Natural Attenuation of Contaminated Soil: A Case Study of the Former Kremikovtsi Plant, Bulgaria

The bioaccumulation and biomagnification of PAHs along successive trophic levels is an important means of exposure to human and animal life. This study evaluated Polycyclic Aromatic Hydrocarbons (PAHs) and heavy metals in fresh fish and fish samples processed/ roasted with smoke/heat/flame generated from firewood, waste tyre and polyethylene materials. PAHs and heavy metals were determined with Gas chromatography with flame ionization detector (GC-FID) and Atomic Absorption Spectrophotometer (AAS) respectively. Significant differences (P<0.05) were observed in the concentrations of PAHs and heavy metals in the heat-processed fish when compared to fresh fish. Appreciable amount of carcinogenic PAHs; benzo(a)pyrene, benz(a)anthracene and dibenz(a,h)anthracene benz(a)anthracene and dibenz(a,h)anthracene and heavy metals such as cadmium (Cd), zinc (Zn) and lead (Pb) were detected in processed/roasted fish samples.

To date, few studies on the potential utilization of agricultural residue torrefaction products have been performed. Thus, torrefaction product characterization aimed at its potential utilization was performed. Wheat–barley straw pellets and wheat–rye chaff were used in the study. The impact of the torrefaction temperature (280–320 °C) on polycyclic aromatic hydrocarbons (PAHs) content in the biochar and noncondensable gas (noncondensables) composition was investigated. The impact of the torrefaction time (30–75 min) on the composition of the condensable volatiles (condensables) and their toxicity were also studied. The torrefaction process was performed in a batch-scale reactor. The PAH contents were measured using high-performance liquid chromatography (HPLC), and the noncondensables composition was measured online using a gas analyzer and then gas chromatograph with flame ionization detector (GC-FID). The condensables composition and main compound quantification were determined and quantified using gas chromatography–mass spectrometry (GC/MS). Three toxicity tests, for saltwater bacteria (Microtox® bioassay), freshwater crustaceans (Daphtoxkit F magna®), and vascular plants (Lemna sp. growth inhibition test), were performed for the condensables. The PAHs content in the biochar, regardless of the torrefaction temperature, allows them to be used in agriculture. The produced torgas shall be co-combusted with full-caloric fuel because of its low calorific value. Toxic compounds (furans and phenols) were identified in the condensable samples, and regardless of the processing time, the condensables were classified as highly toxic. Therefore, they can be used either as pesticides or as an anaerobic digestion substrate after their detoxification.

This study was carried out to evaluate PAHs concentration in crabs (Callinectes pali)and shrimps (Penaeus notialis) collected from Kaa, B-Dere and Bodo City in Ogoniland, Rivers State, Nigeria. These samples were measured by gas chromatography with flame ionization detector (GC/FID). The Average concentrations of these PAHs ranged from below detection limit of 0.0001 to 90.7 ± 1.00 µg/kg wet wt. in Callinectes paliand from 0.0001 to 77.5 ± 1.65 µg/kg wet wt. in Penaeus notialis. The highest average concentration of90.7 ± 1.00 µg/kg wet wt. was recorded for Benzo(b)fluoranthene from Bodo City. Between the two species, Callinectes pali accumulated significantly higher concentrations (P < 0.05) of total PAHs at all the sites except at Kaa. High molecular weight PAHs (HMW-PAHs) were generally predominant compared to low molecular weight PAHs (LMW-PAHs). The LMW- PAH/HMW-PAH ratios were < 1 for both species, indicating anthropogenic, mainly pyrogenic, origin of PAHs in Kaa, B-Dere and Bodo City of OgoniLand. Concentration of benzo(a)pyrene in Callinectes pali collected from B-Dere and Bodo City analyzed exceeded the EU recommended limit of 2 µg/kg wet wt., while that in Penaeus notialis collected from the three sites were below EU recommended limit of 2 µg/kg wet wt. in food. Thus, PAHs residues in the examined Callinectes pali were high and would constitute threat to human health than those in Penaeus notialis. The public health concerns of PAHs are cancer, mutations and birth defects as discussed.

