The Influence of Soil Characteristics on the Toxicity of Oil Refinery Waste for the Springtail Folsomia candida (Collembola)

Geospatial pattern of topsoil pollution and multi-endpoint toxicity in the petrochemical area of Augusta-Priolo (eastern Sicily, Italy)

The present study was aimed at identifying geospatial patterns of pollutants including concentrations and toxicity as complex environmental mixtures, in topsoil samples close to petrochemical facilities in the heavily industrialized area of Augusta and Priolo in south-eastern Sicily (Italy). Elemental analysis of soil was conducted by ICP-MS for 23 metals and 16 rare earth elements (REEs). Organic analyses were primarily focused on polycyclic aromatic hydrocarbons (PAHs) (16 parent homologs) and total aliphatic hydrocarbons (C10 - C40). Topsoil samples were tested for toxicity in multiple bioassay models including: 1) developmental defects and cytogenetic anomalies in sea urchin Sphaerechinus granularis early life stages; 2) growth inhibition of diatom Phaeodactylum tricornutum; 3) mortality in nematode Caenorhabditis elegans; and 4) induction of mitotic abnormalities in onion Allium cepa. Samples collected at sites closest to defined petrochemical facilities were highest in select pollutants and correlated with biological effects in different toxicity endpoints. A noteworthy finding was the increased level of total REEs in sites closest to petrochemical facilities, suggesting their contributions to identifying petrochemical sources of pollutants to the environment. The combined data obtained in the different bioassays allowed exploration of geospatial patterns of effect in biota as a function of contaminant levels. In conclusion, this study provides consistent data of soil toxicity, metal and REE contamination at Augusta-Priolo sampling sites, and may provide an appropriate baseline for epidemiological studies on high incidences of congenital birth defects in the area and identification of at-risk localities.

Assessment of trace metal contamination in the core sediment of Ramsar wetland (Kabar Tal), Begusarai, Bihar (India)

The concentration of trace metals Mn, Pb, Ni, Zn, and Cu in the core sediment from Kabar Tal wetland was analyzed to understand the level of contamination in the vertical profile. Additionally, total organic carbon (TOC) and available phosphorus (AP) were also analyzed to infer the biogeochemistry of trace metals and the correlation that exists among them. Five core sediments were collected at the end of the monsoon season from different locations in the study area, representing diverse anthropogenic and agricultural activities. The average concentration of trace metals in sediments followed the order Mn > Pb > Ni > Zn > Cu. The trace metal concentration in the surface sediments was higher and decreased with depth in the vertical profile. Contamination factor (CF), geoaccumulation index (Igeo), enrichment factor (EF), and pollution load index (PLI) were used to evaluate sediment quality and the pollution status of the lake sediments. Cu, Zn, and Ni showed minor to moderate enrichment, and Pb showed a severe level of enrichment in all the core sediment samples. However, the sediment quality guidelines' index indicates that the sediments are moderately polluted with copper, zinc, and nickel and severely polluted with lead. There exists a strong positive correlation among Pb-Ni, Ni-AP, and AP-Pb, and a strong negative correlation among TOC-Ni, TOC-Pb, and TOC-AP for all the sediment samples. Additionally, the principal component analysis (PCA) and cluster analysis (CA) suggest that a good similarity exists among Pb, Ni, and Zn. The study indicates that trace metals in wetland sediments have originated from multiple anthropogenic sources like agricultural runoff (fertilizers), direct addition of solid wastes, discharge of untreated wastewater, and long-range transport from the oil refinery in the wetland.

