Impact of long-term nitrogen deposition on the response of dune grassland ecosystems to elevated summer ozone.

Nitrogen deposition and tropospheric ozone are important drivers of vegetation damage, but their interactive effects are poorly understood. This study assessed whether long-term nitrogen deposition altered sensitivity to ozone in a semi-natural vegetation community. Mesocosms were collected from sand dune grassland in the UK along a nitrogen gradient (5-25 kg N/ha/y, including two plots from a long-term experiment), and fumigated for 2.5 months to simulate medium and high ozone exposure. Ozone damage to leaves was quantified for 20 ozone-sensitive species. Soil solution dissolved organic carbon (DOC) and soil extracellular enzymes were measured to investigate secondary effects on soil processes. Mesocosms from sites receiving the highest N deposition showed the least ozone-related leaf damage, while those from the least N-polluted sites were the most damaged by ozone. This was due to differences in community-level sensitivity, rather than species-level impacts. The N-polluted sites contained fewer ozone-sensitive forbs and sedges, and a higher proportion of comparatively ozone-resistant grasses. This difference in the vegetation composition of mesocosms in relation to N deposition conveyed differential resilience to ozone. Mesocosms in the highest ozone treatment showed elevated soil solution DOC with increasing site N deposition. This suggests that, despite showing relatively little leaf damage, the 'ozone resilient' vegetation community may still sustain physiological damage through reduced capacity to assimilate photosynthate, with its subsequent loss as DOC through the roots into the soil. We conclude that for dune grassland habitats, the regions of highest risk to ozone exposure are those that have received the lowest level of long-term nitrogen deposition. This highlights the importance of considering community- and ecosystem-scale impacts of pollutants in addition to impacts on individual species. It also underscores the need for protection of 'clean' habitats from air pollution and other environmental stressors.

Variation in hepatitis C services may lead to inequity of heath-care provision: a survey of the organisation and delivery of services in the United Kingdom.

BACKGROUND: Chronic hepatitis C infection (CHC) is a major healthcare problem. Effective anti-viral therapy is available. To maximise population effectiveness, co-ordinated services for detection and management of patients with CHC are required. There is a need to determine patterns of healthcare delivery to plan improvements. A study was conducted to determine workload, configuration and care processes of current UK services available to manage patients with CHC. METHODS: A cross-sectional questionnaire survey of consultant members of British Association for the Study of the Liver (n = 53), Infectious Disease consultants (n = 43), and a 1 in 5 sample of Genito-Urinary Medicine (n = 48) and gastroenterologists (n = 200). RESULTS: Response rate was 70%. 40% of respondents provided a comprehensive service (included treatment and follow-up): speciality of clinical leads identified as Hepatology (37%); Gastroenterology (47%); and Infectious Disease (16%). The estimated number of patients managed by respondents was about 23,000 with an upward trend over the previous 3 years. There was variation between comprehensive service providers, including unit size, eligibility criteria for treatment, and drug regimes. Key barriers to quality of care identified were staffing capacity, funding of treatment and patient non-attendance. Most English strategic health authorities had at least one comprehensive service provider. CONCLUSION: There was significant variation in all aspects of the patient pathway which may contribute to inequity of health care provision. Services need to be expanded to form geographical clinical networks, and properly resourced to ensure greater uptake and more equitable delivery of services if the future burden of chronic liver disease is to be reduced.