Polymer Chemical Identity as a Key Factor in Microplastic-Insecticide Antagonistic Effects during Embryogenesis of Sea Urchin Arbacia lixula.

As a proxy for pollutants that may be simultaneously present in urban wastewater streams, the effects of two microplastics-polystyrene (PS; 10, 80 and 230 µm diameter) and polymethylmethacrylate (PMMA; 10 and 50 µm diameter)-on fertilisation and embryogenesis in the sea urchin Arbacia lixula with co-exposure to the pyrethroid insecticide cypermethrin were investigated. Synergistic or additive effects were not seen for plastic microparticles (50 mg L-1) in combination with cypermethrin (10 and 1000 µg L-1) based on evaluation of skeletal abnormalities or arrested development and death of significant numbers of larvae during the embryotoxicity assay. This behaviour was also apparent for male gametes pretreated with PS and PMMA microplastics and cypermethrin, where a reduction in sperm fertilisation ability was not evidenced. However, a modest reduction in the quality of the offspring was noted, suggesting that there may be some transmissible damage to the zygotes. PMMA microparticles were more readily taken up than PS microparticles, which could suggest surface chemical identity as potentially modulating the affinity of larvae for specific plastics. In contrast, significantly reduced toxicity was noted for the combination of PMMA microparticles and cypermethrin (100 µg L-1), and may be related to less ready desorption of the pyrethroid than PS, as well as cypermethrin activating mechanisms that result in reduced feeding and hence decreased ingestion of microparticles.

Hormetic Effects of Cerium, Lanthanum and Their Combination at Sub-micromolar Concentrations in Sea Urchin Sperm.

Rare earth elements (REEs) cerium (Ce) and lanthanum (La) and their combination were tested across a concentration range, from toxic (10-4 to 10-5 M) to lower concentrations (10-6 to 10-8 M) for their effects on sea urchin (Sphaerechinus granularis) sperm. A significantly decreased fertilization rate (FR) was found for sperm exposed to 10-5 M Ce, La and their combination, opposed to a significant increase of FR following 10-7 and 10-8 M REE sperm exposure. The offspring of REE-exposed sperm showed significantly increased developmental defects following sperm exposure to 10-5 M REEs vs. untreated controls, while exposure to 10-7 and 10-8 M REEs resulted in significantly decreased rates of developmental defects. Both of observed effects-on sperm fertilization success and on offspring quality-were closely exerted by Ce or La or their combination.

Cytogenetic and developmental toxicity of bisphenol A and bisphenol S in Arbacia lixula sea urchin embryos.

Bisphenol S (BP-S) is one of the most important substitutes of bisphenol A (BP-A), and its environmental occurrence is predicted to intensify in the future. Both BP-A and BP-S were tested for adverse effects on early life stages of Arbacia lixula sea urchins at 0.1 up to 100 µM test concentrations, by evaluating cytogenetic and developmental toxicity endpoints. Embryonic malformations and/or mortality were scored to determine embryotoxicity (72 h post-fertilization). It has been reported in academic dataset that bisphenols concentration reached µg/L in aquatic environment of heavily polluted areas. We have chosen concentrations ranging from 0.1-100 µM in order to highlight, in particular, BP-S effects. Attention should be paid to this range of concentrations in the context of the evaluation of the toxicity and the ecological risk of BP-S as emerging pollutant. Cytogenetic toxicity was measured, using mitotic activity and chromosome aberrations score in embryos (6 h post-fertilization). Both BP-A and BP-S exposures induced embryotoxic effects from 2.5 to 100 µM test concentrations as compared to controls. Malformed embryo percentages following BP-A exposure were significantly higher than in BP-S-exposed embryos from 0.25 to 100 µM (with a ~5-fold difference). BP-A, not BP-S exhibited cytogenetic toxicity at 25 and 100 µM. Our results indicate an embryotoxic potential of bisphenols during critical periods of development with a potent rank order to BP-A vs. BP-S. Thus, we show that BP-A alternative induce similar toxic effects to BP-A with lower severity.

