Role of physiological energetics in ecotoxicology

• 1.1. The role of physiological energetic measurements combined with chemical analyses of contaminants in body tissues of mussels in fundamental toxicological studies and pollution monitoring programmes is outlined.
• 2.2. Important features of this toxicological approach are briefly reviewed, including aspects of bioaccumulation, sensitivity, quantitative concentration-response relationships, QSARs, mechanistic interpretation, ecological relevance, integration of the consequences of multiple mechanisms of toxicity and effects of contaminant mixtures and application to laboratory and field studies.
• 3.3. This review focuses particularly on recent advances in understanding and predicting the effects of complex mixtures of contaminants.

     

Toxicological effects of silver nanoparticles and cadmium chloride in macrophage cell line (RAW 264.7): An in vitro approach

BackgroundSilver nanoparticles (AgNP) are largely used in nanotechnological products, but the real risks for human and environment are still poorly understood if we consider the effects of mixtures of AgNP and environmental contaminants, such as non-essential metals.MethodsThe aim of the present study was to investigate the cytotoxicity and toxicological interaction of AgNP (1−4 nm, 0.36 and 3.6 μg mL⁻¹) and cadmium (Cd, 1 and 10 μM) mixtures. The murine macrophage cell line RAW 264.7 was used as a model.ResultsEffects were observed after a few hours (4 h) on reactive oxygen species (ROS) and became more pronounced after 24 h-exposure. Cell death occurred by apoptosis, and loss of cell viability (24 h-exposure) was preceded by increases of ROS levels and DNA repair foci, but not of NO levels. Co-exposure potentiated some effects (decrease of cell viability and increase of ROS and NO levels), indicating toxicological interaction.ConclusionThese effects are important findings that must be better investigated, since the interaction of Cd with AgNP from nanoproducts may impair the function of macrophages and represent a health risk for humans.     

Chemical Contamination of Aquatic Organisms from an Urbanized River in the New York/New Jersey Harbor Estuary

The lower 6 miles of the tidal Passaic River, part of the New York/New Jersey (NY/NJ) Harbor Estuary system, are contaminated with a variety of organic and inorganic chemicals as a result of more than 150 years of heavy industrialization and urbanization. The River's ecology is substantially degraded due to habitat removal/alteration, and the organisms that reside in or utilize the River are exposed to and bioaccumulate chemicals from sediments and food web interactions. We quantify in this study the extent and magnitude of chemical contamination in several fish species (representing a range of trophic levels) and blue crab (Callinectes sapidus). In addition, the concentration of several contaminants of concern are compared to concentrations in similar organisms from other areas of the NY/NJ Harbor Estuary, as well as available tissue-based toxicological effects benchmarks that are reported in the literature. The results suggest that a variety of contaminants are present at elevated levels in each of the species collected from the River. Several contaminants, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), total DDT (2,2-bis[4-chlorophenyl]1,1-dichloroethene), copper, and mercury are present at average concentrations that exceed those from other waterways in the NY/NJ Harbor Estuary. However, the concentrations of contaminants in the River, with few exceptions do not exceed available toxic effects levels as reported in the literature for these or similar fish and crustaceans. This suggests that toxicological risks from bioaccumulative contaminants in the lower Passaic River are limited to select contaminants and species.     

海洋微塑料污染的生态效应研究进展

海洋微塑料污染已成为全球性环境问题。微塑料粒径小,易与海洋生物发生相互作用,可通过多种途径进入海洋生物体内,并在其组织和器官中蓄积和转移,对机体产生毒害。微塑料可沿食物链进行传递,威胁海洋生态系统的健康与稳定。因此,海洋生物与微塑料的相互作用以及海洋微塑料污染的生态效应成为当前研究的热点。综述微塑料的生物附着、生物摄入、对海洋生物的毒性效应及其与化学污染物的复合毒性效应研究的基础上,提出未来微塑料生态效应研究应重点关注我国海洋环境中微塑料的污染现状及生物摄入状况、微塑料的生物效应及其毒理学机制研究、微塑料与其他污染物的复合效应、以及微塑料在海洋生态系统中的作用及其生物地球化学行为等。     

Multi response biomarker approach in the crab Carcinus aestuarii experimentally exposed to benzo a pyrene, polychlorobiphenyls and methyl mercury

The aim of this study was to test a multi response biomarker approach for evaluating toxicological risk due to some of the main contaminants in the Mediterranean benzo a pyrene, polychlorobiphenyls and methyl mercury , using the Mediterranean crab Carcinus aestuarii as bioindicator organism. Forty crabs were injected with different doses of these contaminants. Several molecular, biochemical and genotoxic biomarkers were tested in different tissues and biological materials. The main conclusions were: 1 hepatopancreas, gills, haemolymph and excreta seem to be useful for biomarker studies in this species; 2 several biochemical, molecular and genotoxic biomarkers were found suitable for testing in these tissues; 3 several biomarkers were found suitable for evaluating chemical stress due to different Mediterranean contaminants.     

