Effects of diesel from direct and indirect coal liquefaction on combustion and emissions in a six-cylinder turbocharged diesel engine

The aim of this study is to evaluate the effects of diesel from direct coal liquefaction (DDCL) and diesel from indirect coal liquefaction (DICL) on combustion and emissions. A six-cylinder turbocharged diesel engine fueled with DDCL, DICL, petroleum diesel (PD), 58% DDCL, and 42% DICL blended by volume (BD58) is used. The experiments are carried out at 1400 and 2300rpm engine speeds and various engine loads (10%, 25%, 50%, 75%, and 90% of the full-load). The results show that the brake thermal efficiency (BTE) of PD was higher than that of CTL (the maximum difference was 2%) at medium and high loads. At 10% load of 1400 rpm, the CO, HC and formaldehyde emissions of DDCL are 88.9%, 44.3% and 26.5% higher than those of PD respectively, and the CO, HC, and formaldehyde emissions of DICL are 30.1%, 15.3%, and 15.2% lower than those of PD. The differences among four fuels decrease rapidly with the increase of load. The NOX emissions of PD are the highest due to high nitrogen content (102.3 μg/g) and low hydrogen-carbon (H/C) ratio. The fuel with higher cetane number has less formaldehyde emission at low loads, while the fuel with lower H/C has less formaldehyde emission at high loads. The particle size distribution shows a bimodal shape at different loads and the peak particle size of accumulation mode and nucleation mode all increases with the increase of load. The particulate emission of different fuels from high to low is the order of PD > DDCL > BD58 > DICL. In addition, the emissions of polycyclic aromatic hydrocarbons (PAHs) and toxicity equivalent (TE) of PD are highest at all loads. The proportion of soluble organic fractions (SOF) from DDCL, DICL, and BD58 is higher than that of PD.

Carcinogenic Content of PM10-Bound PAHs in University Classrooms and Outdoors at an Urban Location in Rome, Italy, during Winter Working and Not-Working Days

To assess the contribution of carcinogenic Polycyclic Aromatic Hydrocarbons (PAHs) in ambient air, EU Directive 2004/107/EC indicates to monitor relevant carcinogenic PAHs in PM10 fraction other than benzo(a)pyrene at a limited number of measurement sites. This indication refers to outdoor environments, and the environmental air quality being taken as a reference also for indoors, it can be extended to indoor environments. In this work, the contribution of carcinogenic PAHs bound to PM10 has been evaluated in winter in two classrooms of a University campus in Rome with the aim of studying the relationship with the outdoors and with working activity. PM10-boundPAHs were monitored over five different periods selected to distinguish Weekend from daytime and nighttime Weekdays, separated into two parts of the week. Data aggregated over Weekend and Weekdays allowed calculating of the concentration of carcinogenic PAHs, the mass contribution to PM10, the Infiltration Factor, the indoor to outdoor Ratio, and the Total Carcinogenic Potency by Toxicity Equivalent Factors, for “not-working” and “working” days. In addition, some indications on contributions to the source have been obtained from the chemical profile normalized to the maximum value of concentration, which also provides the source fingerprint compound. Indoor PAH concentrations were lower than outdoor, and both accumulated as the week progressed. Although the two indoor environments were on the same floor and had a similar volume, they presented different contribution to PM10 and infiltration capacity, both higher during Weekend than on Weekdays. The analysis of indoor and outdoor chemical profiles normalized to the maximum concentration indicated an external source infiltrating the indoors environment. During Weekdays, the indoor fingerprint compound changed compared to that observed during Weekend, probably due to an additional contribution of local “fresh-traffic” source. The calculation of Total Carcinogenic Potency gave indoor values always lower than outdoor, confirming in the two classrooms different dynamics for carcinogenic PAHs. Moreover, the Total Carcinogenic Potency on Weekdays was twice that of Weekend, meaning a higher toxicological impact when urban “fresh-traffic” source is added. The present study shows that the dynamics of PM10-related carcinogenic PAHs can be different within adjacent classrooms of a building and during working and not-working days. This evidence suggests the possibility of a potential different impact on occupant exposure to be taken into account in planning monitoring programs of indoor pollution.