Review of Rare Earth Elements as Fertilizers and Feed Additives: A Knowledge Gap Analysis.

Rare earth elements (REEs) are key constituents of modern technology and play important roles in various chemical and industrial applications. They also are increasingly used in agricultural and zootechnical applications, such as fertilizers and feed additives. Early applications of REEs in agriculture have originated in China over the past several decades with the objective of increasing crop productivity and improving livestock yield (e.g., egg production or piglet growth). Outside China, REE agricultural or zootechnical uses are not currently practiced. A number of peer-reviewed manuscripts have evaluated the adverse and the positive effects of some light REEs (lanthanum and cerium salts) or REE mixtures both in plant growth and in livestock yield. This information was never systematically evaluated from the growing body of scientific literature. The present review was designed to evaluate the available evidence for adverse and/or positive effects of REE exposures in plant and animal biota and the cellular/molecular evidence for the REE-associated effects. The overall information points to shifts from toxic to favorable effects in plant systems at lower REE concentrations (possibly suggesting hormesis). The available evidence for REE use as feed additives may suggest positive outcomes at certain doses but requires further investigations before extending this use for zootechnical purposes.

Microplastic-induced damage in early embryonal development of sea urchin Sphaerechinus granularis.

Two microplastic sets, polystyrene (PS) and polymethyl methacrylate (PMMA), were tested for adverse effects on early life stages of Sphaerechinus granularis sea urchins. Microparticulate PS (10, 80 and 230 µm diameter) and PMMA (10 and 50 µm diameter) were tested on developing S. granularis embryos from 10 min post-fertilisation (p-f) to the pluteus larval stage (72 h p-f), at concentrations ranging from 0.1 to 5 mg L-1. Both PS and PMMA exposures resulted in significant concentration-related increase of developmental defects and of microplastic uptake in plutei. Moreover, embryo exposures to PS and PMMA (5 and 50 mg L-1) from 10 min to 5 h p-f resulted in a significant increase of cytogenetic abnormalities, expressed as significantly increased mitotic aberrations, while mitotoxicity (as % embryos lacking active mitoses) was observed in embryos exposed to PS, though not to PMMA. When S. granularis sperm suspensions were exposed for 10 min to PS or to PMMA (0.1-5 mg L-1), a significant decrease of fertilisation success was observed following sperm exposure to 0.1 mg L-1 PS, though not to higher PS concentrations nor to PMMA. Sperm pretreatment, however, resulted in significant offspring damage, as excess developmental defects in plutei, both following sperm exposure to PS and PMMA, thus suggesting transmissible damage from sperm pronuclei to the offspring. The overall results point to relevant developmental, cytogenetic and genotoxic effects of PS and PMMA microplastics to S. granularis early life stages, warranting further investigations of other microplastics and other target biota.

Soil pollution and toxicity in an area affected by emissions from a bauxite processing plant and a power plant in Gardanne (southern France).

Soil pollution and toxicity have been investigated in the Gardanne area (southern France) at a range of sites around a recognized pollution source, a bauxite processing plant (BPP), and a power plant (PP). Soil samples were submitted to inorganic and organic analyses and tested for toxicity in two invertebrate models. Inorganic analysis was based on determining elemental concentrations by ICP-MS, encompassing a total of 26 elements including 13 rare earth elements (REEs), of the soil samples and their leachates after 24 or 48 h in seawater. Organic analyses were performed by measuring the sums of 16 polycyclic aromatic hydrocarbons (PAHs) and of total hydrocarbons (C-10 to C-40). Bioassays were carried out on the early life stages of three sea urchin species (Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis), and on a nematode (Caenorhabditis elegans). Sea urchin bioassays were evaluated by the effects of soil samples (0.1-0.5% dry wt/vol) on developing embryos and on sperm, and scored as: a) % developmental defects, b) inhibition of sperm fertilization success and offspring damage, and c) frequencies of mitotic aberrations. C. elegans 24 h-mortality assay showed significant toxicity associated with soil samples. The effects of soil samples showed heightened toxicity at two groups of sites, close to the BPP main entrance and around the PP, which was consistent with the highest concentrations found for metals and PAHs, respectively. Total hydrocarbon concentrations displayed high concentrations both close to BPP main entrance and to the PP. Further studies of the health effects of such materials in Gardanne are warranted.

