Meta-analysis of environmental contamination by phthalates

Phthalate acid esters (PAE), commonly named phthalates, are toxics classified as endocrine-disrupting compounds; they are primarily used as additives to improve the flexibility in polyvinyl chloride. Many studies have reported the occurrence of phthalates in different environmental matrices; however, none of these studies has yet established a complete overview for those compounds in the water cycle within an urban environment. This review summarizes PAE concentrations for all environmental media throughout the water cycle, from atmosphere to receiving waters. Once the occurrences of compounds have been evaluated for each environmental compartment (urban wastewater, wastewater treatment plants, atmosphere, and the natural environment), we reviewed data in order to identify the fate of PAE in the environment and establish whether geographical and historical trends exist. Indeed, geographical and historical trends appear between Europe and other countries such as USA/Canada and China, however they remain location dependent. This study aimed at identifying both the correlations existing between environmental compartments and the processes influencing the fate and transport of these contaminants into the environment. In Europe, the concentrations measured in waterways today represent the background level of contamination, which provides evidence of a past diffuse pollution. In contrast, an increasing trend has actually been observed for developing countries, especially for China.     

Meta-analysis of environmental contamination by alkylphenols

Alkylphenols and alkylphenol ethoxylates (APE) are toxics classified as endocrine-disrupting compounds; they are used in detergents, paints, herbicides, pesticides, emulsifiers, wetting and dispersing agents, antistatic agents, demulsifiers, and solubilizers. Many studies have reported the occurrence of alkylphenols in different environmental matrices, though none of these studies have yet to establish a comprehensive overview of such compounds in the water cycle within an urban environment. This review summarizes APE concentrations for all environmental media throughout the water cycle, from the atmosphere to receiving waters. Once the occurrence of compounds has been assessed for each environmental compartment (urban wastewater, wastewater treatment plants [WWTP], atmosphere, and the natural environment), data are examined in order to understand the fate of APE in the environment and establish their geographical and historical trends. From this database, it is clear that the environment in Europe is much more contaminated by APE compared to North America and developing countries, although these APE levels have been decreasing in the last decade. APE concentrations in the WWTP effluent of developed countries have decreased by a factor of 100 over the past 30?years. This study is aimed at identifying both the correlations existing between environmental compartments and the processes that influence the fate and transport of these contaminants in the environment. In industrial countries, the concentrations observed in waterways now represent the background level of contamination, which provides evidence of a past diffuse pollution in these countries, whereas sediment analyses conducted in developing countries show an increase in APE content over the last several years. Finally, similar trends have been observed in samples drawn from Europe and North America.     

Glyphosate: environmental contamination,toxicity and potential risks to human health via food contamination

Glyphosate has been the most widely used herbicide during the past three decades. The US Environmental Protection Agency (EPA) classifies glyphosate as ‘practically non-toxic and not an irritant’ under the acute toxicity classification system. This classification is based primarily on toxicity data and due to its unique mode of action via a biochemical pathway that only exists in a small number of organisms that utilise the shikimic acid pathway to produce amino acids, most of which are green plants. This classification is supported by the majority of scientific literature on the toxic effects of glyphosate. However, in 2005, the Food and Agriculture Organisation (FAO) reported that glyphosate and its major metabolite, aminomethylphosphonic acid (AMPA), are of potential toxicological concern, mainly as a result of accumulation of residues in the food chain. The FAO further states that the dietary risk of glyphosate and AMPA is unlikely if the maximum daily intake of 1 mg kg^?1 body weight (bw) is not exceeded. Research has now established that glyphosate can persist in the environment, and therefore, assessments of the health risks associated with glyphosate are more complicated than suggested by acute toxicity data that relate primarily to accidental high-rate exposure. We have used recent literature to assess the possible risks associated with the presence of glyphosate residues in food and the environment.     

