Assessing neonicotinoid accumulation and ecological risks in the aquatic environment of Yangtze River Basin, China.

Neonicotinoids (NNIs) constitute commonly used pesticides across various regions, however, the lack of research and data on its long-term effects and threshold levels within specific ecosystems have left an important knowledge gap. This study aimed to comprehensively examine NNI concentrations and their potential impacts on human health and aquatic organisms in the region of the Yangtze River Basin (YRB). The study employed datasets on seven commonly applied NNIs across 244 surface water samples collected from 12 distinct geographic sites within the YRB. The relative potency factor was used to evaluate human exposure risks, while the species sensitivity distribution could estimate acute and chronic hazardous concentrations for 5% of species (HC5) for NNIs impacting aquatic organisms. Analysis revealed varying NNI concentrations across the sampled sites, with thiacloprid recording the lowest concentration at 0.1 ng L-1, and dinotefuran recording a high concentration of 408 ng L-1. The observation indicated NNI concentration declined at sampling sites downstream of the YRB. Infants were identified as the most vulnerable to NNI exposure, with an estimated daily intake of 40.8 ng kg-1 bw d-1. The acute HC5 was determined at 946 ng L-1 and a chronic HC5 at 338 ng L-1, to NNI hazards. These findings highlight the urgent need for a more comprehensive understanding of the ecological implications and hazards posed by NNIs within the YRB. Variations in NNI concentrations across sites, potential risks to human health, and increased vulnerability of aquatic organisms from this study underscore the necessity for further research and concerted efforts to mitigate these ecological threats in the region.

Remote sensing and GIS-based study of land use/cover dynamics, driving factors, and implications in southern Ethiopia, with special reference to the Legabora watershed.

This paper investigates the trends, drivers, and consequences of LULC changes in Legabora watershed, Ethiopia, by utilizing remote sensing and geographic systems. Landsat Maltispectiral scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper (ETM+), and Operational Land Imager (OLI) images of years 1976, 1991, 2001, and 2022, respectively, were used to study the dynamics of LULC. Essential image pre-processing steps were carefully carried out to correct distortions caused by sensor limitations. Eight main LULC categories were identified based on supervised image categorization methods and the maximum likelihood classification algorithm.The findings of change detection and cross-tabulation matrix demonstrate that there has been a significant increase in the area of cropland 345.1 ha/year, settlement 5.9 ha/year, forest 38.2 ha/year, and degraded lands 2.56 ha/year, respectively, over the period between 1976 and 2022. In contrast, considerable decreases were observed in grasslands (-248 ha/year) and shrublands (-144 ha/year), whereas other LULC categories augmented. The results revealed that the overall accuracy rates stood at 88.3 %, 88.4 %, and 85.6 % for 1976, 1991, and 2022, respectively. The overall kappa coefficient demonstrated values of 0.86 %, 0.86 %, and 0.83 % for the same period. Surveyed respondents perceived population growth, settlement, agricultural expansion, and infrastructure development as the most noticeable drivers of these LULC changes. In contrast, deforestation, land degradation, lack of livestock fodder, and biodiversity loss were identified as the main consequences of LULC changes. The factors and implications addressed in this study may be helpful tool for the formulation and implementation of evidence-based land use policies and strategies within in the study area and elsewhere.

Land use and land cover change, and analysis of its drivers in Ojoje watershed, Southern Ethiopia.

There have been incredible changes that have taken place in the land use pattern globally over the last 50 years, which resulted from environmental degradation and climate change impacts. Quantitative analysis of the LULC dynamics helps in land-use management and ecosystem degradation at large. The study was conducted in the Doyogena district, southern Ethiopia to identify LULC change dynamics, and analyze the driving forces using combined approaches: remote sensing, field observations, in-depth household interviews, key informants, and Focus Group Discussions (FGDs). A supervised maximum likelihood image cataloging method was employed in conjunction with feature extraction of satellite images to categorize and map LULC classes of the study area. Satellite image handing out, classification technique, and remotely sensed data were processed using ArcGIS map 10.6, and ERDAS Imagine 2014. Common LULC categories were identified, and a change analysis was conducted. Accordingly, seven LULC categories were determined. The result showed a considerable decline in forestland from 1756.7 ha (38.8%) in 1973 to 71.6 ha (1.6%) in 2020. Similarly, wetlands have declined successively from 16.8 in 2000-2010 to 6.3 in 1986-2020 ha/year over the last three and half decades respectively. On the other hand, cropland has increased from 34.1% in 1986-2000 to 46.3% between 1986-2020, which is linked to population growth, settlement, and expansion of farmlands. The study watershed has experienced a considerable change in LULC change over the last >3 decades. Hence, local and national regimes should implement sustainable land planning, management strategies including integrated land- use planning, and policy reform into development projects and programs.