Comparative acute toxicity of leachates from plastic products made of polypropylene, polyethylene, PVC, acrylonitrile–butadiene–styrene, and epoxy to Daphnia magna

Purpose

The large global production of plastics and their presence everywhere in the society and the environment create a need for assessing chemical hazards and risks associated with plastic products. The aims of this study were to determine and compare the toxicity of leachates from plastic products made of five plastics types and to identify the class of compounds that is causing the toxicity.

Methods

Selected plastic types were those with the largest global annual production, that is, polypropylene, polyethylene, and polyvinyl chloride (PVC), or those composed of hazardous monomers (e.g., PVC, acrylonitrile?Cbutadiene?Cstyrene [ABS], and epoxy). Altogether 26 plastic products were leached in deionized water (3?days at 50°C), and the water phases were tested for acute toxicity to Daphnia magna. Initial Toxicity Identification Evaluations (C18 filtration and EDTA addition) were performed on six leachates.

Results

For eleven leachates (42%) 48-h EC50s (i.e the concentration that causes effect in 50 percent of the test organisms) were below the highest test concentration, 250 g plastic/L. All leachates from plasticized PVC (5/5) and epoxy (5/5) products were toxic (48-h EC50s ranging from 2 to 235?g plastic/L). None of the leachates from polypropylene (5/5), ABS (5/5), and rigid PVC (1/1) products showed toxicity, but one of the five tested HDPE leachates was toxic (48-h EC50 17?C24?g plastic/L). Toxicity Identification Evaluations indicated that mainly hydrophobic organics were causing the toxicity and that metals were the main cause for one leachate (metal release was also confirmed by chemical analysis).

Conclusions

Toxic chemicals leached even during the short-term leaching in water, mainly from plasticized PVC and epoxy products.     

Quantitative–spatial assessment of soil contamination in S. Francisco de Assis due to mining activity of the Panasqueira mine (Portugal)

Through the years, mining and beneficiation processes produces large amounts of As-rich mine wastes laid up in huge tailings and open-air impoundments (Barroca Grande and Rio tailings) that are the main source of pollution in the surrounding area once they are exposed to the weathering conditions leading to the formation of AMD and consequently to the contamination of the surrounding environments, in particularly soils. In order to investigate the environmental contamination impact on S. Francisco de Assis (village located between the two major impoundments and tailings) agricultural soils, a geochemical survey was undertaken to assess toxic metals associations, related levels and their spatial distribution, and to identify the possible contamination sources. According to the calculated contamination factor, As and Zn have a very high contamination factor giving rise to 65.4 % of samples with a moderate to high pollution degree; 34.6 % have been classified as nil to very low pollution degree. The contamination factor spatial distribution put in evidence the fact that As, Cd, Cu, Pb, and Zn soils contents, downstream Barroca Grande tailing, are increased when compared with the local Bk soils. The mechanical dispersion, due to erosion, is the main contamination source. The chemical extraction demonstrates that the trace metals distribution and accumulation in S. Francisco de Assis soils is related to sulfides, but also to amorphous or poorly crystalline iron oxide phases. The partitioning study allowed understanding the local chemical elements mobility and precipitation processes, giving rise to the contamination dispersion model of the study area. The wind and hydrological factors are responsible for the chemical elements transport mechanisms, the water being the main transporter medium and soils as one of the possible retention media.     

Samsum ant venom protects against carbon tetrachloride–induced acute spleen toxicity in vivo

Environmental Science and Pollution Research - Many active molecules used in the development of new drugs are produced by ants. Present study assessed antioxidant and anti-inflammatory properties...     

Is the OECD acute worm toxicity test environmentally relevant? The effect of mineral form on calculated lead toxicity

In a series of experiments the toxicity of lead to worms in soil was determined following the draft OECD earthworm reproduction toxicity protocol except that lead was added as solid lead nitrate, carbonate and sulphide rather than as lead nitrate solution as would normally be the case. The compounds were added to the test soil to give lead concentrations of 625-12 500 microg Pb g(-1) of soil. Calculated toxicities of the lead decreased in the order nitrate> carbonate> sulphide, the same order as the decrease in the solubility of the metal compounds used. The 7-day LC50 (lethal concentration when 50% of the population is killed) for the nitrate was 5321+/-275 microg Pb g(-1) of soil and this did not change with time. The LC50 values for carbonate and sulphide could not be determined at the concentration ranges used. The only parameter sensitive enough to distinguish the toxicities of the three compounds was cocoon (egg) production. The EC50s for cocoon production (the concentration to produce a 50% reduction in cocoon production) were 993, 8604 and 10246 pg Pb g(-1) of soil for lead nitrate, carbonate and sulphide, respectively. Standard toxicity tests need to take into account the form in which the contaminant is present in the soil to be of environmental relevance.     

