The Combined Effects of Wood Vinegar and Perfluorooctanoic Acid on Enzymatic Activities, DNA Integrity and Gene Transcription in Dugesia Japonica

Perfluorooctanoic acid (PFOA) has been identified widely in aquatic environments, while there are few reports detailing the environmental risk of wood vinegar (WV) on freshwater ecosystems. We used freshwater planarians, Dugesia japonica, to evaluate the combined effects of PFOA and WV by examining the adverse influence of enzymatic activities, DNA damage and gene transcription on planarians. Compared with control and PFOA groups, the malonaldehyde content was lower in planarians treated with WV. In addition, WV enhanced the activities of antioxidant enzymes and mitochondrial enzymes, relieving the toxicity effects of PFOA. We also studied the genotoxicity of PFOA and WV on planarians using the comet assay. WV decreased the proportion of DNA in the tail and the olive tail moment. Furthermore, expression of gpx, gst and gr genes in planarians was significantly altered following exposure to both PFOA and WV, compared with individual exposure. Our results suggest that WV could alleviate the adverse effects of PFOA on the aquatic environment, but ecological risk assessments and toxicological safety evaluations of WV are necessary.

Application of a soil quality triad in assessing ecological risk posed to croplands

Healthy soil ecosystems fulfil multiple functions (e.g. cycling nutrients and controlling pests), which play an important role in sustainable food production. However, the application of polluted irrigation water poses a major risk to soil quality (health) and warrants investigation to ultimately inform decision-making. We hypothesised that the standardised soil quality TRIAD approach (ISO 19204), which integrates the chemistry, ecology, and ecotoxicology lines of evidence, can be used as part of an ecological risk assessment of cropland soils. To investigate the applicability of this approach in an agricultural setting, we collected soils from croplands associated with the Hartbeespoort and Crocodile (West) irrigation schemes, which utilise water known to be heavily impacted by anthropogenic (metal, nutrient, and salt) pollution. Croplands associated with the Marico-Bosveld Irrigation Scheme served as the reference systems. Data from the three lines of evidence were scaled, weighted, and integrated. Moderate risk was evidenced for nutrient and salt content in most croplands associated with the Hartbeespoort Irrigation Scheme. However, either no or low risk was recorded for the ecology and ecotoxicology lines of evidence. Finally, the integrated risk assessment concluded that only low ecological risk was posed to soil quality, likely as a result of agricultural activities (e.g. tillage and fertiliser application) that deteriorated soils also at the reference system. This study shows important limitations in the application of ecological risk assessments in conventionally farmed soils, but still holds promise for organic and conservation systems.

Selecting Bioassay Test Species at the Screening Level of Soil Ecological Risk Assessments

For site-specific soil ecological risk assessments (SERAs), an integrated chemical, ecotoxicological, and ecological analysis needs to be performed. The SERA guidelines of international institutions and countries recommend that a SERA be initiated at the screening level to save time and social economic cost; however, they provide no unified test species for this screening level. This study performed SERAs for field soils and confirmed the importance of selecting bioassay test species that reflect the ecotoxicity of field soils at the screening level. To confirm test species that reflect the ecological risk of field soils, correlation analysis was performed on the results of each bioassay with the integrated ecotoxicological risk index (EtoxRI). Our results showed that soil algae, nematodes, and plants were the most representative species in soil assays, with high correlation coefficients with EtoxRI. The results imply the importance of selecting test species that represent ecological risk for the screening level of SERAs. Based on these findings, when using SERAs, species sensitivity, ecological relevance, and economic aspects should be considered when selecting the bioassay test species.

Characteristics and Risk Assessment of Soil Polluted by Lead around Various Metal Mines in China

The contamination of soil by lead (Pb) is a serious and widespread problem in China, especially in mining areas. This paper summarized the available data regarding Pb-contaminated soils around various metal mines in China. Based on these data, the Pb concentration in the soil and its temporal and spatial changes were analyzed. Potential ecological hazards and adult lead models were also used to estimate ecological and health risks. The results indicated that the concentration of Pb was closely related with the type of mine. Compared with other types of mine, soil around lead-zinc (Pb-Zn) and tin (Sn) mines with high Pb contents in the metallic ores and high pollutant emission coefficient were more strongly polluted by Pb. The characteristic spatial and temporal variations of Pb pollution status in China were clarified, and the results showed that the concentration was high in the southern, southwestern, and central regions of China where many mining areas were located, and the mean value passed a turning point in 2012. Ecological risk assessments indicated that some areas around mines were at considerable to high risk, and the risk was relatively severe in Pb-Zn mining areas. According to the adult lead model, Pb-Zn mines had a greater impact on blood Pb concentration than the other types of mine.

Integrating Ecosystem Function and Structure to Assess Landscape Ecological Risk in Traditional Village Clustering Areas

Land use in traditional village clustering areas often exhibits slight dynamic changes; however, significant hidden ecological hazards may be present in local settlements. There is still a lack of dynamic ecological risk assessments for the corresponding classification-based prevention strategies and landscape ecosystem attributes’ enhancement. Based on the land-use changes, this study integrated the ecosystem structure and function to explore the characteristics of the landscape ecological risk in traditional village clustering areas. The clustering area of 24 national traditional villages in Songyang County of Lishui City in Zhejiang Province, China, served as the study region to evaluate and analyze the changes in the landscape ecological risk from 2010 to 2019. The results showed that the land-use transitions were subtle but dominated by changes from forest cultivated land, posing high risk and medium—high risk increased slowly in size. Additionally, significantly increased risks were located mainly in the boundary area of the five villages. Moreover, 22 settlements were found in the sensitive area with increased risks less than 600 m away. This assessment will provide a basis for traditional villages’ risk prevention and ecosystem protection.

A Review of Heavy Metals in Coastal Surface Sediments from the Red Sea: Health-Ecological Risk Assessments

The heavy metal (HM) pollution in sediment is of serious concern, particularly in the Red Sea environment. This study aimed to review and compile data on the concentrations of four HMs (Cd, Cu, Pb, and Zn) in the coastal surface sediments from the Red Sea, mainly from Saudi Arabia, Egypt, and Yemen, published in the literature from 1992 to 2021. The coastal sediments included those from mangrove, estuaries, and intertidal ecosystems. It was found that the mean values of Cd, Cu, Pb, and Zn in coastal Red Sea sediments were elevated and localized in high human activity sites in comparison to the earth upper continental crust and to reference values for marine sediments. From the potential ecological risk index (PERI) aspect, 32 reports (47.1%) were categorized as ‘considerable ecological risk’ and 23 reports (33.8%) as ‘very high ecological risk’. From the human health risk assessment (HHRA) aspect, the non-carcinogenic risk (NCR) values (HI values < 1.0) of Cd, Cu, Pb, and Zn represented no NCR for the ingestion and the dermal contact routes for sediments from the Red Sea countries. The reassessment of the HM data cited in the literature allowed integrative and accurate comparisons of the PERI and HHRA data, which would be useful in the management and sustainable development of the Red Sea area, besides being a helpful database for future use. This warrants extensive and continuous monitoring studies to understand the current and the projected HM pollution situation and to propose possible protective and conservative measures in the future for the resource-rich Red Sea ecosystem.