Microplastics and hydrocarbons in soils: Quantification as an anthropic carbon source

The literature on the presence of microplastics (MPs) and their potential impact on terrestrial ecosystems is still scarce. Interestingly, soil MPs are detected as organic carbon (SOC) using traditional quantification methods (e.g., loss on ignition [LOI]), although its dynamics in the environment will be different. The objective of this study was to quantify the carbon (C) contribution of MPs to the SOC in superficial soil samples from a coastal urban wetland (Avellaneda, Buenos Aires, Argentina) with the features of a humid subtropical forest and compare with hydrocarbon contribution. Soil samples were split for analysis of moisture content; texture (sieve and pipet method); organic matter as a LOI (8 h at 450 °C); total hydrocarbons (THCs; gravimetry of solvent extractable matter); n-alkanes (solvent extraction and gas chromatography-flame ionization detection analysis); and extraction of MPs (floatation in NaCl_aq , filtration, H₂ O₂ digestion, and visual sorting under a stereomicroscope). The superficial soil was a sandy clay loam with a large organic matter content (19%-30%). The THC averaged 2.5 ± 1.9 g kg and the marked predominance of odd-numbered carbon n-alkanes maximizing at C29 and C31 show the contribution of the terrestrial plant waxes. The average number of MPs was 587 ± 277 items kg of dry soil, predominantly fibers. Taking account of the C content, THCs and MPs add to the soil 1.23 ± 1.10 ton C ha and 0.10-0.97 ton C ha, respectively. Therefore, in this system with humid forest characteristics, the MPs represent between 0.12% and 1.25% of soil estimated carbon, in a magnitude similar to the C contribution of THCs (0.6%-4.2%). This preliminary study shows the relevance of discriminating MPs from other carbon sources and presents a description of their impact on soils to advance future research or tools for decision-makers. Integr Environ Assess Manag 2023;19:698-705. © 2022 SETAC.

Transverse myelitis as a first manifestation of systemic lupus erythematosus: a case report

Transverse myelitis as a first manifestation of systemic lupus erythematosus (SLE) is very uncommon. No pathognomonic clinical or biochemical characteristics exist, and therefore an early diagnosis is often difficult. Therapy with intravenous pulses of methylprednisolone and cyclophosphamide has been shown to improve the prognosis. However, morbidity and mortality rates in transverse myelitis are still high due to the fact that complications such as opportunistic infections and pulmonary embolism are still frequent causes of death. We report a woman with relapsing transverse myelitis which was the first manifestation of SLE. A good response to pulse methylprednisolone and cyclophosphamide therapy was obtained but she died later as a result of a pulmonary embolism. We conclude that intravenous pulse methylprednisolone and cyclophosphamide therapy improve the prognosis of transverse myelitis associated with SLE but that a careful follow-up is needed to avoid complications due to the illness itself or secondary to the therapy.