Reduced activity of alkaline phosphatase due to host–guest interactions with humic superstructures

Nuclear Magnetic Resonance (NMR) spectroscopy was applied to directly study the interactions between the alkaline phosphatase enzyme (AP) and two different humic acids from a volcanic soil (HA-V) and a Lignite deposit (HA-L). Addition of humic matter to enzyme solutions caused signals broadening in ¹H-NMR spectra, and progressive decrease and increase of enzyme relaxation (T₁ and T₂) and correlation (τ_C) times, respectively. Spectroscopic changes were explained with formation of ever larger weakly-bound humic–enzyme complexes, whose translational and rotational motion was increasingly restricted. NMR diffusion experiments also showed that the AP diffusive properties were progressively reduced with formation of large humic–enzyme complexes. The more hydrophobic HA-L affected spectral changes more than the more hydrophilic HA-V. ¹H-NMR spectra also showed the effect of progressively greater humic–enzyme complexes on the hydrolysis of an enzyme substrate, the 4-nitrophenyl phosphate disodium salt hexahydrate (p-NPP). While AP catalysis concomitantly decreased NMR signals of p-NPP and increased those of nitrophenol, addition of humic matter progressively and significantly slowed down the rate of change for these signals. In agreement with the observed spectral changes, the AP catalytic activity was more largely inhibited by HA-L than by HA-V. Contrary to previous studies, in which humic–enzyme interactions were only indirectly assumed from changes in spectrophotometric behavior of enzyme substrates, the direct measurements of AP behavior by NMR spectroscopy indicated that humic materials formed weakly-bound host–guest complexes with alkaline phosphatase, and the enzyme catalytic activity was thereby significantly inhibited. These results suggest that the role of extracellular enzymes in soils may be considerably reduced when they come in contact with organic matter dissolved in the soil solution.     

Measurements of air–surface exchange rates of volatile organic compounds

Vertical gradients of volatile organic compounds (VOCs) were measured over a maize field and a soybean field in 1995 and 1996, respectively, in the Lower Coastal Plains of North Carolina. The measurements over the maize field were conducted in its early growth period, during May 1995, and the measurements over the soybean field were conducted in its middle and later growth periods during July through August 1996 at the same location. These measurements were combined with micrometeorological flux measurements to determine emission flux measurements for various VOCs. This measurement programme was part of project NOVA (Natural emissions of Oxidant precursors: Validation of techniques and Assessment) to estimate the flux of VOCs. Methanol was identified as the major biogenic compound for both years with the average flux of 3450 ± 1456 µg/m²/hr over maize and 3079 ± 2766 µg/m²/hr over soybean. Acetone is another compound that was identified as a biogenic compound for both years with the average flux of 425 ± 223 µg/m²/hr over maize and 2701 ± 1710 µg/m²/hr over soybean. In addition to biogenic compounds, a large number of aromatic compounds, including styrene and 1,2,4-trimethylbenzene, were also identified as emissions from the ground over the soybean field.     

Estrogenic effects of dissolved organic matter and its impact on the activity of 17β-estradiol

Background and purpose  

The ubiquitous dissolved organic matter (DOM) is actually not inert as we always think, and the hormone-like effects of DOM have been reported. The objective of this study was to investigate the estrogenic effects of DOM and its impact on the activity of the natural estrogen 17β-estradiol (E2).     

Evaluation of removal efficiency for acute toxicity and genotoxicity on zebrafish in anoxic–oxic process from selected municipal wastewater treatment plants

The anoxic–oxic (A/O) process has been extensively applied for simultaneous removal of organic contaminants and nitrogen in wastewater treatment. However, very little is known about its ability to remove toxic materials. Municipal wastewater contains various kinds of pollutants, some of which have recalcitrant genotoxicity and may cause potential threat to environment, and even can lead to extinction of many species. In this study, we have selected three municipal wastewater treatment plants (WWTPs) employing anoxic–oxic (A/O) process to evaluate their ability to remove acute toxicity and genotoxicity of wastewater. Mortality rate of zebrafish (Danio rerio) was used to evaluate acute toxicity, while micronucleus (MN) and comet assays were used to detect genotoxicity. Results showed that in this process the acute toxicity was completely removed as the treatment proceeded along with decrease in chemical oxygen demand (COD) (<50 mg L^?1) in the effluent. However, in these treatment processes the genotoxicity was not significantly reduced, but an increase in genotoxicity was observed. Both MN and comet assays showed similar results. The eliminated effluent may pose genotoxic threaten although its COD level has met the Chinese Sewage Discharge Standard. This study suggests that further treatment of the wastewater is required after the A/O process to remove the genotoxicity and minimize the ecotoxicological risk.     