Effect of soil on microbial responses to metal contamination

An experiment was conducted to investigate microbial responses to metal inputs in five soils with varying clay and organic contents; one soil had also a higher pH. These soils were treated with a low metal, sewage sludge control or with this sludge contaminated to achieve Cu=112, Ni=58 and Zn=220 mg kg(-1) in medium and Cu=182, Ni=98 and Zn=325 mg kg(-1) in high metal soils. CO(2) evolution rates were measured at 1 week and at 4-5-day intervals thereafter until the end of the incubation (7 weeks). Extractable metals (CaCl(2) and water), biomass C, metabolic quotient, ergosterol, bacterial-fungal phospholipid fatty acid (PLFA-3 weeks only) ratio and mineral N were measured at 3 and 7 weeks. Metal inputs caused a marked increase in metal availability in the slightly acidic sandy loams, a smaller increase in slightly acidic clays and had little effect in the alkaline loam. After an initial increase in CO(2) evolution with metal inputs in all soils, the high metal treatment alone caused a significant decrease at later stages, mainly in sandy loams. Although biomass C and metabolic quotient decreased in all soils with higher metal inputs, the effect was more pronounced in the sandy loams. Metal inputs increased ergosterol and decreased bacterial-fungal PLFA ratios in most soils. Larger mineral N contents were found in all high metal soils at 3 weeks but, after 7 weeks, metals caused a significant decrease in sandy loams. CaCl(2) and water-extractable Cu, Ni and Zn contents were closely correlated with microbial indices in sandy loam but not in clay soils. Overall, the effect of treatments on microbial and extractable metal indices was greater in loams. Within a single series, higher organic soils showed less pronounced responses to metal inputs, although this trend was not always consistent.     

Differences in the bioaccumulation of arsenic by oysters from Southeast coastal US and Chesapeake Bay: environmental versus genetic control

The potential sources of relatively great concentrations of arsenic (As) in oysters from the Southeastern United States coast was examined in a study conducted from August 1998 through October 1999. A transplant experiment was conducted to determine whether genetic or environmental differences accounted for the observed difference between Southeastern oysters, and oysters elsewhere on the east coast. Oysters originating in South Carolina (a region where As in oysters is usually greater) and Maryland (a region where arsenic is oysters is less) were reciprocally transplanted to determine whether site of growth or site of origin would determine the accumulation of As. To examine the potential role of various potential sources of As exposure on the concentrations of As in oysters, samples of native oysters, water, pore water and suspended particles were collected and analyzed for As monthly, while the sediments were examined four times during the year. Concentrations of As in transplanted oysters matched the concentrations of As in oysters native to the area in which they were grown, rather than that of oysters from their site of origin. Oysters from South Carolina had average concentrations of As approximately 3.2 times that of oysters from Maryland. This enrichment was similar to enrichments of water (3.4 times), sediment (2.5 times), suspended particles (1.7 times), and pore water (3.1 times) from South Carolina compared to Maryland. This supports the hypothesis that the cause of the apparent As enrichments in the Southeastern oysters is environmental, but leaves the question of the primary source for arsenic incorporation by oysters open.     

Informal e-waste recycling: environmental risk assessment of heavy metal contamination in Mandoli industrial area,Delhi, India