Topsoil and urban dust pollution and toxicity in Taranto (southern Italy) industrial area and in a residential district.

Adverse environmental conditions in the Taranto area (southern Italy) were investigated in studies of air, marine sediment, and human health. The present study aimed at providing unprecedented information on soil pollution and toxicity in a set of sites around recognized pollution sources in the Taranto area, since previous studies were focused on marine or air pollution, or on human health effects. The investigated area included a steel foundry and a power plant, as well as some sites located in an adjacent neighborhood. Surface soil samples and urban dust were collected and submitted to inorganic and organic analyses and tested for toxicity in two invertebrate bioassay models; a sea urchin (Sphaerechinus granularis) and an annelid (Caenorhabditis elegans). Inorganic analysis was carried out using ICP-MS for elemental composition for a total of 34 elements, whose levels were evaluated as a function of bioassay data analyzed through principal component analysis (PCA). Other analyses included asbestos search by powder X-ray diffraction (PXRD) and organic analysis for polycyclic aromatic hydrocarbons (PAHs) and aliphatic compounds (C10-C40). Toxicity bioassays were carried out on a sea urchin (Sphaerechinus granularis), and an annelid (Caenorhabditis elegans). Sea urchin bioassays evaluated effects of topsoil or street dust sample exposures (0.1 to 0.5% dry wt/vol) on developing embryos and on sperm, and scored as (a) % developmental defects, (b) inhibition of fertilization success and offspring damage, and (c) frequencies of mitotic aberrations. C. elegans mortality assay displayed significant toxicity associated with soil samples. The overall effects of samples showed very high toxicity at four out of nine sites. These effects were consistent with the highest levels measured for metals and PAHs. Further studies of health effects related to dust exposures in residential areas are warranted. Graphical abstract ᅟ.

Heavy Rare Earth Elements Affect Sphaerechinus granularis Sea Urchin Early Life Stages by Multiple Toxicity Endpoints.

Heavy rare earth elements (HREEs) were tested for adverse effects to early life stages of the sea urchin Sphaerechinus granularis. Embryos were exposed to analytically measured HREE concentrations ranging from 10-7 to 10-5 M. No significant developmental defect (DD) increases were observed in embryos exposed to 10-7 M HREEs, whereas 10-5 M HREEs resulted in significant DD increase up to 96% for HoCl3 versus 14% in controls. Embryos exposed to 10-6 M HREEs showed the highest DD frequency in embryos exposed to 10-6 M DyCl3 and HoCl3. Cytogenetic analysis of HREE-exposed embryos revealed a significant decrease in mitotic activity, with increased mitotic aberrations. When S. granularis sperm were exposed to HREEs, the offspring of sperm exposed to 10-5 M GdCl3 and LuCl3 showed significant DD increases. The results warrant investigations on HREEs in other test systems, and on REE-containing complex mixtures.

Heavy rare earth elements affect early life stages in Paracentrotus lividus and Arbacia lixula sea urchins.