Quantitative evaluation of environmental risks of flotation tailings from hydrothermal sulfidation–flotation process

Floatation tailings (FT) are the main by-products of the hydrothermal sulfidation–flotation process. FT (FT₁ and FT₂) were obtained by treating two different neutralization sludges (NS) (NS₁ and NS₂). This paper quantitatively evaluated the environmental risks of heavy metals (Zn, Cd, Cu, Pb, and As) in FT versus NS. The total concentration and leaching rates (R ₂) of heavy metals in FT were much lower than those in NS, demonstrating that the hydrothermal sulfidation–flotation process was able to effectively suppress the mobility and leachability of heavy metals. The BCR-three sequence leaching procedure of FT confirmed that all metals were transformed into more stable forms (residue and oxidizable forms) than were found that in NS. The potential ecological risk index indicated that the overall risks caused by heavy metals decreased significantly from 6627.59 and 7229.67 (very serious risk) in NS₁ and NS₂, respectively, to 80.26 and 76.27 (low risk) in FT₁ and FT₂, respectively. According to the risk assessment code, none of the heavy metals in FT posed significant risk to the natural environment except Zn (with low risk). In general, the risk of heavy metals in FT had been well controlled.     

The effect of acute administration of the mycotoxin zearalenone to female pigs∗

Abstract

Crystalline zearalenone was administered to young female pigs at dose levels of 0, 3.5, 7.5 and 11.5 mg zearalenone/kg body weight. All animals receiving the mycotoxin exhibited vulva vag‐initis and had enlarged reproductive tracts, 1 week after dosing. Free zearalenone was found in the blood, feces and urine of dosed animals. The highest zearalenone level detected was 2.61 ng/ml from a pig that received the 7.5 mg/kg dose. After 24 hours, feces collected contained on average up to 308 ng zearalenone per g of dried feces. Zearalenone levels of up to 59 ng/ml, and a ‐zearalenol levels of up to 155 ng/ml urine were found. ß ‐zearalenol was also detected in the urine.     

Acute toxicity of arsenic to Aliivibrio fischeri (Microtox® bioassay) as influenced by potential competitive–protective agents

In this study, we investigated the effect of some potential alleviative compounds against the acute toxicity of arsenic (As^V, As^III and DMA^V) on Aliivibrio fischeri (formerly Vibrio fischeri), a bioluminescent model bacterium, through the Microtox® bioassay. The compounds studied differed in their mechanism of action, and they included the following: phosphate and glycerol, as chemical analogues (and potential competitors) of As^V or As^III, respectively; citrate, a weak natural organic ligand; and the antioxidant ascorbic acid. Special attention was paid to phosphate effects, a widespread pollutant in natural environments. As^V was found to be more acutely toxic than As^III to A. fischeri, in accordance with its higher interaction with the bacteria. Both As^V and As^III were found to be much more acutely toxic than DMA^V, which was essentially non-acutely toxic even at very high concentrations. Phosphate presence (at equimolar P/As ratios or higher) resulted in the almost total suppression of bioluminescence inhibition, suggesting it exerts an alleviative effect against As^V acute toxicity on A. fischeri. Interestingly, the uptake and the percentage of extracellular As^V were not affected by the addition of phosphate, suggesting that such protective effect does not result from the competition for their common transporters. In contrast, the acute toxicity of As^III was essentially unaffected by phosphate. Glycerol did not decrease the acute toxicity or the uptake of As^III by A. fischeri, denoting the likely occurrence of an additional mechanism for As^III uptake in such bacteria. Similarly, citrate and ascorbic acid essentially did not caused alleviation of As^V or As^III acute toxicity. As for environmental and operational implications, P could beneficially protect aquatic microorganisms against acute detrimental effects of As^V, whilst its presence could mask the toxicity due to As^V when assessed using the Microtox® bioassay, thus leading to seriously underestimate the actual ecological and health risks.     

Immunotoxic effects of environmental toxicants in fish �� how to assess them?