Ecological Effects of Metals in Streams on a Defense Materials Processing Site in South Carolina,USA

The Savannah River Site (SRS) is a 780 km² U.S. Department of Energy facility near Aiken, South Carolina, established in 1950 to produce nuclear materials. SRS streams are “integrators” that potentially receive water transportable contaminants from all sources within their drainage basins, necessitating a watershed approach to organize contaminant distribution data and characterize the effects of multiple contaminants on aquatic organisms. This study used several lines-of-evidence to assess the ecological effects of metals in SRS streams, including contaminant exposure models for apex predators and bioassessments of fish and macroinvertebrate assemblages. Concentrations of metals in sediments, fish, and water were elevated in streams affected by SRS operations, but contaminant exposure models for the river otter Lontra Canadensis and belted kingfisher Ceryle alcyon indicated that toxicological reference values were exceeded only by Hg and Al. Macroinvertebrate assemblage structure was unrelated to sediment metal concentrations. Fish assemblage data were inconclusive. This study indicated that (1) modeling studies and field bioassessments provide a complementary basis for addressing the individual and cumulative effects of contaminants, (2) habitat effects must be controlled when assessing contaminant impacts, (3) sensitivity analyses of contaminant exposure models can help to apportion sampling effort, and (4) most individual metals in SRS streams are unlikely to have significant ecological effects.     

Mycotoxins and food contamination

The contamination of food and feed by fungi and their toxins (mycotoxins) has to be considered as a serious hazard in the daily live. Mycotoxins are natural contaminants in foods and could induce several syndromes. Many mycotoxicosis are described. The control and surveillance of mycotoxins involve the carrying out of surveys, toxicological studies and institution of regulations.     

The application of combined tissue residue chemistry and physiological measurements of mussels (Mytilus edulis) for the assessment of environmental pollution

The rationale for the use of combined tissue residue chemistry and physiological energetics measurements of Mytilus edulis in the assessment and monitoring of environmental pollution is outlined. Laboratory derived relationships between the concentration of toxicants in tissues and sublethal responses (eg. feeding, respiration and growth rate) provide a toxicological database for the interpretation of physiological responses measured in the field. The role of quantitative structure-activity relationships (QSAR's) in establishing tissue concentration-effect relationships for organic contaminants is discussed. The application of this approach is illustrated with reference to two field studies, a monitoring programme in the Shetlands and a practical biological effects workshop in Oslo.     

Toxicological evaluation of three contaminants of emerging concern by use of the Allium cepa test

Di(2-ethylhexyl)phthalate, triclosan and propylparaben are contaminants of emerging concern that have been subjected to extensive toxicological studies, but for which limited information is currently available concerning adverse effects on terrestrial plant systems. The Allium cepa test, which is considered one of the most efficient approaches to assess toxic effects of environmental chemicals, was selected to evaluate the potential risks of these ubiquitous pollutants. Our data demonstrate that all three compounds studied may in some way be considered toxic, but different effects were noted depending on the chemical and the end point analysed. Results derived from the analysis of macroscopic parameters used in testing for general toxicity, revealed that while di(2-ethylhexyl)phthalate had no apparent effects, the other two chemicals inhibited A. cepa root growth in a dose-dependent manner. On the other hand, although all three compounds caused alterations in the mitotic index of root-tip cells, propylparaben was the only one that did not show evidence of genotoxicity in assays for chromosome aberrations and micronuclei. The results of the present study clearly indicate that sensitive plant bioassays are useful and complementary tools to determine environmental impact of contaminants of emerging concern.     

The immunotoxicity of environmental contaminants to marine wildlife: A review

Virus-associated mass mortalities among several marine mammal populations inhabiting industrialized coastal areas have generated an interest in wildlife immunotoxicology. Despite the isolation of previously uncharacterized viruses from victims, a contribution of immunotoxic contaminants to the severity of the outbreaks could not be ruled out. Fish-eating marine mammals, including seals, occupy high trophic levels in the aquatic food chain, and accumulate high levels of contaminants including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychorinated dibenzofurans (PCDFs). Such chemicals have been found to be immunotoxic at low doses in studies of laboratory animals. While associations have been established between environmental contaminants and various adverse biological effects in certain free-ranging seal populations, evidence for immunotoxicity has, until recently, been lacking. To this end, we carried out an immunotoxicological study, in which captive harbor seals were fed herring from either relatively uncontaminated sites of the Atlantic Ocean, or from the highly contaminated Baltic Sea. In this review, we summarize the contaminant-related immunosuppression observed in the captive group of seals fed herring from the Baltic Sea, and discuss these results in the context of what is currently known about outbreaks of virus infection, comparative immunology, and environmental contaminants. We also describe two parallel studies, in which laboratory rats exposed as adults or perinatally to the contaminants in the Baltic Sea herring, exhibited immunotoxicity. On the basis of these and other studies, we conclude that complex mixtures of environmental contaminants may represent a real immunotoxic risk to free-ranging marine mammals in many areas of Europe and North America.     

