freshwater benthic macroinvertebrates: Impact of species and sediment organic carbon content

Per- and polyfluoroalkyl substances (PFAS) in aquatic environments have caused global concern due to their persistence, toxicity, and potential bioaccumulation of some compounds. As an important compartment of the aquatic ecosystem, sediment properties impact PFAS partitioning between aqueous and solid phases, but little is known about the influence of sediment organic carbon content on PFAS bioaccumulation in benthic organisms. In this study, three freshwater benthic macroinvertebrates – worms (Lumbriculus variegatus), mussels (Elliptio complanata) and snails (Physella acuta) – were exposed for 28 days to PFAS spiked synthetic sediment equilibrated with a synthetic surface water. Using microcosms, sediment organic carbon content – 2%, 5% and 8% – was manipulated to assess its impact on PFAS bioaccumulation. Worms were found to have substantially greater PFAS bioaccumulation compared to mussels and snails. The bioaccumulation factors (BAFs) and biota sediment accumulation factors (BSAFs) in worms were both one to two magnitudes higher than in mussels and snails, likely due to different habitat-specific uptake pathways and elimination capacities among species. In these experiments, increasing sediment organic carbon content decreased the bioaccumulation of PFAS to benthic macroinvertebrates. In worms, sediment organic carbon content was hypothesized to impact PFAS bioaccumulation by affecting PFAS partitioning and sediment ingestion rate. Notably, the BSAF values of 8:2 fluorotelomer sulfonic acid (FTS) were the largest among 14 PFAS for all species, suggesting that the benthic macroinvertebrates probably have different metabolic mechanisms for fluorotelomer sulfonic acids compared to fish evaluated in published literature. Understanding the impact of species and sediment organic carbon on PFAS bioaccumulation is key to developing environmental quality guidelines and evaluating potential ecological risks to higher trophic level species.

Bioaccumulation of Metals in Mangrove Snail (Cerithidea obtusa) from Southwest Johor, Malaysia

Pollutants are persistent in the environment, taint the food chain, and harm people's health because of their toxicity. In this study, mangrove snails called Cerithidea obtusa (C. Obtusa) were gathered from Southwest Johor, Malaysia, and the amounts of macro and micro elements Ca, Fe, K, Mg, Na, As, Mn, and Zn in their soft tissues, shells, and related surface sediments were analysed. The Neutron Activation Analysis (NAA) method was used to calculate the elements concentration. The mean concentrations of Ca, Fe, K, Mg, Mn, Na, As, Mn and Zn were found to be followed by the order Fe > Na > K > Mg > Ca > Na > Mn > Zn > As in the sediment, while Ca > Na > K > Mg > Fe > Zn > Mn > As and Ca > K > Na > Mg > Fe > Mn > Zn > As in the soft tissue and shell of C. Obtusa respectively. The Enrichment Factor (EF) of Ca, K, Mg, Na, As, Zn, and Mn ranged from 0.58 to 2.58, 0.82 to 1.04, 1.14 to 2.34, 2.32 to 4.18, 1.31 to 3.45, 1.11 to 1.52, and 0.23 to 0.38, respectively. Mn had the lowest EF (0.23), and 4.18 had the greatest (Na). Most of the elements showed geoaccumulation index (Igeo) < 0 except for As and Na. Based on the Biota-Sediment Accumulation Factor (BSAF), the shell of C. Obtusa acts as a deconcentrator for all the elements except for Ca.

Nationwide monitoring of cyclic and linear siloxanes in sediment and bivalves from Korean coastal waters: Occurrence, geographical distribution, and bioaccumulation potential.

Contamination of coastal environments by siloxanes is of growing concern. Sediment and bivalves were collected from 50 locations along the Korean coast to assess the geographical distribution, sources, and bioaccumulation potential of siloxanes. Cyclic and linear siloxanes were detectable in all sediment and bivalve samples. The highest siloxane concentrations were detected in sediment (656ng/g dw) and bivalves (3273ng/g dw) from highly industrialized bays and harbor-zones, suggesting that industrial and shipping activities are major sources of siloxanes in coastal environment. The geographical distribution of siloxanes was similar in sediment and bivalves. Sedimentary siloxanes were dominated by cyclic siloxanes, while linear siloxanes were predominant in bivalves. Bioaccumulation of linear siloxanes in bivalves originated mainly from the sedimentary environment. Mean biota-sediment accumulation factors (BSAFs) of seven siloxanes ranged from 1.26 to 6.03, indicating potential for bioaccumulation. This is the first report on the nationwide survey on siloxanes in Korean coastal waters.

