A Chemicals Strategy for a Toxic-Free Future

Dr. Ramesh Halappa of Chemical Safety & Regulatory Affairs (CSRA) at Evalueserve, an experienced Ecotoxicologist, and Risk Assessor, shares his thoughts on a current hot topic within the world of chemical safety. Government agencies and Chemical product companies are tackling the environmental issue of toxic chemicals that persist in our environment, causing widespread harm. Read on to understand more and how we at Evalueserve can support your ecological risk assessment needs.

Hazardous chemicals in the ecosphere:

Substances exhibiting the characteristics of remaining in the environment for a long time, building up in the bodies of living organisms, and posing a potential risk to human health and the ecosystem are known as PBT (Persistent, Bioaccumulative, and Toxic) or vPvB (very Persistent and very Bioaccumulative). Those Chemicals are substances that do not decompose or disintegrate naturally in the surroundings, leading to their accumulation in living organisms and biological systems. This process risks individual organisms and species within the ecosystems they currently thrive in. Several perfluoroalkyl and poly-fluoroalkyl substances (PFASs) exhibit PBT properties and can potentially undergo transboundary and long-range transport. Many PFASs are used and permitted in various products (your household and cosmetic products, dental floss, textiles, food contact materials, biocides, electronics, construction, aviation, aerospace & defense), with possible implications for human exposure and environmental fate. Following their release into the environment, such pollutants may persist and enter food chains with biomagnification effects and adverse health outcomes.

Examples of PBTs include Dichlorodiphenyltrichloroethane (DDT, a banned insecticide in some countries), Polychlorinated dibenzo-p-dioxins (Dioxins, an organic group of chlorinated compounds produced from burning or the synthesis of industrial chemicals and products), and chlordane (an organochlorine termite pesticide now banned from use) (History of Persistent, Bioaccumulative, and Toxic Chemicals).

The PBT/vPvB concern!

Chemical compounds that can endure in the environment for extended periods and have a high likelihood of accumulating within living organisms are a cause for concern due to the difficulty in forecasting their long-term impact. This process highlights the significance of addressing the potential harm caused by persistent substances in the ecosystem. These substances pose a challenge to reverse their exposure once they enter the environment, as they do not degrade. Stopping the primary source of pollution or emission does not solve the problem, as it persists.

Protection of pristine, remote areas from PBT/vPvB substances is rugged as they readily migrate away from the source of pollution, contaminating the environment much further afield.

Humans and multiple animal species can suffer harm from toxicity, which can impact entire food chains. The PBTs, which are very persistent and bioaccumulative, cause deep concern because of their ability to accumulate in living organisms, their capacity to travel long distances, and their high toxicity. Detecting organochlorides such as DDT and Polychlorinated biphenyl chemicals (PCBs) in Northern sea otters in Alaska provides evidence of these effects (Concentrations of organohalogens (PCBs, DDTs, PBDEs) in hunted and stranded Northern sea otters (Enhydra lutris kenyoni) in Alaska from 1992 to 2010: Links to pathology and feeding ecology).

Persistent toxic pollutants know no borders. They are found everywhere in the world, causing extensive pollution near the sources of origin and hidden places on the planet, even in Antarctica and other remote islands of the Pacific. Synthetic Chemical pollutants produced or used in industrialized areas circulate globally through ocean currents and atmospheric transport, disseminating them to all areas of the planet, as shown by this situation (PBT and vPvB substances). Scientists found that certain chemicals exist in untouched and pristine places, such as the Arctic, despite the minimal human activities that could cause pollution. Researchers have found concentrations of these chemicals to exceed those in their producing regions. Their studies discovered higher amounts of chemicals. This concentration is due to the distillation process of these substances in the cold areas of the planet. 

Animals that habit cold environments tend to have much larger fat depots: fish, birds, and mammals need thicker layers of fatty tissue as natural insulation against low temperatures. Indigenous peoples in the Arctic have traditional diets containing plenty of rich foods from local wild animal sources, and their diets have limited other means of nutrition. These people have higher levels of persistent pollutants in their bodies than many populations with devastating health effects. The toxic products of PBTs range from cancer, endocrine disruption, reproductive dysfunction, behavioral abnormalities, congenital disabilities, disturbance of the immune system, and damage to the liver and nervous system (PBT and vPvB substances)

What can Toxicologists do to prevent new persistent toxic chemicals from being produced?

Fortunately, computational toxicology methods and toxicological risk assessment can evaluate the potential of newly produced chemicals to be a PBT or vPvB. These in-silico methods comprise computational models that integrate information and data from various sources to develop statistical and rules-based models to predict adverse health effects caused by chemicals (In silico toxicology: computational methods for predicting chemical toxicity). The Chemical Safety team at Evalueserve routinely uses the OECD QSAR ToolBox for hazard and risk assessment of chemicals, a widely used tool in the industry.     

How is the OECD QSAR Toolbox assisting toxicologists in screening safer environmental chemicals?

The Toolbox is a software application used by government agencies, the chemical industry, and chemical safety professionals to predict and fill gaps in human and ecotoxicity data required for assessing the hazards of chemicals. The European Chemicals Agency collaborated closely in developing it (The OECD QSAR Toolbox). 

The ECHA PBT screening profiler screens substances for PBT/vPvB assessment by identifying implications with the potential for Persistent (P), very Persistent (vP), Bioaccumulative (B), very Bioaccumulative (vB) properties, and toxicity to aquatic organisms (T, Environmental). The results of this screening are based on single threshold values for P/vP, B/vB, and T (Environmental) according to Annex XIII to REACH Regulation (EC) No. 1907/2006 and ECHA Guidance on Information Requirements and Chemical Safety Assessment Chapter R.11: PBT/vPvB assessment (ECHA PBT screening). 

PBT/vPvB chemicals screening in day-to-day consumer products – Evalueserve case study

The consumer goods industry client needs to learn about the PBT/vPvB chemicals used in their product line to eliminate substances that pose a risk to the environment in their subsequent products. This situation led the client to commission the Evalueserve CSRA team to assess PBT/vPvB properties using the OECD QSAR Toolbox on a structurally diverse set of chemicals (52 chemicals screened). During the screening process, we have elucidated and predicted persistent, very persistent, non-bio accumulative, bioaccumulative, and non-toxic to aquatic organisms chemicals. Our analyses for the client aided their product design by enabling them to eliminate ongoing, very persistent, and very bio-accumulative chemicals from future products. 

Do you need to screen your chemicals for PBT/vPvB properties?

Have you an unmet regulatory or scientific need relating to the safety evaluation of chemicals? Do you need support in identifying PBT/vPvB properties in chemicals? If so, Evalueserve CSRA can help you. We support individual and recurring on-demand projects to long-term programs of work where we have the capability and capacity to support your business. Our team of experts can deploy into an agile workstream and deliver data and interpretation on time. Our chemical safety work will support your goals of developing and marketing products that do not contain persistent, bioaccumulative and toxic chemicals and help protect human health and the environment.

Contact CSRAsolutions@evalueserve.com for more information.

Ramesh Halappa
Principal Consultant, CSRA Posts

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