Assessing the Cost of an Invasive Forest Pathogen: A Case Study with Oak Wilt

Economic assessment of damage caused by invasive alien species provides useful information to consider when determining whether management programs should be established, modified, or discontinued. We estimate the baseline economic damage from an invasive alien pathogen, Ceratocystis fagacearum, a fungus that causes oak wilt, which is a significant disease of oaks (Quercus spp.) in the central United States. We focus on Anoka County, Minnesota, a 1,156 km² mostly urban county in the Minneapolis-Saint Paul metropolitan region. We develop a landscape-level model of oak wilt spread that accounts for underground and overland pathogen transmission. We predict the economic damage of tree mortality from oak wilt spread in the absence of management during the period 2007–2016. Our metric of economic damage is removal cost, which is one component of the total economic loss from tree mortality. We estimate that Anoka County has 5.92 million oak trees and 885 active oak wilt pockets covering 5.47 km² in 2007. The likelihood that landowners remove infected oaks varies by land use and ranges from 86% on developed land to 57% on forest land. Over the next decade, depending on the rates of oak wilt pocket establishment and expansion, 76–266 thousand trees will be infected with discounted removal cost of $18–60 million. Although our predictions of removal costs are substantial, they are lower bounds on the total economic loss from tree mortality because we do not estimate economic losses from reduced services and increased hazards. Our predictions suggest that there are significant economic benefits, in terms of damage reduction, from preventing new pocket establishment or slowing the radial growth of existing pockets.     

Investigation of saponification for determination of polychlorinated biphenyls in marine sediments

The effects of saponification conditions (temperature and water content of saponifying solution) on the determination of chlorinated biphenyls (CBs) in marine sediments were investigated. Although highly chlorinated biphenyls (nona- to deca-CBs) decomposed during high-temperature saponification, the degree of degradation was reduced by adding water to the ethanolic potassium hydroxide saponifying solution. Room-temperature saponification yielded quantitative recovery of highly chlorinated biphenyl surrogates but low extraction efficiencies of lightly chlorinated biphenyls (mono- to di-CBs). The same samples were analyzed by other extraction techniques, for example, pressurized liquid extraction, and analytical results were compared. The mono- and di-CB concentrations were correlated with the extraction temperatures of various extraction techniques. In particular, the concentrations of some CB congeners (CB11, CB14) were higher with saponification. The low degree of degradation of highly chlorinated biphenyls and the high recovery of lightly chlorinated biphenyls were compatible when room-temperature and high-temperature saponification were combined. Except for the anomalies of CB11 and CB14, the combined method gave satisfactory results for analysis of PCBs.     

Investigation on chemical species of arsenic, selenium and antimony in fly ash from coal fuel thermal power stations

Investigations of the existing chemical forms and the concentrations of arsenic (As), selenium (Se) and antimony (Sb) in samples of fly ash obtained from six coal-fired power stations in various countries were carried out. The concentration of As was found to vary from 5.4 to 22.3 mg kg(-1), and the most common mode of occurrence of As in the fly ashes is in association with carbonates or Fe-Mn oxides. The concentrations of Se and Sb ranged from 2.3-5.2 and 1.0-3.9 mg kg(-1), respectively. The dominant chemical forms of Se and Sb in the fly ashes were as extractable species. Also, water-soluble As, Se and Sb in the fly ashes were extracted, and the chemical species of As, Se and Sb in the extract determined using HPLC-ICP-MS. This was done as the potential release of soluble As, Se and Sb through leaching of fly ash is of environmental concern. The most abundant form of As in the extract was the low toxicity As(V). The main species of Se was Se(IV), although it was found that the ratio of Se(VI) to Se(IV) in acidic fly ashes is higher than in alkaline fly ash samples. Antimony was mostly present as Sb(III).     

A survey of indoor workplace radon concentration in Japan

Radon ((222)Rn) concentration was measured at indoor workplaces in Japan to estimate effective dose to the public from (222)Rn and its progeny. Measurements were made from 2000 to 2003 at 705 sites in four categories of office, factory, school and hospital. Passive type Rn monitors equipped with two sheets of polycarbonate thin films for measuring radon concentrations were installed at observation sites and replaced every 3 months to observe seasonal variations in (222)Rn concentrations. The range of annual mean (222)Rn concentrations for all sites was 1.4-182 Bq m(-3), with the arithmetic mean and standard deviation were 20.8 and 19.5 Bq m(-3). Annual mean (222)Rn concentration observed at office, factory, school and hospital were 22.6, 10.1, 28.4 and 19.8 Bq m(-3), respectively. Seasonal variations in (222)Rn concentrations at offices, schools and hospitals were similar to those found in dwellings, and variations in factories were similar to those found in outdoor environments. (222)Rn concentration observed in every quarter period was found to decrease as follows: school>office>hospital>factory. The average effective dose to the public due to (222)Rn was estimated to be 0.41 mSv y(-1) weighted by the working population. Considering the (222)Rn exposure in indoor workplaces, effective dose to the general public is estimated to be in the range from approximately 0.42 to 0.52 mSv y(-1).     

Individual variations in fatty acid composition and concentration as indicators of the nutritional condition of wild pointhead flounder larvae

We investigated the fatty acid compositions and concentrations of wild marine fish larvae with a highly accurate method because our knowledge of them has been seriously limited compared with cultured larvae. This study presents estimates of the fatty-acid-based nutritional condition of individual larvae in the field. Because the pointhead flounder Cleisthenes pinetorum displays relatively high stock size fluctuations, we investigated the developmental change in the fatty acid compositions of the body trunk, head, and eye and the annual fluctuations in the fatty acid concentrations in the trunk. We show that the process of fatty acid accumulation is not uniform across body parts and that the trunk is a better indicator of larval nutritional status than other parts because there is less time lag. Starved larvae with simultaneously high docosahexaenomic acid ratios and low total fatty acid concentrations, as observed in laboratory experiments, are rare in the wild. Thus, starved larvae must be removed rapidly by predators before they can experience a relatively long period of starvation in the wild. Fatty acid accumulation was greater in the larvae of the 2005 year class than in those of the 2006 year class in their first feeding stage, according to the optimal model derived with generalized linear model. A previous study indicated that the 2005 year class showed stronger recruitment than the 2006 year class. We conclude that the fatty acid analysis of wild larvae is a useful index of their nutritional status and mortality, especially in the first feeding stage.     

Degradation of dibromophenols by UV irradiation

We examined the degradation of dibromophenols （DBPs）, i.e. 2,4-DBP, 2,6-DBP and 3,5-DBP by ultraviolet （UV） irradiation and estimated the relationship between degradability and molecular orbital properties of each dibromopbenol. The removal of DBPs under a UV lamp system was successfully performed in an aqueous solution. After 5 min of irradiation, the initial DBPs concentration of 20 mg/L was decreased to below 1 mg/L, and about 60% of bromide ion was released. A decrease in the concentration of dissolved organic carbon （DOC） suggested the mineralization of DBPs, The mineralization may occur after release of bromide ions because the decrease of DOC was slower than the release of bromide ions. The degradability of 3,5-DBP was slightly lower than 2,6-DBP and 2,4-DBE Molecular orbital calculation suggested that the electrophilic frontier density and the highest occupied molecular orbital （HOMO） energy may be related to the degradability of DBPs.