Effects of coagulation pre-treatment on chemical and microbial properties of water-soil-plant systems of constructed wetlands.

Chemical coagulation has gained recognition as an effective technique to enhance the removal efficiency of pollutants in wastewater prior to their entry into a constructed wetland (CW) system. However, its potential impact on the chemical and microbial properties of soil and plant systems within CWs requires further research. This study investigated the impact of using ferric chloride (FeCl3) as a pre-treatment stage for dairy wastewater (DWW) on the chemical and microbial properties of water-soil-plant systems of replicated pilot-scale CWs, comparing them to CWs treating untreated DWW. CWs treating amended DWW had better performance than CWs treating raw DWW for all water quality parameters (COD, TSS, TP, and TN), ensuring compliance with the EU wastewater discharge directives. Soil properties remained mostly unaffected except for pH, calcium and phosphorus (P), which were lower in CWs treating amended DWW. As a result of lower nitrogen (N) and P loads, the plants in CWs receiving FeCl3-amended DWW had lower N and P contents than the plants of raw DWW CWs. However, the lower loads of P into amended DWW CWs did not limit the growth of Phragmites australis, which were able to accumulate trace elements higher than CWs receiving raw DWW. Alpha and Beta-diversity analysis revealed minor differences in community richness and composition between both treatments, with only 3.7% (34 genera) showed significant disparities. Overall, the application of chemical coagulation produced superior effluent quality without affecting the properties of soil and plant of CWs or altering the functioning of the microbial community.

Considerations for Research Funders and Managers to Facilitate the Translation of Scientific Knowledge into Practice.

Research funders and managers can play a critical role in supporting the translation of knowledge into action by facilitating the brokering of knowledge and partnerships. We use semi-structured interviews with a research funding agency, the Australian Centre for International Agricultural Research (ACIAR), to explore (i) ways that funders can facilitate knowledge brokering, the (ii) barriers to, and (iii) enablers for, facilitating knowledge brokering, and (iv) the individual skills and attributes for research program funders and managers to be effective brokers. Based on these findings, we generate three considerations for research funders elsewhere, in particular R4D funders, seeking to build capacity for knowledge brokering: (i) formalise the process and practice, (ii) develop shared language and understanding, and (iii) build individual competencies and capabilities. Our findings complement the existing literature with a context specific analysis of how research funders can facilitate knowledge brokering, and by identifying the barriers and enablers in doing so.

Drainage status of grassland peat soils in Ireland: Extent, efficacy and implications for GHG emissions and rewetting efforts.

Peatlands have been artificially drained and degraded over 100s of years and have released huge amounts of carbon dioxide (CO2) as a result. In organic grassland soils, raising the water table to prevent such emissions is being proposed to meet national greenhouse gas emission targets for the land use sector. At present, all of these soils (335,000 ha) are assumed to be drained (as no information has been available on their drainage status) within national emission inventory reporting and are therefore responsible for significant emissions (8-9 million tonnes CO2-equivalent annually). The objective of the present study was to collate studies relating to the drainage status of peat soils in Ireland to present alternative scenarios with regard to actual drainage status of organic soils and their estimated emissions. From a drainage design perspective, evidence suggests that relatively small proportions of the grassland peat area was drained effectively using optimal in-field drain spacings required to control the water table at 0.4-0.5 m. Open drains excavated on such soils have limited capacity to laterally control the water table depth beyond short distances. Furthermore, the lack of long-term routine maintenance post installation ensures the redundancy of many drainage systems over time. New drainage installations are therefore likely replacing existing infrastructure and not necessarily increasing the drained area at any given time. This evidence supports literature from the 1980s which state that relatively low proportions of the grassland peat area has been subjected to effective drainage. Scenario testing results showed that likely emissions from the most probable scenario (with total area drained equating to 90,000-120,000 ha) are 3.6-4.7 million tonnes CO2-equivalent, approximately 40-53% of current national emission inventory estimates. The incorporation of such a refinement into the national inventory could offer a significant reduction in estimated GHG emissions from the grassland land use sector in national emission inventory reporting.

Assessment of the current performance of grazing infrastructure across Irish dairy farms.