The occurrence of polycyclic aromatic hydrocarbons (PAH) in organic mate tea (Ilex paraguariensis) was investigated to evaluate whether the roasting and drying processes under milder temperatures would promote lower PAH levels in the product. Gas Chromatography with Flame Ionization Detector (GC-FID) was used to quantify PAH contents. Different concentrations of PAH were found in all samples of mate tea analyzed, such as acenaphthylene varied between 1.209 and 1.524 µg·g−1; acenaphthene varied between 2.504 and 4.375 µg·g−1; fluorene varied between 1.488 and 1.843 µg·g−1; chrysene ranged between 0.093 and 0.263 µg·g−1; benzo[a]pyrene varied between 0.988 and 3,398 µg·g−1; dibenzo(a,h) anthracene was identified in all the samples, but at concentrations below the limit of quantification. Naphthalene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, benzo[b]fluoranthene, and benzo[k]fluoranthene were identified in the sample used for the extraction of soluble solids that have been encapsulated. The PAH concentration in mate tea samples was above the recommended by European Union legislation for dried herbs and powders of food of plant origin for the preparation of beverages. New yerba mate processing strategies should be studied to minimize PAH contamination and promote healthier products, in addition to government policies for quality control and regulation specifying limit values for the PAHs.

This study investigated the presence of polycyclic aromatic hydrocarbons (PAHs) and heavy metals in commonly consumed roasted meats and smoked fish in Owerri, Imo State, Nigeria. The processed foods were grouped as; freshly processed6 to 12 hours heat/flame/smoke exposure and long processed7 days heat/flame/smoke exposure. Freshly processed (FP) and long processed (LP) beef, fatty beef, chicken, fish and pork samples were purchased from road-side food vendors, wrapped in clean labelled paper foil and taken to the laboratory for analysis. Gas chromatography with flame ionization detector (GC-FID) was used for the evaluation of PAH and atomic absorption spectrophotometer (AAS) was used to determine heavy metals. Our result showed that the total concentration of PAHs in LP food samples were higher when compared to FP samples. Benzo(a)pyrene and other PAHs which are probable human carcinogen, were present in varying concentrations in the samples. Toxic heavy metals such as lead and cadmium were present at varying concentrations in the samples, while mercury was not detected in any of the samples. This study have added to the numerous evidences that processing of food by Research Article British Journal of Applied Science & Technology, 4(1): 249-260, 2014 250 exposure to heat, flame and smoke encourages the generation of toxic compounds and the nature of the food chain and certain environmental activities can impact negatively on their nutritional content. This therefore places consumers at potential health risk.

Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Sediment Cores of Selected Creeks in Delta State, Nigeria

Source characterization and the environmental impact of urban street dusts from Egypt based on hydrocarbon distributions

Polycyclic aromatic hydrocarbons (PAHs) are persistent, carcinogenic contaminants.We tracked the 16 U.S. Environmental Protection Agency (EPA) priority PAHs in surface waters of the Tigris River at five stations spanning 100 m upstream to 1.5 km downstream of Baghdad Medical City's wastewater outfall during October 2024, January 2025, and April 2025.Samples underwent liquid-liquid extraction (LLE), copper desulfurization, and gas chromatography with flame-ionization detector (GC-FID) analysis.Total PAH concentrations (16 PAHs) peaked at the sewer outlet in all seasons (up to 31 g L) and declined at 1.5 km downstream to levels close to the pre-sewage discharge point.Site explained 93.75% of the spatiotemporal variance (p < 0.001).The share of high-molecular-weight PAHs rose from 48% at the outfall to 67% after 1.5 km.Total risk quotient (RQ) peaked at 2.5 10 in January, exceeding the safety threshold, while benzo[a]pyrene-equivalent toxicity (BaP-TEQ) peaked at 1.9 g BaP eq L.Winter benzo[a]pyrene (0.262 g L) exceeded Dutch and Canadian aquatic criteria by 17-26-fold.Diagnostic ratios trace the origin of PAHs to medical waste and biomass combustion

