Status of short-chain chlorinated paraffins in matrices and research gap priorities in Africa: a review

Abstract

Chlorinated paraffins (CPs) have been applied as additives in a wide range of consumer products, including polyvinyl chloride (PVC) products, mining conveyor belts, paints, sealants, adhesives and as flame retardants. Consequently, CPs have been found in many matrices. Of all the CP groups, short-chain chlorinated paraffins (SCCPs) have raised an alarming concern globally due to their toxicity, persistence and long-range transportation in the environment. As a result, SCCPs were listed in the Stockholm Convention on Persistent Organic Pollutants (POPs) in May 2017. Additionally, a limit for the presence of SCCPs in other CP mixtures was set at 1% by weight. CPs can be released into the environment throughout their life cycle; therefore, it becomes crucial to assess their effects in different matrices. Although about 199 studies on SCCP concentration in different matrices have been published in other continents; however, there are scarce/or limited studies on SCCP concentration in Africa, particularly on consumer products, landfill leachates and sediment samples. So far, published studies on SCCP concentration in the continent include SCCPs in egg samples, e-waste recycling area and indoor dust in Ghana and South Africa, despite absence of any production of SCCPs in Africa. However, there still remains a huge research gap in the continent of Africa on SCCPs. Consequently, there is a need to develop robust SCCP inventories in Africa since the Stockholm Convention has already developed guidance document in this respect. This review, therefore, examines the state of knowledge pertaining to the levels and trends of these contaminants in Africa and further provides research gaps that need to be considered in order to better understand the global scale of the contaminant.

Ecological and health risks of polycyclic aromatic hydrocarbons in the sediment core of Phayao Lake, Thailand

“…In external plasticization, plasticizers are blended into base polymers without forming chemical bonds [3] , such that subsequent exudation from the polymer matrices can occur [4] . As some external plasticizers are carcinogenic, mutagenic, or toxic to reproduction (CMRs), endocrine-disrupting, or persistent [5][6][7][8] , their release during lifecycle stages has raised safety concerns.…”

“…Globally, the production volume of CPs is estimated at more than 1 million tonnes per year, with the production of MCCPs being much higher than that of SCCPs [15] . As much as 236.4 kilotons (kt) of SCCPs and 450.2 kt of MCCPs were used in China in 2019, mainly to produce PVC products [6] .…”

“…To date, most investigated applications have been related to toys and childcare items [18][19][20][21][22][23][24] , followed by cosmetics/personal care products and medical devices [19,[25][26][27] . Although it is common knowledge that SCCPs and MCCPs are used in PVC, the number of studies is limited [6,7,[28][29][30][31] . Furthermore, the number of reports on patterns of PAEs and CPs blended in the same PVC items is very limited.…”

“…Furthermore, SCCPs (C 10 to C 13 and with chlorine contents greater than 48% by weight) have been listed as Persistent Organic Pollutants (POPs) in Annex A of the Stockholm Convention (SC) in 2017 [36] and in the EU POPs Regulation in 2019 [37] . According to the SC, any CPs with SCCP contents greater than 1% are considered POPs [6] . These global restrictions have resulted in the transition from LMW PAEs to either HMW PAEs (such as DINP, DIDP, and DPHP) or non-phthalates (such as DEHT, TOTM, and DOA) [38] , and from SCCPs to MCCPs [6,7,39] .…”

“…According to the SC, any CPs with SCCP contents greater than 1% are considered POPs [6] . These global restrictions have resulted in the transition from LMW PAEs to either HMW PAEs (such as DINP, DIDP, and DPHP) or non-phthalates (such as DEHT, TOTM, and DOA) [38] , and from SCCPs to MCCPs [6,7,39] . However, in July 2021, MCCPs, a common replacement for SCCPs, were added to the EU Candidate List of SVHCs [32] , and are currently being reviewed by the POPs Reviewing Committee for possible inclusion as SC POPs.…”