The increased average Irish dairy herd size in a post-quota environment has put heightened pressure on grazing infrastructure. In a rotational grazing system, grazing infrastructure consists of the paddock system, which delineates the grazing areas into appropriately sized grazing parcels, and the roadway network, which connects these paddocks to the milking parlor. Where herd size has increased without corresponding adaptations to the infrastructure, farm management and roadway network performance has been affected. The links between suboptimal grazing infrastructure and roadway network efficiency are poorly understood and not widely documented. The aims of this study were to (1) analyze the effect of herd expansion and paddock size on pasture allocations per paddock, (2) identify the factors that affect the total distance walked per year, and (3) create a metric to compare the efficiency of roadway networks across farms of varying grazing platforms. A sample population of 135 Irish dairy farms with a median herd size of 150 cows was used for this analysis. Herds were split into the following 5 categories: <100 cows, 100 to 149 cows, 150 to 199 cows, 200 to 249 cows, and ≥250 cows. Herds with ≥250 cows had a greater number of paddocks per farm and rotated around the grazing paddocks more frequently, with 46% of paddocks only suitable for 12 h allocations relative to herd size, compared with just 10% to 27% of paddocks for herds with <100 cows to herds with 200-249 cows. When predicting the total distance walked per year on each study farm, the mean distance from a paddock to the milking parlor was the strongest indicator (R2 = 0.8247). Other metrics, such as herd size, have failed to account for the location of the milking parlor relative to the grazing platform. The creation of the relative mean distance from a paddock to milking parlor (RMDMP) metric allowed the calculation of a farm's roadway network efficiency for moving the herd between paddocks and the milking parlor. The analyzed farms increased their efficiency in terms of RMDMP (0.34-40.74%) as they increased herd size post quota. However, the position of new additional paddocks relative to the milking parlor substantially affected their RMDMP.

Effects of wastewater pre-treatment on clogging of an intermittent sand filter.

Intermittent sand filters (ISFs) are widely used in rural areas to treat domestic and dilute agricultural wastewater due to their simplicity, efficacy and relative low cost. However, filter clogging reduces their operational lifetime and sustainability. To reduce the potential of filter clogging, this study examined pre-treatment of dairy wastewater (DWW) by coagulation with ferric chloride (FeCl3) prior to treatment in replicated, pilot-scale ISFs. Over the study duration and at the end of the study, the extent of clogging across hybrid coagulation-ISFs was quantified, and the results were compared to ISFs treating raw DWW without a coagulation pre-treatment, but otherwise operated under the same conditions. During operation, ISFs receiving raw DWW recorded higher volumetric moisture content (θv) than ISFs treating pre-treated DWW, which indicated that biomass growth and clogging rate was higher in ISFs treating raw DWW, which were fully clogged after 280 days of operation. The hybrid coagulation-ISFs remained fully operational until the end of the study. Examination of the field-saturated hydraulic conductivity (Kfs) showed that ISFs treating raw DWW lost approximately 85 % of their infiltration capacity in the uppermost layer due to biomass build-up versus 40 % loss for hybrid coagulation-ISFs. Furthermore, loss on ignition (LOI) results indicated that conventional ISFs developed five times the organic matter (OM) in the uppermost layer compared to ISFs treating pre-treated DWW. Similar trends were observed for phosphorus, nitrogen and sulphur, where proportionally higher values were observed for raw DWW ISFs than pre-treated DWW ISFs, with values decreasing with depth. Scanning electron microscopy (SEM) showed a clogging biofilm layer on the surface of raw DWW ISFs, while pre-treated ISFs maintained distinguishable sand grains on the surface. Overall, hybrid coagulation-ISFs are likely to sustain infiltration capacity for a longer period than filters treating raw wastewater; therefore, requiring smaller surface area for treatment and minimal maintenance.

Evaluating connectivity risk of farm roadway runoff with waters - Development and sensitivity analysis of a semi quantitative risk model.

