28 research outputs found
Nanomolar levels of PAHs in extracts from urban air induce MAPK signaling in HepG2 cells.
Polycyclic aromatic hydrocarbons (PAHs) are common environmental pollutants that
occur naturally in complex mixtures. Many of the adverse health effects of PAHs
including cancer are linked to the activation of intracellular stress response
signaling. This study has investigated intracellular MAPK signaling in response
to PAHs in extracts from urban air collected in Stockholm, Sweden and Limeira,
Brazil, in comparison to BP in HepG2 cells. Nanomolar concentrations of PAHs in
the extracts induced activation of MEK4 signaling with down-stream increased gene
expression of several important stress response mediators. Involvement of the
MEK4/JNK pathway was confirmed using siRNA and an inhibitor of JNK signaling
resulting in significantly reduced MAPK signaling transactivated by the AP-1
transcription factors ATF2 and c-Jun. ATF2 was also identified as a sensitive
stress responsive protein with activation observed at extract concentrations
equivalent to 0.1 nM BP. We show that exposure to low levels of environmental PAH
mixtures more strongly activates these signaling pathways compared to BP alone
suggesting effects due to interactions. Taken together, this is the first study
showing the involvement of MEK4/JNK/AP-1 pathway in regulating the intracellular
stress response after exposure to nanomolar levels of PAHs in environmentalFormasAccepte
Sensitivity of Salmonella YG5161 for detecting PAH-associated mutagenicity in air particulate matter.
The Salmonella/microsome assay is the most used assay for the evaluation of air
particulate matter (PM) mutagenicity and a positive correlation between strain
TA98 responses and benzo[a]pyrene (B[a]P) levels in PM has been found. However,
it seems that the major causes of PM mutagenicity in this assay are the nitro and
oxy-PAHs. Salmonella YG5161, a 30-times more responsive strain to B[a]P has been
developed. To verify if YG5161 strain was sufficiently sensitive to detect
mutagenicity associated with B[a]P mutagenicity, PM samples were collected in
Brazil and Sweden, extracted with toluene and tested in the Salmonella/microsome
microsuspension assay. PAHs and B[a]P were determined and the extracts were
tested with YG5161 and its parental strain TA1538. The extracts were also tested
with YG1041 and its parental strain TA98. For sensitivity comparisons, we tested
B[a]P and 1-nitropyrene (1-NP) using the same conditions. The minimal effective
dose of B[a]P was 155 ng/plate for TA1538 and 7 ng/plate for YG5161. Although the
maximum tested dose, 10 m(3) /plate containing 9 ng of B[a]P in the case of
Brazilian sample, was sufficient to elicit a response in YG5161, mutagenicity was
detected at a dose as low as 1 m(3) /plate (0.9 ng). This is probably caused by
nitro-compounds that have been shown to be even more potent than B[a]P for
YG5161. It seems that the mutagenicity of B[a]P present in PM is not detectable
even with the use of YG5161 unless more efficient separation to remove the
nitro-compounds from the PAH extract is performed.FormasAccepte
Detection of benz[j]aceanthrylene in urban air and evaluation of its genotoxic potential.
Benz[j]aceanthrylene (B[j]A) is a cyclopenta-fused polycyclic aromatic
hydrocarbon with strong mutagenic and carcinogenic effects. We have identified
B[j]A in air particulate matter (PM) in samples collected in Stockholm, Sweden
and in Limeira, Brazil using LC-GC/MS analysis. Determined concentrations ranged
between 1.57 and 12.7 and 19.6-30.2 pg/m(3) in Stockholm and Limeira,
respectively, which was 11-30 times less than benzo[a]pyrene (B[a]P)
concentrations. Activation of the DNA damage response was evaluated after
exposure to B[j]A in HepG2 cells in comparison to B[a]P. We found that
significantly lower concentrations of B[j]A were needed for an effect on cell
viability compared to B[a]P, and equimolar exposure resulted in significant more
DNA damage with B[j]A. Additionally, levels of gammaH2AX, pChk1, p53, pp53, and
p21 proteins were higher in response to B[j]A than B[a]P. On the basis of dose
response induction of pChk1 and gammaH2AX, B[j]A potency was 12.5- and 33.3-fold
higher than B[a]P, respectively. Although B[j]A levels in air were low, including
B[j]A in the estimation of excess lifetime cancer risk increased the risk up to
2-fold depending on which potency factor for B[j]A was applied. Together, our
results show that B[j]A could be an important contributor to the cancer risk of
air PM.FormasAccepte
Genotoxicity biomonitoring of sewage in two municipal wastewater treatment plants using the Tradescantia pallida var. purpurea bioassay
