The problem of acid rain: An overview

Summary The solution to the problem of acid rain is perhaps one of the main environmental and political issues facing the peoples of the industrialized nations, and their neighbours today. There is no doubt about the damage which acid rain has caused, but what remains unclear are the precise causes of acid rain and the most efficacious means of reducing its environmental, economic and political impacts. We have presented a balanced look at the differing points of view on the current state of knowledge in acid rain research with respect to atmospheric processes, environmental effects, measurement procedures, and the legal and political issues surrounding acid rain. This review indicates that the atmospheric processes creating and transporting acid rain are not well enough understood to enable its reduction with any guarantee of success. This conclusion is based on the confusing or conflicting evidence presented by recent scientific studies. It appears that more research must be undertaken to understand the problem of acid rain before final recommendations may be made for its solution.Mr Eney is a lecturer and Dr. Petzold is Professor of Climatology in the Department of Geography at the University of Maryland. They have recently completed research on the spatial distribution of acid rain over the Washington, D.C. metropolitan area of USA.     

Prioritization of climate change adaptation approaches in the Gambia

Adaptation to climate change has been recognized as very important in developing countries that face the greatest threats from global warming. In proposing various adaptation approaches, the United Nations Intergovernmental Panel on Climate Change required nations to prepare adaptation plans of action. However, the areas of priority in climate change adaptation have not been considered. This study has developed a new prioritization methodology for climate change adaptation in developing countries. Five categories and 25 approaches in climate change adaptation were adopted through a thorough and detailed analysis of pertinent literature related to the National Adaptation Program of Action (NAPA) in the Gambia. A fuzzy analytic hierarchy process-based questionnaire survey was designed and presented to 12 experts chosen from the committee members of the Gambia’s NAPA. The survey was made to determine the relative importance of the strategies for climate change adaptation. The results indicate that the five most important adaptation categories are health (0.223), forestry (0.213), water (0.210), food (0.181), and energy (0.174), with health as the number one priority in climate change adaptation. Further findings show that the prioritization order of the adaptation approaches to climate change in the Gambia is as follows: “Health education,” “public sensitization,” “water supply infrastructure development,” “microfinance,” and “infrastructure and technology enhancement.”     

Total organic halogen (TOX) in human urine: A halogen-specific method for human exposure studies

Disinfection by-products(DBPs) are a complex mixture of compounds unintentionally formed as a result of disinfection processes used to treat drinking water. Effects of long-term exposure to DBPs are mostly unknown and were the subject of recent epidemiological studies. However,most bioanalytical methods focus on a select few DBPs. In this study, a new comprehensive bioanalytical method has been developed that can quantify mixtures of organic halogenated compounds, including DBPs, in human urine as total organic chlorine(TOCl), total organic bromine(TOBr), and total organic iodine(TOI). The optimized method consists of urine dilution, adsorption to activated carbon, pyrolysis of activated carbon, absorption of gases in an aqueous solution, and halide analysis with ion chromatography and inductively coupled plasma-mass spectrometry. Spike recoveries for TOCl, TOBr, and TOI measurements ranged between 78% and 99%. Average TOCl, TOBr, and TOI concentrations in five urine samples from volunteers who consumed tap water were 1850, 82, and 21.0 μg/L as X~-, respectively.Volunteers who consumed spring water(control) had TOCl, TOBr, and TOI average concentrations in urine of 1090, 88, and 10.3 μg/L as X~-, respectively. TOCl and TOI in the urine samples from tap water consumers were higher than the control. However, TOBr was slightly lower in tap water urine samples compared to mineral water urine samples, indicating other sources of environmental exposure other than drinking water. A larger sample population that consumes tap water from different cities and mineral water is needed to determine TOCl, TOBr, and TOI exposure from drinking water.     

Coastal flooding in the Northeastern United States due to climate change

With dense population and development along its coastline, the northeastern United States is, at present, highly vulnerable to coastal flooding. At five sea level stations in the United States, from Massachusetts to New Jersey, sea level rise (SLR) trends and tidal effects were removed from the hourly sea level time series and then frequency analysis was performed on the positive remaining anomalies that represent storm surge heights. Then using eustatic SLR estimates for lower and higher greenhouse gas emissions scenarios and assumed trends in local sea level rise, new recurrence intervals were determined for future storm surges. Under the higher emissions scenario, by 2050, the elevation of the 2005 100-year event may be equaled or exceeded at least every 30 years at all sites. In more exposed US cities such as Boston, Massachusetts and Atlantic City, New Jersey, this could occur at the considerably higher frequency of every 8 years or less. Under the lower emissions scenario, by 2050, the elevation of the 2005 100-year event may be equaled or exceeded at least every 70 years at all sites. In Boston and Atlantic City, this could occur every 30 years or less.     

