The exposure of benzo [a]pyrene (BaP) in recent times is rather unavoidable than ever before. BaP emissions are sourced majorly from anthropogenic rather than natural provenance from wildfires and volcanic eruptions. A major under-looked source is via the consumption of foods that are deep-fried, grilled, and charcoal smoked foods (meats in particular). BaP being a component of poly aromatic hydrocarbons has been classified as a Group I carcinogenic agent, which has been shown to cause both systemic and localized effects in animal models as well as in humans; has been known to cause various forms of cancer, accelerate neurological disorders, invoke DNA and cellular damage due to the generation of reactive oxygen species and involve in multi-generational phenotypic and genotypic defects. BaP's short and accumulated exposure has been shown in disrupting the fertility of gamete cells. In this review, we have discussed an in-depth and capacious run-through of the various origins of BaP, its economic distribution and its impact as well as toxicological effects on the environment and human health. It also deals with a mechanism as a single compound and its ability to synergize with other chemicals/materials, novel sensitive detection methods, and remediation approaches held in the environment.

Microbial-mediated Sb volatilization is a poorly understood part of the Sb biogeochemical cycle. This is mostly due to a lack of laboratory and field-deployable methods that are capable of quantifying low-level emissions of Sb from diffuse sources. In this study, we validated two methods using a H₂O₂ -HNO₃ liquid chemotrap and an activated coconut shell charcoal solid-phase trap, achieving an absolute limit of detection of 4.6 ng and below 2.0 ng Sb, respectively. The activated charcoal solid-phase trapping method, the most easily operated method, was then applied to contaminated shooting range soils. Four treatments were tested: 1) flooded, 2) manure amended + flooded, 3) 70 % water holding capacity, and 4) manure amendment +70 % water holding capacity, since agricultural practices and flooding events may contribute to Sb volatilization. Volatile Sb was only produced from flooded microcosms and manure amendment greatly influenced the onset and amount of volatile Sb produced. The highest amount of volatile Sb produced, up to 62.1 ng kg⁻¹ d⁻¹, was from the flooded manure amended soil. This suggests that anaerobic microorganisms may potentially be drivers of Sb volatilization. Our results show that polluted shooting range soils are a source of volatile Sb under flooded conditions, which may lead to an increase in the mobility of Sb. Some of these volatile Sb species are toxic and genotoxic, highlighting the role of Sb volatilization on environmental health, especially for individuals living in contaminated areas exposed to wetlands or flooded conditions (e.g., rice paddy agriculture surrounding mining areas). This work paves way for research on Sb volatilization in the environment.

In this study, functional microbial sequencing, quantitative PCR, and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) were employed to understand the microbial mechanisms related to the effects of bamboo charcoal (BC) and bamboo vinegar (BV) on the degradation of organic matter (OM) and methane (CH₄) emissions during composting. BC + BV resulted in the highest degradation of OM. BV was most effective treatment in controlling CH₄ emissions and it significantly reduced the abundance of the mcrA gene. Methanobrevibacter, Methanosarcina, and Methanocorpusculum were closely related to CH₄ emissions during the thermophilic composting period. PICRUSt analysis showed that BC and/or BV enhanced the metabolism associated with OM degradation and reduced CH₄ metabolism. Structural equation modeling indicated that BC + BV strongly promoted the metabolic activity of microorganisms, which had a positive effect on CH₄ emissions. Together these results suggest that BC + BV may be a suitable composting strategy if the aerobic conditions can be effectively improved during the thermophilic composting period.

Marine oil spill often causes contamination of drinking water sources in coastal areas. As the use of oil dispersants has become one of the main practices in remediation of oil spill, the effect of oil dispersants on the treatment effectiveness remains unexplored. Specifically, little is known on the removal of dispersed oil from contaminated water using conventional adsorbents. This study investigated sorption behavior of three prototype activated charcoals (ACs) of different particle sizes (4–12, 12–20 and 100 mesh) for removal of dispersed oil hydrocarbons, and effects of two model oil dispersants (Corexit EC9500A and Corexit EC9527A). The oil content was measured as n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and total petroleum hydrocarbons (TPHs). Characterization results showed that the smallest AC (PAC100) offered the highest BET surface area of 889 m2/g and pore volume of 0.95 cm3/g (pHPZC = 6.1). Sorption kinetic data revealed that all three ACs can efficiently adsorb Corexit EC9500A and oil dispersed by the two dispersants (DWAO-I and DWAO-II), and the adsorption capacity followed the trend: PAC100 > GAC12 × 20 > GAC4 × 12. Sorption isotherms confirmed PAC100 showed the highest adsorption capacity for dispersed oil in DWAO-I with a Freundlich KF value of 10.90 mg/g∙(L/mg)1/n (n = 1.38). Furthermore, the presence of Corexit EC9500A showed two contrasting effects on the oil sorption, i.e., adsolubilization and solubilization depending on the dispersant concentration. Increasing solution pH from 6.0 to 9.0 and salinity from 2 to 8 wt% showed only modest effect on the sorption. The results are useful for effective treatment of dispersed oil in contaminated water and for understanding roles of oil dispersants.