Groundwater contamination by polycyclic aromatic hydrocarbons (PAH) may pose a risk to human health, as these compounds are considered to be highly toxic, carcinogenic and/or mutagenic and bioaccumulative. The aim of this study was to evaluate and determine PAH levels in groundwater samples collected from tubular wells in a city of northern Brazil by gas chromatography with flame ionization detector (GC-FID) used by the population for consumption. Sample pre-treatment using solid-phase extraction cartridges was performed in order to promote an enrichment of the PAH fraction of interest and to remove interferences from the matrix to further determine PAH in samples by GC-FID. The results obtained showed that all groundwater samples studied presented PAH levels lower than maximum values allowed by MS 2914/2011 and CONAMA 396/2008. The developed procedure is characterized by low limits of detection and quantification, equal to 0.024–0.113 µg L−1 and 0.079–0.378 μg L−1, respectively, good linearity (r2 > 0.99). The recoveries obtained for 16 PAH by the addition and recovery method ranged from 85.4 to 105.7% with good precision (RSD < 5.0%). The results of this study showed that the method developed is fast, accurate and robust with high efficiency for identification and determination of 16 PAH in groundwater samples.

Moringa oleifera infusion is a popular drink among herbal infusion consumers. Although M. oleiferais claimed to have medicinal value and promoted health benefits, it does not be simply considered safe if no specific study is conducted to determine Polycyclic aromatic hydrocarbons (PAHs) content in commercial M. oleifera herbal drink. Therefore, this study was conducted to investigate 10 PAHs content in M. oleiferadried leaves and in its infusion. The second objective was to assess the effect of mass-volume ratio on PAHs content in M. oleifera infusion. PAHs extraction procedure was performed using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method. PAHs determination and quantification were performed using Gas Chromatography and Flame Ionization Detector (GC-FID). The mean of total 10 PAHs (∑10PAH) in M. oleifera dried leaves and infusion ranged from 1.06 µg/kg to 5.51 µg/kg and 0.62 µg/kg to 4.80 µg/kg, respectively. Four different mass-volume ratios were used in this study to determine PAHs content that could be extracted from M. oleifera dried leaves into an infusion; 2:250, 20:250, 10:100, and 10:50. The ratio of 2:250 showed the lowest PAHs content in comparison with other ratios. The PAHs content in M. oleifera dried leaves and infusion have statistically significantly different (p &gt; 0.01) from each other. The toxic equivalency quotient (TEQ) value of M. oleifera dried leaves and infusion ranged from 0.01 to 0.09 and 0.00 to 0.07, respectively. PAHs content in M. oleifera dried leaves and infusions complied with the maximum limit set by Commission Regulation (EU) No. 2015/1933.

Polycyclic aromatic hydrocarbons (PAHs) are mainly accumulated in soil. Plants secrete enzymes that transform or biodegrade PAHs in soil. Some plant species are more effective in stimulating the biodegradation of these pollutants than other species. This study was undertaken to evaluate the influence of crop rotation on PAH concentrations in soil. Four crops were grown in rotation: sugar beets, spring barley, maize, and spring wheat. Soil samples for the study were obtained from a long-term field experiment established in 1986 in Bałcyny, Poland. The concentrations of PAHs were analyzed in soil samples gathered over a period of 12 years (1998–2009). An attempt was made to evaluate the effect of crop rotation (sugar beets, spring barley, maize, and spring wheat) on PAH concentrations in soil. The content of PAHs in soil samples was measured by gas chromatography with flame ionization detection. Data were processed statistically by repeated measures ANOVA. The concentrations of ∑16 PAHs were lowest in soil after sugar beet cultivation, and highest in soil after maize cultivation. It can be concluded that maize was the plant with the greatest adverse effect on the content of heavy PAH in the soil, a completely different effect can be attributed to spring wheat, which has always been shown to reduce the content of heavy PAH in the soil. Weather conditions affected PAHs levels in soil, and PAH content was highest in soil samples collected in a year with the driest growing season. This arrangement suggests a greater influence of weather conditions than of the cultivated plant.