BACKGROUND: Heavy rare earth elements (HREEs) have been scarcely studied for their toxicity, in spite of their applications in several technologies. Thus HREEs require timely investigations for their adverse health effects. METHODS: Paracentrotus lividus and Arbacia lixula embryos and sperm were exposed to trichloride salts of five HREEs (Dy, Ho, Er, Yb and Lu) and to Ce(III) as a light REE (LREE) reference to evaluate: 1) developmental defects (% DD) in HREE-exposed larvae or in the offspring of HREE-exposed sperm; 2) mitotic anomalies; 3) fertilization success; and 4) reactive oxygen species (ROS) formation, and nitric oxide (NO) and malondialdehyde (MDA) levels. Nominal HREE concentrations were confirmed by inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: HREEs induced concentration-related DD increases in P. lividus and A. lixula larvae, ranging from no significant DD increase at 10-7M HREEs up to ≅100% DD at 10-5M HREE. Larvae exposed to 10-5M Ce(III) resulted in less severe DD rates compared to HREEs. Decreased mitotic activity and increased aberration rates were found in HREE-exposed P. lividus embryos. Significant increases in ROS formation and NO levels were found both in HREE-exposed and in Ce(III) embryos, whereas only Ce(III), but not HREEs resulted in significant increase in MDA levels. Sperm exposure to HREEs (10-5-10-4M) resulted in a concentration-related decrease in fertilization success along with increase in offspring damage. These effects were significantly enhanced for Dy(III), Ho(III), Er(III) and Yb(III), compared to Lu(III) and to Ce(III). CONCLUSION: HREE-associated toxicity affected embryogenesis, fertilization, cytogenetic and redox endpoints showing different toxicities of tested HREEs.

Comparative toxicities of selected rare earth elements: Sea urchin embryogenesis and fertilization damage with redox and cytogenetic effects.

BACKGROUND: Broad-ranging adverse effects are known for rare earth elements (REE), yet only a few studies tested the toxicity of several REE, prompting studies focusing on multi-parameter REE toxicity. METHODS: Trichloride salts of Y, La, Ce, Nd, Sm, Eu and Gd were tested in Paracentrotus lividus sea urchin embryos and sperm for: (1) developmental defects in either REE-exposed larvae or in the offspring of REE-exposed sperm; (2) fertilization success; (3) mitotic anomalies in REE-exposed embryos and in the offspring of REE-exposed sperm, and (4) reactive oxygen species (ROS) formation, and malondialdehyde (MDA) and nitric oxide (NO) levels. RESULTS: REEs affected P. lividus larvae with concentration-related increase in developmental defects, 10(-6) to 10(-4)M, ranking as: Gd(III)>Y(III)>La(III)>Nd(III)≅Eu(III)>Ce(III)≅Sm(III). Nominal concentrations of REE salts were confirmed by inductively coupled plasma mass spectrometry (ICP-MS). Significant increases in MDA levels, ROS formation, and NO levels were found in REE-exposed embryos. Sperm exposure to REEs (10(-5) to 10(-4)M) resulted in concentration-related decrease in fertilization success along with increase in offspring damage. Decreased mitotic activity and increased aberration rates were detected in REE-exposed embryos and in the offspring of REE-exposed sperm. CONCLUSION: REE-associated toxicity affecting embryogenesis, fertilization, cytogenetic and redox endpoints showed different activities of tested REEs. Damage to early life stages, along with redox and cytogenetic anomalies should be the focus of future REE toxicity studies.

Rare earth elements in human and animal health: State of art and research priorities.

BACKGROUND: A number of applications have been developed using rare earth elements (REE), implying several human exposures and raising unsolved questions as to REE-associated health effects. METHODS: A MedLine survey was retrieved from early reports (1980s) up to June 2015, focused on human and animal exposures to REE. Literature from animal models was selected focusing on REE-associated health effects. RESULTS: Some REE occupational exposures, in jobs such as glass polishers, photoengravers and movie projectionists showed a few case reports on health effects affecting the respiratory system. No case-control or cohort studies of occupational REE exposures were retrieved. Environmental exposures have been biomonitored in populations residing in REE mining areas, showing REE accumulation. The case for a iatrogenic REE exposure was raised by the use of gadolinium-based contrast agents for nuclear magnetic resonance. Animal toxicity studies have shown REE toxicity, affecting a number of endpoints in liver, lungs and blood. On the other hand, the use of REE as feed additives in livestock is referred as a safe and promising device in zootechnical activities, possibly suggesting a hormetic effect both known for REE and for other xenobiotics. Thus, investigations on long-term exposures and observations are warranted. CONCLUSION: The state of art provides a limited definition of the health effects in occupationally or environmentally REE-exposed human populations. Research priorities should be addressed to case-control or cohort studies of REE-exposed humans and to life-long animal experiments.

