Environmental pollution has posed a major threat to terrestrial, aquatic, and marine ecosystems, thereby affecting microflora and micro-fauna populations. This study assessed the growth attributes of maize plants on crude oil-polluted soils amended with agro-wastes. Six kilograms each of composite soil sample was weighed and transferred into one hundred and fifty labeled plastic buckets with drainage holes for soil aeration and spiked with 300mls each of crude oil, allowing for 14 days of soil acclimatization. Soil amendments such as groundnut husks, cassava peels, empty fruit bunch of oil palm, and maize cob powder were applied and allowed for 90 days. Maize seeds were sowed, while periodic data were collected and subjected to a three-way ANOVA. The result obtained revealed that maize seeds grown on agro-wastes treated and pristine control soils show early seed germination than the crude oil-polluted control soil. The plant height obtained for GnH14P + MaC14P at 10% was the highest with a mean (of 152.81cm2), and the leaf area of the maize from soil treated with GnH14P + EFBOP14P at 10% had the highest mean (756cm2), the leaf length of maize from soil treated with GnH14P + CasP14P at 3%, 6%, and 10% was the highest with mean ranging (54-97 cm2) with no significant difference in mean values obtained. The stem girth, number of leaves, and leaf width were generally improved in the bio-remediated soils. The result for the yield performance of maize shows that the days to flowering were shortened in the bio-remediated soil compared to the prolonged flowering days observed in the crude-oil polluted control. The number of seeds per cob was high in the bio-remediated soils while no seed was obtained in the crude-oil-polluted control soils. It can be concluded that the ameliorated treatment with the agro-wastes improves the performance of maize plants in crude oil-polluted soils.

Polycyclic Aromatic Hydrocarbon profile of Kpite oil spill impacted site in Rivers state, Nigeria was evaluated to determine the level of contamination of the soil. Four composite oil impacted soil samples were collected at different depths; surface (0-15cm) and subsurface (15-30cm) after a field reconnaissance. Extraction of the oil was carried out on the soil samples and the Polycyclic Aromatic Hydrocarbons were quantified using the Gas Chromatography- flame ionization detector. Results showed that Naphthalene was the most abundant in the range of 0.25 to 1.49 mg kg-1. Fluoranthene followed closely with concentrations in the range of 0.01 to 1.28 mg kg-1. PAHs like Benzo (k) fluoranthene, Benzo (e) pyrene, Dibenzo (a, h)anthracene, Indeno (1, 2, 3-cd) pyrene and Benzo (g, h, i) showed low concentrations of less than 0.01 indicating that strong weathering had occurred. The diagnostic ratios such as Phenanthrene/Anthracene (Phen/Anth), Benzo (a) anthracene Chrysene ((BaA)/Chry) and Fluoranthene/Pyrene (Flth/Py) and sum of chrysene/Phenanthrene ΣChry/ΣPhen were calculated and used to unravel the source of hydrocarbons. Results showed ratios of Flth/Py >1.0 and Phen/Anth ranges from 1.19 to 2.03 (< 10) which denote contamination sources, implying that the hydrocarbon sources are not just petrogenic but rather may due to contamination sources of combustion processes or the area was exposed to bush burning.

The primary goal of this study was to isolate hydrocarbon-degrading organisms and assess their ability to bioremediate petroleum-contaminated soil and water. Nigeria is one of the major oil producing countries and petroleum contamination is widespread in agricultural soil. Alcaligenes sp. strain 3k was isolated from a kerosene-polluted soil in Ilorin, Nigeria. We also assessed its ability to degrade plant lignin, as lignin is a complex aromatic heteropolymer commonly found in soil and aquifer environment.  Strain 3k was originally grown on mineral salts medium with kerosene as a sole energy and carbon source. The capacity of the isolate to degrade both aromatic, aliphatic hydrocarbons and lignin-like compounds was tested. Among the tested compounds, the organism utilized kerosene, hexadecane, cyclohexane, phenol and benzoate as the sole sources of carbon. In addition, strain 3k also degraded various lignocellulose compounds as the sole source of carbon.  However, hexane, benzene, toluene, ethylbenzene and xylene were not metabolized. Our study demonstrates that soil organisms like Alcaligenes could play important role in the reclamation of petroleum-contaminated soil and water.  Utilization capacity of lignin as the sole carbon source suggest that these organisms can survive on plant detritus and also have the ability to degrade hydrocarbons upon accidental or deliberate contamination of agricultural soil and water.

