26 research outputs found
Bioaccumulation and Toxicity of Organic Chemicals in Terrestrial Invertebrates
Terrestrial invertebrates are key components in ecosystems, with crucial roles in soil structure, functioning, and ecosystem services. The present chapter covers how terrestrial invertebrates are impacted by organic chemicals, focusing on up-to-date information regarding bioavailability, exposure routes and general concepts on bioaccumulation, toxicity, and existing models. Terrestrial invertebrates are exposed to organic chemicals through different routes, which are dependent on both the organismal traits and nature of exposure, including chemical properties and media characteristics. Bioaccumulation and toxicity data for several groups of organic chemicals are presented and discussed, attempting to cover plant protection products (herbicides, insecticides, fungicides, and molluscicides), veterinary and human pharmaceuticals, polycyclic aromatic compounds, polychlorinated biphenyls, flame retardants, and personal care products. Chemical mixtures are also discussed bearing in mind that chemicals appear simultaneously in the environment. The biomagnification of organic chemicals is considered in light of the consumption of terrestrial invertebrates as novel feed and food sources. This chapter highlights how science has contributed with data from the last 5Â years, providing evidence on bioavailability, bioaccumulation, and toxicity derived from exposure to organic chemicals, including insights into the main challenges and shortcomings to extrapolate results to real exposure scenarios
Contribution for the derivation of a soil screening value (SSV) for uranium, using a natural reference soil
In order to regulate the management of contaminated land, many countries have been deriving soil screening values (SSV). However, the ecotoxicological data available for uranium is still insufficient and incapable to generate SSVs for European soils. In this sense, and so as to make up for this shortcoming, a battery of ecotoxicological assays focusing on soil functions and organisms, and a wide range of endpoints was carried out, using a natural soil artificially spiked with uranium. In terrestrial ecotoxicology, it is widely recognized that soils have different properties that can influence the bioavailability and the toxicity of chemicals. In this context, SSVs derived for artificial soils or for other types of natural soils, may lead to unfeasible environmental risk assessment. Hence, the use of natural regional representative soils is of great importance in the derivation of SSVs. A Portuguese natural reference soil PTRS1, from a granitic region, was thereby applied as test substrate. This study allowed the determination of NOEC, LOEC, EC20 and EC50 values for uranium. Dehydrogenase and urease enzymes displayed the lowest values (34.9 and ,134.5 mg U Kg, respectively). Eisenia andrei and Enchytraeus crypticus revealed to be more sensitive to uranium than Folsomia candida. EC50 values of 631.00, 518.65 and 851.64 mg U Kg were recorded for the three species, respectively. Concerning plants, only Lactuca sativa was affected by U at concentrations up to 1000 mg U kg1. The outcomes of the study may in part be constrained by physical and chemical characteristics of soils, hence contributing to the discrepancy between the toxicity data generated in this study and that available in the literature. Following the assessment factor method, a predicted no effect concentration (PNEC) value of 15.5 mg kg21dw was obtained for U. This PNEC value is proposed as a SSV for soils similar to the PTRS1
State of the science and the way forward for the ecotoxicological assessment of contaminated land
Applying a GLM-based approach to model the influence of soil properties on the toxicity of phenmedipham to Folsomia candida
Effects of NaCl and seawater induced salinity on survival and reproduction of three soil invertebrate species
The increase of global mean temperature is raising serious concerns worldwide due to its potential negative
effects such as droughts and melting of glaciers and ice caps leading to sea level rise. Expected
impacts on soil compartment include floodings, seawater intrusions and use of saltwater for irrigation,
with unknown effects on soil ecosystems and their inhabitants. The present study aimed at evaluating
the effects of salinisation on soil ecosystems due to sea level rise. The reproduction and mortality of three
standard soil invertebrate species (Folsomia candida, Enchytraeus crypticus, Hypoaspis aculeifer) in standard
artificial OECD soil spiked with serial dilutions of seawater/gradient of NaCl were evaluated according
to standard guidelines. An increased sensitivity was observed in the following order: H. aculeifer E.
crypticus F. candida consistent with the different exposure pathways: springtails and enchytraeids are
exposed by ingestion and contact while mites are mainly exposed by ingestion due to a continuous and
thick exoskeleton. Although small differences were observed in the calculated effect electrical conductivity
values, seawater and NaCl induced the same overall effects (with a difference in the enchytraeid tests
where a higher sensitivity was found in relation to NaCl). The adverse effects described in the present
study are observed on soils not considered saline. Therefore, the actual limit to define saline soils
(4000 lS cm 1) does not reflect the existing knowledge when considering soil fauna
Evaluating a bioremediation tool for atrazine contaminated soils in open soil microcosms: The effectiveness of bioaugmentation and biostimulation approaches
A previously developed potential cleanup tool for atrazine contaminated soils was evaluated
in larger open soil microcosms for optimization
under more realistic conditions, using a natural
crop soil spiked with an atrazine commercial formulation (Atrazerba FL). The doses used were 20ÂŁ or 200ÂŁ higher than the recommended dose (RD) for an agricultural
application, mimicking over-use or spill situations. Pseudomonas sp. strain ADP was used for bioaugmentation (around 107 or 108 viable cells gÂĄ1 of soil) and citrate for biostimulation (up to 4.8 mg gÂĄ1 of soil). Bioremediation treatments providing fastest
and higher atrazine biodegradation proved to differ according to the initial level of soil ontamination. For 20£ RD of Atrazerba FL, a unique inoculation with Pseudomonas sp. ADP (9 ± 1 £ 107 CFU g¥1) resulted in rapid atrazine removal (99% of the initial 7.2 ± 1.6 lg g¥1 after 8 d), independent of citrate.
For 200ÂŁ RD, an inoculation with the atrazine-
degrading bacteria (8.5 ± 0.5 £ 107 CFU g¥1) supplemented with citrate amendment (2.4 mg g¥1) resulted in improved biodegradation
(87%) compared with bioaugmentation alone (79%), even though 7.8 ± 2.1 lg of atrazine
gÂĄ1 still remained in the soil after 1 wk. owever, the same amount of inoculum, distributed over three successive inoculations
and combined with citrate, increased Pseudomonas sp. ADP survival and atrazine
biodegradation (to 98%, in 1 wk). We suggest
that this bioremediation tool may be valuable
for efficient removal of atrazine from contaminated field soils thus minimizing atrazine and its chlorinated derivatives from reaching water compartments.FEDER, POCI Programme, PPCDT Programme and Fundação para a CiĂȘncia e a Tecnologia,
Portuga