Calcium polysulphide, its applications and emerging risk of environmental pollution—a review article

Abstract

Easy availability, preparation technique, and economic value make calcium polysulphide (CaS ) a very useful inorganic chemical for various field and industrial applications. In this article, disparate applications of CaS solution have been reviewed to suggest potential and future consolidation. This article also encompasses the physiochemical properties and production of CaS solution, with critical appraisal on research focusing on CaS application in agriculture industries and removal of potentially toxic elements (PTEs) from the environment. The kinetics of CaS , technical issues associated with optimization of its dosage and environmental fate is also discussed in detail. This study covers almost all of the peer-reviewed research that has been performed since 1914. Some of the critiques in this article include the lack of integration between the exposure effect and the efficiency of treatment method, effects of oxidizing environments on the long-term performance of CaS solution, and kinetics of CaS solution with the PTEs. The working model of CaS with PTEs is still system dependent, and therefore cannot be used with other applications. The kinetics of CaS is described in detail with various phase stoichiometric reactions. Environmental fate is discussed based on applications, government reports, peer-reviewed articles and kinetics of CaS , which provides a clear picture of emerging contaminants in the environment in relation to the insect resistance and ecotoxicology. Real time, lab based research articles are needed to identify toxicity limits of CaS in environment in order to describe its effective permissible limit in environmental system. This review article provides a risk assessment of environmental pollution by CaS based on its physicochemical characteristic, stoichiometry, kinetics, field, and industrial applications.

Effects of lime sulfur on Neoseiulus californicus and Phytoseiulus macropilis, two naturally occurring enemies of the two‐spotted spider mite Tetranychus urticae

“…Lime sulfur has been a common practice recommended as an alternative product capable of controlling multiple insect pests in the organic production of strawberries particularly the two‐spotted spider mite T. urticae and even more recently, the spotted‐wing drosophila , Drosophila suzukii . The toxic effects of the lime sulfur on mites can be attributed to the elemental sulfur and hydrogen sulfide (H 2 S) released by the degradation of the lime sulfur after application . The H 2 S inhibits the cytochrome oxidize, whereas the elemental sulfur oxidizes the cytochrome B to C, releasing more H 2 S inside the cell …”

“…40,41 The toxic effects of the lime sulfur on mites can be attributed to the elemental sulfur and hydrogen sulfide (H 2 S) released by the degradation of the lime sulfur after application. 42 The H 2 S inhibits the cytochrome oxidize, whereas the elemental sulfur oxidizes the cytochrome B to C, releasing more H 2 S inside the cell. 43,44 Nevertheless, lethal effects were found also for the two species of predator N. californicus and P. macropilis.…”

Toxicity to and egg‐laying avoidance of Drosophila suzukii (Diptera: Drosophilidae) caused by an old alternative inorganic insecticide preparation

“…Coefficients from a three‐parameter Gaussian peak nonlinear regression model: Y = a * exp(−0.5 * ((X − X 0 )/ b )); a = maximum peak value at y‐axis (number of emerged flies); b = rate of change; X 0 = location of the peak on the x‐axis (time).…”

“…Successful organic cultivation of soft‐skinned fruits (e.g., strawberries) requires effective and economical control of insect pests. However, because synthetic insecticides are not permitted in organic fruit production systems and because of the continued requirement for more environmentally benign pest control methods (coupled with regulatory actions to reduce the risks associated with these methods), the return to old inorganic insecticide preparations has recently gained popularity in agriculture, particularly in organic production …”

“…The application of inorganic preparations rich in calcium polysulfides [under the general term ‘lime sulfur’ and easily prepared by combining water (H 2 O) with elemental sulfur (S) and hydrated lime (CaO·H 2 O)], has been recommended since the 19th century, representing one of the oldest effective pest (including insects) control methods , . Degradation of lime sulfur upon application on the plant surface releases both hydrogen sulfide (H 2 S) and elemental sulfur, which act as decouplers of the electron transport chain . The H 2 S inhibits the cytochrome oxidize, whereas the elemental sulfur oxidizes the cytochrome B to C, releasing more H 2 S inside the cell , .…”