Health effects and toxicity mechanisms of rare earth elements-Knowledge gaps and research prospects.

In the recent decades, rare earth elements (REE) have undergone a steady spread in several industrial and medical applications, and in agriculture. Relatively scarce information has been acquired to date on REE-associated biological effects, from studies of bioaccumulation and of bioassays on animal, plant and models; a few case reports have focused on human health effects following occupational REE exposures, in the present lack of epidemiological studies of occupationally exposed groups. The literature is mostly confined to reports on few REE, namely cerium and lanthanum, whereas substantial information gaps persist on the health effects of other REE. An established action mechanism in REE-associated health effects relates to modulating oxidative stress, analogous to the recognized redox mechanisms observed for other transition elements. Adverse outcomes of REE exposures include a number of endpoints, such as growth inhibition, cytogenetic effects, and organ-specific toxicity. An apparent controversy regarding REE-associated health effects relates to opposed data pointing to either favorable or adverse effects of REE exposures. Several studies have demonstrated that REE, like a number of other xenobiotics, follow hormetic concentration-related trends, implying stimulatory or protective effects at low levels, then adverse effects at higher concentrations. Another major role for REE-associated effects should be focused on pH-dependent REE speciation and hence toxicity. Few reports have demonstrated that environmental acidification enhances REE toxicity; these data may assume particular relevance in REE-polluted acidic soils and in REE mining areas characterized by concomitant REE and acid pollution. The likely environmental threats arising from REE exposures deserve a new line of research efforts.

Evaluation of Rare Earth Element-Associated Hormetic Effects in Candidate Fertilizers and Livestock Feed Additives.

Rare earth elements (REEs) are recognized as emerging contaminants with implications in human and environmental health. Apart from their adverse effects, REEs have been reported as having positive effects when amended to fertilizers and livestock feed additives, thus suggesting a hormetic trend, implying a concentration-related shift from stimulation to inhibition and toxicity, with analogous trends that have been assessed for a number of xenobiotics. In view of optimizing the success of REE mixtures in stimulating crop yield and/or livestock growth or egg production, one should foresee the comparative concentration-related effects of individual REEs (e.g., Ce and La) vs. their mixtures, which may display distinct trends. The results might prompt further explorations on the use of REE mixtures vs. single REEs aimed at optimizing the preparation of fertilizers and feed additives, in view of the potential recognition of their use in agronomy and zootechny.

Geospatial pattern of topsoil pollution and multi-endpoint toxicity in the petrochemical area of Augusta-Priolo (eastern Sicily, Italy).

The present study was aimed at identifying geospatial patterns of pollutants including concentrations and toxicity as complex environmental mixtures, in topsoil samples close to petrochemical facilities in the heavily industrialized area of Augusta and Priolo in south-eastern Sicily (Italy). Elemental analysis of soil was conducted by ICP-MS for 23 metals and 16 rare earth elements (REEs). Organic analyses were primarily focused on polycyclic aromatic hydrocarbons (PAHs) (16 parent homologs) and total aliphatic hydrocarbons (C10 - C40). Topsoil samples were tested for toxicity in multiple bioassay models including: 1) developmental defects and cytogenetic anomalies in sea urchin Sphaerechinus granularis early life stages; 2) growth inhibition of diatom Phaeodactylum tricornutum; 3) mortality in nematode Caenorhabditis elegans; and 4) induction of mitotic abnormalities in onion Allium cepa. Samples collected at sites closest to defined petrochemical facilities were highest in select pollutants and correlated with biological effects in different toxicity endpoints. A noteworthy finding was the increased level of total REEs in sites closest to petrochemical facilities, suggesting their contributions to identifying petrochemical sources of pollutants to the environment. The combined data obtained in the different bioassays allowed exploration of geospatial patterns of effect in biota as a function of contaminant levels. In conclusion, this study provides consistent data of soil toxicity, metal and REE contamination at Augusta-Priolo sampling sites, and may provide an appropriate baseline for epidemiological studies on high incidences of congenital birth defects in the area and identification of at-risk localities.

