Bioaccumulation and Biotransformation of Chlorinated Paraffins

Abstract

Chlorinated paraffins (CPs), a class of persistent, toxic, and bioaccumulated compounds, have received increasing attention for their environmental occurrence and ecological and human health risks worldwide in the past decades. Understanding the environmental behavior and fate of CPs faces a huge challenge owing to the extremely complex CP congeners. Consequently, the aims of the present study are to summarize and integrate the bioaccumulation and biotransformation of CPs, including the occurrence of CPs in biota, tissue distribution, biomagnification, and trophic transfer, and biotransformation of CPs in plants, invertebrates, and vertebrates in detail. Biota samples collected in China showed higher CP concentrations than other regions, which is consistent with their huge production and usage. The lipid content is the major factor that determines the physical burden of CPs in tissues or organs. Regarding the bioaccumulation of CPs and their influence factors, inconsistent results were obtained. Biotransformation is an important reason for this variable. Some CP congeners are readily biodegradable in plants, animals, and microorganisms. Hydroxylation, dechlorination, chlorine rearrangement, and carbon chain decomposition are potential biotransformation pathways for the CP congeners. Knowledge of the influence of chain length, chlorination degree, constitution, and stereochemistry on the tissue distribution, bioaccumulation, and biotransformation is still scarce.

Chlorinated Paraffin Pollution in the Marine Environment

“…The above logBAFs and logBSAFs implied the bioaccumulation of SCCPs and MCCPs in zooplankton, crustacea, fish, and invertebrates in Chinese areas. In addition, the bioaccumulation of SCCPs and MCCPs has been observed to have correlations with logKow values, lipid contents, carbon chain length, chlorine atoms, octanol/water partition coefficients, and biotransformation capacity. ,,− Besides, studies have shown that demersal marine organisms have higher exposure to CPs than plankton, suggesting a more significant accumulation of CPs in benthic organisms. , …”

Tissue-Specific Accumulation of Orally Administered Short- and Medium-Chain Chlorinated Paraffins in Honeybees (Apis mellifera L.)

“…3,4 Chen et al summarized the biological data on CPs published from 1982 to 2022 and found high concentrations of CPs in aquatic and terrestrial organisms from e-waste recycling areas and in plants and animals from Tibet, China. 5 For humans, CPs have been frequently detected in numerous foodstuffs 6−8 and consumer products 9 and can enter the body through ingestion and then spread to organ tissues. 10,11 The concentrations of CPs in these studies ranged from below the detection limit to hundreds or thousands of nanograms per gram of wet weight (ww).…”

“…Chlorinated paraffins (CPs) are an important class of environmental contaminants utilized in the production of flame retardants and plasticizers in plastics, rubbers, inks, paints, adhesives, and surface coatings, among other products. They are persistent and ubiquitous in the environment and have been widely found in various abiotic media , and biota. , Chen et al summarized the biological data on CPs published from 1982 to 2022 and found high concentrations of CPs in aquatic and terrestrial organisms from e-waste recycling areas and in plants and animals from Tibet, China . For humans, CPs have been frequently detected in numerous foodstuffs − and consumer products and can enter the body through ingestion and then spread to organ tissues. , The concentrations of CPs in these studies ranged from below the detection limit to hundreds or thousands of nanograms per gram of wet weight (ww).…”

Biomonitoring, exposure routes and risk assessment of chlorinated paraffins in humans: a mini-review

“…3,5 CPs have been considered as a global threat due to their ubiquitous existence, persistence, bioaccumulation and potential adverse health effects. 1,[6][7][8] CPs are widely distributed in various environmental media such as air, 9,10 water, 11 sediment, 12 soil 9,13 and biota. 14,15 CPs have been detected in the Arctic Ocean, indicating long-range transport.…”

“…16,17 Bioaccumulation and biomagnication of SCCPs, MCCPs and LCCPs are reported in aquatic and/or terrestrial food webs. 6,18,19 Toxicological studies indicated that SCCP exposure can lead to liver and renal toxicity, 2,20 embryotoxicity, 21,22 endocrine and metabolic disruption 21,23 and immunomodulatory effects 24,25 in various organisms or cell lines. But the toxicity of MCCPs and/or LCCPs is extremely rare.…”