Analysis of the toxicogenomic effects of exposure to persistent organic pollutants (POPs) in Slovakian girls: correlations between gene expression and disease risk

The chemical composition of persistent organic pollutants (POPs) in the environment is not uniform throughout the world, and these contaminants contain many structurally different lipophilic compounds. In a well-defined study cohort in the Slovak Republic, the POP chemicals present in the peripheral blood of exposed children were chemically analyzed. The chemical analysis data revealed that the relative concentration and profile of structurally different organic pollutants, including polychlorinated biphenyls (PCBs), 2,2′-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p′-DDE), 2,2′-bis(4-chlorophenyl)-1,1,1-trichloro-ethane (p,p′-DDT), hexachlorobenzene (HCB) and β-hexachlorocyclohexane (β-HCH), may vary from individual to individual, even within the same exposure area. These chemicals can be broadly classified into two groups. The first group, the PCB congeners, primarily originated from industrial compounds and their byproducts. The second group of compounds originated from or was commonly used in the agricultural sector (e.g., DDT, HCB). The objective of this study was to examine the effects of the two POP exposure profiles on gene expression. For the study population, we selected pre-pubertal girls (mean age of 46.2 ± 1.4 months) with high POP concentrations in their blood (> 75% tile of total POP) and classified them in the high ‘PCB’ group when the total PCB concentration was significantly higher than the total concentration of other POP components and in the ‘Other Than PCB’ (OTP) group, when the total PCB concentration was significantly lower than the concentration of the other major POP constituents. A matched control group of girls (< 25% tile of total POP) was selected for comparison purpose (n = 5 per group). Our aims were to determine whether there were any common effects of high POP exposure at a toxicogenomic level and to investigate how exposure may affect physiological functions of the children in two different exposure scenarios. Global gene expression analysis using a microarray (Affymetrix Gene Chip Human genome U133 Plus 2.0 Array) platform was conducted on the total RNA of peripheral blood mononuclear cells from the girls. The results were analyzed by Partek GS, Louis, MI, which identified twelve genes (ATAD2B, BIVM, CD96, CXorf39, CYTH1 ETNK1, FAM13A, HIRA, INO80B, ODG1, RAD23B, and TSGA14) and two unidentified probe sets, as regulated differentially in both the PCB and OTP groups against the control group. The qRT-PCR method was used to validate the microarray results. The Ingenuity Pathway Analysis (IPA) software package identified the possible molecular impairments and disease risks associated with each gene set. Connective tissue disorders, genetic disorders, skeletal muscular disorders and neurological diseases were associated with the 12 common genes. The data therefore identified the potential molecular effects of POP exposure on a genomic level. This report underscores the importance of further study to validate the results in a random population and to evaluate the use of the identified genes as biomarkers for POP exposure.     

Approaches to assess the oral bioaccessibility of persistent organic pollutants: a critical review

Oral bioaccessibility, also known as in vitro gastrointestinal extraction or the physiologically based extraction test (PBET), is an important tool when assessing the risk to humans from persistent organic pollutants (POPs) (and metals). The approach seeks to mimic the processes of human food digestion and thereby assess the bioavailability of POPs (and metals) from materials consumed either accidentally or intentionally in the diet. In vitro conditions are created to simulate various actions in the stomach and intestines (although some methods also include the mouth compartment). This paper reviews the current status of oral bioaccessibility with respect to the release of POPs from soil and related samples of environmental importance. Particular emphasis is placed on the parameters that influence gastrointestinal extraction including gastric and intestinal pH, enzymes, bile salts, food constituents and residence time. In addition, important developments in the use of in vitro gastrointestinal extraction are highlighted. These developments include the use of epithelial Caco-2 cells to mimic the intestinal cell lining, the potential for biotransformation of POPs into estrogenic metabolites as a result of colon microbiota, and the use of in vivo studies to validate existing approaches.     

Relationships between hope,optimism, and conservation engagement

The loss and degradation of nature can lead to hopelessness and despair, which may undermine engagement in conservation actions. Emerging movements, such as that behind the organization Conservation Optimism, aim to avert potential despair of those involved in conservation. Some argue that fostering positive states, such as hope or optimism, can motivate engagement and action; however, others question whether fostering hope or optimism may inadvertently undermine perceived gravity of conservation challenges. We examined this issue by quantifying dispositional hope and optimism with a representative sample of Australians (n = 4285) and assessing their relationship with indicators of conservation engagement. We used the Great Barrier Reef (GBR) in Australia as a case study. We asked participants what they could do to help the GBR, then classified their responses into 2 outcome variables: identifying climate actions (i.e., actions that tackle the main threat to the reef) and identifying plastic actions (i.e., actions that are popular among community members). We also quantified likelihood of performing these actions and appraisals of both threats and actions. One dimension of hope, hope pathways (defined by Snyder's hope theory as knowing different ways to act), was associated with greater capacity to identify climate-related behaviors (odds ratio [OR] = 1.44) and plastic reduction behaviors (OR = 1.22) and greater likelihood of adopting climate-related actions (β = 0.20). Optimism was associated with recognition of plastic reduction behaviors only (OR = 1.22). Neither hope nor optimism undermined appraisal of conservation threats. The effects of optimism were mediated by reduced action futility, and effects of hope pathways were mediated by stronger perceptions of threats to the reef (threat appraisal) and confidence in performing useful actions (coping appraisal). Our findings suggest that dispositional hope can strengthen, rather than undermine, appraisal of conservation challenges and solutions and thereby increase conservation engagement.     

