Effects of three surfactants on the degradation and environmental risk of metolachlor in aquatic environment

To be or not to be degraded: in defense of persistence assessment of chemicals

“…Many factors can contribute to the uncertainty of P assessment outcomes for substances belonging to the group with intermediate degradability. There are factors related to the testing conditions, including the environmental conditions such as temperature, pH, exposure to light, the presence of further contaminants [13][14][15] as well as the state of the environmental matrix such as its nutrient status, microbial activity, and potential adaptation due to pre-exposure to the pollutant or structurally related chemicals. 8,16 Apart from these natural variabilities, another particular factor that renders P assessments difficult for this group of chemicals is bioavailability limitations due to the interaction of substances with solid environmental media such as soils, sediments, and particulate matter, which leads to sorption and covalent binding, with the latter particularly resulting in the formation of non-extractable residues (NER).…”

“…Many factors can contribute to the uncertainty of P assessment outcomes for substances belonging to the group with intermediate degradability. There are factors related to the testing conditions, including the environmental conditions such as temperature, pH, exposure to light, the presence of further contaminants 13–15 as well as the state of the environmental matrix such as its nutrient status, microbial activity, and potential adaptation due to pre-exposure to the pollutant or structurally related chemicals. 8,16…”

Transport and Environmental Risks of Propachlor Within the Soil–Plant–Water Phase as Affected by Dissolved Organic Matter as a Nonionic Surfactant

“…The environmental behaviors of herbicides depend on many natural factors such as the inherent properties of soil chemicals, the timing of organic matter decay, soil properties, and so forth. The nonionic surfactants are widely used for household applications like laundry, shampoo, paints, coatings, and food emulsifiers because of their low critical micelle concentration (CMC), electrical neutrality, and surface tension value over the ionic surfactants . They are also useful in mixed surfactant systems due to electrical neutrality .…”

“…Triton X-100 (TX-100) is a kind of commonly used nonionic surfactant with the chemical formula of R–C 6 H 4 –(OC 2 H 4 )­p–OH, where R is a branched octyl group and p is the average number of oxyethylene groups ( p ≈ 9.5) . It was found that the TX-100 supply in the subsurface of the soil elevated the level of residual contaminants, resulting in the delayed goal of clean-up. , On the other hand, the addition of nonionic surfactants into the soil can facilitate the biodegradation of contaminants. , Dissolved organic matter is a mixture of natural organic compounds, usually generated by well-decayed crop straw in farmland soil. The DOM complex is composed of carbohydrates, proteins, lignin, organic acids, and many other uncharacterized compounds and has some functional similarities to nonionic surfactants .…”

“…The nonionic surfactants are widely used for household applications like laundry, shampoo, paints, coatings, and food emulsifiers because of their low critical micelle concentration (CMC), electrical neutrality, and surface tension value over the ionic surfactants. 14 They are also useful in mixed surfactant systems due to electrical neutrality. 15 Triton X-100 (TX-100) is a kind of commonly used nonionic surfactant with the chemical formula of R–C 6 H 4 –(OC 2 H 4 )p–OH, where R is a branched octyl group and p is the average number of oxyethylene groups ( p ≈ 9.5).…”