Nowadays, e-waste is a major source of environmental problems and opportunities due to presence of hazardous elements and precious metals. This study was aimed to evaluate the pollution risk of heavy metal contamination by informal recycling of e-waste. Environmental risk assessment was determined using multivariate statistical analysis, index of geoaccumulation, enrichment factor, contamination factor, degree of contamination and pollution load index by analysing heavy metals in surface soils, plants and groundwater samples collected from and around informal recycling workshops in Mandoli industrial area, Delhi, India. Concentrations of heavy metals like As (17.08 mg/kg), Cd (1.29 mg/kg), Cu (115.50 mg/kg), Pb (2,645.31 mg/kg), Se (12.67 mg/kg) and Zn (776.84 mg/kg) were higher in surface soils of e-waste recycling areas compared to those in reference site. Level exceeded the values suggested by the US Environmental Protection Agency (EPA). High accumulations of heavy metals were also observed in the native plant samples (Cynodon dactylon) of e-waste recycling areas. The groundwater samples collected form recycling area had high heavy metal concentrations as compared to permissible limit of Indian Standards and maximum allowable limit of WHO guidelines for drinking water. Multivariate analysis and risk assessment studies based on total metal content explains the clear-cut differences among sampling sites and a strong evidence of heavy metal pollution because of informal recycling of e-waste. This study put forward that prolonged informal recycling of e-waste may accumulate high concentration of heavy metals in surface soils, plants and groundwater, which will be a matter of concern for both environmental and occupational hazards. This warrants an immediate need of remedial measures to reduce the heavy metal contamination of e-waste recycling sites.     

TXRF analysis of soils and sediments to assess environmental contamination

Total reflection x-ray fluorescence spectroscopy (TXRF) is proposed for the elemental chemical analysis of crustal environmental samples, such as sediments and soils. A comparative study of TXRF with respect to flame atomic absorption spectroscopy and inductively coupled plasma optical emission spectroscopy was performed. Microwave acid digestion and suspension preparation methods are evaluated. A good agreement was found among the results obtained with different spectroscopic techniques and sample preparation methods for Cr, Mn, Fe, Ni, Cu, and Zn. We demonstrated that TXRF is suitable for the assessment of environmental contamination phenomena, even if the errors for Pb, As, V, and Ba are ingent.     

Variation in the mineral composition of eggs of the snail, Helix aspersa between populations exposed to different levels of metal contamination

The eggs of terrestrial gastropods represent a major investment of resources by the parent, not least in the provision of essential metals. In this experiment 11 populations of Helix aspersa were collected from habitats with different histories of lead exposure and allowed to reproduce in the laboratory. After 4 months on a low metal diet, five four-egg samples were taken from a single clutch of each population and analysed for their metal content. Within-clutch and between population variation in the eggs were measured. No Pb or Cd was detected in any of the eggs. Both trace and essential metals show considerable variation between eggs within the same clutch. Cu levels were consistent across populations while egg Zn was closely correlated with soil Zn. Median Ca and Mg levels show little relation to soil concentrations. However, Ca provision declines with soil Pb across the populations. While the metal content of the eggs appears to be closely regulated, an interaction between Pb and Ca in the parental tissues may mediate the supply of Ca to the eggs.     

Image processing tools in the study of environmental contamination by microplastics: reliability and perspectives

Environmental Science and Pollution Research - Microplastic pollution is one of the greatest environmental concerns for contemporary times and the future. In the last years, the number of...     

Heavy metal removal by activated sludge: influence of Nocardia amarae.

The goal of this research was to examine the metal binding capacity of Nocardia amarae cells and to assess the influence of Nocardia cells on the overall metal binding capacity of activated sludge. Metal sorption capacities of the pure Nocardia cells and activated sludge biomass containing various levels of added Nocardia pure cultures were determined by a series of batch experiments. Batch sorption isotherms for nickel (Ni), copper (Cu), and cadmium (Cd) showed that the pure culture of N. amarae exhibited significantly higher metal sorption capacity than the activated sludge biomass obtained from Wilmington Wastewater Treatment Plant (Wilmington, DE). Surface area of biomass estimated by a dye technique showed that pure N. amarae cells growing at stationary phase have substantially more specific surface area than that of activated sludge from Wilmington Treatment Plant. A two-fold difference in specific surface area indicated that the higher metal sorption capacity of Nocardia cells may be due to the higher specific surface area. The metal sorption capacity of activated sludge increased proportionally with the amount of Nocardia cells present in the mixed liquor. This increase was attributed to the greater specific surface area of the mixed liquor samples containing greater amounts of Nocardia cells.     