Numerous environmental chemicals, both long-known toxicants such as persistent organic pollutants as well as emerging contaminants such as pharmaceuticals, are known to modulate immune parameters of wildlife species, what can have adverse consequences for the fitness of individuals including their capability to resist pathogen infections. Despite frequent field observations of impaired immunocompetence and increased disease incidence in contaminant-exposed wildlife populations, the potential relevance of immunotoxic effects for the ecological impact of chemicals is rarely considered in ecotoxicological risk assessment. A limiting factor in the assessment of immunotoxic effects might be the complexity of the immune system what makes it difficult (1) to select appropriate exposure and effect parameters out of the many immune parameters which could be measured, and (2) to evaluate the significance of the selected parameters for the overall fitness and immunocompetence of the organism. Here, we present - on the example of teleost fishes - a brief discussion of how to assess chemical impact on the immune system using parameters at different levels of complexity and integration: immune mediators, humoral immune effectors, cellular immune defenses, macroscopical and microscopical responses of lymphoid tissues and organs, and host resistance to pathogens. Importantly, adverse effects of chemicals on immunocompetence may be detectable only after immune system activation, e.g., after pathogen challenge, but not in the resting immune system of non-infected fish. Current limitations to further development and implementation of immunotoxicity assays and parameters in ecotoxicological risk assessment are not primarily due to technological constraints, but are related from insufficient knowledge of (1) possible modes of action in the immune system, (2) the importance of intra- and inter-species immune system variability for the response against chemical stressors, and (3) deficits in conceptual and mechanistic assessment of combination effects of chemicals and pathogens.     

Use of a gas chromatography–mass spectrometry organic aerosol monitor for in-field detection of fine particulate organic compounds in source apportionment

A study was conducted on the Brigham Young University campus during January and February 2015 to identify winter-time sources of fine particulate material in Utah Valley, Utah. Fine particulate mass and components and related gas-phase species were all measured on an hourly averaged basis. Light scattering was also measured during the study. Included in the sampling was the first-time source apportionment application of a new monitoring instrument for the measurement of fine particulate organic marker compounds on an hourly averaged basis. Organic marker compounds measured included levoglucosan, dehydroabietic acid, stearic acid, pyrene, and anthracene. A total of 248 hourly averaged data sets were available for a positive matrix factorization (PMF) analysis of sources of both primary and secondary fine particulate material. A total of nine factors were identified. The presence of wood smoke emissions was associated with levoglucosan, dehydroabietic acid, and pyrene markers. Fine particulate secondary nitrate, secondary organic material, and wood smoke accounted for 90% of the fine particulate material. Fine particle light scattering was dominated by sources associated with wood smoke and secondary ammonium nitrate with associated modeled fine particulate water.

Implications: The identification of sources and secondary formation pathways leading to observed levels of PM_2.5 (particulate matter with an aerodynmaic diameter <2.5 μm) is important in making regulatory decisions on pollution control. The use of organic marker compounds in this assessment has proven useful; however, data obtained on a daily, or longer, sampling schedule limit the value of the information because diurnal changes associated with emissions and secondary aerosol formation cannot be identified. A new instrument, the gas chromtography–mass spectrometry (GC-MS) organic aerosol monitor, allows for the determination on these compounds on an hourly averaged basis. The demonstrated potential value of hourly averaged data in a source apportionment analysis indicates that significant improvement in the data used for making regulatory decisions is possible.     

Separation and remediation of environmental pollutants using metal–organic framework-based tailored materials

Environmental Science and Pollution Research - Metal–organic frameworks (MOFs) are a polymer hybrid family of compounds comprising metal ions that have been deliberately incorporated in...     

Effect of DTPA on Cd solubility in soil – Accumulation and subsequent toxicity to lettuce

In a controlled environment experiment, using Cd spiked soil, lettuce plants were grown under a range of DTPA levels and were subsequently harvested to determine levels of phytoaccumulation. Cadmium phytoaccumulation significantly increased with increasing soil Cd level (P < 0.05) but unexpectedly decreased with increasing DTPA levels, despite the fact that solubility of Cd was increased in the soil. Cadmium translocation (from root to shoot) increased after DTPA application. Lettuce growth was inhibited by both Cd and DTPA (at and above 10 and 500 mg kg^?1 respectively), as a result of higher Cd mobility and subsequent toxicity which was caused by DTPA higher dosages. Metal solubility in the soil (ranged between 2.8 and 26.5 mg kg^?1) was found to be significantly higher (P < 0.01) as compared to control with increasing DTPA levels even after 3 months of DTPA application. Cadmium tissue concentration in all DTPA treatments was less than in the corresponding control treatment, indicating a negative effect of DTPA application on Cd uptake. In conclusion, lettuce was an unsuitable plant species for Cd accumulation, at least when associated with a DTPA chelator.     

Controlled release of molasses melanoidin-like product from hybrid organic–inorganic silica xerogels and its application to the phytoextraction of lead through the Indian mustard

Environmental Science and Pollution Research - In this study, we investigate the release of melanoidin-like product (MLP) from hybrid silica xerogels to control the quantity of MLP in the medium...     

Composition and toxicity of particulate matter emitted from turbocharged common rail DME–biodiesel engine

Environmental Science and Pollution Research - Both ultrafine particle and toxicity emissions originating from diesel engine gain an increasing concern. In this study, size distribution and...