Organophosphate ester exposure among Chinese waste incinerator workers: Urinary levels, risk assessment and associations with oxidative stress.

Organophosphate esters (OPEs), which are frequently used as flame retardants and plasticizers in versatile products, are readily released to the external environment. Although workers at municipal waste incineration plants may be extensively exposed to OPEs, only scarce health monitoring and risk assessments have been conducted in this population. In this study, we investigated the levels of eight metabolites of organophosphate esters (mOPEs) and the oxidative stress marker 8-hydroxy-2-deoxyguanosine (8-OHdG) in urine samples from 73 waste incinerator workers and 97 general residents from Shenzhen, China between September 2016 and June 2017. The overall detection rate of mOPEs was 82.2 %-100 %, and higher concentrations of di-p-cresyl phosphate and chlorinated mOPEs [bis(2-chloroethyl) phosphate (BCEP), bis(1-chloro-2propyl) phosphate (BCIPP), bis(1,3-dichloro-2-propyl) phosphate) (BDCIPP)] were found among incinerator workers than among general residents. The incinerator workers also showed significantly higher levels of 8-OHdG than general residents, but the measured levels of most mOPEs were not significantly correlated with the level of 8-OHdG; this may be because co-exposure to multiple toxic compounds can lead to oxidative stress. Risk assessment using Monte Carlo simulations revealed that 95 % of the incinerator workers were free from non-carcinogenic effects due to OPEs exposure (hazard index = 0.27, 95 % CI: 0.09, 0.77). However, the carcinogenic risk of tris(2-chloroethyl) phosphate (TCEP) for incinerator workers was between 10-6 and 10-4. These results indicate that incinerator workers are extensively exposed to OPEs, and better protective measures need to be implemented.

Distributions, influencing factors, and risk assessment of Dechlorane Plus and related compounds in surficial water and sediment from the Jiulong River Estuary, Southeast China.

Dechloranes, a type of additive polychlorinated flame retardant, which include Dechlorane (Dec) Plus (DP), Dec 602, Dec 603, and Dec 604, were detected in surficial water and sediment from the Jiulong River Estuary (JRE). The total concentration of dechloranes in the water and sediments ranged from 1.4 to 4.1 ng/L and 9.3 to 36.2 ng/g dry weight, respectively. The distribution patterns of dechloranes in the water and sediments were both dominated by DP. The average values of the anti-DP fractional abundances (fanti) in the water and sediment samples both were fell in the range of commercial DP mixtures. The relationships of DP in the water with suspended particulate matter (SPM), total organic carbon (TOC), and tides indicated that the combined actions of these environmental factors influenced the distribution of DP in the JRE. The deleterious risk associated with exposure to dechloranes via the water for adults was very low, suggesting that exposure of the local population of dechloranes via water is relatively safe in the JRE.

Assessment of dermal hazard from acid burns with fire retardant garments in a full-size simulation of an engulfment flash fire.

There have been concerns that fire-derived acid gases could aggravate thermal burns for individuals wearing synthetic flame retardant garments. A comparative risk assessment was performed on three commercial flame retardant materials with regard to relative hazards associated with acidic combustion gases to skin during a full engulfment flash fire event. The tests were performed in accordance with ASTM F1930 and ISO 13506: Standard Test Method for Evaluation of Flame Resistant Clothing for Protection against Fire Simulations Using an Instrumented Manikin. Three fire retardant textiles were tested: an FR treated cotton/nylon blend, a low Protex(®) modacrylic blend, and a medium Protex(®) modacrylic blend. The materials, in the form of whole body coveralls, were subjected to propane-fired flash conditions of 84kW/m(2) in a full sized simulator for a duration of either 3 or 4s. Ion traps consisting of wetted sodium carbonate-impregnated cellulose in Teflon holders were placed on the chest and back both above and under the standard undergarments. The ion traps remained in position from the time of ignition until 5min post ignition. Results indicated that acid deposition did increase with modacrylic content from 0.9µmol/cm(2) for the cotton/nylon, to 12µmol/cm(2) for the medium modacrylic blend. The source of the acidity was dominated by hydrogen chloride. Discoloration was inversely proportional to the amount of acid collected on the traps. A risk assessment was performed on the potential adverse impact of acid gases on both the skin and open wounds. The results indicated that the deposition and dissolution of the acid gases in surficial fluid media (perspiration and blood plasma) resulted in an increase in acidity, but not sufficient to induce irritation/skin corrosion or to cause necrosis in open third degree burns.