Interactive effects of metal contamination and pathogenic organisms on the introduced marine bivalve Ruditapes philippinarum in European populations

In natural environment, marine organisms are concomitantly exposed to pollutants and multiple disease agents resulting in detrimental interactions. The present study evaluated interactive effects of metal contamination (cadmium) and pathogenic organisms (trematode parasites Himasthla elongata and pathogenic bacteria Vibrio tapetis) singularly and in combination on the bivalve Ruditapes philippinarum, an introduced species to Europe, under laboratory controlled conditions. After 7 days, metal bioaccumulation and pathogen load were analyzed as well as metallothionein (MT) response and hemocyte concentrations and activities. Results showed that infection by opportunistic pathogens affects metal accumulation, leading to maximal Cd accumulation in co-infected clams. Among stressors only V. tapetis induced significant effects on immune parameters whereas a particular interaction “trematode-bacteria” was shown on MT responses. Despite low trematode infection in agreement with the resistant status of R. philippinarum to these macroparasites, significant interaction with bacteria and metal occurred. Such results highlight the necessity of taking pathogens into account in ecotoxicological studies.     

Long-term sustainability of metal immobilization by soil amendments: Cyclonic ashes versus lime addition

A soil column leaching experiment was used to gain insight into the long-term metal immobilization capacity of cyclonic ashes (CAH) compared to lime (LIME). Twenty six years of rainfall were simulated. Initially, all amended soils were brought to an equal soil pH. This was done to obtain optimal conditions for the detection of metal immobilization mechanisms different from just a pH effect. During the simulation period, soil pH in all treatments decreased in parallel. However, the evolution of metal mobility and phytoavailability showed a clearly distinct pattern. The strong reduction in metal immobilizing efficiency observed in the lime treatment at the end of the simulation period was much less pronounced, or even absent, in the CAH treatments. Moreover, metal accumulation in plants grown on the CAH amended soil was significantly lower compared to the untreated and the lime treated soil. CAH + SS treatment delivered the strongest reductions in metal mobility and bioavailability.     

Comparison of two wild rodent species as sentinels of environmental contamination by mine tailings

Background

Contamination with heavy metals is among the most hazardous environmental concerns caused by mining activity. A valuable tool for monitoring these effects is the use of sentinel organisms. Particularly, small mammals living inside mine tailings are an excellent study system because their analysis represents a realistic approach of mixtures and concentrations of metal exposure.

Purpose

We analyzed metal tissue concentrations and DNA damage levels for comparison between genders of a sentinel (Peromyscus melanophrys) and a nonsentinel (Baiomys musculus) species. Also, the relationship between DNA damage and the distance from the contamination source was evaluated.

Methods

This study was conducted in an abandoned mine tailing at Morelos, Mexico. Thirty-six individuals from both species at the exposed and reference sites were sampled. Metal concentrations in bone and liver of both species were analyzed by atomic absorption spectrophotometry, and DNA damage levels were assayed using the alkaline comet assay.

Results

In general, concentrations of zinc, nickel, iron, and manganese were statistically higher in exposed individuals. A significant effect of the organ and the site on all metal tissue concentrations was detected. Significant DNA damage levels were registered in the exposed group, being higher in B. musculus. Females registered higher DNA damage levels than males. A negative relationship between distance from the mine tailing and DNA damage in B. musculus was observed.

Conclusions

We consider that B. musculus is a suitable species to assess environmental quality, especially for bioaccumulable pollutants??such as metals??and recommend that it may be considered as a sentinel species.     