Phytoremediation is an emerging green technology that uses plants and their associated microbes to remediate different environments contaminated with various pollutants. Phytoremediation, as an effective soil remediation technology, has gained popularity in the past ten years both in developed and developing countries. The main goal of the current article is to improve the understanding of phytoremediation of organic pollutants with emphasis on hydrocarbons. To design phytoremediation systems and also enhancement of their efficiency, either in laboratory or in field experiments, there is a serious need for better knowledge of phytoremediation mechanisms and also of factors affecting phytoremediation. In addition to phytoremediation applications, advantages, and limitations, its mechanisms and related new developments have been discussed in this article.

peer reviewed | Polycyclic aromatic hydrocarbons (PAHs) are pollutants that occur in mangrove sediments. Their removal by bacteria often depends on specific characteristics as the number of benzene rings they possess and their solubility. Their removal also depends on environmental factors, such as pH, temperature, oxygen, and the ability of the endogenous or exogenous microflora to metabolize hydrocarbons.With the aim of treating mangrove sediments polluted by hydrocarbons in a biological way, a biodegradation experiment was conducted using mangrove sediments artificially contaminated with a mixture of four PAHs. The study used Rhodococcus erythropolis as an exogenous bacterial strain in order to assess the biodegradation of the PAH mixture by natural attenuation, biostimulation, bioaugmentation, and a combination of biostimulation and bioaugmentation. The results showed that the last three treatments were more efficient than natural attenuation. The biostimulation/bioaugmentation combination proved to be the most effective PAH degradation treatment.