Food carts are common along streets in cities throughout the world. In North America, food cart vendors generally use propane, charcoal, or both propane and charcoal (P and C) for food preparation. Although cooking emissions are known to be a major source of indoor air pollution, there is limited knowledge on outdoor cooking’s impact on the ambient environment and, in particular, the relative contribution of the different cooking fuels. This field study investigated the air pollution the public is exposed to in the micro-environment around 19 food carts classified into 3 groups: propane, charcoal, and P and C carts. Concentrations near the food carts were measured using both real-time and filter-based methods. Mean real-time concentrations of PM₂.₅, BC₂.₅, and particle counts were highest near the charcoal food carts: 196 μg/m³, 5.49 μg/m³, and 69,000 particles/cm³, respectively, with peak exposures of 1520 μg/m³, 67.9 μg/m³, and 235,000 particles/cm³, respectively. In order of pollution emission impacts: charcoal > P and C > propane carts. Thus, significant differences in air pollution emissions occurred in the vicinity of mobile food carts, depending on the fuel used in food preparation. Local air pollution polices should consider these emission factors in regulating food cart vendor operations.

Previous studies of solid fuel emissions in household stoves focused more on emission measurements of the overall combustion process instead of the dynamic burning rate and its connection to the emissions. This study put forward a measurement system to monitor the dynamic fuel burning rate and emission rate directly, and explored their relationships during different combustion phases. Experiments were conducted using two types of wood charcoal consumed in a small open pan (i.e. fire basin) used commonly for space heating in rural China. The measured real-time CO emission rate (ERCO), fuel burning rate (BRF), and calculated carbon burning rate (BRC) all rose and then subsided as the combustion progressed. The relationships between ERCO and BRF and between ERCO and BRC were different for the two charcoals during a phase with rising carbon content in the combusted fuel (Phase I), likely because moisture evaporation and volatile matter release were the dominant processes and the reaction was complex during this phase. ERCO and BRF or BRC had linear relationships during a phase with stable carbon content in the combusted fuel (Phase II) for the two charcoals, which may be generalized to other solid fuels, because this phase is associated to fixed carbon dominating phase which usually exist during solid fuel combustion. The study presented a novel measurement approach to the combustion properties of solid fuels. The results implied that a complex relationship between the combustion and pollutant emissions existed in Phase I, and presented the possibility of estimating the fuel burning rate based on emission measurements in Phase II, or vice versa.

The application of compost in agriculture has led to the accumulation of antibiotic resistance genes (ARGs) and heavy metal resistance genes (MRGs) in the soil environment. In this study, the response of ARGs and MRGs to bamboo charcoal (BC) and bamboo vinegar (BV) during aerobic composting was investigated. Results showed that BC + BV treatment reduced the abundances of ARGs and mobile genetic elements (MGEs) during the thermophilic period, as well as achieved the lowest rebound during the cooling period. BC + BV promoted the growth of Firmicutes, thereby facilitating the thermophilic period of composting. The rebound of ARGs and MGEs can be explained by increasing the abundance of Actinobacteria and Proteobacteria at the end of composting. Composting reduced the abundances of MRGs comprising pcoA, tcrB, and cueO, whereas cusA and copA indicated the selective pressure imposed by heavy metals on bacteria. The fate of ARGs was mainly driven by MGEs, and heavy metals explained most of the variation in MRGs. Interestingly, nitrogen conversion also had an important effect on ARG and MRG profiles. Our current findings suggest that the addition of BC + BV during compost preparation is an effective method in controlling the mobility of ARGs and MRGs, thereby reducing the environmental problems.

Polybrominated diphenyl ethers (PBDEs) are widely found in sediments, especially congeners from the penta-BDE formula. Due to their strong affinity for black carbon (BC), bioavailability of PBDEs may be decreased in BC-amended sediments. In this study, we used a matrix-SPME method to measure the freely dissolved concentration (Cfree) of PBDEs as a parameter of their potential bioavailability and evaluated the differences among biochar, charcoal, and activated carbon. Activated carbon displayed a substantially greater sequestration capacity than biochar or charcoal. At 1% amendment rate in sediment with low organic carbon (OC) content (0.12%), Cfree of six PBDEs was reduced by 47.5–78.0%, 47.3–77.5%, and 94.1–98.3% with biochar, charcoal, and activated carbon, respectively, while the sequestration was more limited in sediment with high OC content (0.87%). Therefore, it is important to consider the type and properties of the BC and the sediment in BC-based remediation or mitigation.

The influence of biochar (5%) on the loss, partitioning and bioaccessibility of 14C-isoproturon (14C-IPU) was evaluated. Results indicated that biochar had a dramatic effect upon 14C-IPU partitioning: 14C-IPU extractability (0.01 M CaCl2) in biochar-amended treatments was reduced to <2% while, 14C-IPU extractability in biochar free treatments decreased with ageing from 90% to 40%. A partitioning model was constructed to derive an effective partition coefficient for biochar:water (KBW of 7.82 × 104 L kg−1). This was two orders of magnitude greater than the apparent Kfoc value of the soil organic carbon:water (631 L kg−1). 14C-radiorespirometry assays indicated high competence of microorganisms to mineralise 14C-IPU in the absence of biochar (40.3 ± 0.9%). Where biochar was present 14C-IPU mineralisation never exceeded 2%. These results indicate reduced herbicide bioaccessibility. Increasing IPU application to ×10 its recommended dose was ineffective at redressing IPU sequestration and its low bioaccessibility.

Biochar plays an important role in the behaviors of organic pollutants in the soil environment. The role of humic acid (HA) and metal cations on the adsorption affinity of polychlorinated biphenyls (PCBs) to the biochars in an aqueous medium and an extracted solution from a PCBs-contaminated soil was studied using batch experiments. Biochars were produced with pine needles and wheat straw at 350 °C and 550 °C under anaerobic condition. The results showed that the biochars had high adsorption affinity for PCBs. Pine needle chars adsorbed less nonplanar PCBs than planar ones due to dispersive interactions and separation. Coexistence of HA and metal cations increased PCBs sorption on the biochars accounted for HA adsorption and cation complexation. The results will aid in a better understanding of biochar sorption mechanism of contaminants in the environment.