Soil microbial response to waste potassium silicate drilling fluid

Potassium silicate drilling fluids (PSDF) are a waste product of the oil and gas industry with potential for use in land reclamation. Few studies have examined the influence of PSDF on abundance and composition of soil bacteria and fungi. Soils from three representative locations for PSDF application in Alberta, Canada, with clay loam, loam and sand textures were studied with applications of unused, used once and used twice PSDF. For all three soils, applying ≥40 m³/ha of used PSDF significantly affected the existing soil microbial flora. No microbiota was detected in unused PSDF without soil. Adding used PSDF to soil significantly increased total fungal and aerobic bacterial colony forming units in dilution plate counts, and anaerobic denitrifying bacteria numbers in serial growth experiments. Used PSDF altered bacterial and fungal colony forming unit ratios of all three soils.     

Soil microbial response to waste potassium silicate drilling fluid

Potassium silicate drilling fluids(PSDF) are a waste product of the oil and gas industry with potential for use in land reclamation. Few studies have examined the influence of PSDF on abundance and composition of soil bacteria and fungi. Soils from three representative locations for PSDF application in Alberta, Canada, with clay loam, loam and sand textures were studied with applications of unused, used once and used twice PSDF. For all three soils, applying ≥ 40 m3/ha of used PSDF significantly affected the existing soil microbial flora. No microbiota was detected in unused PSDF without soil. Adding used PSDF to soil significantly increased total fungal and aerobic bacterial colony forming units in dilution plate counts, and anaerobic denitrifying bacteria numbers in serial growth experiments.Used PSDF altered bacterial and fungal colony forming unit ratios of all three soils.     

Remediation of chloroform in fine-textured soil using zero-valent iron

Chloroform, a probable human carcinogen, is mainly produced anthropogenically for industrial use and may be released to the environment from a large number of sources related to its manufacture and use, including pulp and paper mills, hazardous waste sites, and sanitary landfills. Remediation of chloroform through conventional technologies has been met with limited success due to the conditions required and the formation of hazardous substances such as dichloromethane. The objective of this study was to investigate chloroform reduction in multicontaminated fine-textured soil using zero-valent iron (Fe⁰) in anaerobic microcosms. Four amended matrices were tested: simple matrix control (glass beads), soil matrix control (glass beads + soil), Fe⁰ in a simple matrix (glass beads + Fe⁰), and Fe⁰ in a soil matrix (soil + Fe⁰). Headspace chloroform and its transformation products dichloromethane, chloromethane, and methane were measured over 230 days and during short intervals in the initial 3 days. Chloroform (~0.3 mM initial mass) persisted in both control microcosms but was completely transformed in microcosms containing soil + Fe⁰ by 12 h and glass beads + Fe⁰ by 48 h. Reductive dechlorination of chloroform occurred with simultaneous production of dichloromethane (~0.11 to 0.14 mM mass) and chloromethane (~0.02 to 0.13 mM mass). Little methane (~0.07 to 0.26 μM mass) production as an end product of chloroform reduction was observed in microcosms amended with Fe⁰. Produced dichloromethane and chloroform almost disappeared by 230 days. The results showed a complete chloroform transformation pathway that has good potential for the remediation of chlorinated compounds in fine-textured soil. The role of soil clay minerals in redox reactions can be further investigated to improve the reductive dechlorination of chlorinated compounds in contaminated environments.     

The virtue of compassion in compassionate conservation

The role of ethics is becoming an increasingly important feature of biodiversity conservation dialogue and practice. Compassionate conservationists argue for a prohibition of, or at least a strong presumption against, the adoption of conservation policies that intentionally harm animals. They assert that to be compassionate is to care about animals and that it is antithetical to caring for animals to intentionally harm them. Compassionate conservationists thus criticize many existing conservation practices and policies. Two things together challenge the philosophical foundation of compassionate conservation. First, compassionate conservationists ground their theory in virtue ethics, yet virtue ethics permits exceptions to moral rules, so there cannot be an in-principle prohibition on adopting intentional harm-inducing policies and practices. But not all compassionate conservationists advocate for a prohibition on intentionally harming animals, only a strong presumption against it. This leads to the second point: compassion can motivate a person to adopt a harm-inducing conservation policy or practice when doing so is the best available option in a situation in which animals will be harmed no matter what policy or practice is adopted. Combining these insights with the empirical observation that conservationists regularly find themselves in tragic situations, we arrive at the conclusion that conservationists may regularly advocate for harm-inducing policies and practices from a position of compassion. Article Impact Statement: Compassionate conservationists should accept that the virtuously compassionate person may adopt harm-causing conservation policies.