Most Australian vegetable growers apply fumigants or nematicides as a precautionary nematode control measure when crops susceptible to root-knot nematode (RKN, Meloidogyne spp.) are grown in soils and environmental conditions suitable for the nematode. The only way growers can make rational decisions on whether these expensive and environmentally disruptive chemicals are required is to regularly monitor RKN populations and decide whether numbers prior to planting are high enough to cause economic damage. However, such monitoring programs are difficult to implement because nematode quantification methods vary in efficiency and the damage threshold for RKN on highly susceptible vegetable crops is often < 10 root-knot nematodes /200 mL soil. Consequently, five nematode quantification methods were tested to see whether they could reliably detect these very low population densities of RKN. Two novel methods produced consistent results: 1) extracting nematodes from 2 L soil samples using Whitehead trays, quantifying the RKN DNA in the nematode suspension using molecular methods, and generating a standard curve so that the molecular results provided an estimate of the total number of RKN individuals in the sample, and 2) a bioassay in which two tomato seedlings were planted in pots containing 2 L soil and the number of galls produced on roots were counted after 21-25 days. Both methods could be used to quantify low populations of RKN, but bioassays are more practical because expensive equipment and facilities are not required and they can be done at a local level by people lacking nematological or molecular skills.

The EU plastic strategy aims to reduce the environmental impact of the increasing plastic production, by replacing petrochemical-based polymers with biodegradable ones. But this mitigation measure for the plastamination might, in turn, generate bio-based microplastics in environments that are not necessarily safe. Biodegradable and non-biodegradable plastics, polylactic acid (PLA) and polypropylene (PP) respectively, and their leachates were used for testing microplastic (MP) effects on seven marine species from different trophic levels, including bacteria, algae, rotifers, copepods, amphipods and branchiopods. Results highlighted the toxic effects of both MPs for three consumers, but no toxicity for decomposers and primary producers. Leachates did not induce negative effects for five species tested. A dose-dependent toxic effect of both PP and PLA on different life stages of A. franciscana was observed, with more advanced stages being more sensitive to MPs in terms of mortality. Molecular analysis revealed increased mRNA levels of Heat shock proteins in A. franciscana metanauplii and adults, suggesting their role in oxidative stress response, and decreasing in juveniles, indicating potential irreversible damage. These results indicated that PLA and PP might have comparable ecotoxicological impacts, raising concerns about the effectiveness of biodegradable polymers in mitigation plastic pollution. The study also emphasizes the importance of considering different trophic levels, life stages, and feeding strategies when evaluating the toxic effects of MPs from a One Health perspective.

Exposure to xenobiotics can increase the production of reactive oxygen species (ROS). When detoxification organs such as the intestines and liver cannot neutralise these xenobiotics, it can induce oxidative stress and cause damage to tissues. Therefore, cell-based bioassays that indicate intracellular ROS production are a useful screening tool to evaluate the effect of these chemicals. Although flow cytometry is commonly used to measure ROS in cells, many research laboratories in the Global South do not always have access to such specialised instrumentation. Therefore, we describe a sensitive but low-cost method that can easily be used to determine ROS production in vitro. This method employs the fluorogenic dye, 2 ' ,7 ' -dichlorodihydrofluorescein diacetate (H2DCF-DA), which emits fluorescence after being oxidised to a fluorescent derivative. Since the H2DCF-DA bioassay indicates non-specific ROS production it can be used as a marker of overall oxidative stress. This method was validated by exposing human duodenum epithelial adenocarcinoma (HuTu-80) and rat liver epithelial hepatoma (H4IIE-luc) cells to agricultural soil samples. center dot Production of ROS can be determined in vitro in intestinal and liver cells. center dot This method is inexpensive and can be easily performed in standard laboratories. center dot The method provides a tool for the high-throughput screening of environmental samples.

Leachate is a highly complex waste with high toxicological potential that poses a significant threat to the terrestrial environment. Determining leachate physicochemical parameters and identifying xenobiotics alone is, however, not enough to determine the real environmental impacts. In this context, the use of terrestrial model organisms has been highlighted as a tool in ecotoxicological leachate assessments and as a guiding principle in risk assessments. In this context, this review aimed to present the most current state of knowledge concerning leachate toxicity and the bioassays employed in this evaluation concerning terrestrial plants and animals. To this end, a literature search on leachate effects on terrestrial organisms was carried out using ten search terms, in 32 different combinations, at the Web of Science and Scopus databases. A total of 74 eligible articles were selected. The retrieved studies analyzed 42 different plant and animal species and employed nine endpoints, namely phytotoxicity, genotoxicity, bioaccumulation, antioxidant system, cytotoxicity, reproduction, physiological changes, behavior and lethality. A frequent association of toxic leachate effects with metals was observed, mainly Pb, Cd, Cr, Mg, Zn and Cr, which can cause antioxidant system alterations and cytoand genotoxicity. These elements have also been associated to reproductive effects in earthworms and mice. Specifically concerning plants, most of the retrieved studies employed Allium cepa in toxicity assays, reporting phytotoxic effects frequently associated to metals and soil parameter changes. Animal studies, on the other hand, mostly employed mice and evaluated genotoxicity and antioxidant system effects. Even with the description of toxic leachate effects in both plants and animals, a lack of knowledge is still noted concerning reproductive, physiological, cytotoxic, and behavioral effects in terrestrial species. We, thus, suggest that further studies be carried out on other animals, advancing our understanding on potential environmental leachate effects, also allowing for human health risk assessments.