Farm roadways are an important sub-component of the nutrient transfer continuum (NTC) and roadway runoff (RR), leading to nutrient pressures in receiving waters at different times of the year at catchment scale. This study developed a semi-quantitative risk assessment model for dairy farms that once populated with data identifies roadway sections where RR enters waters. The model contains parameters that represent source, mobilisation and transport-connectivity stages of the NTC defined as continuous or categorical variables. Each parameter has a corresponding scoring system in terms of connectivity likelihood to waters (L) and the associated impact on water quality (I) from which field data can be converted to a risk score (RS). The connectivity or impact risk of any roadway section is a sum of all parameter scores, i.e. 'Total Risk Score' (TRS). The risk scores were classified into 5 categories (very low, low, moderate, high and very high). Field data from seven farms enabled five equal interval risk score classifications to be developed (very low (110-134), low (135-158), moderate (159-182), high (183-206), very high (207-230)). Fieldwork data showed differences between the number of mapped roadway sections ranging from 35 to 76, with the lowest and highest risk scores being 110 and 230, respectively. Out of all sections scored 25.9 %, 45.6 %, 20.4 %, 6.4 %, and 2 % were in very low, low, moderate, high and very high categories, respectively. In terms of management, only 8.4 % (i.e. high or very high scores) had all components of the NTC and required RR mitigation. An examination of the mobilisation parameter showed that the % of roadway sections needing mitigation is likely to increase if rainfall increases on these farms. An uncertainty assessment limiting the model to different levels of connectivity confirmed that all components of the NTC and those with greater than moderate risk should only be considered in future mitigation plans. Future work should concentrate on adapting this methodology to a wide range of farm enterprises.

A novel hybrid coagulation-constructed wetland system for the treatment of dairy wastewater.

Constructed wetlands (CWs) are a cost-effective and sustainable treatment technology that may be used on farms to treat dairy wastewater (DWW). However, CWs require a large area for optimal treatment and have poor long-term phosphorus removal. To overcome these limitations, this study uses a novel, pilot-scale coagulation-sedimentation process prior to loading CWs with DWW. This hybrid system, which was operated on an Irish farm over an entire milking season, performed well at higher hydraulic loading rates than conventional CWs, and obtained removal efficiencies ≥99 % for all measured water quality parameters (chemical oxygen demand, total nitrogen and phosphorus, total suspended solids and turbidity), which complied with EU directives concerning urban wastewater treatment. Overall, the hybrid coagulation-CW is a promising technology that requires a smaller area than conventional CWs and minimal operator input, and produces high effluent quality.

Field scale estimates of soil carbon stocks on ten heavy textured farms across Ireland.

The world's soils store vast amounts (≈2,500 GT) of Carbon which acts as a vital sink to counterbalance the effects of increasing atmospheric carbon dioxide. There have been fruitful efforts to quantify soil Carbon stocks at national scales, which are required for policy level decisions but lack the high resolution required to support farm specific decisions. It is hypothesised that farm scale evaluations of soils can provide insight that is masked in national scale studies and can allow for spatially explicit management approaches to optimise soil Carbon storage and sequestration, such that it can be prioritized within profitable production systems. The objective of the present study was to estimate Carbon stocks on a range of heavy textured soils at field and farm scale and to quantify Carbon storage relative to national scale estimates. Ten grassland dairy farms (mean area of 52.2 Ha) were surveyed, sampled and classified to determine soil types and quantify soil Carbon stores. The level of Carbon present (mean: 346.0 T/Ha) at these sites was greater than previous averages on such soils quantified at national scale (by a factor of 1.1-3.9 depending on soil type). Furthermore, if Carbon saturation potential was realised, the amount of Carbon stored could be increased by an average of 792.1 T/Ha in each profile (from 346.0 to 1138.1 T/Ha). Current management has fostered the retention of large stores of soil Carbon on such soils/farms which co-exist within highly productive farm systems. As there is a societal demand to retain and enhance soil carbon stores to mitigate climate change, high Carbon soils should be identified and, under appropriate policies, commodified to offer a direct incentive to retain soil Carbon. The value of this resource should be recognised and polices to ensure a spatially explicit approach for soil Carbon management should be adopted.

Appraisal and ranking of poly-aluminium chloride, ferric chloride and alum for the treatment of dairy soiled water.

Land spreading of dairy soiled water (DSW) may result in pollution of ground and surface waters. Treatment of DSW through sludge-supernatant separation using chemical coagulants is a potential option to reduce the negative environmental impacts of DSW. The aims of this study were to (1) assess the effectiveness of three chemical coagulants - poly-aluminium chloride (PACl), ferric chloride (FeCl3) and alum - in improving effluent quality, and (2) assess the properties of the sludge that is generated as by-product from the process for its suitability for land application. Taking into consideration optimum doses to minimize pollutants (turbidity, chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), and E. coli), optimum mixing times and cost, FeCl3 was the best performing coagulant. Generated sludges had higher nutrient content and fewer E. coli than raw DSW, and did not display any evidence of phytotoxicity to the growth of Lolium perenne L. using germination tests. The study discussed the results in a sustainable farm management context, and suggested that the effluent (supernatant) from the treatments may be recycled to wash farm yards, saving water. In parallel, the sludge portion can be applied to amend soil properties with no adverse impacts on the grass growth, providing an agronomic value as an organic fertilizer, and reducing the risk of nutrient losses. This management approach could minimize the overall net cost compared to land application of raw DSW.

