Reviews of environmental contamination and toxicology最新文献

Atmospheric contamination by heavy metal-enriched particulate matter (metal-PM) is highly topical nowadays because of its high persistence and toxic nature. Metal-PMs are emitted to the atmosphere by various natural and anthropogenic activities, the latter being the major source. After being released into the atmosphere, metal-PM can travel over a long distance and can deposit on the buildings, water, soil, and plant canopy. In this way, these metal-PMs can contaminate different parts of the ecosystem. In addition, metal-PMs can be directly inhaled by humans and induce several health effects. Therefore, it is of great importance to understand the fate and behavior of these metal-PMs in the environment. In this review, we highlighted the atmospheric contamination by metal-PMs, possible sources, speciation, transport over a long distance, and deposition on soil, plants, and buildings. This review also describes the foliar deposition and uptake of metal-PMs by plants. Moreover, the inhalation of these metal-PMs by humans and the associated health risks have been critically discussed. Finally, the article proposed some key management strategies and future perspectives along with the summary of the entire review. The abovementioned facts about the biogeochemical behavior of metal-PMs in the ecosystem have been supported with well-summarized tables (total 14) and figures (4), which make this review article highly informative and useful for researchers, scientists, students, policymakers, and the organizations involved in development and management. It is proposed that management strategies should be developed and adapted to cope with atmospheric release and contamination of metal-PM.

Safeners are a group of chemicals applied with herbicides to protect crop plants from potential adverse effects of agricultural products used to kill weeds in monocotyledonous crops. Various routes of dissipation of safeners from their point of applications were evaluated. Despite the large numbers of safeners (over 18) commercially available and the relatively large quantities (~2 × 10⁶ kg/year) used, there is little information on their mobility and fate in the environment and occurrence in various environmental matrices. The only class of safeners for which a significant amount of information is available is dichloroacetamide safeners, which have been observed in some rivers in the USA at concentrations ranging from 42 to 190 ng/L. Given this gap in the literature, there is a clear need to determine the occurrence, fate, and bioavailability of other classes of safeners. Furthermore, since safeners are typically used in commercial formulations, it is useful to study them in relation to their corresponding herbicides. Common routes of dissipation for herbicides and applied safeners are surface run off (erosion), hydrolysis, photolysis, sorption, leaching, volatilization, and microbial degradation. Toxic potencies of safeners vary among organisms and safener compounds, ranging from as low as the LC₅₀ for fish (Oncorhynchus mykiss) for isoxadifen-ethyl, which was 0.34 mg/L, to as high as the LC₅₀ for Daphnia magna from dichlormid, which was 161 mg/L. Solubilities and octanol-water partition coefficients seem to be the principal driving force in understanding safener mobilities. This paper provides an up-to-date literature review regarding the occurrence, behaviour, and toxic potency of herbicide safeners and identifies important knowledge gaps in our understanding of these compounds and the potential risks posed to potentially impacted ecosystems.

Metalliferous mining, a major source of metals and metalloids, has severe potential environmental impacts. However, the number of papers published in international peer-reviewed journals seems to be low regarding its effects in terrestrial wildlife. To the best of our knowledge, our review is the first on this topic. We used 186 studies published in scientific journals concerning metalliferous mining or mining spill pollution and their effects on terrestrial and semi-terrestrial vertebrates. We identified the working status of the mine complexes studied, the different biomarkers of exposure and effect used, and the studied taxa. Most studies (128) were developed in former mine sites and 46 in active mining areas. Additionally, although several mining accidents have occurred throughout the world, all papers about effects on terrestrial vertebrates from mining spillages were from Aznalcóllar (Spain). We also observed a lack of studies in some countries with a prominent mining industry. Despite >50% of the studies used some biomarker of effect, 42% of them only assessed exposure by measuring metal content in internal tissues or by non-invasive sampling, without considering the effect in their populations. Most studied species were birds and small mammals, with a negligible representation of reptiles and amphibians. The information gathered in this review could be helpful for future studies and protocols on the topic and it facilitates a database with valuable information on risk assessment of metalliferous mining pollution.