建立污染土壤修复标准的探讨

随着污染土壤修复技术的发展和污染土壤修复环境工程的实施,污染土壤修复标准的建立已成为检验污染土壤修复工程效果的瓶颈.我国现行的土壤环境质量标准已不能适应污染土壤修复效果评判的需要.本文在分析我国土壤环境质量标准不足的基础上,结合一些发达国家土壤修复标准以及我国土壤污染实际情况,提出建立污染土壤修复标准应从污染物的选择、分析检测方法、修复标准的分类、对地下水的保护和生态毒理学评价方面综合考虑.     

Community ecology theory predicts the effects of agrochemical mixtures on aquatic biodiversity and ecosystem properties

Ecosystems are often exposed to mixtures of chemical contaminants, but the scientific community lacks a theoretical framework to predict the effects of mixtures on biodiversity and ecosystem properties. We conducted a freshwater mesocosm experiment to examine the effects of pairwise agrochemical mixtures [fertiliser, herbicide (atrazine), insecticide (malathion) and fungicide (chlorothalonil)] on 24 species‐ and seven ecosystem‐level responses. As postulated, the responses of biodiversity and ecosystem properties to agrochemicals alone and in mixtures was predictable by integrating information on each functional group's (1) sensitivity to the chemicals (direct effects), (2) reproductive rates (recovery rates), (3) interaction strength with other functional groups (indirect effects) and (4) links to ecosystem properties. These results show that community ecology theory holds promise for predicting the effects of contaminant mixtures on biodiversity and ecosystem services and yields recommendations on which types of agrochemicals to apply together and separately to reduce their impacts on aquatic ecosystems.     

Genotoxicological characterisation of complex mixtures. Genotoxic effects of a complex mixture of perhalogenated hydrocarbons

Toxicological and genotoxicological investigation of complex mixtures is one of the main focus of the recent research in toxicology. Testing complex mixtures present a formidable scientific problem since most recently available toxicological data has been obtained from single substance studies and is not simply transferable to mixtures of chemicals. Although there are no special strategies and standard protocols available for determining toxic and genotoxic effects of complex mixtures, the fundamental concepts of evaluation are the same as those for single substances.The focus of interest of the submitted paper is the genotoxicological characterisation of a complex mixture of mostly perhalogenated hydrocarbons which is generated as a waste product from the plasma etching process in the semiconductor industry. By use of several in vitro test systems (comet assay and micronucleus test), the clastogenic potency of the mixture was tested in various human cell types (lymphocytes and normal bronchial epithelial cells) and in rat hepatocytes. Results demonstrated that the complex perhalogenated hydrocarbons mixture causes DNA single-strand breaks and micronuclei formation, and direct concentration-to-effect correlations were proved in all experiments. The presence of an external metabolising system (S9 mix from rat hepatocytes) in human cell culture systems did not cause any change of the observed effects when compared to experiments performed in the absence of the S9 mix. Therefore, we conclude that the mixture acts as direct genotoxicant and that there is no detoxification by the external enzyme system.Further, convincing and reproducible results of the in vitro comet assay and the micronucleus assay in primary human cell cultures indicated these tests may be utilized for the genotoxicological analyses of complex mixtures with concern to human health hazard.     

Zebrafish obesogenic test: a tool for screening molecules that target adiposity

Dietary and xenobiotic compounds may alter endocrine signaling and lipid homeostasis, thus inducing obesity. We describe a short-term assay method, the zebrafish obesogenic (ZO) test, for examining the effects of diet, drugs, and environmental contaminants, singly or in combination, on white adipose tissue (WAT) dynamics in live larvae. The ZO test is an intermediate step in obesity research, between in vitro and rodent assays, and may be also used to study the effect of environmental toxicants on the adiposity of aquatic species. The procedure, using Nile Red (NR) fluorescent probe to reveal adipocyte lipid droplets, is suitable for pharmaceutical or toxicological screening. Larvae treated at an environmentally-relevant concentration of tributyltin chloride (TBT), an environmental obesogen, exhibited a remarkable increase in adiposity, irrespective of the lipid composition of the background diet. Exogenous compounds, e.g., rosiglitazone or TBT, known to increase adiposity in the fasting state, were classified as obesogenic. Anti-obesogenic compounds favored a decrease in adiposity in the fasting state. The ZO test, using adipocyte lipid droplet size and adiposity as its endpoints, is a whole-organism alternative testing assay for obesogenic and anti-obesogenic compounds and mixtures and provides relevant information for environmental and human risk assessments.     