Topical application of synthetic pyrethroids to cattle as a source of persistent environmental contamination

Abstract

Following the application of permethrin or cyhalothrin to cattle for the control of ectoparasites, the occurrence and persistence of these chemicals was assessed on the animals and in their environment. The release of permethrin from ear tags containing 1g of the drug on cattle was followed for 65 days and lead to concentrations of 5 to 35 μg of permethrin per gram of hair on the shoulders. On the flanks of the animals, the corresponding values were 10 times lower. Across the 1.5 acre pasture, high concentrations of permethiin were measured at various locations and long after treatment: 6 μg/g on bark of a birch after one week, 5 μg/g on a pole of the fence after two weeks, 1 μg/g in grass from a resting site of the animal after six weeks, and 0.5 μg/g in bark of a pine tree after three month and two weeks after the animals had left the pasture. In similar assays, cyhalothrin applied to milk cows as a pour‐on preparation was monitored. One week following treatment with 0.2 g/animal, hair cut from the shoulders contained 5 μg/g of the insecticide, which disappeared with a half‐life of 12 days. Dust collected two weeks after the pour‐on treatment from the milk barn where the cows were milked twice daily contained 47 μg/g of cyhalothrin, which disappeared with a half‐life of 44 days. These results show that synthetic pyrethroids used on farm animals can be the source of widespread and persistent contamination.     

Heavy metal contamination from mining sites in South Morocco: 1. Use of a biotest to assess metal toxicity of tailings and soils

Our work was conducted to investigate the heavy metal toxicity of tailings and soils collected from five metal mines located in the south of Morocco. We used the MetPAD biotest Kit which detects the toxicity specifically due to the heavy metals in environmental samples. This biotest initially developed to assess the toxicity of aquatic samples was adapted to the heterogeneous physico-chemical conditions of anthropogenic soils. Contrasted industrial soils were collected from four abandoned mines (A, B, C and E) and one mine (D) still active. The toxicity test was run concurrently with chemical analyses on the aqueous extracts of tailings materials and soils in order to assess the potential availability of heavy metals. Soil pH was variable, ranging from very acidic (pH 2.6) to alkaline values (pH 8.0-8.8). The tailings from polymetallic mines (B and D) contained very high concentrations of Zn (38,000-108,000 mg kg(-1)), Pb (20,412-30,100 mg kg(-1)), Cu (2,019-8,635 mg kg(-1)) and Cd (148-228 mg kg(-1)). Water-extractable metal concentrations (i.e., soil extracts) were much lower but were highly toxic as shown by the MetPAD test, except for soils from mines A, E and site C3 from mine C. The soil extracts from mine D were the most toxic amongst all the soils tested. On this site, the toxicity of soil water extracts was mainly due to high concentrations of Zn (785-1,753 mg l(-1)), Cu (1.8-82 mg l(-1)) and Cd (2.0-2.7 mg l(-1)). The general trend observed was an increase in metal toxicity measured by the biotest with increasing available metal contents in tailings materials and soils. Therefore, the MetPAD test can be used as a rapid and sensitive predictive tool to assess the heavy metal availability in soils highly contaminated by mining activities.     

Acute toxicity of disinfection by-products from chlorination of algal organic matter to the cladocerans Ceriodaphnia silvestrii and Daphnia similis: influence of bromide and quenching agent

Environmental Science and Pollution Research - Algal organic matter (AOM) in water reservoirs is a worldwide concern for drinking water treatment; once it is one of the main precursors for...     

Reflectance properties and physiological responses of Salicornia virginica to heavy metal and petroleum contamination

Wetland ecosystems of California are located in highly populated areas and subject to high levels of contamination. Monitoring of wetlands to assess degrees of pollution damage requires periodic retrieval of information over large areas, which can be effectively accomplished by rapidly evolving remote sensing technologies. The biophysical principles of remote sensing of vegetation under stress need to be understood in order to correctly interpret the information obtained at the scale of canopies. To determine the potential to remotely characterize and monitor pollution, plants of Salicornia virginica, a major component of wetland communities in California, were treated with two metals and two crude oil types to study their sensitivity to pollutants and how this impacted their reflectance characteristics. Several growth and physiological parameters, as well as shoot reflectance were measured and correlated with symptoms and contamination levels. Significant differences between treatments were found in at least some of the measured parameters in all pollutants. Reflectance was sensitive to early stress levels only for cadmium and the lightweight petroleum. Pollutants that differ in their way of action also had different plant reflectance signatures. The high degree of correlation between reflectance features and stress indicators highlights the potential of using remote sensing to assess the type and degree of pollution damage.     

