Is the polychaete, Perinereis rullieri (Pilato 1974), a reliable indicator of PCB and PAH contaminants in coastal sediments?

First characterization of the ecotoxicity of paraffin particles: assessment of biochemical effects in the marine polychaete Hediste diversicolor

Plastics are a widespread environmental problem, particularly in the form of small particles or fragments (microplastics). With the purpose of gradually replacing the use of plastics in cosmetic products (primary microplastics), the use of paraffin in microspheres has recently been applied. Paraffin waxes are composed by organic molecules usually derived from petroleum, thus assumed to be chemically and biologically inert, having a lower (eco)toxicity and residence time compared with plastic particles. However, the low ecotoxicity of paraffin waxes may be somewhat questionable, because some paraffin constituents can be absorbed and catabolized, thus exerting biological effects. The main objective of this study was to understand the potential toxic effects of paraffin microparticles on key physiological processes of the polychaete Hediste diversicolor. To attain this objective, this work assessed the acute and chronic effects of three densities (5, 20, and 80 mg L^-1) of four size ranges of paraffin particles (from 100 to 1200 μm) on this epibenthic organism. Although paraffin wax can be generically considered innocuous, the present study was able to demonstrate a significant inhibition in the activity of acetylcholinesterase in acutely exposed organisms and an increase in the activity of glutathione peroxidase, catalase, and glutathione S-transferase under some specific scenarios.

Occurrence of 3-nitrobenzanthrone and other powerful mutagenic polycyclic aromatic compounds in living organisms: polychaetes

In this work we report the occurrence of powerful mutagenic 3-nitrobenzanthrone (3-NBA), in addition to 18 polycyclic aromatic hydrocarbons (PAHs), 6 oxygenated PAHs and 27 nitrated PAHs in polychaete worms. Benzanthrone (BA), another important mutagenic polycyclic aromatic compound (PAC) also was detected in the samples. Polychaete annelids have great ecological relevance, being widely distributed in different environmental conditions, from intertidal zones up to seven thousand feet deep areas. They are abundantly found in both contaminated and uncontaminated areas and, therefore, used as indicators of the pollution status of a given area. As we know, so far, most of these PACs has not been previously reported in living organisms before. The 3-NBA concentrations determined in this study were within 0.11-5.18 µg g^-1. Other relevant PACs such as PAHs, quinones and nitro-PAHs were found in maximum concentrations at 0.013 µg g^-1 (coronene) to 11.1 µg g^-1 (benzo[k]fluoranthene), 0.823 µg g^-1 (9,10-phenenthrenequinone) to 12.1 µg g^-1 (1,4-benzoquinone) and 0.434 (1-nitronaphthalene) µg g^-1 to 19.2 µg g^-1 (6-nitrobenzo[a]pyrene), respectively. Principal component analysis (PCA), ternary correlations and diagnostic ratios were employed in order to propose probable sources for PACs. Although statistical analysis preliminarily has indicated both pyrogenic and petrogenic contributions, petrogenic sources were predominant reflecting the impacts of petroleum exploration and intensive traffic of boats in the study area.

Significance of the goby Zosterisessor ophiocephalus as a sentinel species for Venice Lagoon contamination: Combining biomarker responses and bioaccumulation

The Venice Lagoon is an interesting example of an ecosystem suffering for a considerable anthropogenic impact, resulting in high concentrations of persistent organic pollutants (POPs) in lagoon sediments and seafood. In this context, biomonitoring is a crucially important task. The present study aimed at evaluating the validity of a multiple biomarker approach in a benthic fish species. A total of 567 Zosterisessor ophiocephalus (Gobiidae) fish were collected in spring and autumn from three areas of Venice Lagoon (Porto Marghera, Val di Brenta, and Cà Roman) showing high, intermediate and low amounts of POPs, respectively. Aryl hydrocarbon receptor (AHR) and cytochrome P450 1A (CYP1A) mRNA levels, CYP1A protein amount and ethoxyresorufin O-deethylase activity (EROD) were measured in pooled liver and gills (mRNA levels only). Such biological data were then compared with polychlorinated biphenyls (PCBs) residues, measured in grass goby muscle by gas chromatography. Aryl hydrocarbon receptor and CYP1A mRNAs, protein and EROD were upregulated in accordance with PCB amounts measured in Z. ophiocephalus muscles. In fact, the highest AHR and CYP1A induction was observed in fish sampled in close proximity of the industrial area of Porto Marghera. Overall, the present study confirm the grass goby as a reliable sentinel species for Venice Lagoon, and AHR/CYP1A/EROD as a sensitive set of biomarkers of exposure for AHR ligands.