Can Ecological Receptors Really Be At Risk?

Birds and mammals at hazardous waste sites are routinely modeled for their potential to display harmful toxicological effects as a result of their exposures to contaminants. Although standard desktop measures of the potential for toxicological endpoints to be reached commonly suggest that these receptors should be at ill health (e.g., experiencing reproductive impairment), evidence is lacking from the field that such effects are occurring. Plausibly, the excessive time lapse (frequently several decades) from contaminant release event to site ecological risk assessment, can explain the disconnect. Aided by their relatively brief life spans, these modeled ecological receptors have produced multiple generations to date and may have outbred the chemical stress. In light of the absence of observed health impacts in birds and mammals since the creation of the U.S. Environmental Protection Agency's Superfund program, there may be no need to continue assessing the health of these species. Additionally, given the very few reported instances of observed health effects at terrestrial sites, it may be prudent to replace risk assessment with impact assessment as the essence of a revamped ecological assessment process.     

Epidermal diseases in bottlenose dolphins: impacts of natural and anthropogenic factors.

Experimental studies have highlighted the potential influence of contaminants on marine mammal immune function and anthropogenic contaminants are commonly believed to influence the development of diseases observed in the wild. However, estimates of the impact of contaminants on wild populations are constrained by uncertainty over natural variation in disease patterns under different environmental conditions. We used photographic techniques to compare levels of epidermal disease in ten coastal populations of bottlenose dolphins (Tursiops truncatus) exposed to a wide range of natural and anthropogenic conditions. Epidermal lesions were common in all populations (affecting > 60% of individuals), but both the prevalence and severity of 15 lesion categories varied between populations. No relationships were found between epidermal disease and contaminant levels across the four populations for which toxicological data were available. In contrast, there were highly significant linear relationships with oceanographic variables. In particular, populations from areas of low water temperature and low salinity exhibited higher lesion prevalence and severity. Such conditions may impact on epidermal integrity or produce more general physiological stress, potentially making animals more vulnerable to natural infections or anthropogenic factors. These results show that variations in natural environmental factors must be accounted for when investigating the importance of anthropogenic impacts on disease in wild marine mammals.     

Mycotoxins as harmful indoor air contaminants

Fungal metabolites (mycotoxins) that pose a health hazard to humans and animals have long been known to be associated with mold-contaminated food and feed. In recent times, concerns have been raised about exposures to mycotoxin-producing fungi in indoor environments, e.g., damp homes and buildings. The principal mycotoxins that contaminate food and feed (alfatoxins, fumonisins, ochratoxin A, deoxynivalenol, zearalenone) are rarely if ever found in indoor environments, but their toxicological properties provide an insight into the difficulties of assessing the health effects of related mycotoxins produced by indoor molds. Although the Penicillium and Aspergillus genera of fungi are major contaminants of both food and feed products and damp buildings, the particular species and hence the array of mycotoxins are quite different in these environments. The mycotoxins of these indoor species and less common mycotoxins from Stachybotrys and Chaetomium fungi are discussed in terms of their health effects and the need for relevant biomarkers and long-term chronic exposure studies.     

Assessment of possible sediment toxicity of contaminated sediments in Port Jackson, Sydney, Australia

A considerable amount of chemical data is available for surficial sediments in Port Jackson. Some of the highest concentrations of heavy metals, organochlorines and polycyclic aromatic hydrocarbons of any capital port occur in sediments mantling shallow tributaries and embayments close to central Sydney. However, these data have limited ability to predict adverse effects on living resources and in the absence of toxicological data, sediment quality guidelines (SQG) have been used to assess the possible adverse biological effects of sedimentary contaminants in this estuary. Several SQGs are currently available for both fresh and marine environments, but the scheme used in the current study is based on empirical analysis of matching chemical and biological data compiled by the National Oceanographic and Atmospheric Administration (NOAA) in the U.S. The NOAA SQG can be used to assess individual chemicals, or to estimate the probability of acute sediment toxicity by calculating `mean quotients' for a large range of contaminants. Although many individual chemicals in sediment exceed SQG over extensive parts of Port Jackson, `mean quotient' results suggest that only a small proportion (1%) of the harbour may be highly toxic (74% probability of toxicity). However, sediment in a considerably larger proportion of the port (almost 25%) is estimated to have a 49% probability of being toxic using the `mean quotient' approach. These results are indicative at best and contemporaneous chemical/biological/ecotoxicological studies are needed to verify the applicability of SQG developed in the U.S. for use outside North America and site specific studies of this type are still required to determine the toxicity of sediments in Port Jackson.