Environment bioaccumulated chemicals

Burkhard, L.P. Cook, P.M. Mount, D.R. 2003, The relationship of bioaccumulative chemicals in water and sediment to residues in fish A visualization approach. Environ. Toxicol. Chem. 22 2822-2830. 

The toxicity, bioaccumulative potential, and ecological impact of organohalogenated substances such as polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), polychlorinated d iben zo -pa ra - diox i n s (PCDDs), or polybrominated diphenylethers (PBDEs) have been extensively reviewed.95 98 All are referred to as persistent organic pollutants (POPs), that is, chemical substances that remain in the environment, bioaccumulate through the food chain, and pose a risk to human health and the environment. The international community is calling for action to reduce and then eliminate the production or formation of these substances and to monitor their emission. In this case, the detectability obtainable by analytical methods should be very low, since the limits established for these residues are in the ng per liter range. 

Little data exist on the effects of vinylidene chloride in the aquatic and terrestrial environments. Bioaccumulation is expected to be low based on the low octanol/water partition coefficient and low water solubility. A bioconcentration factor of 4 and a bioaccumulation factor of 6.9 were reported for fish, and a bioaccumulation factor of less than 13 reported for common carp. Because of the rapid volatilization of the chemical from the aquatic and terrestrial environments and the low concentrations found in surface water (microgram per liter range), no significant risk is expected. 

A great deal can occur to a xenobiotic between its introduction to the environment and its interaction at the site of action. Many materials are altered in specific ways depending upon the particular chemical characteristics of the environment. Bioaccumulation, the increase in concentration of a chemical in tissue compared to the environment, often occurs with materials that are more soluble in lipids and organics (lipophilic) than in water (hydrophilic). Compounds are often transformed into other materials by the various metabolic systems that reduce or alter the toxicity of materials introduced to the body. This process is biotransformation. Biodegradation is the... 

Additionally some PBDEs, like pentaBDE, bioaccumulate in animals—meaning the chemicals collect in the fatty tissue of animals— and biomagnify—increase in concentration as they move up the food chain. Persistent and bioaccumulative chemicals such as pentaBDE and octaBDE are of high concern to animals at the top of the food chain, like humans, because they receive the highest exposures. The combination of long life and collecting in tissue means even small releases of persistent and bioaccumulative chemicals matter the chemicals will be active in the environment and our bodies for long periods of time. 

Highly persistent and bioaccumulative chemicals are generally recognized as environmental hazards prompting national and international regulatory agencies to develop standards and guidelines to characterize these chemical attributes. Persistent ehemicals resist natural environmental breakdown and may be present in the environment for many decades. Persistence... 

Many brominated flame retardants (BFRs) are persistent and bioaccumulative chemicals that are now present throughout the environment. Polybrominated diphenyl ethers (PBDEs) are one of the most common groups of BFRs and have been used to fireproof a wide variety of materials, including textiles. Some PBDEs are capable of interfering with the hormone systems involved in growth and sexual development. Under EU law, the use of some types... 

Chemicals, which are persistent, toxic and liable to bioaccumulation, are called PTBs. They have primarily local effects. Persistence is the evidence that the substances half-life is greater than two months in water and greater than sue months in soil or sediment. Toxicity is the potential to adversely affect human health and/or the environment. Bioaccumulation is the evidence that the Bio-Accumulation Factor (BAF) is greater than 5000. Up to 1995, there was no clear definition of which products belong to this class [394]. Heavy metals, such as mercury and POPs fall into this category. 

The toxicological or cumulative effect of illicit drugs on the ecosystems has not been studied yet. Moreover, their fate and transport in the environment is to a big extent still unknown. Due to their physical-chemical properties (octanol-water partition coefficient, solubility, etc.) some of them, such as cannabinoids, are likely to bioaccumulate in organisms or concentrate in sediments whereas the rest, much more polar compounds, will tend to stay in aqueous environmental matrices. However, continuous exposure of aquatic organisms to low aquatic concentrations of these substances, some of them still biologically active (e.g., cocaine (CO), morphine (MOR) and MDMA) may cause undesirable effects on the biota. 