Spatio-temporal trends and body size differences of OCPs and PCBs in Laeonereis culveri (Polychaeta: Nereididae) from Southwest Atlantic estuaries

Southwest Atlantic (SWA) estuaries have been historically impacted by industrial and agricultural activities that represent an important source of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). Intraspecific differences in OCPs and PCBs levels were evaluated in the benthic polychaete Laeonereis culveri from SWA estuaries (Samborombón; Mar Chiquita; Quequén Grande and Bahía Blanca) at different spatio-temporal scales. Regarding inter- and intra-estuarine spatial comparisons polychaetes showed significant differences in OCPs/PCBs levels (p < 0.05) being DDTs, endosulfan, penta- and hexa-CBs homologues the most representative compounds. Intra-estuarine comparisons also showed significant differences in terms of seasonality and body size (p < 0.05). OCPs/PCBs concentrations were negatively correlated with animal weight, but this covariable was not relevant on differences observed. OCPs/PCBs levels in polychaetes showed strong relationships with those of sediments, being suitable for estuarine biomonitoring studies. Seasonal and body-size differences found in OCPs and PCBs levels in tissues reveal the importance of these factors for intra-estuarine monitoring.

Antioxidant responses in estuarine invertebrates exposed to repeated oil spills: Effects of frequency and dosage in a field manipulative experiment

We have experimentally investigated the effects of repeated diesel spills on the bivalve Anomalocardia brasiliana, the gastropod Neritina virginea and the polychaete Laeonereis culveri, by monitoring the responses of oxidative stress biomarkers in a subtropical estuary. Three frequencies of exposure events were compared against two dosages of oil in a factorial experiment with asymmetrical controls. Hypotheses were tested to distinguish between (i) the overall effect of oil spills, (ii) the effect of diesel dosage via different exposure regimes, and (iii) the effect of time since last spill. Antioxidant defense responses and oxidative damage in the bivalve A. brasiliana and the polychaete L. culveri were overall significantly affected by frequent oil spills compared to undisturbed controls. The main effects of diesel spills on both species were the induction of SOD and GST activities, a significant increase in LPO levels and a decrease in GSH concentration. N. virginea was particularly tolerant to oil exposure, with the exception of a significant GSH depletion. Overall, enzymatic activities and oxidative damage in A. brasiliana and L. culveri were induced by frequent low-dosage spills compared to infrequent high-dosage spills, although the opposite pattern was observed for N. virginea antioxidant responses. Antioxidant responses in A. brasiliana and L. culveri were not affected by timing of exposure events. However, our results revealed that N. virginea might have a delayed response to acute high-dosage exposure. Experimental in situ simulations of oil exposure events with varying frequencies and intensities provide a useful tool for detecting and quantifying environmental impacts. In general, antioxidant biomarkers were induced by frequent low-dosage exposures compared to infrequent high-dosage ones. The bivalve A. brasiliana and the polychaete L. culveri are more suitable sentinels due to their greater responsiveness to oil and also to their wider geographical distribution.

The effects of salinity changes on the Polychaete Diopatra neapolitana: Impacts on regenerative capacity and biochemical markers

Polychaetes have been identified by several authors as a group of marine invertebrates that respond rapidly to anthropogenic stressors. However, studies investigating alterations in Polychaetes affected by climate changes are scarce. Thus, the present study aimed to assess the impact of salinity changes (14, 21, 28, 35, 42g/L) on the physiological and biochemical performance of the Polychaete Diopatra neapolitana, evaluating the species regenerative ability and biochemical alterations. The results obtained demonstrated that organisms exposed to extreme salinity conditions (14, 21 and 42g/L) presented higher mortality rates, needed more days to completely regenerate the missing body region and also regenerated less chaetigers, when compared to organisms exposed to salinities 28 and 35g/L. The present study further demonstrated that D. neapolitana presented significantly lower glycogen and protein content at salinities 21 and 42g/L, which can be explained by higher energy expenditure in the physiological and biochemical processes. A marked impairment of the glutathione redox status was also recorded at salinities 21 and 42g/L. Increased antioxidant enzyme activities were observed at salinity 21g/L while LPO levels were increased at salinity 42g/L. Overall the present study demonstrated that the regenerative capacity of D. neapolitana can be used as a tool to assess environmental changes, namely salinity shifts. Moreover, stress related biomarkers revealed to be useful to evaluate the alterations in Polychaetes due to salinity changes. D. neapolitana revealed to be a good bioindicator to salinity alterations.

