The Harm of Bioethics: A Critique of Singer and Callahan on Obesity

Debate concerning the social impact of obesity has been ongoing since at least the 1980s. Bioethicists, however, have been relatively silent. If obesity is addressed it tends to be in the context of resource allocation or clinical procedures such as bariatric surgery. However, prominent bioethicists Peter Singer and Dan Callahan have recently entered the obesity debate to argue that obesity is not simply a clinical or personal issue but an ethical issue with social and political consequences. This article critically examines two problematic aspects of Singer and Callahan's respective approaches. First, there is an uncritical assumption that individuals are autonomous agents responsible for health‐related effects associated with food choices. In their view, individuals are obese because they choose certain foods or refrain from physical activity. However, this view alone does not justify intervention. Both Singer and Callahan recognize that individuals are free to make foolish choices so long as they do not harm others. It is at this point that the second problematic aspect arises. To interfere legitimately in the liberty of individuals, they invoke the harm principle. I contend, however, that in making this move both Singer and Callahan rely on superficial readings of public health research to amplify the harm caused by obese individuals and ignore pertinent epidemiological research on the social determinants of obesity. I argue that the mobilization of the harm principle and corresponding focus on individual behaviours without careful consideration of the empirical research is itself a form of harm that needs to be taken seriously.     

Analysis and assessment of heavy metals pollution in soils around a Pb and Zn smelter in Baoji City,Northwest China

Soil heavy metal pollution from mining activities is potentially harmful to human health through the food chain. In this study, a total of 43 soil samples were collected from a depth of 0–20 cm from fields close to a Pb and Zn smelter. The samples were used to: 1) analyze the pollution level of heavy metals (Pb, Zn, Cr, and Cu) and spatial distribution pattern; 2) evaluate the degree of accumulation and enrichment, potential ecological risk, and human health risk; and 3) perform source apportionment in Fengxiang County, Shaanxi Province of China. The results showed that the concentration ranged from 43.67 to 189.55, 131.43 to 239.53, 74.77 to 112.25, and 24.69 to 37.71 mg·kg^?1 for Pb, Zn, Cr, and Cu, respectively, and the mean concentration for Pb, Zn, Cr, and Cu was 129.46, 192.85, 91.98 and 31.67 mg·kg^?1, respectively. The concentrations were greater than the Shaanxi Province background values, while they were lower than the second-level limits of Environmental Quality Standard for Soils of China (EQSS). The spatial distribution of heavy metal contents showed a banded in soil except Cu. The spatial distribution pattern and pollution assessment indexes (I_geo, EF) indicated that the investigated metals had been accumulated in the study areas, and implied significant influences from anthropogenic activities, local meteorological situation, and soil properties. The ecological risk assessment showed that the risks were relatively low (RI<150). Compared with the exposure risk for adults, that for children was significantly greater. The ingestion of heavy metals in the soils by humans was the main exposure pathway compared with the dermal exposure. There may be a risk of noncarcinogenic adverse health effects (HQ < 1, 0.377 ≤ HI≤1.553) on children, but the adults were unlikely to experience obvious adverse health effects (HQ < 1, HI < 1). The carcinogenic risk of Cr for adults and children was at an unacceptable level. The carcinogenic and noncarcinogenic risks were in the order of children > adults. The correlation analysis showed that Pb, Cr, and Cu have identical anthropogenic and natural sources, while Zn has another identical source. This study could provide a basis for the sustainable management of this region by reducing metal inputs and to protect soils from long-term heavy metal accumulation.     

Catastrophic disturbance, logging and the ecology of mahogany (Swietenia macrophylla King): grounds for listing a major tropical timber species in CITES

Recent debate on whether or not mahogany ( Swietenia macrophylla King) is threatened by the international timber trade has focused on the breadth of its range and estimates of the remaining stock of mahogany trees. These data are inadequate to reveal the status of mahogany populations, both because they are incomplete in areal extent and because they do not reveal population parameters such as the existence or density of young trees smaller than commercial size. However, there is sufficient information on the regeneration ecology of mahogany to indicate that under natural conditions this species regenerates in essentially even-aged stands after catastrophic disturbances destroy many or most trees, and, in the case of fires and flooding, saplings and seedlings as well. Adult mahoganies tend to survive these events, and regenerate by shedding seed onto the resulting gaps or clearings. This ecological strategy makes mahogany vulnerable to logging, first because juvenile mahoganies are not found in the understorey, and secondly because logging operations shortcircuit mahogany regeneration processes by selectively removing almost all mahogany seed sources while leaving standing competing vegetation of other species. Listing of mahogany in CITES Appendix II could provide both a mechanism to fill in gaps in information and an incentive to change current practices in favour of silvicultural management to provide for regeneration of this valuable timber species in forests subjected to logging.     

Individualistic responses of forest herb traits to environmental change

• Intraspecific trait variation (ITV; i.e. variability in mean and/or distribution of plant attribute values within species) can occur in response to multiple drivers. Environmental change and land‐use legacies could directly alter trait values within species but could also affect them indirectly through changes in vegetation cover. Increasing variability in environmental conditions could lead to more ITV, but responses might differ among species. Disentangling these drivers on ITV is necessary to accurately predict plant community responses to global change.
• We planted herb communities into forest soils with and without a recent history of agriculture. Soils were collected across temperate European regions, while the 15 selected herb species had different colonizing abilities and affinities to forest habitat. These mesocosms (384) were exposed to two‐level full‐factorial treatments of warming, nitrogen addition and illumination. We measured plant height and specific leaf area (SLA).
• For the majority of species, mean plant height increased as vegetation cover increased in response to light addition, warming and agricultural legacy. The coefficient of variation (CV) for height was larger in fast‐colonizing species. Mean SLA for vernal species increased with warming, while light addition generally decreased mean SLA for shade‐tolerant species. Interactions between treatments were not important predictors.
• Environmental change treatments influenced ITV, either via increasing vegetation cover or by affecting trait values directly. Species’ ITV was individualistic, i.e. species responded to different single resource and condition manipulations that benefited their growth in the short term. These individual responses could be important for altered community organization after a prolonged period.

     

Health risk assessment of heavy metals in soils and maize (Zea mays L.) from Yushu,Northeast China

To investigate heavy metal accumulation in soils and evaluate health risk through maize consumption, a total of 196 soils and 55 maize samples were collected from Yushu, China, one of the most important maize production bases. The mean contents of Cd, Cr, Cu, Zn and Pb were 0.119, 56.51, 19.21, 70.58, and 34.42 mg kg^?1 for soils and were 0.014, 0.68, 1.33, 17.15 and 0.02 mg kg^?1 for maize, respectively. The contents of Cr, Cu, Zn and Pb in all soil and maize samples did not exceed safety thresholds, but the percentages of Cd content above guideline values of Chinese Environmental Quality Standards for Soil and maximum permissible limits for maize were 6.6% and 1.8%, respectively. The spatial distribution and correlation analysis suggested that Cr and Cu in soil were of lithogenic origin, while Zn and Pb were associated with coal combustion exhausts and chemical fertilizer application. The main source of Cd may be phosphate fertilizer application. The average target hazard quotients were all less than 1 and the average hazard index for adults was 0.065, indicating that there was not a potential health risk through maize.