The occupational exposure to airborne manganese (Mn) has been linked for decades with neurological effects. With respect to its environmental exposure, the first reviews on this matter stated that the risk posed to human health by this kind of exposure was still unknown. Later, many studies have been developed to analyze the association between environmental Mn exposure and health effects, most of them including the measure of Mn in selected human biomarkers. This review aims at collecting and organizing the literature dealing with the environmental airborne Mn exposure (other routes of exposure were intentionally removed from this review), the biomonitoring of this metal in different body matrices (e.g., blood, urine, nails, hair), and the association between exposure and several adverse health effects, such as, e.g., neurocognitive, neurodevelopmental, or neurobehavioral outcomes. From the different exposure routes, inhalation was the only one considered in this review, to take into account the areas influenced by industrial activities closely related to the Mn industry (ferromanganese and silicomanganese plants, Mn ore mines, and their processing plants) and by traffic in countries where a fuel additive, methylcyclopentadienyl manganese tricarbonyl (MMT), has been used for years. In these areas, high air Mn levels have been reported in comparison with the annual Reference Concentration (RfC) given by the US EPA for Mn, 50 ng/m³. This review was performed using Scopus and MEDLINE databases with a keyword search strategy that took into account that each valid reference should include at least participants that were exposed to environmental airborne Mn and that were subjected to analysis of Mn in biomarkers or subjected to neurological/neuropsychological tests or both. Overall, 47 references matching these criteria were included in the discussion. Most of them report the measure of Mn in selected biomarkers (N = 43) and the assessment of different neurological outcomes (N = 31). A negative association is usually obtained between Mn levels in hair and some neurological outcomes, such as cognitive, motor, olfactory, and emotional functions, but not always significant. However, other biomarkers, such as blood and urine, do not seem to reflect the chronic environmental exposure to low/moderate levels of airborne Mn. Further studies combining the determination of the Mn exposure through environmental airborne sources and biomarkers of exposure and the evaluation of at least cognitive and motor functions are needed to better understand the effects of chronic non-occupational exposure to airborne Mn.

In freshwater environments, microbial assemblages attached to submerged substrates play an essential role in ecosystem processes such as primary production, supported by periphyton, or organic matter decomposition, supported by microbial communities attached to leaf litter or sediments. These microbial assemblages, also called biofilms, are not only involved in nutrients fluxes but also in contaminants dynamics. Biofilms can accumulate metals and organic contaminants transported by the water flow and/or adsorbed onto substrates. Furthermore, due to their high metabolic activity and their role in aquatic food webs, microbial biofilms are also likely to influence contaminant fate in aquatic ecosystems. In this review, we provide (1) a critical overview of the analytical methods currently in use for detecting and quantifying metals and organic micropollutants in microbial biofilms attached to benthic substrata (rocks, sediments, leaf litter); (2) a review of the distribution of those contaminants within aquatic biofilms and the role of these benthic microbial communities in contaminant fate; (3) a set of future challenges concerning the role of biofilms in contaminant accumulation and trophic transfers in the aquatic food web. This literature review highlighted that most knowledge on the interaction between biofilm and contaminants is focused on contaminants dynamics in periphyton while technical limitations are still preventing a thorough estimation of contaminants accumulation in biofilms attached to leaf litter or sediments. In addition, microbial biofilms represent an important food resource in freshwater ecosystems, yet their role in dietary contaminant exposure has been neglected for a long time, and the importance of biofilms in trophic transfer of contaminants is still understudied.

Aflatoxins are the most harmful mycotoxins causing health problems to human and animal. Many acute aflatoxin outbreaks have been reported in Africa, especially in Kenya and Tanzania. When ingested, aflatoxin B1 is converted by hydroxylation in the liver into aflatoxin M1, which is excreted in milk of dairy females and in urine of exposed populations. This review aims to highlight the AFM1 studies carried out in African regions (North Africa, East Africa, West Africa, Central Africa, and Southern Africa), particularly AFM1 occurrence in milk and dairy products, and in human biological fluids (breast milk, serum, and urine) of the populations exposed. Strategies for AFM1 detoxification will be considered, as well as AFM1 regulations as compared to the legislation adopted worldwide and the assessment of AFM1 exposure of some African populations. Egypt, Kenya, and Nigeria have the highest number of investigations on AFM1 in the continent. Indeed, some reports showed that 100% of the samples analyzed exceeded the EU regulations (50 ng/kg), especially in Zimbabwe, Nigeria, Sudan, and Egypt. Furthermore, AFM1 levels up to 8,000, 6,999, 6,900, and 2040 ng/kg have been reported in milk from Egypt, Kenya, Sudan, and Nigeria, respectively. Data on AFM1 occurrence in human biological fluids have also shown that exposure of African populations is mainly due to milk intake and breastfeeding, with 85-100% of children being exposed to high levels. Food fermentation in Africa has been tried for AFM1 detoxification strategies. Few African countries have set regulations for AFM1 in milk and derivatives, generally similar to those of the Codex alimentarius, the US or the EU standards.