Fourteen formulations of chemical alternatives were submitted to EPA under confidentiality and they were assessed based on numerous human health and ecotoxicity endpoints in addition to bioaccumulation potential and environmental persistence. They were also screened for potential exposure to workers, users and the aquatic environment. Where data gaps existed, EPA experts used models and chemical analogs to estimate the hazard for a particular endpoint. The literature and test data reviews were published in the final report, Environmentally Preferable Options for Furniture Fire Safety Low Density Furniture Foam . In addition, each hazard endpoint was ranked with a concern level (High, Moderate or Low) based on the criteria used by the EPA s New Chemicals Program to rate the concern level of new chemicals submitted under the Toxic Substance Control Act (TSCA). As seen in Figure 8.2, where the hazard endpoint rankings are bold, the value is based on experimental data. Where the hazard endpoints are presented in italic font, the value is estimated based on models or chemical analogs. In this way, detailed hazard information was summarized and presented in a clear and concise format. 

Amot JA, Mackay D (2008) Policies for chemical hazard and risk priority setting can persistence, bioaccumulation, toxicity, and quantity information be combined Environ Sci Technol 42(13) 4648 1654... 

The environmental fate of chemicals describes the processes by which chemicals move and are transformed into the environment. Environmental fate processes that should be addressed include persistence in air, water and soil reactivity and degradation migration in groundwater removal from effluents by standard waste-water treatment methods and bioaccumulation in aquatic or terrestrial organisms. 

Chiou, C., Freed, D., Schmedding, D., Kohnert, R. (1977) Partition coefficient and bioaccumulation of selected organic chemicals. Environ. Sci. Technol. 11(5),475 -78. 

Thomann, R.V. (1989) Bioaccumulation model of organic chemical distribution in aquatic food chains. Environ. Sci. Technol. 23, 699-707. 

Mercury (Hg) can occur in a large number of physical and chemical forms with a variety of properties, thus determining complex distribution, bioavailability, and toxicity patterns [1]. The most important chemical forms are elemental Hg (Hg°), ionic Hg (Hg2+ and Hg22+), and alkylmercury compounds. Because of their capability to permeate through biological membranes and to bioaccumulate and to biomagnificate through the trophic chain, alkylmercury compounds are the most toxic mercury species found in the aquatic environment [2]. 

Berthet, B., J.C. Amiard, C. Amiard-Triquet, M. Martoja, and A.Y. Jeantet. 1992. Bioaccumulation, toxicity and physico-chemical speciation of silver in bivalve molluscs ecotoxicological and health consequences. Sci. Total Environ. 125 97-122. 

Van der Oost, R., H. Heida, and A. Opperhuizen. 1988. Polychlorinated biphenyl congeners in sediments, plankton, mollusks, crustaceans, and eel in a freshwater lake implications of using reference chemicals and indicator organisms in bioaccumulation studies. Arch. Environ. Contam. Toxicol. 17 721-729. 

The water insoluble, highly chemically and thermally stable PCBs used as insulating fluids for transformers and capacitors, in paints, copy paper, etc., are extremely toxic, persistent in the environment and bioaccumulating. PCBs are currently destroyed by incineration of concentrates at high temperatures or chemically with sodium metals or organosodium. Both processes are costly. The cathodic reduction/elimination of the chlorine from polychlorinated biphenyl... 

The replacement of established chemistries with newer ones is one of the classic drivers of change in the chemical industry. One of the current hotbeds of this kind of change is the replacement of brominated flame retardants in polymer formulations. The brominated flame retardants under the most scrutiny have been polybrominated diphenyl ethers, particularly penta- and octabromodiphenyl ether, which have been shown to be persistent in the environment and to bioaccumulate. Great Lakes Chemical is voluntarily phasing out penta- and octa-BDEs by the end of next year. The phaseout is made possible by the clean bill of health granted by EPA for Firemaster 550, a replacement for penta-BDE in flexible PU applications. BRG Townsend claims the phaseout of penta-BDE and octa-BDE is not as earth shattering as would be an exit from deca-BDE, a styrenics additive that is produced in the highest volume of the PBDEs. 

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