Accumulation and endocrine disrupting effects of the flame retardant mixture Firemaster® 550 in rats: an exploratory assessment.

Firemaster® 550 (FM 550), a fire-retardant mixture used in foam-based products, was recently identified as a common contaminant in household dust. The chemical structures of its principle components suggest they have endocrine disrupting activity, but nothing is known about their physiological effects at environmentally relevant exposure levels. The goal of this exploratory study was to evaluate accumulation, metabolism and endocrine disrupting effects of FM 550 in rats exposed to 100 or 1000 µg/day across gestation and lactation. FM 550 components accumulated in tissues of exposed dams and offspring and induced phenotypic hallmarks associated with metabolic syndrome in the offspring. Effects included increased serum thyroxine levels and reduced hepatic carboxylesterease activity in dams, and advanced female puberty, weight gain, male cardiac hypertrophy, and altered exploratory behaviors in offspring. Results of this study are the first to implicate FM 550 as an endocrine disruptor and an obesogen at environmentally relevant levels.

Risk migration and scientific advance: the case of flame-retardant compounds.

It is a common experience that attempts to mitigate a risk lead to new risks, and that risks formerly thought to be of one kind become another kind as technical knowledge evolves. This phenomenon of risk migration suggests that we should take processes over time, rather than specific risks or specific technologies, as a unit of analysis. Several of our existing models of the social management of risks-such as that of social risk amplification-are process models of a kind but are still oriented around the playing out of a particular event or issue. A case study of risk in a group of flame-retardant compounds was used as the basis of a grounded, exploratory analysis of migration processes, the phenomena that influence them, and their consequences. This illustrated how migration naturally occurs from risks that are understood, in which risk bearers have at least some agency, to risks that are not understood and not capable of being influenced by risk bearers. It illustrated how the simultaneous improvement in measuring technology, which detects potential toxins at increasingly small concentrations, combines with intuitive models that ignore concentration to produce conditions likely to generate anxiety. And it illustrated how pressure groups and commercial interests exploit this effect. It also showed how migration makes precautionary action problematic, and how more generally it tends to undermine a society's capacity to cope with risk.

Uncertainties and data needs in risk assessment of three commercial polybrominated diphenyl ethers: probabilistic exposure analysis and comparison with European Commission results.

Some environmental monitoring programs have reported increasing levels of certain polybrominated diphenyl ether (PBDE) isomers in aquatic biota and in human breast milk. The commercial PBDE products are known as penta-, octa-, and deca-brominated diphenyl ethers (PeBDE, OBDE and DBDE, respectively). Aside from the current European Commission's risk assessment initiative and efforts underway in Sweden, Canada and elsewhere to evaluate environmental levels, little is understood about sources of exposure and risks to humans. In this study, a multi-pathway human health risk assessment was performed to predict theoretical chronic daily intakes (CDIs) of PeBDE, OBDE, and DBDE by five different age groups: 0-2, 2-6, 6-12, 12-18, and 18-70 years. Sources of exposure included air, drinking water, consumption of fish, vegetables, meat and dairy products, and ingestion of breast milk by infants. In addition to a deterministic analysis, the risk assessment included a probabilistic analysis to derive the probability density functions describing the range of plausible exposures associated with eight different pathways, as well as aggregate lifetime exposures for each age group. The results were compared to CDI point estimates calculated by the European Chemicals Bureau as part of the European Commission's Existing Substances Programme. The major sources of uncertainties are discussed, including environmental sources, levels in different environmental compartments, toxicity, and human exposure. This paper also discusses the limitations in the current state-of-the-science and provides recommendations for improving the scientific relevance and accuracy of future environmental risk assessments of PBDEs.

Air Force approach to risk assessment for halon replacements.

Finding safe, environmentally acceptable, and effective replacements for Halon fire-extinguishing agents and other chemicals banned by the Montreal Protocol is a formidable task for Air Force research and development organizations. One factor that makes this task a challenge is the uncertainty in relating toxicology studies in laboratory animals to the human situation. This uncertainty from toxicology studies affects the risk assessment process by calling for very conservative decisions. Because of this uncertainty, public pressure and politics also impact the regulatory process. The Air Force approach to assessing health hazards for Halon replacements is to provide scientific information that directly applies to the parts of the extrapolation process that are responsible for the most uncertainty. Most regulatory agencies readily incorporate scientific information, when it is available, which can reduce uncertainty. These Air Force studies will be used to provide realistic exposure levels for replacement chemicals which will allow mission accomplishment and provide safety for the worker and the populace.