Pollution by metals and toxicity assessment using Caenorhabditis elegans in sediments from the Magdalena River, Colombia

Abstract

a b s t r a c tThe Magdalena River is the most important river in Colombia, supplying over 70% of the population of fish and drinking water, and it also is the main river transportation way of the country. It receives effluents from multiple sources along its course such as contaminant agricultural and industrial discharges. To evaluate the toxicity profile of Magdalena River sediments through endpoints such as survival, locomotion, and growth, wild type strains of Caenorhabditis elegans were exposed to aqueous extracts of the sediments. To identify changes in gene expression, GFP transgenic strains were used as reporter genes. Physiological and biochemical data were correlated with metal concentration in the sediments, identifying patterns of toxicity along the course of the river. Levels of some metals such as Cd, Cu, and Ni were above TEC and PEC limits. Effects in survival, growth, and locomotion were observed in most of the samples, and changes in gene expression were evident in the genes mtl-2, sod-4, and gst-1 using fluorescence expression. Cadmium and lead were the metals which were primarily associated with sediment toxicity, and the sampling sites with the highest increased expression of stress response genes were Barrancabermeja and Girardot. However, the diverse nature of toxic profiles observed in C. elegans in the study area showed the pervasiveness of different types of discharges throughout the river system.

Monitoring and assessment of sediment contamination with toxic heavy metals: case study of industrial effluent dispersion in Alaro River, Nigeria

“…Studies have shown that these industries contribute to increased concentration of heavy metals in river sediment. For instance, the heavy metal pollution derived from the Magdalena River in Columbia was a clear consequence of direct discharges from coal mining and oil transportation sources (Tejeda-Benitez et al 2016). Kumarkhali textile in Kushtia industrial area of Bangladesh contaminated Goral River sediment with toxic heavy metals (Islam et al 2015).…”

2008–2017 Bogota River Water Quality Assessment Based on the Water Quality Index

“…According to Tejeda-Benitez et al [32], 99% of the population of Colombia, including Bogota, are located in the Magdalena watershed, which is exposed to land-use practices such as illicit crops, deforestation, agriculture, industry, mining and increasing rates of urbanization. Furthermore, clear evidence of high loads of heavy metals in the majority of Colombian rivers has been reported, with the Bogota River being one of the most polluted by these kind of contaminants [33].…”

Antimicrobial and toxicological effects of phytosynthesized silver nanoparticles in contact with E-coli and C-elegans

“…Locomotion: Nematodes in L2 larval stage were exposed for 24 h to AgNPs concentrations. Then they were scored for the number of body bends in 20 s. A body bend was assumed as a change in the direction of the posterior bulb of the pharynx along the axis [15]. Growth: L2 larval stage were exposed to AgNPs (500, 1000, 2000 and 4000 g/L) for 72 h, with addition of Escherichia coli OP50 each 24 h, each experiment was done by triplicate.…”

“…Growth: L2 larval stage were exposed to AgNPs (500, 1000, 2000 and 4000 g/L) for 72 h, with addition of Escherichia coli OP50 each 24 h, each experiment was done by triplicate. The body length after exposure was measured using images from a Nikon smz 745T microscope and the ImageJ software [15]. Mortality: C. elegans in L4 larval stage were exposed for 24 h to AgNPs (500, 1000, 2000 and 4000 g/L).…”

“…Mortality: C. elegans in L4 larval stage were exposed for 24 h to AgNPs (500, 1000, 2000 and 4000 g/L). About 15 ± 1 nematodes were used for this treatment [15].…”