Assessing bioaccumulation potential of sediment associated fipronil degradates in oligochaete Lumbriculus variegatus based on passive sampler measured bioavailable concentration

The degradates of fipronil have equivalent or even more toxicity to non-target aquatic invertebrates. To assess their environmental risks, information of bioaccumulation is required. Currently, little is known about the bioaccumulative property of fipronil degradates in sediment, while it is well known that passive sampler may measure bioavailable concentration (Cfree) which links with the environmental effect more tightly than the total environment concentration. The goal of the present study was to characterize bioaccumulation potential in oligochaete Lumbriculus variegatus for a fipronil degradate sulfide. The sediment organic carbon-water partition coefficient (KOC) was measured with polymethyl methacrylate (PMMA) film passive sampler, and KOC was used to bridge the gap between biota-sediment accumulation factor (BSAF) and bioconcentration factor (BCF). The bioavailable concentration (Cfree)-based KOC values were 5371 ± 152 and 5013 ± 152 (mL/g OC) for fipronil sulfide (FSI) and sulfone (FSO), respectively. Since the two fipronil degradates were produced continuously in sediment by the parent compound, the time-weighted-average (TWA) concentration of FSI in the sediment was estimated from a bioassay with L. variegatus to calculate BSAF value (0.581 ± 0.211 g OC/g lipid) and BCF (3046 ± 1103 or log 3.48 ± 0.16 mL/g). This approach is able to estimate the Cfree-based KOC and BCF values of fipronil degradate in sediment with ongoing degradation of the parent compound.

ECOLOGICAL ASSESSMENT OF STREAMBED SEDIMENTS AND FRESHWATER FISH SPECIES OF EDE-ONYIMA LAKE, IN OKARKI-ENGENNI, RIVERS STATE, NIGERIA

Aquatic ecosystems are heavily polluted by potentially toxic substances deposited in the sediment as a result of anthropogenic activities. These substances have the potential to enter the food chain, posing significant risks to human health and the environment. Five trace metals such as chromium (Cr), nickel (Ni), cadmium (Cd), lead (Pb) and Polycyclic Aromatic hydrocarbons (PAHs) which are regarded as potentially toxic substances were determined in sediments and soft tissues of three commonly consumed fish species, Ageneiosus ucayalensis, Alestes baremoze, and Clarias gariepinus, collected at six sampling sites in Ede Onyima Creek, Okarki-Engenni, Rivers State, Nigeria. The results of trace metals in sediments showed the following range: Ni (1.25 – 11.90 mg/kg); Pb (0.23 – 20.21 mg/kg), Cd (0.09 – 0.72 mg/kg); Cr (0.25 – 11.96 mg/kg) and PAHs (1.25 – 11.90 mg/kg). The mean whole-body concentration of the analyte in three fish species followed the order: Pb &gt; Ni &gt; Cd &gt; PAHs &gt; Cr. The concentrations of the trace metals in sediment were below the quality guideline values; PAHs, had higher threshold and probable effect concentrations (LEL, TEL-HA28, PEL-HA28), indicating toxicity to benthic organisms. The biota-sediment accumulation factor (BSAF) for the fish species ranked in the following order Cd&gt;Pb&gt; Ni&gt;PAHs&gt; Cr. Trace metal concentrations in the fish species exceeded the international permissible limits, indicating that these species are not suitable for human consumption. The contamination level of analytes was determined using the metal pollution index (MPI), which revealed gross contamination of fish species by Cd and Pb in the order Clarias gariepinus (1.8) &gt; Ageneiosus ucayalensis (1.5) &gt; Alestes baremoze (1.4). Furthermore, the flood event had a significant effect on the sedimentary compartment, remobilizing PTSs availability for fish ingestion while washing away legacy contaminated streambed deposits during baseflow.

Level and risk assessment of selected polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and organochlorine pesticides in walnut and soil.