The genotoxicity of untreated and treated sewage from two municipal wastewater treatment plants (WTP BN and WTP SJN) in the municipality of Porto Alegre, in the southern Brazilian state of Rio Grande do Sul, was evaluated over a one-year period using the Tradescantia pallida var. purpurea (Trad-MCN) bioassay. Inflorescences of T. pallida var. purpurea were exposed to sewage samples in February (summer), April (autumn), July (winter) and October (spring) 2009, and the micronuclei (MCN) frequencies were estimated in each period. The high genotoxicity of untreated sewage from WTP BN in February and April was not observed in treated sewage, indicating the efficiency of treatment at this WTP. However, untreated and treated sewage samples from WTP SJN had high MCN frequencies, except in October, when rainfall may have been responsible for reducing these frequencies at both WTPs. Physicochemical analyses of sewage from both WTPs indicated elevated concentrations of organic matter that were higher at WTP SJN than at WTP BN. Chromium was detected in untreated and treated sewage from WTP SJN, but not in treated sewage from WTP BN. Lead was found in all untreated sewage samples from WTP SJN, but only in the summer and autumn at WTP BN. These results indicate that the short-term Trad-MCN genotoxicity assay may be useful for regular monitoring of municipal WTPs
One planet: one health. A call to support the initiative on a global science–policy body on chemicals and waste
The chemical pollution crisis severely threatens human and environmental health globally. To tackle this challenge the establishment of an overarching international science–policy body has recently been suggested. We strongly support this initiative based on the awareness that humanity has already likely left the safe operating space within planetary boundaries for novel entities including chemical pollution. Immediate action is essential and needs to be informed by sound scientific knowledge and data compiled and critically evaluated by an overarching science–policy interface body. Major challenges for such a body are (i) to foster global knowledge production on exposure, impacts and governance going beyond data-rich regions (e.g., Europe and North America), (ii) to cover the entirety of hazardous chemicals, mixtures and wastes, (iii) to follow a one-health perspective considering the risks posed by chemicals and waste on ecosystem and human health, and (iv) to strive for solution-oriented assessments based on systems thinking. Based on multiple evidence on urgent action on a global scale, we call scientists and practitioners to mobilize their scientific networks and to intensify science–policy interaction with national governments to support the negotiations on the establishment of an intergovernmental body based on scientific knowledge explaining the anticipated benefit for human and environmental health.Projekt DEA
Identification of alpha-beta unsaturated aldehydes as sources of toxicity to activated sludge biomass in polyester manufacturing wastewater
Wastewater generated in industrial production processes are often contaminated by hazardous chemicals. Characterization by means of toxicity-directed analysis is useful for identifying which fractions of a waste stream possess the most toxicity. We applied this approach to evaluate toxic components of a polyester manufacturing wastewater. Using the reduction in oxygen uptake rate of activated sludge as an indicator of toxicity, it was determined that increasing the pH from 3 to 11 followed by air stripping significantly reduced the toxicity of the wastewater. Comparative headspace GC/MS analysis of wastewater at different pHs selected a group of Volatile Organic Compounds (VOCs) associated with the observed effect of air stripping at pH 11. Ten of these compounds were identified as alpha,beta unsaturated aldehydes (acrolein (2-propenal) congeners); these compounds are known to be toxic as well as mutagenic. Confirmation that these compounds were a cause of toxicity was achieved by demonstrating that removal of these compounds by air stripping significantly reduced the wastewater mutagenic potency in a Salmonella mutagenicity assay. Formation of these volatile compounds by base catalyzed aldol condensation at pH 11 may account for the effectiveness of air stripping in reducing toxicity. To date there is no record in the literature about the toxicity and presence of acrolein congeners in polyester manufacturing wastewater.61923172324Ministry of Education of Brazi
Filamentous fungi isolated from estuarine sediments contaminated with industrial discharges
Filamentous fungi were isolated from estuarine sediments collected from two contaminated sites. One site was contaminated mainly by polycyclic aromatic hydrocarbon (PAH) with a concentration around 407 mug g(-1) of different PAHs, and the other by different sources of industrial pollutants; both were compared to a pristine site. All three sites were located in the Baixada Santista, Sao Paulo State, Brazil. The aim of the present investigation was the isolation of filamentous fungi from pristine and industrially polluted sediments in order to assess the mycobiota present in those sites and to evaluate their tolerance to phenanthrene and pyrene. Most of the isolated fungi were mitosporic ascomycetes, including Aspergillus sp., Chrysosporium sp., Cyclothyrium spp., Gliocladium sp., Penicillium spp., Phoma spp., and Trichoderma spp. There were also representatives of sexual Ascomycetes, Basidiomycetes, and Zygomycetes. The results showed that 59% of the evaluated fungi were tolerant to pyrene and 30% to phenanthrene. Representatives of Trichoderma were the most tolerant among the filamentous fungi investigated. A representative of Penicillium simplicissimum was the only isolate tested that had a better growth in the presence of pyrene than in its absence.12334535