Biochemical and behavioral responses in the estuarine polychaete Perinereis gualpensis (Nereididae) after in situ exposure to polluted sediments

In situ translocation experiments are advantageous relative to traditional laboratory experiments, particularly for understanding the bioavailability of trace metals like mercury (Hg). Individuals of the polychaete Perinereis gualpensis were translocated from a reference site (Raqui estuary, Chile) to an estuarine site with significant sediment Hg concentrations (Lenga estuary: 1.78-9.89 mg/kg). Individuals were exposed in polluted and non-polluted sediments for 21 days and sampled every 7 days with cages deployed at three different depths. Tissue Hg concentrations were measured in conjunction with oxidative stress responses. Translocated polychaetes rapidly accumulated Hg. Glutathione S-transferase (GST) activities measured from posterior body regions were 2-fold higher than control activities after 21 days of exposure. Other antioxidant measures were idiosyncratic. Distinct burrowing behavior differences were observed; control polychaetes exhibited more homogenous vertical distributions, whereas in Lenga, worms tended to remain in upper layers. These studies demonstrate that under natural conditions, Hg is highly bioavailable to polychaetes affecting both biochemical and behavioral responses after relatively short-term exposure.

Assessing the significance of Ruditapes philippinarum as a sentinel for sediment pollution: bioaccumulation and biomarker responses

The present study assessed whether the bivalve Ruditapes philippinarum may be appropriately deployed as a bioindicator in monitoring transitional environments, in terms of bioaccumulation potential and biomarker responses. The concentrations of trace metals, PAHs and PCBs were determined in sediments and clam tissue, and biomarkers were estimated at various levels of biological complexity (i.e. metallothioneins, lipofuscins, survival-in-air and reburrowing behaviour). Sediments and clams were collected biannually in 2004 and 2005 at eight sites within Venice lagoon, which were influenced differently by natural and anthropogenic impacts. Results highlighted that the broad variations of pollutant concentrations in sediments were not consistent either with the body residuals or with the biomarker responses. Consequently, on the basis of the observed weak responsiveness and sensitivity to anthropogenic stressors we suggest a more cautious use for R. philippinarum as sentinel organism, at least in estuarine sediments in the north Adriatic transitional areas.

The polychaete, Perinereis nuntia ESTs and its use to uncover potential biomarker genes for molecular ecotoxicological studies

The polychaete, Perinereis nuntia, has been used as an indicator species to assess the environmental condition of benthic communities in coastal marine environments. Recently, high-throughput sequencing technology has been proven to be a useful method for analyzing expressed sequence tags (ESTs) in non-model species. Thus, we have obtained extensive cDNA information by the pyrosequencing method, to utilize the polychaete species as a test organism for sediment quality monitoring studies. From the total RNA of P. nuntia, cDNA was reversely synthesized and randomly sequenced using a GS-FLX sequencer. In the assembly stage 1, 40,379 transcripts (13,666 contigs and 26,713 singletons) were acquired and showed 47% hitting rate compared with the GenBank non-redundant (NR) amino acid sequence database using BLASTX. After the stage-2 assembly, 21,657 transcripts were identified and showed 28% hitting rate. Finally, we obtained 6 064 unigenes that corresponded to the GenBank NR amino acid sequence database using BLASTX. Of the transcripts obtained in this species, we found a number of stress- and cell defense-related genes (e.g. heat shock protein family, antioxidant-related genes, cytochrome P450 genes) that are potentially useful for sediment monitoring at the molecular level, indicating that the pyrosequencing method is an effective approach to uncover gene families of potential biomarker genes simultaneously, and thus make transcriptomic studies possible. To confirm the usefulness of those potential biomarker genes, we analyzed the comparative profiling of P. nuntia mRNA transcripts between the samples collected from the polychaete aquaculture farm and the southern coast field of South Korea. In this paper, we summarize the expressed cDNA information of P. nuntia and discussed its potential use in environmental genomics and ecotoxicological studies for uncovering the potential molecular mechanisms of environmental stresses and chemical toxicity to the indicator species, P. nuntia in marine sediments.