It is unknown how hydrophobic organic contaminants (HOCs) are distributed and how they affect the environment in high-fat nuts and their planted soil. The profile of HOCs in walnut/soil system was investigated in this study. Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs) were found in walnuts at concentrations of 0.67, 127, and 116 μg/kg, respectively. The target hazard quotients (THQ) of 17 PCBs, 16 PAHs, and 21 OCPs from walnut consumption by human were 0.06, 0.01, and 0.11, respectively. The highest concentrations of HOC in the soil were found in Nap and toxaphene, with concentrations of 2580 and 902 μg/kg, respectively. Bioaccumulation factors (BAF) and biota-sediment accumulation factors (BSAF) in walnuts were ranged from <0.01 to 7.04 and <0.01 to 3.83, respectively. Concentrations of most individual HOCs in soil samples were significantly correlated with soil organic matter (SOM) (p < 0.01) and minerals (p < 0.01), with maximum correlation coefficients of 0.70 (OM-PCB81) and -0.84 (P-BaP). According to this study, high-fat walnuts do not have a high bioaccumulation of HOCs from soil, and the risk of consumption is within the safe range.

Bioaccumulation and biomagnification of emerging poly- and perfluoroalkyl substances in marine organisms

Accumulating evidence has demonstrated the wide environmental presence of 6:2 chlorinated polyfluoroalkyl ether sulfonates (6:2 Cl-PFAES) and p-perfluorous nonenoxybenzene sulfonate (PFNOBS). However, data on the bioaccumulation and trophic magnification of these emerging poly- and perfluoroalkyl substances (PFASs) in subtropical marine environment is still limited. In this study, seawater (n = 17), sediment (n = 14), and marine organism (27 species; n = 177) samples were collected from East China Sea, and analyzed them for legacy and emerging PFASs. Besides perfluoroalkyl carboxylates and perfluorooctane sulfonate (PFOS), 6:2 Cl-PFAES was always among the predominant PFASs detected in seawater, sediment, and marine organism. For emerging PFASs, 6:2 Cl-PFAES (mean ± SD, 3.1 ± 0.17), 8:2 Cl-PFAES (3.3 ± 0.35), and PFNOBS (3.3 ± 0.19) had lower bioaccumulation factors (BAF) than PFOS (3.4 ± 0.22) in marine fish. In crab, PFNOBS (3.7 ± 0.33) had a lower biota-sediment accumulation factor (BSAF) than PFOS (3.9 ± 0.45). In snail, among all detected PFASs, PFNOBS (4.0 ± 0.42) had the highest mean log BSAF value. 8:2 Cl-PFAES consistently had a higher log BSAF value than 6:2 Cl-PFAES in snail and crab. Notably, these differences in BAF and BSAF are not significant. Among PFASs, 6:2 Cl-PFAES (2.3; 95 % confidence interval, CI: 1.9–2.6) displayed the highest trophic magnification factor (TMF). PFNOBS had the lowest TMF value (1.8, 95 % CI: 1.4–2.1), but which still indicates its weak biomagnification through the current marine food web. This is the first study reporting the bioaccumulation and biomagnification of PFNOBS in marine organisms, which deepens the understanding of its environmental behavior in the marine ecosystem.

Uptake and photoinduced degradation of phthalic acid esters (PAEs) in Ulva lactuca highlight its potential application in environmental bioremediation

The bioaccumulation of phthalates was studied in fragments of Ulva lactuca exposed for a maximum of 31 days at different concentrations of a solution of six phthalic acid esters (PAEs). The algal matrix showed rapid uptake since the first sampling, which increased over the time of the experimental period, at the end of which seaweed’s bioaccumulation potential was also evaluated. After the uptake, the algal matrix was subjected to UV irradiation in order to verify the removal of the phthalates. PAEs with higher octanol–water partition coefficients (logKow) and molecular weights were preferentially uptaken by U. lactuca in all the exposure experiments. It was observed that both accumulation (biota-sediment accumulation factor (log10BSAF) ranging from 3.75 to 4.02) and photodegradation (higher than 70% removal for all phthalates in 8 h) are more efficient at lower concentration levels. These results suggest the potential use of the algal matrices for environmental bioremediation, in order to mitigate the impact of pollution from ubiquitous pollutants such as PAEs.