Genotoxicity and carcinogenicity of traditionally roasted meat using indicator polycyclic aromatic hydrocarbons (PAHs), Port Harcourt, Nigeria

This research is targeted to employ indicator like PAHs, mainly PAH4 and PAH8 to evaluate the genotoxicity and carcinogenicity of PAHs in traditionally roasted meat (Suya) in selected locations at Port Harcourt metropolis, Nigeria, since its estimation using toxicity equivalent factor (TEF) model is not convenient. Suya sample were obtained at designated locations in the metropolitan city and were analyzed for PAHs present in them by using GC-FID and Chemstation after the PAHs were extracted using USEPA 8270 method. The series of results clearly indicated that indicator PAHs, i.e., PAH4 gave the best outlook on genotoxicity and carcinogenicity potential of the Suya over PAH8, PAH2 and Bap indicator PAHs and also visibly showed peak loadings of 0.15131 μg/Kg, which indicates that the sample Suya meat is not genotoxic or carcinogenic especially when correlated with current maximum regulatory value of 12 μg/Kg for PAH4. Regular consumption of Suya is however risky and may expose consumers to cancer.

Genotoxicity and carcinogenicity of traditionally roasted meat using indicator polycyclic aromatic hydrocarbons (PAHs), Port Harcourt, Nigeria

This research is targeted to employ indicator like PAHs, mainly PAH4 and PAH8 to evaluate the genotoxicity and carcinogenicity of PAHs in traditionally roasted meat (Suya) in selected locations at Port Harcourt metropolis, Nigeria, since its estimation using toxicity equivalent factor (TEF) model is not convenient. Suya sample were obtained at designated locations in the metropolitan city and were analyzed for PAHs present in them by using GC-FID and Chemstation after the PAHs were extracted using USEPA 8270 method. The series of results clearly indicated that indicator PAHs, i.e., PAH4 gave the best outlook on genotoxicity and carcinogenicity potential of the Suya over PAH8, PAH2 and Bap indicator PAHs and also visibly showed peak loadings of 0.15131 μg/Kg, which indicates that the sample Suya meat is not genotoxic or carcinogenic especially when correlated with current maximum regulatory value of 12 μg/Kg for PAH4. Regular consumption of Suya is however risky and may expose consumers to cancer.

Characterization of PM10-Bound Polycyclic Aromatic Hydrocarbons and Associated Carcinogenic Risk in Bangkok, Thailand

Concentrations of ambient particulate-bound polycyclic aromatic hydrocarbons (pPAHs) were measured in PM10 samples collected at roadside, industrial and urban background sites in Bangkok between May 2013 and May 2014. The annual average PM10 concentrations were not significantly different between the roadside (56.4 ± 27.3 µg m−3) and industrial (51.0 ± 31.1 µg m−3) sites. The lowest annual mean PM10 was observed at the urban background site (39.8 ± 22.2 µg m−3). Seasonal variations of pPAHs were observed at the three sampling sites. The total pPAHs ranged between 1.09 and 13.10 ng m−3 (mean 4.85 ± 2.51 ng m−3), 1.49 and 9.39 ng m−3 (mean 3.84 ± 2.01 ng m−3) and 0.77 and 5.20 ng m−3 (mean 2.28 ± 1.16 ng m−3) at the roadside, industrial and urban background sites, respectively. The observed annual average benzo[a]pyrene concentrations were 0.47 ± 0.39 ng m−3, 0.35 ± 0.27 ng m−3 and 0.24 ± 0.19 ng m−3 at the roadside, industrial and urban background sites. Long-term carcinogenic health risk of inhalation exposure expressed as the toxicity equivalent to benzo[a]pyrene concentrations were calculated as 0.83, 0.72 and 0.39 ng m−3 at the industrial, roadside and urban background sites, respectively. The composition of pPAHs plays an important role in the carcinogenicity of a PAHs mixture.