Explaining differences between bioaccumulation measurements in laboratory and field data through use of a probabilistic modeling approach

In the regulatory context, bioaccumulation assessment is often hampered by substantial data uncertainty as well as by the poorly understood differences often observed between results from laboratory and field bioaccumulation studies. Bioaccumulation is a complex, multifaceted process, which calls for accurate error analysis. Yet, attempts to quantify and compare propagation of error in bioaccumulation metrics across species and chemicals are rare. Here, we quantitatively assessed the combined influence of physicochemical, physiological, ecological, and environmental parameters known to affect bioaccumulation for 4 species and 2 chemicals, to assess whether uncertainty in these factors can explain the observed differences among laboratory and field studies. The organisms evaluated in simulations including mayfly larvae, deposit-feeding polychaetes, yellow perch, and little owl represented a range of ecological conditions and biotransformation capacity. The chemicals, pyrene and the polychlorinated biphenyl congener PCB-153, represented medium and highly hydrophobic chemicals with different susceptibilities to biotransformation. An existing state of the art probabilistic bioaccumulation model was improved by accounting for bioavailability and absorption efficiency limitations, due to the presence of black carbon in sediment, and was used for probabilistic modeling of variability and propagation of error. Results showed that at lower trophic levels (mayfly and polychaete), variability in bioaccumulation was mainly driven by sediment exposure, sediment composition and chemical partitioning to sediment components, which was in turn dominated by the influence of black carbon. At higher trophic levels (yellow perch and the little owl), food web structure (i.e., diet composition and abundance) and chemical concentration in the diet became more important particularly for the most persistent compound, PCB-153. These results suggest that variation in bioaccumulation assessment is reduced most by improved identification of food sources as well as by accounting for the chemical bioavailability in food components. Improvements in the accuracy of aqueous exposure appear to be less relevant when applied to moderate to highly hydrophobic compounds, because this route contributes only marginally to total uptake. The determination of chemical bioavailability and the increase in understanding and qualifying the role of sediment components (black carbon, labile organic matter, and the like) on chemical absorption efficiencies has been identified as a key next steps.

Multibiomarker approach at different organization levels in the estuarine Perinereis gualpensis (Polychaeta; Nereididae) under chronic and acute pollution conditions

This work aimed to study biochemical biomarkers and population responses in the polychaete Perinereis gualpensis (Nereididae) from two Chilean estuaries, Lenga (36°45'S; 73°10'W) and Tubul-Raqui (37°14'S,73°26'W). Lenga estuary is characterized by high mercury and PAH levels as consequence of several historic incidental spills while Tubul is mainly impacted by intensive fish activity. Raqui estuary, with low anthropogenic impact was considered the reference site. Worms were collected in winter and summer periods and tissues were differentiated between anterior (first 40 segments) and posterior region (the rest of the body). Levels of the antioxidant glutathione (GSH), glutathione-S-transferase (GST) activity, total antioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation (TBARS) levels, Na+, K+-ATPase activity (NKA) and metalothioneins (MTs) content were determined in each region. L3 (combined length of prostomiun+peristomiun+first segment) length, size, frequency, histograms and density of individuals were studied in all sites and seasons. Significant differences (p<0.05) were observed among sites for most of the biochemical responses (GSH, GCL, GST, ACAP and TBARS), showing variation between seasons and body regions. Population responses in the most polluted estuary (Lenga) showed differences in size, frequency, lengths and low densities compared with lower impacted sites, indicating the costs associated with tolerance in organisms chronically exposed to estuarine pollution.

Ethoxyresorufin-O-deethylase enzyme activities and accumulation of secondary/tertiary lysosomes in rabbitfish Siganus oramin as biomarkers for xenobiotic exposures

The sensitivities of using hepatic and intestinal ethoxyresorufin-O-deethylase (EROD) activities and hepatic accumulation of secondary/tertiary (2 degrees/3 degrees) lysosomes to detect xenobiotic exposures were assessed in the rabbitfish Siganus oramin in a metropolitan harbour, subtropical Hong Kong, over a complete seasonal cycle of one year. Additional information on the body-burden pollutants and physiological indices in S. oramin, and seasonal variables in seawater quality, were extracted from published data and re-analyzed. Under the influences of pollutant cocktail and seasonal factors, neither the hepatic nor intestinal EROD activity was indicative of total polycyclic aromatic hydrocarbons (Sigma PAH), total polychlorinated biphenyls, condition factor and hepatosomatic index (HSI) in S. oramin. However, the relative ratio of hepatic to intestinal EROD activities provided an indication to differentiate the xenobiotic intake route in the fish through diffusion via gills/skin or consumption of contaminated food. In addition, the elevated hepatic accumulation of 2 degrees/3 degrees lysosomes was closely associated with the dominant temporal trends of zinc and Sigma PAH, as well as reduced HSI, in S. oramin. Being minimally influenced by any investigated seasonal factors, the hepatic 2 degrees/3 degrees lysosomes in S. oramin was recommended as an effective biomarker of xenobiotic exposures and toxic effects for use in coastal pollution monitoring programmes.