Distribution of metals in water, sediment and fish tissue. Consequences for human health risks due to fish consumption in Lake Hawassa, Ethiopia

Water pollution may be a serious environmental problem for Lake Hawassa, an important fishing and recreational site as well as a drinking-water source in Ethiopia. The present study aims at determining the distribution of metals and metalloids in the lake's water, sediment and fish tissues and assessing the resulting human health and ecological risks. Metals were detected in both abiotic and biotic samples. In water, only the Hg concentration was significantly different among sampling sites. The average concentration of As, Cd, Cr, Cu, Ni, Pb, and Zn in water were below the environmental quality thresholds, thus not having potentially adverse effect on aquatic life. In sediment, significant differences in metals concentration among sites were found for As, Cd, Pb, Co, Zn and Hg (p < 0.05). Exceedances of As, Cr, Cu, Hg, Ni and Zn were found in sediment, with Cr, Ni and Zn above the probable effect concentration and being potentially toxic to aquatic life. Fish stored more metals in their liver than in their muscle. The concentration of metals in carnivorous fish (Barbus intermedius) was not higher in muscle and liver than those in herbivores fish (Oreochromis niloticus). The Bioaccumulation Factor of Cr in all fish species muscle was >1. The Biota-Sediment Accumulation Factor of all metals in all fish species muscle were <1. Positive correlations among metals in water and correlations among metals in sediment were found, indicating a potential common pollution source. Positive correlation of total organic carbon with Cd, Co and Se and clay content with Pb, As and Hg was found and may imply that metals are easily adsorbed by the organic matter and fine sediment. With respect to the measured metals no potential health risk due to consumption of fish from Lake Hawassa was observed.

Heavy metals in marine food web from Laizhou Bay, China: Levels, trophic magnification, and health risk assessment

Heavy metals in ocean may accumulate in seafood through food web and pose risks to human health. This study investigated the occurrence, trophic magnification, and health risks of 7 heavy metals in 20 marine organisms (n = 222) in Laizhou Bay (LZB), China. Results showed that Zn was the most abundant metal, followed by Cu, As, Cd, Cr, Ni and Pb. The total concentrations of 7 heavy metals in the organisms ranked in the order of crab ˃ shellfish ˃ algae ˃ fish ˃ starfish. Interspecific differences were found in the concentrations of Cr, Ni, Cu and Cd in marine organisms from LZB. Crab and shellfish showed much higher enrichment ability of heavy metals than that of algae, starfish and fish. Cd is the most biological accumulated element with the mean biota-sediment accumulation factor (BSAF) of 12.9. Stable isotope analysis showed a significant difference of δ15N among these five species (p < 0.01), and a food web was constructed accordingly. A biodilution pattern was found for Pb, As and Ni and no trophic interference in metal uptake was observed for Zn, Cu, Ni and Cr in the food web of LZB. The estimated daily intake (EDI) and target hazard quotients (THQs) of As and Cd indicated an adverse health effect on consumption of the seafood. The mean lifetime cancer risks (LCRs) for Cd and As suggested a potential carcinogenic effect on consumption of these seafood. This study provides a basis for health risk assessment of heavy metals in marine foods.

Bioaccumulation of Mercury and Other Trace Elements in the Edible Holothurian Holothuria (Halodeima) atra in Relation to Gold Mining Activities in North Sulawesi, Indonesia

Artisanal and small-scale gold mines (ASGMs) have been accompanied by widespread usage of mercury amalgamation to extract gold from ores, putting Indonesia among the top three global emitters of this pollutant and posing potential risks to the marine ecosystem and human health. Although the use of mercury has been largely eliminated following the signature of the Minamata Convention on Mercury, the practice of mercury amalgamation in ASGM has persisted in several regions, including the North Sulawesi. This study assesses how on the contamination of mercury and other trace elements coming from both industrial mines and ASGMs affects marine sediments and their bioaccumulation in two tissues (body wall and guts) of the edible holothurian Holothuria (Halodeima) atra, by comparing samples collected downstream of four mining areas to four control sites in the North Sulawesi province, Indonesia. In sediments, mean concentrations of arsenic, gold, cobalt, chromium, copper, mercury, nickel, lead, antimony, and zinc were significantly higher at sites receiving mine discharges than at control sites. Downstream to gold mines, compared to control sites, significant higher concentrations of As, Au, Cr, Hg, and Ni in holothurians body walls and of As, Au, Co, Cr, Cu, Hg, Pb, Sb, Sn, and Zn in holothurians guts were found. In general, higher contaminations in sediments and tissues were found at the site near the oldest artisanal mine. Trace element levels in H. atra specimens in North Sulawesi were generally higher than those reported in other regions. In the study area, these holothurians significantly bioaccumulate Hg, As, Zn, Cd, Cu, Sn, and biota-sediment accumulation factors were higher in guts than in body walls. From an environmental and human health perspective, Hg is resulted the most concerning element in surface sediment and H. atra specimens. Based on this evidence, further studies are urgently needed to understand better the effect of mercury and other potentially toxic trace elements in marine ecosystems and food webs in mining areas both in North Sulawesi and in many still poorly investigated southeast Pacific areas.