Phosphorus and nitrogen losses from temperate permanent grassland on clay-loam soil after the installation of artificial mole and gravel mole drainage.

Mole (M) and gravel-mole (GM) drainage systems improve the permeability of soils with high clay contents. They collect and carry away infiltrating water during episodic rainfall events. Characterisation of nutrient fluxes (concentration and flows) in overland flow (OF) and in mole drain flow (MF) across sequential rainfall events is important for environmental assessment of such drainage systems. The objective of this study is to assess the impact of drainage systems on soil nutrient losses. Three treatments were imposed on grazed permanent grassland on a clay loam soil in Ireland (52°30'N, 08°12'W) slope 1.48%: undrained control (C), mole drainage (M) and gravel mole drainage (GM). Plots (100 m × 15 m) were arranged in a randomized complete block design with four replicated blocks. Nitrogen (N) and phosphorus (P) concentrations in OF, MF and groundwater (GW) were measured from each plot over 15 consecutive rainfall events. The results showed that M and GM (P < 0.05) deepened the watertable depth and decreased OF. M and GM increased losses of nitrate-N (22%) and ammonium-N (14%) in GW. Nitrate-N concentrations from all the flow pathways (mean and standard error (s.e.): 0.99 s.e. 0.10 mg L-1) were well below the 11.3 mg L-1 threshold for drinking water. Ammonium-N concentrations from all the flow pathways (mean: 0.64 s.e. 0.14 mg L-1) exceeded drinking water quality standards. On the other hand M and GM lowered total P losses (mean annual losses from C, M and GM: 918, 755 and 853 s.e. 14.1 g ha-1 year-1) by enhancing soil P sorption. Hence M and GM can be implemented on farms under similar management to that described in the present study with a minor impact on N (increased concentration on averaged 18% to GW) and P (reduced by on avenged 114 g ha-1 year-1).

Influence of artificial drainage system design on the nitrogen attenuation potential of gley soils: Evidence from hydrochemical and isotope studies under field-scale conditions.

In North Atlantic Europe intensive dairy farms have a low nitrogen (N) use efficiency, with high N surpluses often negatively affecting water quality. Low feed input systems on heavy textured soils often need artificial drainage to utilise low cost grassland and remain profitable. Heavy textured soils have high but variable N attenuation potential, due to soil heterogeneity. Furthermore, drainage system design can influence the potential for N attenuation and subsequent N loadings in waters receiving drainage from such soils. The present study utilises end of pipe, open ditch and shallow groundwater sampling points across five sites in SW Ireland to compare and rank sites based on N surplus, water quality and "net denitrification", and to develop a conceptual framework for the improved management of heavy textured dairy sites to inform water quality N sustainability. This includes both drainage design and "net denitrification" criterion, as developed within this study.N surplus ranged from 211 to 292 kg N/ha (mean of 252 kg N/sourha) with a common source of organic N across all locations. The predicted soil organic matter (SOM) N release potential from top-subsoil layers was high, ranging from 115 to >146 kg N/ha. Stable isotopes analyses showed spatial variation in the extent of specific N-biotransformation processes, according to drainage location and design. Across all sites, nitrate (NO3-N) was converted to ammonium (NH4+-N), which migrated offsite through open ditch and shallow groundwater pathways. Using the ensemble data the potential for soil N attenuation could be discriminated by 3 distinct groups reflecting the relative dominance of in situ N-biotransformation processes deduced from water composition: Group 1 (2 farms, ranked with high sustainability, NH4+ < 0.23 mg N/l, δ15N-NO3- > 5‰ and δ18O-NO3- > 10‰), low NH4+-N concentration coupled with a high denitrification potential; Group 2 (1 farm with moderate sustainability, NH4+ < 0.23 mg N/l, δ15N-NO3- < 8‰ and δ18O-NO3- < 8‰), low NH4+-N concentration with a high nitrification potential and a small component of complete denitrification; Group 3 (2 farms, ranked with low sustainability, NH4+ > 0.23 mg N/l, 14‰ > Î´15N-NO3- > 5‰ and 25‰ > Î´18O-NO3- > -2‰), high NH4+-N concentration due to low denitrification. The installation of a shallow drainage system (e.g. mole or gravel moles at 0.4 m depth) reduced the "net denitrification" ranking of a site, leading to water quality issues. From this detailed work an N sustainability tool for any site, which presents the relationship between drainage class, drainage design (if present), completeness of denitrification, rate of denitrification and NH4-N attenuation was developed. This tool allows a comparison or ranking of sites in terms of their N sustainability. The tool can also be used pre-land drainage and presents the consequences of future artificial land drainage on water quality and gaseous emissions at a given site.

