Jun Sekizawa

Persistence and partitioning of eight selected pharmaceuticals in the aquatic environment: laboratory photolysis, biodegradation, and sorption experiments.

We selected eight pharmaceuticals with relatively high potential ecological risk and high consumption-namely, acetaminophen, atenolol, carbamazepine, ibuprofen, ifenprodil, indomethacin, mefenamic acid, and propranolol-and conducted laboratory experiments to examine the persistence and partitioning of these compounds in the aquatic environment. In the results of batch sunlight photolysis experiments, three out of eight pharmaceuticals-propranolol, indomethacin, and ifenprodil-were relatively easily photodegraded (i.e., half-life<24h), whereas the other five pharmaceuticals were relatively stable against sunlight. The results of batch biodegradation experiments using river water suggested relatively slow biodegradation (i.e., half-life>24h) for all eight pharmaceuticals, but the rate constant was dependent on sampling site and time. Batch sorption experiments were also conducted to determine the sorption coefficients to river sediments and a model soil sample. The determined coefficients (K(d) values) were much higher for three amines (atenolol, ifenprodil, and propranolol) than for neutral compounds or carboxylic acids; the K(d) values of the amines were comparable to those of a four-ring polycyclic aromatic hydrocarbon (PAH) pyrene. The coefficients were also higher for sediment/soil with higher organic content, and the organic carbon-based sorption coefficient (logK(oc)) showed a poor linear correlation with the octanol-water distribution coefficient (logD(ow)) at neutral pH. These results suggest other sorption mechanisms-such as electrochemical affinity, in addition to hydrophobic interaction-play an important role in sorption to sediment/soil at neutral pH.

Integrated Human and Ecological Risk Assessment: A Case Study of Tributyltin and Triphenyltin Compounds

Tributyltin and triphenyltin (TBT and TPT) are biocides that have been used to prevent fouling of boats, preserve wood, kill molluscs, and other uses. Due to observed effects on oysters and snails, their use in boat paints has been banned in many nations. However, use on ships and some uses other than as antifouling paints continue. These uses, the relative persistence of these compounds, their tendency to bioaccumulate, and their toxicity cause lingering concerns about risks to humans and non-human organisms. This paper outlines an integrated assessment of TBT and TPT. Based on prior human health and ecological assessments, it suggests that an integrated assessment that recognized common pathways of transport, fate and exposure, and common modes of action would be more efficient and complete than additional independent assessments. The presentation of risks in an integrated manner could also lead to better decisions by defining the various benefits of any management action.

Types of Integration in Risk Assessment and Management, And Why They Are Needed

Risk-based decision making requires that the decision makers and stakeholders are informed of all risks that are potentially significant and relevant to the decision. The International Programme on Chemical Safety of the World Health Organization has developed a framework for integrating the assessment of human health and ecological risks. However, other types of integration are needed to support particular environmental decisions. They are integration of exposure and effects, of multiple chemicals and other hazardous agents, of multiple routes of exposure, of multiple endpoints, multiple receptors, multiple spatial and temporal scales, a products life cycle, management alternatives, and socioeconomics with risk assessment. Inclusion of all these factors in an integrated assessment could lead to paralysis by analysis. Therefore, it is important that assessors be cognizant of the decision process and that decision makers and those who will influence the decision (stakeholders) be involved in planning the assessment to ensure that the degree of integration is necessary and sufficient.

An Assessment of Integrated Risk Assessment

ABSTRACT In order to promote international understanding and acceptance of the integrated risk assessment process, the World Health Organization/International Programme on Chemical Safety (WHO/IPCS), in collaboration with the U.S. Environmental Protection Agency and the Organization for Economic Cooperation and Development, initiated a number of activities related to integrated risk assessment. In this project, the WHO/IPCS defines integrated risk assessment as a science-based approach that combines the processes of risk estimation for humans, biota, and natural resources in one assessment. This article explores the strengths and weaknesses of integration as identified up to this date and the degree of acceptance of this concept by the global risk assessment/risk management community. It discusses both opportunities and impediments for further development and implementation. The major emerging opportunities for an integrated approach stem from the increasing societal and political pressure to move away from vertebrate testing leading to a demand for scientific integrated approaches to in vitro and in vivo testing, as well as to computer simulations, in so-called Intelligent Testing Strategies. In addition, by weighing the evidence from conventional mammalian toxicology, ecotoxicology, human epidemiology, and eco-epidemiology, risk assessors could better characterize mechanisms of action and the forms of the relationships of exposures to responses. It is concluded that further demonstrations of scientific, economic and regulatory benefits of an integrated approach are needed. As risk assessment is becoming more mechanistic and molecular this may create an integrated approach based on common mechanisms and a common systems-biology approach.

Evaluation of Human Health Risks From Exposures to Four Air Pollutants in the Indoor and the Outdoor Environments in Tokushima, and Communication of the Outcomes to the Local People

The Law concerning Reporting etc., of Releases to the Environment of Specific Chemical Substances, and Promoting Improvement in Their Management (the so‐called Pollutant Release and Transfer Register Law or the PRTR Law) was promulgated in Japan in 1999. Estimated amounts of the specific chemical substances released from their major emission sources to local environments are publicly available by law. Concentrations of benzene, toluene, xylene (i.e., volatile organic compounds or VOCs) and formaldehyde specified by law were measured in different seasons from 2003 to 2005 both at outdoor and indoor sites within the Tokushima University campus and in a nearby local area to estimate their human exposures. There were no substantial differences between the indoor and the outdoor concentrations of benzene, toluene, and xylene. Higher concentrations observed for formaldehyde in the indoor environment than in the outdoor environment in the 2003 winter season could be explained by the fact that there was renovation of the building nine months before the measurement. The exposure data obtained were used to evaluate the possible human health risks of these four chemicals by referring to their health criteria. The results indicated that the overall risks from the exposures to these chemicals both in the indoor and the outdoor environments were not significantly high even if fluctuations are taken into account. The results of our evaluation were released on the university website and also presented and discussed at a public meeting and three PRTR data seminars in the local society.