Associations between self-reported odour annoyance and volatile organic compounds in ‘Chemical Valley’, Sarnia, Ontario

Annoyance produced by air pollution has been suggested as a useful proxy for determining ambient air pollution exposure. However, most of the studies, to date, have focused on nitrogen dioxide and sulphur dioxide, with no work done on volatile organic compounds (VOC). This study is aimed at examining the associations between odour annoyance and VOC in ‘Chemical Valley’, Sarnia, Ontario, Canada. Annoyance scores were extracted from a community health survey (N?=?774), and exposures to VOC were estimated from respondents’ six-digit alphanumeric postal codes using land use regression models. Univariate analyses were used to explore the relationships between odour annoyance and modelled pollutants, whilst multivariate ordinal logistic regression was utilized to examine the determinants of odour annoyance. The results indicate that odour annoyance is significantly associated with modelled benzene, toluene, ethylbenzene, o-xylene and (m?+?p)?xylene (BTEX) pollutants. The findings also show that the determinants of odour annoyance in the context of VOC include gender, number of relatives in the community, perception of air pollution, community satisfaction, medical checkups, ability to cope with daily life demands and general symptoms. When compared, the analysis indicates that Sarnia residents respond to considerably lower BTEX concentrations than the allowable ‘safe’ levels in the province of Ontario. In general, the results exhibit a dose–response gradient with annoyance score increasing with rising modelled pollutant concentrations. The observed relationships suggest that odour annoyance might be a function of true exposure and may serve as a proxy for air quality and ambient air pollution monitoring. However, questionnaire-based odour annoyance scores need to be longitudinally validated across different geographical scales and pollutants if they are to be adopted at the national level.     

What motivates farmers to participate in the Nova Scotia environmental farm plan program? Evidence and environmental policy implications

Program stakeholders are interested in better understanding farmers' experience, and factors that affect farmer participation in the relatively new Environmental Farm Plan (EFP) program, implemented in several provinces in Canada. To increase relevance of the research findings to EFP program administrators and policy makers, the research methods emphasised determining whether relationships exist among program-related variables, and how such relationships affect farmers' decision choices and behaviour. Traditional farmer and farm attributes that have contrasting effects in agricultural innovation adoption and conservation management (namely age, and formal education completed), were not associated with EFP program participation. Farm income, years of farming experience, and type of agribusiness managed were associated with participation in the Nova Scotia EFP program. Although program participants tended to have higher incomes, overall, non-financial considerations dominated monetary considerations in Nova Scotia farmers' reasons for participating in the Nova Scotia EFP. Helping to publicize positive farm stewardship practices was reported as the most important reason for participating in the EFP scheme, followed by its use to help improve relationships with non-farming neighbours, and to comply with government environmental regulations. In contrast, and somewhat a surprising finding, minimizing potential farm environmental risk, program administrators' raison d'être for promoting the NS EFP, was ranked the lowest, with no respondent rating that as a "very important" or "extremely important" reason for participating in the EFP program.     

A superstructure model for the synthesis of single-contaminant water networks with partitioning regenerators

This paper presents a novel superstructure-based optimization model for the synthesis of industrial water networks with partitioning regenerators. Such regenerators function by splitting a contaminated water stream into a regenerated lean stream and a low-quality reject stream. Membrane separation-based processes are examples of these types of regenerators. The optimization model presented in this work integrates a single, centralized partitioning regenerator with a source–demand superstructure under the assumption that the processes within the plant are of the fixed flow rate type. The formulation is non-linear as a result of the presence of bilinear terms in the regenerator balance equations, but global optimal solutions can be found using commercial software. The features of the model are illustrated by solving case studies from the literature. It is notable from these examples that considerable design flexibility exists in networks of this type, since potentially both the lean and reject streams from the partitioning regenerator can be reused/recycled within the plant.     

Fate of CL-20 in sandy soils: degradation products as potential markers of natural attenuation

Hexanitrohexaazaisowurtzitane (CL-20) is an emerging explosive that may replace the currently used explosives such as RDX and HMX, but little is known about its fate in soil. The present study was conducted to determine degradation products of CL-20 in two sandy soils under abiotic and biotic anaerobic conditions. Biotic degradation was prevalent in the slightly acidic VT soil, which contained a greater organic C content, while the slightly alkaline SAC soil favored hydrolysis. CL-20 degradation was accompanied by the formation of formate, glyoxal, nitrite, ammonium, and nitrous oxide. Biotic degradation of CL-20 occurred through the formation of its denitrohydrogenated derivative (m/z 393 Da) while hydrolysis occurred through the formation of a ring cleavage product (m/z 156 Da) that was tentatively identified as CH₂N-C(N-NO₂)-CHN-CHO or its isomer N(NO₂)CH-CHN-CO-CHNH. Due to their chemical specificity, these two intermediates may be considered as markers of in situ attenuation of CL-20 in soil.     