'Everyone's talking Jadelle': the experiences and attitudes of service providers regarding the use of the contraceptive implant, Jadelle in young people in New Zealand.

AIMS: The contraceptive implant Jadelle, along with other types of long-acting reversible contraception, is thought to be an ideal choice for young people wanting to avoid pregnancy, however, uptake is low. This study aimed to explore the attitudes and experiences of health professionals regarding the use of Jadelle in teenagers. METHODS: Semi-structured interviews were carried out with professionals providing contraceptive services to young people. Sampling was by identifying key informants and subsequent snowball sampling. Interviews were transcribed and main themes identified. RESULTS: Ten interviews were done with service providers, including midwives, doctors and nurses. Five main themes were identified: characteristics of young people, contraceptive services, positive features of Jadelle, barriers to contraception and individual choice. Jadelle was seen as a good option due to its effectiveness, discreetness and user independence. Barriers for young people obtaining Jadelle included cost, access, fear of procedure and lack of appropriate services. CONCLUSION: Health professionals had a range of experiences using the contraceptive implant Jadelle. Most felt that Jadelle was a good choice for young people. Improvements to access were identified, including reduced cost and more youth-friendly services, which may lead to increased Jadelle uptake and a subsequent reduction in unintended teenage pregnancies.

The effects of treading by two breeds of dairy cow with different live weights on soil physical properties, poaching damage and herbage production on a poorly drained clay-loam soil.

There is little empirical evidence to indicate that dairy cow live weight affects the extent of soil damage at the hoof-soil interface during grazing on poorly drained permanent grassland. In the present study the impact of Holstein-Friesian (HF) dairy cows with a mean (±standard deviation) live weight of 570 (±61) kg were compared with Jersey × Holstein-Friesian (JX) with a mean live weight of 499 (±52) kg each at two stocking densities: mean 2·42 ± (0·062) and 2·66 (±0·079) cows/ha. Soil physical properties (bulk density, macroporosity, gravimetric water content, air-filled porosity, penetration resistance and shear strength), poaching damage (post-grazing soil surface deformation and hoof-print depth), herbage yield and milk production were measured throughout 2011 and 2012. Soil physical properties, post-grazing soil surface deformation and herbage production were not affected by dairy cow breed or by interactions between breed and stocking density. Hoof-print depth was higher in the HF treatments (39 v. 37 mm, s.e. 0·5 mm). Loading pressure imposed at the soil surface was the same for both breeds due to a direct correlation between live weight and hoof size. Poaching damage was greater at higher stocking density. Using the lighter JX cow offered little advantage in terms of lowering the negative impact of treading on soil physical properties or reducing poaching damage and no advantage in terms of herbage or milk production compared with the heavier HF cow.

Soy infant formula and phytoestrogens.

Soy infant formula contains high levels of the isoflavones, genistein and daidzein, which are commonly referred to as phytoestrogens. These are non-steroidal chemicals with structural similarities to estrogen. Infants consuming soy formula have high levels of circulating isoflavones. These are an order of magnitude greater than the levels of isoflavones which have been shown to produce physiological effects in adult women consuming a high soy diet. There is conflicting evidence about the risks and benefits of soy phytoestrogens, with research presenting a contradictory picture. Some reviewers suggest that early exposure to soy may prevent cancer and heart disease. However, there is very little research on the effects of consumption of soy phytoestrogens by human neonates. Against this generally positive view there is an increasing number of recent reports that suggest that in experimental animals, phytoestrogens have adverse effects with respect to carcinogenesis, reproductive function, immune function, and thyroid disease. Despite the absence of adequate scientific research that quantifies the level of risk to infants, most would argue for a precautionary approach to be taken in situations where there are potential developmental effects from the consumption of pharmacologically active compounds in infancy and childhood.