Distribution, Source Appropriation, and Human Health Risk Assessment of Polycyclic Aromatic Hydrocarbons due to Consumption of Callinectes amnicola from Woji Creek in Sambreiro River

Crabs (Callinectes amnicola) and surface water sampled from the Sambreiro River, Rivers State of Nigeria, were analyzed for polycyclic aromatic hydrocarbons concentrations for four months (December (2019), January, February, and March (2020)). Excess cancer risk due to ingestion of the crabs was assessed for individuals of the age groups: 3 to < 6 years, 16 to < 21 years, 21 to < 50 years, and ≥ 50 years. Although concentrations in surface water (ΣPAH16 = 0.125±011 mg/L) were lower than in the previous study, results obtained revealed considerably higher concentrations of aromatic hydrocarbons in crab tissues (ΣPAH16=10.659±2.399 mg/kg). Hepatopancreas (ΣPAH16=6.590±0.266 mg/kg) accumulated the highest concentration of hydrocarbons followed by the gills (ΣPAH16=2.349±0.029 mg/kg), then the muscles (ΣPAH16=1.720±0.320 mg/kg). Source appropriation results revealed a combination of the petrogenic and pyrogenic contribution of hydrocarbons in the crab tissues. The trend for the toxicity equivalent quotient was hepatopancreas > muscles > gills; while the excess cancer risk exceeded for all age groups, suggesting that humans are at risk of cancer arising from the ingestion of crab species from this study location.

Source Apportionment and Toxic Potency of Polycyclic Aromatic Hydrocarbons (PAHs) in the Air of Harbin, a Cold City in Northern China

A total of 68 PUF samples were collected seasonally from 17 sampling sites in Harbin, China from May 2016 to April 2017 for analyzing 15 congeners of gaseous polycyclic aromatic hydrocarbons (Σ15PAHs). An improved non-negative matrix (NMF) model and a positive matrix factorization (PMF) model were used to apportion the sources of PAHs. The carcinogenic risk due to exposure to PAHs was estimated by the toxicity equivalent of BaP (BaPeq). The results showed that the average concentration of Σ15PAHs was 68.3 ± 22.3 ng/m3, and the proportions of 3-ring, 4-ring, 5-ring, and 6-ring PAHs were 64.4%, 32.6%, 2.10%, and 0.89%, respectively. Among the six typical functional areas in Harbin, the Σ15PAHs concentrations were 98.1 ± 76.7 ng/m3, 91.2 ± 76.2 ng/m3, 71.4 ± 75.6 ng/m3, 67.9 ± 65.6 ng/m3, 42.6 ± 34.7 ng/m3, and 38.5 ± 38.0 ng/m3 in the wastewater treatment plant, industrial zone, business district, residential area, school, and suburb, respectively. During the sampling period, the highest concentration of Σ15PAHs was in winter. The improved NMF model and PMF model apportioned the PAHs into three sources including coal combustion, biomass burning, and vehicle exhaust. The contributions of coal combustion, biomass burning, and vehicle exhausts were 34.6 ± 3.22%, 48.6 ± 4.03%, and 16.8 ± 5.06%, respectively. Biomass burning was the largest contributor of Σ15PAHs concentrations in winter and coal combustion contributed significantly to the concentrations in summer. The average ΣBaPeq concentration was 0.54 ± 0.23 ng/m3 during the sampling period, high concentrations occurred in the cold season and low levels presented in the warm period. Vehicle exhaust was the largest contributor to the ΣBaPeq concentration of PAHs in Harbin.

Study of the Water Quality Index and Polycyclic Aromatic Hydrocarbon for a River Receiving Treated Landfill Leachate