Identification and occurrence of TBBPA and its debromination and O-methylation transformation products in sediment, fish and whelks from a typical e–waste dismantling site

Tetrabromobisphenol A (TBBPA) and its debromination (∑BBPA) and O-methylation (∑MeO-TBBPA) products were widely detected in matched sediments, fish, and whelks samples collected from a typical electronic waste (e-waste) dismantling site in Southern China, with concentrations ranging from 19.8 to 1.52 × 104, 8.05 to 1.84 × 103, and 0.08 to 11.9 ng/g dry weight in sediments, and 6.96 to 1.97 × 105, 3.84 to 7.07 × 103, and 3.42 to 472 ng/g lipid in biotas, for TBBPA, ∑BBPA, and ∑MeO-TBBPA, respectively. Significantly higher concentrations of these targets were found in samples collected close to the e-waste site, indicating their potential e-waste sources. Tri-BBPA was the most abundant debromination products in sediments, whereas diMeO-TBBPA was the dominant O-methylation product in biotas. Relatively higher levels of diMeO-TBBPA found in liver and kidneys, suggesting these chemicals might be mainly derived from the in vivo biotransformation. Furthermore, significantly higher biota-sediment accumulation factor values were found for diMeO-TBBPA than these of TBBPA, indicating that O-methylation would increases their accumulation in aquatic organisms. Our study provides insights into the accumulation and biotransformation of TBBPA in aquatic systems. Further studies should pay attention to the occurrence as well as potential health risks of these transformation products.

Analysis of polycyclic aromatic hydrocarbons (PAHs) in surface sediments and edible aquatic species in an oil-contaminated mangrove ecosystem in Bodo, Niger Delta, Nigeria: Bioaccumulation and human health risk assessment

This work investigated the occurrence and risks associated with polycyclic aromatic hydrocarbons (PAHs) in tissues from five commonly consumed aquatic species (swimming crabs, estuarine shrimp, tiger prawns, periwinkles, and tilapia) and sediment across six sites in the area around Bodo town, in the Niger Delta region of Nigeria. We aimed to establish a relationship between PAH concentrations in sediment and biota, and to derive biota-sediment accumulation factors (BSAFs). Risks to human health associated with consumption of impacted food sources were assessed based on measured biotic concentrations of PAHs. The average concentration of PAHs and the number of PAHs measured above the limit of quantification varied greatly between different biota, with the lowest average concentrations observed in tilapia, followed by tiger prawns, crabs, estuarine shrimp, and the highest concentrations were observed in periwinkles. Similar to biotic concentrations, BSAFs were found to vary greatly across species, sites, and PAHs, though BSAFs for all organisms except periwinkles were below a value of 1. In periwinkles, BSAFs exceeded a value of 1 for phenanthrene (BSAF = 1.7), pyrene (1.5) and benzo[k]fluoranthene (1.7). Risks to human health associated with consumption of these species were assessed using the BaP toxic-equivalent approach for cancer risks and the toxic unit approach which jointly considered carcinogenic but also non-cancer hazards. The BaP toxic-equivalent approach showed that the excess lifetime cancer risk resulting from daily consumption of 0.2 kg of seafood ranged between 1.3 × 10−6 for tiger prawn and tilapia to 4.1 × 10−6 for periwinkles, which is below the excess lifetime cancer risk of 10−4 used by Dutch and Nigerian authorities for sediment intervention values. This finding is supported by the results obtained from the toxic unit approach which indicates that the ratios of the estimated dose and the maximal permissible risk level for summed PAHs never exceeded 1.