Terrestrial Toxicity of Synthetic Gas-to-Liquid versus Crude Oil-Derived Drilling Fluids in Soil

Unlike most other conventional petroleum products that are derived from crude oil, gas-to-liquids (GTLs) are petroleum products that are synthesized from natural gas (methane). This process results in GTL products having no sulfur and low aromatic content, so they should have less impact on human health and the environment compared with crude oil-derived products. The GTLs have been registered for use as nonaqueous base fluids (NABFs) in drilling muds, which aid in the process of drilling wells for oil and gas extraction; it is through these uses and others that they enter terrestrial environments. The primary objective of the present study was to determine whether GTLs were less toxic to terrestrial soil biota than conventional NABFs used for land-based drilling, such as diesel and low-toxicity mineral oil (LTMO). A second objective was to understand the fate and impact of these fluids under more realistic soil and aging conditions of a common west Texas (USA) oil-producing region (i.e., sandy loam soil with low organic matter and a hot arid climate). Acute terrestrial toxicity studies were conducted on the soft-bodied terrestrial invertebrate earthworm (Eisenia fetida) along with 3 plant species-alfalfa (Medicago stavia), thickspike wheatgrass (Elymus lanceolatus), and fourwing saltbrush (Atriplex canescens). We also assessed changes in microbial community structure of the soils following additions of NABF. Overall, the GTL NABFs had lower toxicity compared with conventional NABFs like diesel and LTMO, as measured by invertebrate toxicity, plant seed germination, and impact on the microbial community. Environ Toxicol Chem 2020;39:721-730. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Heavy Metal Threats to Plants and Soil Life in Southern Africa: Present Knowledge and Consequences for Ecological Risk Assessment

In recent times there has been remarkable development in the field of soil ecotoxicology and risk assessment (RA) models. It is, however, debatable if these RA models are robust representatives for worldwide relevance. In order to investigate this, the current overview aims to address heavy metal threats to soil life in southern Africa by investigating present knowledge and consequences for RA using research in southern Africa as a case. To this end, the focus is on southern African soils, soil life and living conditions. To critically discuss these issues, we report on extensive research conducted in the southern African context and looked how comparable these findings are to RA models employed in the western world. This is done by providing an inventory of selected studies focused on the ecotoxicity of metals towards soil life. It is concluded that there is a dearth of information on southern African soil life, most of which are laboratory-based studies carried out by a handful of researchers. Future research incorporating the available information into a soil ecosystem assessment procedure is paramount. It is recommended that a starting point to tackle this might be the development of holistic sight-specific guidelines for ecological risk assessment at larger spatial scales (km²) which takes into cognizance landscapes, vegetation and faunal characteristics.

Response of the Native Springtail Parisotoma insularis to Diesel Fuel-Contaminated Soils Under Field-Realistic Exposure Conditions at Subantarctic Macquarie Island

A number of sites contaminated by petroleum hydrocarbons from past fuel spills are currently undergoing remediation on subantarctic Macquarie Island (under the jurisdiction of Tasmania, Australia). To assess the environmental risks these spills pose, and to establish remediation targets and guideline values, toxicity data for a range of native biota are required. The availability of data for local biota is limited, especially for soil invertebrates, which are critical to soil health. To examine the response of naturally occurring soil invertebrate communities to fuel contamination, intact soil cores from a range of soil types were collected along an organic carbon (OC) gradient. Organic carbon was factored into the toxicity assessment due to its toxicity-modifying potential. Soil cores were spiked with Special Antarctic Blend diesel, to mimic a fresh fuel spill at the soil surface. Springtails were the most abundant taxa, with the community heavily dominated by the native species Parisotoma insularis. This species was sensitive to fuel contamination (EC20 48 mg/kg, CI 5-188), irrespective of soil organic content. This study is the first to derive critical effect concentrations (CECs) for a subantarctic springtail species and provides important data that will be incorporated into future derivation of site-specific soil quality guideline values for fuels for Macquarie Island soils and the broader subantarctic region. Integr Environ Assess Manag 2019;15:565-574. © 2019 SETAC.