This study analyzed the profiles of polycyclic aromatic hydrocarbons (PAHs) in filterable PM2.5 particles collected from a total of 71 boilers and 22 indirect type furnaces that burn liquid and biomass fuels in the Metropolitan Area of Costa Rica, from February 2014 to November 2015. Modified method NIOSH 5506 was used to analyze PAHs content present in the filter samples. The average concentration of PM2.5 showed values between 18 and 735 mg m−3, based on the source and fuel type used, while the total PAHs in the PM2.5 fraction ranged 1.02–592 μgm−3. For biomass boilers, the most abundant species were Benzo[g,h,i]perylene (BghiP) (35.7–46.5%), Indeno[1,2,3-cd]pyrene (IND) (20.6–27.1%), Benzo[a]pyrene (BaP) (5.2–14.7%) and Dibenzo[a,h]anthracene (DBA) (3.2–13.9%), while for liquid fuels IND (12.8–20.5%), BghiP (7.9–21.2%), Fluoranthene (Flu) (14.5–21.3%) and Pyrene (Pyr) (9.8–14.5%) prevailed. The particles from biomass furnace emissions present higher concentrations of PAHs classified by the U.S. EPA as probable human carcinogens causing a greater health risk than other fuels. Among the diagnostic concentration ratios examined, only BaP/(BaP+Chr), BaA/Chr, BaA/BaP and Pyr/BaP coefficients demonstrated codependency on the type of fuel used. | Este estudio analizó los perfiles de hidrocarburos aromáticos policíclicos (HAP) en partículas filtrables PM2.5 recolectadas de un total de 71 calderas y 22 hornos de tipo indirecto que queman combustibles líquidos y de biomasa en el Área Metropolitana de Costa Rica, de febrero de 2014 a noviembre de 2015 Se utilizó el método modificado NIOSH 5506 para analizar el contenido de PAH presentes en las muestras de filtro. La concentración promedio de PM2.5 mostró valores entre 18 y 735 mg m − 3, según la fuente y el tipo de combustible utilizado, mientras que los PAH totales en la fracción de PM2.5 variaron entre 1.02 y 592 μgm − 3. Para las calderas de biomasa, las especies más abundantes fueron Benzo [g, h, i] perileno (BghiP) (35,7–46,5%), Indeno [1,2,3-cd] pireno (IND) (20,6–27,1%), Benzo [a] pireno (BaP) (5,2–14,7%) y Dibenzo [a, h] antraceno (DBA) (3,2–13,9%), mientras que para los combustibles líquidos IND (12,8–20,5%), BghiP (7,9–21,2%) , Predominaron el fluoranteno (gripe) (14,5–21,3%) y el pireno (Pyr) (9,8–14,5%). Las partículas de las emisiones de los hornos de biomasa presentan concentraciones más altas de HAP clasificados por la EPA de los EE. UU. Como probables carcinógenos humanos y causan un mayor riesgo para la salud que otros combustibles. Entre las relaciones de concentración de diagnóstico examinadas, solo los coeficientes BaP / (BaP + Chr), BaA / Chr, BaA / BaP y Pyr / BaP demostraron codependencia en el tipo de combustible utilizado. | Este estudo analisou os perfis de hidrocarbonetos policíclicos aromáticos (PAHs) em partículas filtráveis ​​de PM2,5 coletadas de um total de 71 caldeiras e 22 fornos do tipo indireto que queimam combustíveis líquidos e de biomassa na Área Metropolitana da Costa Rica, de fevereiro de 2014 a novembro de 2015 O método modificado NIOSH 5506 foi usado para analisar o conteúdo de PAHs presentes nas amostras de filtro. A concentração média de PM2,5 apresentou valores entre 18 e 735 mg m − 3, com base na fonte e no tipo de combustível usado, enquanto o total de PAHs na fração PM2,5 variou de 1,02–592 μgm − 3. Para caldeiras de biomassa, as espécies mais abundantes foram Benzo [g, h, i] perileno (BghiP) (35,7-46,5%), Indeno [1,2,3-cd] pireno (IND) (20,6-27,1%), Benzo [a] pireno (BaP) (5,2–14,7%) e Dibenzo [a, h] antraceno (DBA) (3,2–13,9%), enquanto que para combustíveis líquidos IND (12,8–20,5%), BghiP (7,9–21,2%) , Fluoranteno (Flu) (14,5–21,3%) e Pireno (Pyr) (9,8–14,5%) prevaleceram. As partículas das emissões do forno de biomassa apresentam maiores concentrações de PAHs classificados pela U.S. EPA como prováveis ​​carcinógenos humanos, causando um maior risco à saúde do que outros combustíveis. Dentre as razões de concentração diagnósticas examinadas, apenas os coeficientes BaP / (BaP + Chr), BaA / Chr, BaA / BaP e Pyr / BaP demonstraram co-dependência do tipo de combustível utilizado. | Universidad Nacional, Costa Rica | Universidad Autónoma Metropolitana, México | Escuela de Ciencias Ambientales

Inputs of polycyclic aromatic hydrocarbons (PAHs) of regulatory interest from diffuse atmospheric sources within urban areas frequently elevate local soil concentrations to levels requiring remediation despite the lack of in-situ contamination. This research sought to determine the distribution and potential health effects of aerially deposited PAHs in soil within the urban core of metropolitan Milwaukee, Wisconsin, U.S.A. as part of a soil regulatory standards reevaluation. Park areas (n = 27) identified as undisturbed for 80+ years, containing no fill material, and receiving only atmospheric deposition were selected for composite surface and 92 cm core soil sample collection (n = 295). Samples were analyzed for the 16 USEPA priority PAHs, 1- and 2- methylnapthalene and ancillary soil properties. Soil core and ancillary data confirm lack of site disturbance. PAH diagnostic ratios and homologue summations indicate that diffuse multiple point source emissions contribute equally to PAH deposition throughout the area. Benzo(a)pyrene (BaP) and dibenz(a,h)anthracene mean concentrations exceed health-based clean up levels. Risk assessment shows only a worst-case exposure scenario (BaP at the 95% upper confidence limit) increasing cancer risk (1.67 × 10⁻⁶) over current regulatory thresholds (1.0 × 10⁻⁶). Health quotients show potential health risks from fluoranthene and pyrene for daily park users and from BaP for all others. Mean soil PAH values are similar to New Orleans, but lower than Chicago, Boston, and London reflecting industrial history and site selection protocols. The soil PAH results presented here for sites selected for non-manipulated soils combined with an almost 100-year uninterrupted atmospheric exposure effectively show the maximum potential PAH values that can be found at any given undisturbed location within the Milwaukee urban core due solely to atmospheric deposition.