Resolving the effects of environmental micro- and nanoplastics exposure in biota: A knowledge gap analysis.

The pervasive spread of microplastics (MPs) and nanoplastics (NPs) has raised significant concerns on their toxicity in both aquatic and terrestrial environments. These polymer-based materials have implications for plants, wildlife and human health, threatening food chain integrity and ultimate ecosystem resilience. An extensive - and growing - body of literature is available on MP- and NP-associated effects, including in a number of aquatic biota, with as yet limited reports in terrestrial environments. Effects range from no detectable, or very low level, biological effects to more severe outcomes such as (but not limited to) increased mortality rates, altered immune and inflammatory responses, oxidative stress, genetic damage and dysmetabolic changes. A well-established exposure route to MPs and NPs involves ingestion with subsequent incorporation into tissues. MP and NP exposures have also been found to lead to genetic damage, including effects related to mitotic anomalies, or to transmissible damage from sperm cells to their offspring, especially in echinoderms. Effects on the proteome, transcriptome and metabolome warrant ad hoc investigations as these integrated "omics" workflows could provide greater insight into molecular pathways of effect. Given their different physical structures, chemical identity and presumably different modes of action, exposure to different types of MPs and NPs may result in different biological effects in biota, thus comparative investigations of different MPs and NPs are required to ascertain the respective effects. Furthermore, research on MP and NP should also consider their ability to act as vectors for other toxicants, and possible outcomes of exposure may even include effects at the community level, thus requiring investigations in mesocosm models.

Comparative toxicities of aluminum and zinc from sacrificial anodes or from sulfate salt in sea urchin embryos and sperm.

The toxicity of aluminum or zinc from either sacrificial anodes (SA) or their sulfate salts (SS) was evaluated in sea urchin (Paracentrotus lividus) embryos or sperm exposed to Al(III) or Zn(II) (SA or SS, 0.1-10 microM), scoring developmental defects (DDs), fertilization rate (FR), and mitotic abnormalities. A significant DD increase was observed in SS, but not SA Al(III)- and Zn(II)-exposed embryos vs. controls. Both Al(III) and Zn(II), up to 10 microM, from SA and SS, inhibited mitotic activity and induced mitotic aberrations in exposed embryos. SA-Al(III)-exposed sperm displayed a significant FR increase, unlike Al(III) sulfate overlapping with controls. Both SA-Zn(II) and Zn(II) sulfate sperm exposure resulted in a significant FR increase. The offspring of SA-Al(III)-exposed sperm displayed a significant DD decrease, unlike Al(III) sulfate exposure. Zinc sulfate sperm exposure resulted in a significant increase in offspring DDs, whereas SA-Zn(II) sperm exposure decreased DDs. Together, exposures to SA-dissolved Al(III) or Zn(II) resulted in lesser, if any toxicity, up to hormesis, compared to SS. Studies of metal speciation should elucidate the present results.

Mild toxicity of polystyrene and polymethylmethacrylate microplastics in Paracentrotus lividus early life stages.