A role for selective contraception of individuals in conservation

Contraception has an established role in managing overabundant populations and preventing undesirable breeding in zoos. We propose that it can also be used strategically and selectively in conservation to increase the genetic and behavioral quality of the animals. In captive breeding programs, it is becoming increasingly important to maximize the retention of genetic diversity by managing the reproductive contribution of each individual and preventing genetically suboptimal breeding through the use of selective contraception. Reproductive suppression of selected individuals in conservation programs has further benefits of allowing animals to be housed as a group in extensive enclosures without interfering with breeding recommendations, which reduces adaptation to captivity and facilitates the expression of wild behaviors and social structures. Before selective contraception can be incorporated into a breeding program, the most suitable method of fertility control must be selected, and this can be influenced by factors such as species life history, age, ease of treatment, potential for reversibility, and desired management outcome for the individual or population. Contraception should then be implemented in the population following a step‐by‐step process. In this way, it can provide crucial, flexible control over breeding to promote the physical and genetic health and sustainability of a conservation dependent species held in captivity. For Tasmanian devils (Sarcophilus harrisii), black‐flanked rock wallabies (Petrogale lateralis), and burrowing bettongs (Bettongia lesueur), contraception can benefit their conservation by maximizing genetic diversity and behavioral integrity in the captive breeding program, or, in the case of the wallabies and bettongs, by reducing populations to a sustainable size when they become locally overabundant. In these examples, contraceptive duration relative to reproductive life, reversibility, and predictability of the contraceptive agent being used are important to ensure the potential for individuals to reproduce following cessation of contraception, as exemplified by the wallabies when their population crashed and needed females to resume breeding.     

Optimizing process parameters of palm oil bleaching on locally prepared animal bone–based activated carbon using response surface methodology

Adsorptive bleaching potentials of activated animal bone on palm oil was investigated. Palm oil was obtained locally from the mesocarp of oil palm fruits. The obtained palm oil was degummed, neutralized, and subjected to proximate analysis before bleaching. The animal bone–based activated carbon used as a bleaching material was locally prepared by cleaning, drying, carbonization, and chemical activation process. The prepared activated carbon (CBAC) was characterized using Fourier transform infrared, scanning electron microscopy, Braummer–Emmett–Teller, and x‐ray diffraction (XRD) methods. Bleaching of the prepared palm oil on CBAC was done at different process conditions. The characterization results of BET analysis show that CBAC has a surface area of 593.270 m²/g, micropore surface area 595.56 m²/g, micropore volume 0.212 cm³/g, Langmuir surface area 1.38e+04 m²/g, and adsorption energy 3.998 KJ/mol. XRD analysis indicates gypsum as the dominant mineral in the activated carbon sample. The CBAC efficiency of 75.14% was obtained for time/temperature interactions at 50 min/120°C while at 25 g/50 min dosage/time interactions an efficiency of 75.17% was obtained.     

Adapting to Climate Change in Africa

The intersection of present vulnerability and the prospect of climate change in Africa warrants proactive action now to reduce the risk of large-scale, adverse impacts. The process of planning adaptive strategies requires a systematic evaluation of priorities and constraints, and the involvement of stakeholders. An overview of climate change in Africa and case studies of impacts for agriculture and water underlie discussion of a typology of adaptive responses that may be most effective for different stakeholders. The most effective strategies are likely to be to reduce present vulnerability and to enhance a broad spectrum of capacity in responding to environmental, resource and economic perturbations. In some cases, such as design of water systems, an added risk factor should be considered.     

Sex-biased maternal expenditure in Rocky Mountain bighorn sheep

Summary We examined maternal energy expenditure in Rocky Mountain bighorn sheep to test the hypothesis (Trivers and Willard 1973) that individual sons in polygynous mammals should obtain a larger maternal subsidy. In accord with theory, males weighed more at birth (an index of relative prenatal expenditure), tended to suckle more between 40 and 100 days of age (an index of relative postnatal expenditure) and imposed greater delays on their mothers' return to estrus in the subsequent breeding season (an index of relative total preweaning expenditure). Mothers rather than offspring appeared to have primary control over postnatal expenditure. The effect of maternal reproductive effort on return to estrus was cumulative over a period of 3–5 years so that ewes making relatively large expenditures gave birth progressively later. Ewe and lamb mortality was associated with late conception in the previous rut. Thus, differential reproductive effort by ewes in this population appeared to entail a fitness cost involving reductions in both offspring and maternal survivorship. Correspondence to: J.T. Hogg at the present address     

Copulatory tactics in relation to sperm competition in Rocky Mountain bighorn sheep

Summary Sperm competition arises in the bighorn mating system because receptive ewes are some-times defended and mated in sequence by a series of increasingly dominant rams and because subordinate (coursing) rams commonly succeed in forcing matings with defended ewes. To identify potential components in a male strategy of sperm competition, the social circumstances and schedule of copulation among free-ranging bighorns were investigated. Three such components emerged: (i) Defending and coursing rams copulated with estrous ewes at extraordinarily high rates, presumably to increase the proportion of their own versus rivals' sperm present at fertilization by simple numerical preponderance at insemination. (ii) Coursing but not defending rams concentrated copulations later in the period of estrus (sensu this study). Evidence from domestic sheep suggests that this may correspond to the period of maximum female fertility. A greater risk and/or reduced benefit associated with forced versus cooperative copulation may force coursing rams to restrict copulation to periods of highest fertility, whereas defending rams may gain even from copulations outside this period. (iii) Defending rams copulated at unusually high rates immediately after bouts of successful coursing. Such retaliatory copulations were associated with reduced amounts of courtship and were more likely to occur if the defending ram had copulated infrequently recently. The number of retaliatory copulations was independent of the number of preceding forced copulations, probably because defending rams rationed ejaculates in anticipation of future coursing. The function of retaliation is not clear, although the literature on domestic sheep suggests the possibility of some form of mechanical displacement of rival sperm. Unlike females of many ungulate species, bighorn ewes were typically receptive to cooperative copulation over a period of days. Although persistent courtship by defending rams may coerce such extended receptivity, it is also possible that ewes, facing unavoidable forced matings by coursing rams, gain genotypic benefits for offspring by providing prolonged copulatory access to relatively dominant defending rams.