Rising solid waste production has caused high levels of environmental pollution. Population growth, economic patterns, and lifestyle patterns are major factors that have led to the alarming rate of solid waste production. Generally, solid wastes such as paper, wood, and plastic are disposed into landfills due to its low operation and maintenance costs. However, leachate discharged from landfills could be a problem in surfaces and groundwater if not adequately treated. This study investigated the patterns of the water quality index (WQI) and polycyclic aromatic hydrocarbons (PAH) along Johan River in Perak, Malaysia, which received treated leachate from a nearby landfill. An artificial neural network (ANN) was also applied to predict WQI and PAH concentration of the river. Seven sampling stations were chosen along the river. The stations represented the upstream of leachate discharge, point of leachate discharge, and five locations downstream of the landfill. Sampling was conducted for one year starting July 2018. Physicochemical parameters, namely pH, biological oxygen demand, chemical oxygen demand, ammoniacal nitrogen, total suspended solids, and dissolved oxygen, were used to compute the water quality index (WQI). PAH concentrations were determined by liquid–liquid extraction of water samples followed by an analysis using gas chromatography. Results showed that WQI of Johan River was under Class III where intensive treatment was required to make it suitable for drinking purposes. The highest recorded PAH concentrations were fluoranthene (333.4 ppb) in the dry season and benzo(a) pyrene (93.5 ppb) in the wet season. A correlation coefficient (Rp) for a model prediction based on WQI-ANN and TEC-ANN (toxicity equivalent concentration) in the wet and dry seasons was 0.9915, 0.9431, 0.9999, and 0.9999, respectively. ANN results showed good model performance with Rp ≈ 0.9. This study suggested that ANN is a useful tool for water quality studies.

Environmental exposure to persistent organic pollutants measured in breast milk of lactating women from an urban area in central Poland

Mothers’ milk is considered a channel by means of which new-borns are exposed to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs), environmental pollutants entering food chain and accumulating in fat-rich tissues. In this study, the concentrations of selected PCDDs, PCDFs, and dl-PCBs (a total of 29 substances) in milk samples of 110 breast-feeding women from an urban area were analyzed using the high-resolution gas chromatography/high-resolution mass spectrometry method. Environmental exposure to these substances was expressed by means of the World Health Organization Toxicity Equivalent (WHO-TEQ2005) using the Toxicity Equivalent Factor values from van der Berg et al. (Toxicol. Sci. 93: 223-241, 2006). Concentrations and WHO-TEQ2005 values were then searched for plausible relationships with selected demographic and diet-related factors. The total WHO-TEQ2005 toxicity equivalent for all 29 substances was (mean ± SD) 10.57 ± 4.57 pg/g fat, while the WHO-TEQ2005 levels of PCDDs/PCDFs and dl-PCBs were 7.90 ± 4.17 pg/g fat and 2.67 ± 1.36 pg/g fat, respectively. The concentration and WHO-TEQ2005 toxicity equivalent of dl-PCBs correlated significantly with the mothers’ age (rP = 0.3814, p < 0.00005; rP = 0.2817, p < 0.005, respectively). The total WHO-TEQ2005 toxicity equivalent for all analyzed substances was found to be positively associated with the frequency of consumption of fish and dairy products (p < 0.05 for both associations). These outcomes must, however, be interpreted cautiously due to limited size of the study. The results of this paper may provide a basis for further studies on the exposure to PCDDs, PCDFs, and dl-PCBs, and mechanisms underlying their action.

Characterization of PM2.5–bound Polycyclic Aromatic Hydrocarbons in Chiang Mai, Thailand during Biomass Open Burning Period of 2016

Polycyclic aromatic hydrocarbons (PAHs) bounded to ambient fine particles (PM2.5) were determined for enabling health risk assessment and source identification of ambient aerosols. Daily PM2.5 samples (24 h) were collected on quartz fiber filters by using a low volume air sampler (16.7 L min-1) during smoke haze period (March–April 2016) in Chiang Mai, Thailand. An average concentration of PM2.5 (n=54) was 65.3±17.6 μg m-3. The samples were extracted with dichloromethane using ultrasonication prior to PAHs analysis by GC-MS. Average concentrations of 16-PAHs, non-carcinogenic (nc) PAHs and carcinogenic (c) PAHs were 10.23±2.49, 5.48±1.70 and 4.75±1.43 ng m-3, respectively. Ratio values of cPAHs/ncPAHs ranged from 0.44 to 1.98. Strong correlation (r= 0.76) between PM2.5 and cPAHs concentration was observed. Toxicity equivalent concentrations (TEQ) of PAHs was 1.13±0.34 ng m-3. The value of inhalation cancer risk (ICR) for exposure of ambient PAHs calculated from TEQ value was 1.0×10-4 indicating high risk for long term exposure. Diagnostic ratios (DRs) of various pairs of PAHs revealed that biomass burning is a major source during smoke haze period.