The vast category of microplastics in the marine environment, encompassing among other aspects their persistence, degradation and impact on biota, has become an important topic of research. In spite of environmental health concerns, much work has yet to be done on understanding the potential roles of polymer sources, composition and particle sizes in causing adverse effects which have already been observed in a number of biota. The present study was aimed at adding to current knowledge by verifying if, and to what extent, embryogenesis in the sea urchin species Paracentrotus lividus is adversely affected by polystyrene and polymethylmethacrylate virgin microparticles over a size range 1-230 µm and at concentrations of 0.1-10 mg L-1. Developing embryos which came in contact with the microplastics only after fertilisation did not display a significant increase of developmental defects. Unlike embryo exposures, when P. lividus sperm were exposed to the microplastics or their leachates, modest, yet significant effects were observed, both in terms of decreased fertilisation rate and increase of transmissible damage to offspring. Further, it was noted that larvae more readily ingested polymethylmethacrylate than polystyrene microparticles after 3 days which may represent a route for enhancing the toxicity of the former compared to the latter. Overall, these findings provide evidence for lesser sensitivity of P. lividus early life stages to microplastics compared to other urchins such as Sphaerechinus granularis. In turn, the more robust response of P. lividus highlights the importance of choosing an appropriate test species with the highest sensitivity when investigating mildly harmful materials.

Comparative toxicity of seven rare earth elements in sea urchin early life stages.

The widespread use of rare earth elements (REEs) in a number of technological applications raises unanswered questions related to REE-associated adverse effects. We have previously reported on the multiple impact of some REEs on the early life stages of the sea urchin Paracentrotus lividus. The present investigation was to evaluate REE toxicity to early life stages in two unrelated sea urchin species, Sphaerechinus granularis and Arbacia lixula. The comparative toxicities were tested of seven REEs, namely yttrium, lanthanum, cerium, neodymium, samarium, europium and gadolinium as chloride salts at concentrations ranging from 10-7 to 10-4 M. The evaluated endpoints included developmental defects and cytogenetic anomalies in REE-exposed embryos/larvae, and decreased fertilization success and offspring damage following sperm exposure. The results showed different toxicity patterns for individual REEs that varied according to test species and to treatment protocol, thus showing toxicity scaling for the different REEs. Further, the observed effects were compared with those reported for P. lividus either following embryo or sperm exposures. S. granularis showed a significantly higher sensitivity both compared to A. lixula and to P. lividus. This study provides clear-cut evidence for distinct toxicity patterns among a series of REEs. The differences in species sensitivity at micromolar REE levels may warrant investigations on species susceptibility to impacts along polluted coasts.

Cytogenetic and developmental toxicity of cerium and lanthanum to sea urchin embryos.

The aim of this study was to evaluate the toxicity of two rare earth elements (REE), cerium and lanthanum on sea urchin embryos and sperm. Sea urchin (Paracentrotus lividus) embryos were reared for 72 h in Ce(IV)- or La(III)-contaminated seawater at concentrations ranging from 10(-8) to 10(-5) M. Cleaving embryos (5h post-fertilization) were submitted to cytogenetic analysis, scoring mitotic activity and a set of mitotic aberrations. Embryological analysis was carried out to determine percent developmental anomalies and/or embryonic mortality. P. lividus sperm were suspended in Ce(IV) or La(III) (10(-8)-10(-5)M) for 1h, and percent fertilized eggs were scored in cleaving embryos that were cultured up to pluteus stage to score any developmental defects. Embryos reared in 10(-5)M Ce(IV) resulted in 100% embryonic mortality, whereas 10(-5)M La(III) induced 100% developmental defects, without causing any embryonic mortality. A significant concentration-related mitotoxic effect and induction of mitotic aberrations were observed in Ce(IV)-exposed, but not in La(III)-exposed embryos, at concentrations ranging from 10(-7)M to 3 x 10(-6)M. Following sperm exposure, both Ce(IV) and La(III) induced a decrease in sperm fertilization success at the highest tested concentration (10(-5)M). The offspring of Ce(IV)-exposed, but not of La(III)-exposed sperm displayed a significant concentration-related increase in developmental defects. The results may suggest adverse impacts in REE-exposed biota and warrant further studies of a more extended REE series.