The influence of the scale of mining activity and mine site remediation on the contamination legacy of historical metal mining activity

Globally, thousands of kilometres of rivers are degraded due to the presence of elevated concentrations of potentially harmful elements (PHEs) sourced from historical metal mining activity. In many countries, the presence of contaminated water and river sediment creates a legal requirement to address such problems. Remediation of mining-associated point sources has often been focused upon improving river water quality; however, this study evaluates the contaminant legacy present within river sediments and attempts to assess the influence of the scale of mining activity and post-mining remediation upon the magnitude of PHE contamination found within contemporary river sediments. Data collected from four exemplar catchments indicates a strong relationship between the scale of historical mining, as measured by ore output, and maximum PHE enrichment factors, calculated versus environmental quality guidelines. The use of channel slope as a proxy measure for the degree of channel-floodplain coupling indicates that enrichment factors for PHEs in contemporary river sediments may also be the highest where channel-floodplain coupling is the greatest. Calculation of a metric score for mine remediation activity indicates no clear influence of the scale of remediation activity and PHE enrichment factors for river sediments. It is suggested that whilst exemplars of significant successes at improving post-remediation river water quality can be identified; river sediment quality is a much more long-lasting environmental problem. In addition, it is suggested that improvements to river sediment quality do not occur quickly or easily as a result of remediation actions focused a specific mining point sources. Data indicate that PHEs continue to be episodically dispersed through river catchments hundreds of years after the cessation of mining activity, especially during flood flows. The high PHE loads of flood sediments in mining-affected river catchments and the predicted changes to flood frequency, especially, in many river catchments, provides further evidence of the need to enact effective mine remediation strategies and to fully consider the role of river sediments in prolonging the environmental legacy of historical mine sites.     

Application of artificial neural networks to predict the heavy metal contamination in the Bartin River

Environmental Science and Pollution Research - In this study, copper (Cu), iron (Fe), zinc (Zn), manganese (Mn), nickel (Ni), and lead (Pb) analyses were performed, and the results were modelled by...     

Resistance of aerobic microorganisms and soil enzyme response to soil contamination with Ekodiesel Ultra fuel

This study determined the susceptibility of cultured soil microorganisms to the effects of Ekodiesel Ultra fuel (DO), to the enzymatic activity of soil and to soil contamination with PAHs. Studies into the effects of any type of oil products on reactions taking place in soil are necessary as particular fuels not only differ in the chemical composition of oil products but also in the composition of various fuel improvers and antimicrobial fuel additives. The subjects of the study included loamy sand and sandy loam which, in their natural state, have been classified into the soil subtype 3.1.1 Endocalcaric Cambisols. The soil was contaminated with the DO in amounts of 0, 5 and 10 cm³ kg⁻¹. Differences were noted in the resistance of particular groups or genera of microorganisms to DO contamination in loamy sand (LS) and sandy loam (SL). In loamy sand and sandy loam, the most resistant microorganisms were oligotrophic spore-forming bacteria. The resistance of microorganisms to DO contamination was greater in LS than in SL. It decreased with the duration of exposure of microorganisms to the effects of DO. The factor of impact (IF_DO) on the activity of particular enzymes varied. For dehydrogenases, urease, arylsulphatase and β-glucosidase, it had negative values, while for catalase, it had positive values and was close to 0 for acid phosphatase and alkaline phosphatase. However, in both soils, the noted index of biochemical activity of soil (BA) decreased with the increase in DO contamination. In addition, a positive correlation occurred between the degree of soil contamination and its PAH content.