Processing Stability and Biodegradation of Polylactic Acid (PLA) Composites Reinforced with Cotton Linters or Maple Hardwood Fibres

Polylactic acid (PLA) composites comprising up to 25 wt% cotton linter (CL) or up to 50 % maple wood fibre (WF) were prepared by compounding and injection moulding. A reduction of crystallinity in the PLA matrix was observed as a result of the thermal processing method. These PLACL and PLAWF composites provided excellent improvements in both stiffness (with increases in tensile and flexural modulus) and toughness (increases in notched impact strength) properties over the neat PLA resin, while the tensile and flexural strengths of the composites were generally unchanged, while the strain at break values were reduced in comparison to the neat PLA. DMA results indicated incorporating these fibres caused the mechanical loss factor (tan δ) to decrease, suggesting better damping capabilities were achieved with the composites. SEM analysis of the impact fractured surfaces of the PLACL composites showed debonding-cavitation at the matrix-fibre interface while the PLAWF composites showed good wetting along its matrix-fibre interface. The composting of these composites up to 90 days showed that the degradation onset time was increased when increasing the fibre loadings, but the maximum degree of degradation and the maximum daily rates of degradation were decreased compared to neat PLA. On a weight basis of fibre loading, the PLACL composites had a quicker onset of biodegradation, a higher maximum daily rate of biodegradation and, overall, a higher degree of biodegradation at 90 days than the PLAWF composites, possibly due to the quicker thermal hydrolysis observed in the PLA matrix of the PLACL composites during processing and composting.     

拉萨市垃圾焚烧飞灰重金属特性分析及风险评价

焚烧是城市垃圾处理主流技术,飞灰作为垃圾焚烧主要污染物成为垃圾焚烧污染控制关键环节。采集拉萨市垃圾焚烧发电厂飞灰样品,分析了飞灰中重金属含量及浸出毒性特征,并采用改进的潜在风险评价法及健康风险评价法评价飞灰中重金属的潜在风险。结果表明:拉萨市飞灰中重金属含量较高,且Pb的浸出浓度超过GB 5085.3-2007《危险废物鉴别标准 浸出毒性鉴别》浸出液最高允许值的16倍。污染评价结果表明,拉萨市飞灰中Pb对环境具有极强的污染风险。健康风险评价结果表明,飞灰中重金属对人体的致癌风险在可接受范围内,但其非致癌风险值高于美国国家环境保护局(EPA)推荐的非致癌风险值(HQ ≤ 1),对人体具有较高的非致癌风险。其中 Pb对成人和儿童的非致癌风险值分别为3.8975和9.7458,是非致癌风险的主要贡献者。     

Laboratory and field investigations of particulate and carbon monoxide emissions from traditional and improved cookstoves

We implemented a program in which emission characterization is enabled through collaborations between academic, US and international non-governmental entities that focus on evaluation, dissemination, and in-use testing, of improved cookstoves. This effort resulted in a study of field and laboratory emissions from traditional and improved biofuel cookstoves. We found that field measured particulate emissions of actual cooking average three times those measured during simulated cooking in the laboratory. Emission factors are highly dependent on the care and skill of the operator and the resulting combustion; these do not appear to be accurately reproduced in laboratory settings. The single scattering albedo (SSA) of the emissions was very low in both lab and field measurements, averaging about 0.3 for lab tests and around 0.5 for field tests, indicating that the primary particles are climate warming. Over the course of three summers in Honduras, we measured field emissions from traditional cookstoves, relatively new improved cookstoves, and “broken-in” improved cookstoves. We found that well-designed improved cookstoves can significantly reduce PM and CO emission factors below traditional cookstoves. For improved stoves, the presence of a chimney generally resulted in lower emission factors but left the SSA unaffected. Traditional cookstoves had an average PM emission factor of 8.2 g kg^?1 – significantly larger than previous studies. Particulate emission factors for improved cookstoves without and with chimneys averaged about 6.6 g kg^?1 and 4.5 g kg^?1, respectively. The elemental carbon (EC) fraction of PM varied significantly between individual tests, but averaged about 25% for each of the categories.     

Distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans in suspended sediments, dissolved phase and bottom sediment in the Houston Ship Channel

Spatial distributions of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in the water column and bottom sediments of the Houston Ship Channel in Texas were measured three times over a 1-year period. Total TEQ concentrations in water ranged from 0.01 to 0.25 pg/l for the dissolved phase and from 0.09 to 2.91 pg/l for the suspended phase, while TEQ concentrations in bottom sediments varied from 0.9 to 139.8 ng/kg dry wt. The dissolved concentrations were lower than their respective suspended concentrations, with average dissolved/suspended ratios between 0.11 and 0.59 for individual congeners. More than 89% of the total concentration of 2378-substituted PCDD/PCDFs was attributable to OCDD but 2378-TCDD was the major contributor to total TEQ for the three sampled media. Average logs of organic carbon-normalized suspended sediment-dissolved partitioning coefficients (logK(oc)(obs)) varied between 4.92 and 8.59 l/kg-oc; while in the bottom sediment-dissolved interface, logK(oc)(obs) values ranged from 5.48 to 8.48 l/kg-oc. Observed logK(oc)values varied within a factor of 0.64-1.26 from equilibrium logK(oc) values, suggesting fluxes of PCDD/PCDFs across the interfaces. It was found that in the HSC, on average, the tendency of a compound to move from the particulate phase to the dissolved phase decreases with increasing K(ow).     

西南典型高原山地城市大气黑碳气溶胶污染特征及来源解析

利用大气细颗粒物采样仪器(青岛崂应2050型)和黑碳仪(SootScanTM Model OT21),于2016年5月至2017年4月对贵阳市城区大气黑碳进行了连续采样和监测.结果表明,大气黑炭的浓度为1.17～12.77 μg/m3,平均值为5.19±1.91 μg/m3,季节变化特征呈现为冬季＞秋季＞春季≈夏季.大...