With the continued growth in plastic production, its ubiquitous use and insufficient waste management and disposal, the increased levels of plastics in the environment have led to growing ecological concerns. The breakdown of these plastic macromolecules to smaller micro and nanosized particles and their detection in the aerial, aquatic, marine and terrestrial environments has been reviewed extensively, especially for thermoplastics. However, the formation of micro and nanoplastics has typically been explained as a physical abrasion process, largely overlooking the underlying chemical structure-morphology correlations to the degradation mechanisms of the plastics. This is particularly true for the common commodity thermosets. This review focuses on the degradation pathways for the most widely produced commodity thermoplastics and thermosets into microplastics (MP)s and nanoplastics (NP)s, as well as their behaviour and associated toxicity. Special emphasis is placed on NPs, which are associated with greater risks for toxicity compared to MPs, due to their higher surface area to volume ratios. This review also assesses the current state of standardized detection and quantification methods as well as comprehensive regulations for these fragments in the aquatic environment.

Plastic has been an incredibly useful and indispensable material in all aspects of human life. Without it many advances in medicine, technology or industry would not have been possible. However, its easy accessibility and low cost have led to global misuse. Basically, the production of the plastics from different chemical agents is very easy but unfortunately difficult to reuse or recycle, and it is thrown away as litter, incinerated or disposed of in landfill. Plastic once in the environment begins to degrade to very small sizes. Thus, many animals mistake them for food, so plastic enters a marine, terrestrial or freshwater food web. These microplastics although chemically inert have been shown to act as tiny "bio-sponges" for harmful chemicals found in the environment changing the nature of a plastic particle from chemically harmless to potentially toxic. It was believed that microparticles would simply pass through the gastrointestinal tract of animals and humans with no biological effect. However, studies have shown that they are sometimes taken up and distributed throughout the circulatory and lymphatic system and may be stored in the fatty tissues of different organisms. The result of the uptake of them showed potential carcinogenic effects, liver dysfunction and endocrine disruption. This review focuses on micro- and nanoplastics and their way entering marine and freshwater food webs, with particular attention to microplastic trophic transfer, their toxic side effects and influence to the human consumer in health and safety in the future.

The impact of ambient particulate matter (PM) on public health has become a great global concern, which is especially prominent in developing countries. For health purposes, PM is typically defined by size, with the smaller particles having more health impacts. Particles with a diameter <2.5 μm are called PM_2.5. Initial research studies have focused on the impact of PM_2.5 on respiratory and cardiovascular diseases; nevertheless, an increasing number of data suggested that PM_2.5 may affect every organ system in the human body, and the kidney is of no exception. The kidney is vulnerable to particulate matter because most environmental toxins are concentrated by the kidney during filtration. According to the high morbidity and mortality related to chronic kidney disease, it is necessary to determine the effect of PM_2.5 on kidney disease and its mechanism that needs to be identified. To understand the current status of PM_2.5 in the atmosphere and their potential harmful kidney effects in different regions of the world this review article was prepared based on peer-reviewed scientific papers, scientific reports, and database from government organizations published after the year 1998. In this review, we focus on the worldwide epidemiological evidence linking PM_2.5 with chronic kidney disease and the effect of PM_2.5 on the chronic kidney disease (CKD) progression. At the same time, we also discuss the possible mechanisms of PM_2.5 exposure leading to kidney damage, in order to emphasize the contribution of PM_2.5 to kidney damage. A global database on PM_2.5 and kidney disease should be developed to provide new ideas for the prevention and treatment of kidney disease.