The conviction that herbal drugs have enormous health benefits has led to increase the rate of their consumption by Nigerians. The aim of this study was to assess the carcinogenic property of some popularly consumed anti-diarrheal herbal drugs via polycyclic aromatic hydrocarbons (PAHs) quantification. Three prevalent anti-diarrhea herbal drugs , Odunmo herbal drug (Hibiscus rosa-sinensis and Bacopamonnieri), Orogun herbal mixture (Hibiscus sabdariffaI and Hedera helix), and Alora herbal syrup (Aloe vera and Hibiscus sabdariffaI) were bought for the purpose of this study and they were coded as samples A, B, and C, respectively. The ultrasonic extraction of the herbal drugs was carried out using standard procedures. The crude extracts obtained were purified using a chromatographic method. The concentrations of PAHs were quantified using gas chromatography flame ionization detector (GCFID). The diagnostic indices, group distribution, toxicity equivalence and exposure dosage were estimated. The cancer risk values were theoretically speculated based on concentrations of PAHs in the tested herbal drugs, associated with the published estimates of each concentration to cause cancer and the calculated exposure doses of the anti-diarrhea herbal drug samples were within three age groups (children, Preteen and adult). The highest concentration of total PAHs was observed in sample A (58.2815mg/kg) and the lowest concentration in sample B (44.1898mg/kg), but the concentration of total PAHs in sample C was 47.4169 mg/kg. The highest percentage of carcinogenic PAHs in the anti-diarrheal herbal drugs was found in sample C (48.66%) and the lowest in sample B (38.17%). The diagnostic indices confirmed a pyrogenic source of PAHs. Group distribution of PAHs showed that the herbal drugs are weakly carcinogenic due to high concentrations of low and moderate molecular weight PAHs. The cancer risk estimated for all the age groups where below the limit established by the United State Environmental Protection Agency (USEPA) for cancer (1 x 10-6). This ascertained that the use of these herbal drugs cannot cause cancer. However, consumers of these herbal drugs should take necessary precautions as excessive intake can lead to dangerous health implications.

During spills of hydrocarbons in soil, it has been observed that aliphatic and the slightly aromatic hydrocarbons are first to be removed, however, branched aliphatic and aromatic compounds, polycyclic aromatic hydrocarbons (PAHs) and their similar heteroatoms with sulfur (PAS) remain strongly absorbed to soil particles. It is important to point out that studies of biodegradation of alkyl-substituted PAHs and PAS are scarce and most of them have been carried out using only available standard compounds. The aim of this investigation was to identify and to quantify the aliphatic, alkyl polycyclic aromatic, and sulfured recalcitrant fractions present in a contaminated soil with drilling wastes. A modified method of shaking-centrifugation extraction was implemented for the extraction of compounds from contaminated soil. The organic extract obtained was purified and fractionated using aluminum oxide. Gas Chromatograph with flame ionization detector (GC-FID) and Gas Chromatograph with mass spectrometer detector (GC-MS) identified the aliphatic, PAHs and PAS fractions. Hydrocarbon composition in the soil contaminated with 140,000 mg TPHs/Kg soil, consisted in 80% of branched aliphatic compounds of C10 to C22, 15% of alkyl PAHs, and 5% of PAS compounds. Lineal, lineal branched, and cyclic branched aliphatic hydrocarbons, as well as their alkyl naphthalene, anthracene and phenantrene, methyldibenzothiophene, dimethyldibenzothiophene, and dimethylnaphto[2,3-b]thiophene compounds were identified by CG-MS. The identification of compounds in soil P31, allowed us to speculate on the origin of the contamination and the natural attenuation that had occurred at this site.