Occurrence and fate of chlorinated methylsiloxanes in surrounding aqueous systems of Shengli oilfield, China

Mono-chlorinated products of cyclic volatile methylsiloxanes (cVMS), i.e., Monochlormet-hylheptamethylcyclotetrasiloxane [D3D(CH2Cl)], monochlormethylnonamethylcyclopenta-siloxane [D4D(CH2Cl)], and monochlormethylundemethylcyclohexasiloxane [D5D(CH2Cl)], were detected in water [<LOQ (Limit of quantitation) -86.3 ng/L, df (detection frequency) = 23%-38%, n=112] and sediment samples [<LOQ-504 ng/g dw (dry weight), df = 33%-38%, n=112] from 16 lakes located in Shengli oilfield of China, and had apparent increasing trends (31%-34% per annum) in sediments during Year 2014-2020. Simulated experiments showed that chloro-cVMS in sediment-water system had approximately 1.7-2.0 times slower elimination rates than parent cVMS. More specifically, compared with those of parent cVMS, volatilization (86-2558 days) and hydrolysis (135-549 days) half-lives of chloro-cVMS were respectively 1.3-2.0 and 1.8-2.1 times longer. In two species of freshwater mussels (n=1050) collected from six lakes, concentrations of chloro-cVMS ranged from 9.8-998 ng/g dw in Anodonta woodiana and 8.4-970 ng/g dw in Corbicula fluminea. Compared with parent cVMS, chloro-cVMS had 1.1-1.5 times larger biota-sediment accumulation factors (2.1-3.0) and 1.1-1.7 times longer half-lives (13-42 days). Their stronger persistence in sediment and bioaccumulation in freshwater mussels suggested that environmental emission, distribution and risks of chloro-cVMS deserve further attention.

Transfer of 7 Organic UV Filters from Sediment to the Ragworm Hediste diversicolor: Bioaccumulation of Benzophenone-3 and Further Proof of Octocrylene Metabolism

Organic UV filters are continuously released in aquatic ecosystems due to their widespread use, especially in touristic coastal environments. Generally, organic UV filters are poorly soluble in water and tend to accumulate in the sediment compartment. This represents a conceivable risk for sediment-dwelling organisms and a potential for transfer of the UV filters up the food chain. This study aimed to assess the potential transfer of seven UV filters including benzophenone-3 (BP3), bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT), butyl methoxydibenzoylmethane (BM), methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT), 2-ethylhexyl salicylate (ES), diethylhexyl butamido triazone (DBT), and octocrylene (OC) from artificial spiked sediment (10 µg.g−1 dry weight) to sediment-dwelling worms. All UV filters were detected in the worms after 28 days of exposure, but only BP3 was apparently bioaccumulated, with a biota sediment accumulation factor (BSAF) of 12.38 ± 4.65. However, metabolomic profiling revealed that OC was metabolized by the worms into 11 fatty acid conjugates, demonstrating that OC did also accumulate in the worms in the form of OC–fatty acid conjugates. Here, the sole quantification of the parent organic UV filter underestimated the accumulation factor and the exposure of organisms. In general, it is therefore important to pair the conventional method (BSAF calculus) with other techniques, such as metabolomics, to assess the actual potential for bioaccumulation of xenobiotics including transformed xenobiotics.

Bioavailability and trophic magnification of antibiotics in aquatic food webs of Pearl River, China: Influence of physicochemical characteristics and biotransformation

Information on trophodynamics of antibiotics and subsequent relationships to antibiotic metabolism in river ecosystem is still unavailable, limiting the evaluation of their bioaccumulation and trophodynamics in aquatic food webs. In the present study, concentrations and relative abundance of 11 antibiotics were investigated in surface water, sediment and 22 aquatic taxa (e.g., fish, invertebrates and plankton) from Pearl River, South China. The logarithmic bioaccumulation factors (log BAFs) of antibiotics generally showed positive relationships with their log D (pH-adjusted log Kow), implying that their bioaccumulation of ionizable antibiotics depends on it is in an ionized form. Higher BAFs of antibiotics in benthic biota were observed than those in fish, indicating that sediment ingestion was a possible route of antibiotic exposure. The logarithmic biota-sediment accumulation factors (log BSAFs) of benthic biota increased when log D increased from −4.79 to −0.01, but declined thereafter. Trophodynamics of antibiotics was investigated, and intrinsic clearance were measured in liver microsomes of Tilapia zillii (trophic level [TL]: 2.5), Anabas testudineu (TL: 3.9), and Coilia grayi (TL: 5.0). Only ciprofloxacin (CFX) showed significant trophic magnification (Trophic Magnification Factor [TMF] = 1.95), and a higher metabolism rate in lower trophic levels suggest that metabolic biotransformation play a significant role in driving biomagnification of antibiotics.