Assessment of Heavy and Trace Metals in Surface Soil Nearby an Oil Refinery, Saudi Arabia, Using Geoaccumulation and Pollution Indices

The present study deals with the measurement of heavy and trace metals in the soils of Ras Tanura city nearby one of the oldest and largest oil refineries located on Arabian Gulf, eastern Saudi Arabia. Metals were analyzed in 34 surface soil samples using plasma atomic emission spectrometer (ICPE-9820). The result showed that the mean values of the metals concentrations were in the order: Cd > Mo > Tb > Ce > Hf > Eu > Yb > U > Sm > Rb > Cr > Ni > Pb > Sc > Cs > Zn > Lu > Co. The mean values of Cd (39.9 mg/kg), Mo (13.2 mg/kg), Eu (4.01 mg/kg), Hf (6.09 mg/kg), Tb (8.23 mg/kg), and Yb (3.88) in soil samples were higher than the background values in soil and the world average. The obtained results indicated to elevated levels of Cd and Mo in most samples, with mean concentrations exceeded the background levels by 113 times for Cd and 5 times for Mo. Pollution index (PI) and Geoaccumulation (I_geo) for each metal were calculated to assess the metal contamination level of surface soil in the study area. The assessment results of PI and I_geo revealed a significant pollution by Cd, Mo, Eu, Hf, Tb, and Yb in most of sampling sites nearby Ras Tanura refinery.

Toxicity of a Quinaldine-Based Liquid Organic Hydrogen Carrier (LOHC) System toward Soil Organisms Arthrobacter globiformis and Folsomia candida

The study aims to establish a preliminary environmental assessment of a quinaldine-based LOHC system composed of hydrogen-lean, partially hydrogenated, and fully hydrogenated forms. We examined their toxicity toward the soil bacteria Arthrobacter globiformis and the Collembola Folsomia candida in two exposure scenarios, with and without soil, to address differences in the bioavailability of the compounds. In both scenarios, no or only slight toxicity toward soil bacteria was observed at the highest test concentration (EC₅₀ > 3397 μmol L^-1 and >4892 μmol kg^-1 dry weight soil). The effects of the three quinaldines on F. candida in soil were similar, with EC₅₀ values ranging from 2119 to 2559 μmol kg^-1 dry weight soil based on nominal concentrations. Additionally, corrected pore-water-concentration-based EC₅₀ values were calculated by equilibrium partitioning using soil/pore-water distribution coefficients. The tests without soil (simulating pore-water exposure) revealed higher toxicity, with LC₅₀ values between 78.3 and 161.6 μmol L^-1 and deformation of the protective cuticle. These results assign the compounds to the category "harmful to soil organisms". Potential risks toward the soil environment of the test compounds are discussed on the basis of predicted no-effect concentrations.

A brief review and evaluation of earthworm biomarkers in soil pollution assessment

Earthworm biomarker response to pollutants has been widely investigated in the assessment of soil pollution. However, whether and how the earthworm biomarker-approach can be actually applied to soil pollution assessment is still a controversial issue. This review is concerned about the following points: 1. Despite much debate, biomarker is valuable to ecotoxicology and biomarker approach has been properly used in different fields. Earthworm biomarker might be used in different scenarios such as large-scale soil pollution survey and soil pollution risk assessment. Compared with physicochemical analysis, they can provide more comprehensive and straightforward information about soil pollution at low cost. 2. Although many earthworm species from different ecological categories have been tested, Eisenia fetida/andrei is commonly used. Many earthworm biomarkers have been screened from the molecular to the individual level, while only a few biomarkers, such as avoidance behavior and lysosomal membrane stability, have been focused on. Other aspects of the experimental design were critically reviewed. 3. More studies should focus on determining the reliability of various earthworm biomarkers in soil pollution assessment in future research. Besides, establishing a database of a basal level of each biomarker, exploring biomarker response in different region/section/part of earthworm, and other issues are also proposed. 4. A set of research guideline for earthworm biomarker studies was recommended, and the suitability of several earthworm biomarkers was briefly evaluated with respect to their application in soil pollution assessment. This review will help to promote further studies and practical application of earthworm biomarker in soil pollution assessment.