Aim. Assess the ecological state of soils in park areas and public gardens in the city of Kirov, Kirov region, Russia, which are located near areas of heavy traffic, using an integrated approach based on data from physicochemical, microbiological analyzes and biotesting.Material and Methods. Soil samples were taken at various sites in the 60th Anniversary of the USSR Square, in the S.M. Kirov Park and in the 50th Anniversary of the Komsomol Park. The concentration of inorganic ions and the content of polycyclic aromatic hydrocarbons (PAHs) in the soils were determined by ionic and high‐performance liquid chromatography, respectively. The total content of heavy metals (HM)was determined by atomic absorption spectroscopy. Quantitative registration of microorganisms was carried out by the method of limiting dilutions with subsequent inoculation on selective nutrient media. Biotesting was carried out using the protozoa Paramecium caudatum and the Ecolum bacterial test system.Results. The features of the ionic composition of soils in Kirov parks were studied. In the aqueous extract of the studied soils, sulphate and chloride ions predominated among anions, and calcium ions among cations. Among the groups of microorganisms studied, ammonifying bacteria take the leading positions, the share of which in the microbial complex reaches 65.35–86.54%. There is a close relationship between the content of nutrients and the number of ammonifiers. The gross concentration of HMs in soil samples from parks in Kirov did not exceed their approximate permissible concentration, while the content of Pb, Zn, and Cо was up to 3.1 times higher than the regional background. The highest content of PAHs, maximum values of total carcinogenic activity and toxicity to P. caudatum were found in soil samples taken from areas near highways. Conclusion. The ecological state of urban park soils in Kirov in general can be characterised as satisfactory. Nevertheless, for park soils in the immediate vicinity of highways, increased values of PAH concentration were revealed. Determination of the PAH content in soils can be recommended for inclusion in the environmental monitoring programme in cities because of the persistence of PAHs in the environment, their mutagenic and carcinogenic properties, and the lack of standards for the content of most PAHs in natural environments.

Polycyclic aromatic hydrocarbons (PAHs) are scavenged from the atmosphere during snowfall, stored in the seasonal snowpack, and exchanged with PAHs in atmosphere. Thus, the PAHs in fresh snow and snowpack could reflect the PAH levels in atmosphere. This study investigated the concentrations and compositions of 16 priority-controlled PAHs in fresh snow and seasonal snowpack, as well as PAH levels in underlying soils before and after snow melting. The total concentrations of PAHs in fresh snow and snowpack ranged from 26.6 ± 4.2 to 36.9 ± 1.7 μg L−1 and from 40.3 ± 4.4 to 105.9 ± 6.9 μg L−1, respectively. The higher concentrations of PAHs in fresh snow compared with other areas indicated a high PAH level in atmosphere in Changchun city, presenting a potential risk to human health. Higher concentrations of total PAHs in snowpack than those in fresh snow indicated the prominent deposition of PAHs from atmosphere to snowpack in winter. In contrast, a specific reduction of five- to six-ring PAHs in the snowpack suggested that strong photolysis of five- to six-ring PAHs occurred in snowpack. The variation of PAHs in different snowpacks suggested that the deposition may be largely affected by local environment. The results of diagnostic ratios and principal component analysis (PCA) suggested that the PAHs in fresh snow and snowpack are both from a mixed source of coal combustion and from vehicle emissions. However, nonmetric multidimensional scaling (NMDS) divided fresh snow and snowpack into two groups, indicating the different contributions of coal combustion and vehicle emissions to PAHs in fresh snow and snowpack. After snowpack melting, three- to four-ring PAH levels in underlying soils showed no change, indicating that the three- to four-ring PAHs were volatilized to the atmosphere. This study indicated a risk of atmospheric PAHs in Changchun city in winter and in the beginning of spring.