Can CO2 sensors in the ventilation system of a pool facility help reduce the variability in the trihalomethane concentration observed in indoor air?

Volatile and hazardous compounds are formed during the chlorination of pool water. Monitoring components in the air, such as the four trihalomethanes; chloroform, dichlorobromomethane, dibromochloromethane and bromoform (tTHM), is challenging. Carbon dioxide (CO2) sensors are used for controlling air quality in different buildings and can be installed in ventilation systems for continuous surveillance and monitoring purposes. However, such sensors are not used in indoor swimming facilities. In this study, samples of tTHM and CO2 were collected and analysed, along with other air and water quality parameters such as combined chlorine, to evaluate whether CO2 sensors could be used to explain the observed variability in the tTHM concentration in an indoor swimming facility and thereby reduce the exposure of individuals utilising the pool to tTHM. Random intercept models were built for the tTHM and CO2 concentrations, respectively, and the results show that the relationships between combined chlorine in the water, CO2 in the air and number of occupants explain 52% of the variability in tTHM. The correlation between occupancy and CO2 concentration (ρ = 0.65, p ≤ 0.01) suggests that CO2 sensors should be used so that the air supply corresponds to the demand of the users.

Grain protein concentration and harvestable protein under future climate conditions. A study of 108 spring barley accessions.

In the present study a set of 108 spring barley (H. vulgare L.) accessions were cultivated under predicted future levels of temperature and [CO2] as single factors and in combination (IPCC, AR5, RCP8.5). Across all genotypes, elevated [CO2] (700 ppm day/night) slightly decreased protein concentration by 5%, while elevated temperature (+5 °C day/night) substantially increased protein concentration by 29%. The combined treatment increased protein concentration across accessions by 8%. This was an increase less than predicted from strictly additive effects of the individual treatments. Despite the increase in grain protein concentration, the decrease in grain yield at combined elevated temperature and elevated [CO2] resulted in 23% less harvestable protein. There was variation in the response of the 108 accessions, which might be exploited to at least maintain if not increase harvestable grain protein under future climate change conditions.

Status of feral oilseed rape in Europe: its minor role as a GM impurity and its potential as a reservoir of transgene persistence.

PURPOSE: Feral oilseed rape has become widespread in Europe on waysides and waste ground. Its potential as a source of GM impurity in oilseed rape harvests is quantified, for the first time, by a consistent analysis applied over a wide range of study areas in Europe. METHODS: The maximum contribution of feral oilseed rape to impurities in harvested crops was estimated by combining data on feral abundance and crop yield from five established, demographic studies in agricultural habitats in Denmark, Germany (2), France and the UK, constituting over 1,500 ha of land and 16 site-years of observations. Persistence of feral populations over time was compared by visual and molecular methods. RESULTS: Ferals had become established in all regions, forming populations 0.2 to 15 km⁻². The seed they produced was always <0.0001% of the seed on crops of oilseed rape in each region. The contribution of ferals to impurity in crops through accidental harvest of seed and through cross-pollination would be an even smaller percentage. Feral oilseed rape nevertheless showed a widespread capacity to persist in all regions and retain traits from varieties no longer grown. CONCLUSIONS: Feral oilseed rape is not a relevant source of macroscopic impurity at its present density in the landscape but provides opportunity for genetic recombination, stacking of transgenes and the evolution of genotypes that under strong selection pressure could increase and re-occupy fields to constitute an economic weed burden and impurity in future crops.

Long-term persistence of GM oilseed rape in the seedbank.

Coexistence between genetically modified (GM) and non-GM plants is a field of rapid development and considerable controversy. In crops, it is increasingly important to understand and predict the GM volunteer emergence in subsequent non-GM crops. Theoretical models suggest recruitment from the seedbank over extended periods, but empirical evidence matching these predictions has been scarce. Here, we provide evidence of long-term GM seed persistence in conventional agriculture. Ten years after a trial of GM herbicide-tolerant oilseed rape, emergent seedlings were collected and tested for herbicide tolerance. Seedlings that survived the glufosinate herbicide (15 out of 38 volunteers) tested positive for at least one GM insert. The resulting density was equivalent to 0.01 plants m-2, despite complying with volunteer reduction recommendations. These results are important in relation to debating and regulating coexistence of GM and non-GM crops, particularly for planting non-GM crops after GM crops in the same field.

Frequency-dependent fitness of hybrids between oilseed rape (Brassica napus) and weedy B. rapa (Brassicaceae).

Fitness of interspecific hybrids is sometimes high relative to their parents, despite the conventional belief that they are mostly unfit. F(1) hybrids between oilseed rape (Brassica napus) and weedy B. rapa can be significantly more fit than their weedy parents under some conditions; however, under other conditions they are less fit. To understand the reasons, we measured the seed production of B. napus, B. rapa, and different generations of hybrid plants at three different densities and in mixtures of different frequencies (including pure stands). Brassica napus, B. rapa, and backcross plants (F(1) ♀ × B. rapa) produced many more seeds per plant in pure plots than in mixtures and more seeds in plots when each was present at high frequency. The opposite was true for F(1) plants that produced many more seeds than B. rapa in mixtures, but fewer in pure stands. Both vegetative and reproductive interactions may be responsible for these effects. Our results show that the fitness of both parents and hybrids is strongly frequency-dependent and that the likelihood of introgression of genes between the species thus may depend on the numbers and densities of parents and their various hybrid offspring in the population.