Ethnic differences in parent/infant co-sleeping practices in New Zealand.

AIM: This study was designed to monitor changes in the prevalence of risk factors for sudden infant death syndrome (SIDS) in the New Zealand population. The behaviour of interest is parent/infant co-sleeping. This paper reports parent/infant co-sleeping arrangements of different ethnic groups in New Zealand. METHODS: A stratified random sample of 6268 infants attending Plunket clinics for their three and six-month visits was taken over the years 1995-1996. Maori and Pacific infants were oversampled. Parents who shared a bed with their infant were asked how they arranged the babies sleeping place according to pre-coded diagrams. Routine parent/infant co-sleeping was defined as "bed sharing at least four nights over the last two weeks". RESULTS: There were 2693 infants who shared the bed with their sleeping parents during at least one of the previous 14 nights. Of these infants, 1060 routinely shared the parents' bed. At three months, 56% of routinely co-sleeping infants slept directly in the bed, 29% slept in a raised position, 3% slept in a carrycot or basket, and 5% in other positions. At six months, 60% of the routinely co-sleeping infants slept directly in the bed with their parents, 23% slept in a raised position, 1% slept in a carrycot or basket, and 7% in other positions. There were significant differences in the co-sleeping locations by ethnicity. CONCLUSION: There is still some ongoing dispute as to whether parent/infant co-sleeping is a risk factor for SIDS. This study has identified differences in the way infants co-sleep with their parents and this can be used to clarify infant care practices in relation to SIDS.

Risk factors for sudden infant death syndrome following the prevention campaign in New Zealand: a prospective study.

OBJECTIVES: To identify the risk factors for sudden infant death syndrome (SIDS) following a national campaign to prevent SIDS. METHODS: For 2 years (October 1, 1991 through September 30, 1993) data were collected by community child health nurses on all infants born in New Zealand at initial contact and at 2 months. RESULTS: There were 232 SIDS cases in the postneonatal age group (2.0/1000 live births) and these were compared with 1200 randomly selected control subjects. Information was available for 127 cases (54.7%) and 922 (76.8%) of controls. The previously identified modifiable risk factors were examined. The prevalence of prone sleeping position of the infant was very low (0.7% at initial contact and 3. 0% at 2 months), but was still associated with an increased risk of SIDS. In addition, the side sleeping position was also found to have an increased risk of SIDS compared with the supine sleeping position (at 2 months: adjusted odds ratio (OR) = 6.57; 95% confidence interval (CI) = 1.71, 25.23). Maternal smoking was found to be the major risk factor for SIDS. Bed sharing was also associated with an increased risk of SIDS. There was an interaction between maternal smoking and bed sharing on the risk of SIDS. Compared with infants not exposed to either bed sharing or maternal smoking, the adjusted OR for infants of mothers who smoked was 5.01 (95% CI = 2.01, 12.46) for bed sharing at the initial contact and 5.02 (95% CI = 1.05, 24. 05) for bed sharing at 2 months. In this study breastfeeding was not associated with a statistically significant reduction in the risk of SIDS. The other risk factors for SIDS identified were: unmarried mother, leaving school at a younger age, young mother, greater number of previous pregnancies, late attendance for antenatal care, smoking in pregnancy, male infant, Maori ethnicity, low birth weight, and shorter gestation. CONCLUSIONS: After adjustment for potential confounders, prone and side sleeping positions, maternal smoking, and the joint exposure to bed sharing and maternal smoking were associated with statistically significant increased risk of SIDS. A change from the side to the supine sleeping position could result in a substantial reduction in SIDS. Maternal smoking is common in New Zealand and with the reduction in the prevalence of prone sleeping position is now the major risk factor in this country. However, smoking behavior has been difficult to change. Bed sharing is also a major factor but appears only to be a risk to infants of mothers who smoke. Addressing bed sharing among mothers who smoke could reduce SIDS by at least one third. Breastfeeding did not appear to offer a statistically significant reduction in SIDS risk after adjustment of potential confounders, but as breastfeeding rates are comparatively good in New Zealand, this result should be interpreted with caution as the power of this study to detect a benefit is small.