Health impacts of poor water quality on an endangered shorebird breeding programme in Aotearoa New Zealand.

CASE HISTORY: Two clusters of mortality among endangered tuturuatu/tchuriwat'/shore plover (Thinornis novaeseelandiae) have occurred at captive breeding facilities around New Zealand in recent years. In the first, four chicks died at Pukaha National Wildlife Centre (Mount Bruce, NZ) in February 2016, and in the second five adult birds at the Cape Sanctuary (Cape Kidnappers, NZ) died in 2022. CLINICAL FINDINGS: In 2016, four chicks were noted to become weak, have increased vocalisations and closed eyes prior to death. The remaining chicks were treated for 5 days with amoxycillin/clavulanate orally twice daily. Water containers and brooders were cleaned and disinfected with chlorhexidine. No further mortality was seen.In the 2022 cluster, three adult breeding birds died acutely and five others showed inappetence, weight loss and diarrhoea approximately 10 days after heavy rains flooded the local river. The five birds were treated with amoxycillin/clavulanate orally twice daily and oral fluids for 5 days. Two birds died and three survived. No breeding occurred in the aviaries in the following season. PATHOLOGICAL FINDINGS: In 2016, the chicks showed pulmonary changes ranging from congestion and oedema to heterophilic inflammation consistent with septicaemia.In 2022, the adult birds showed proliferation of bacteria in the distal small intestine associated with mucosal ulceration and heterophilic infiltration. Acid-fast staining of the caecal contents in one bird showed organisms consistent with Cryptosporidium spp. LABORATORY FINDINGS: Aerobic bacterial cultures of the lung and liver of two affected chicks carried out in 2016 showed heavy growth of Plesiomonas shigelloides. The same organism was cultured from water trays and holding tanks containing water boatmen (Sigara arguta) on which the chicks were fed.In 2022, cultures from the livers of three dead birds each showed a mixed bacterial growth with differing dominant organisms (Aeromonas sobria, Hafnia alvei, Citrobacter freundii and an Enterococcus sp.). PCR and sequencing confirmed Cryptosporidium parvum in the caecum of one bird. Fresh faeces from 24 breeding birds from the captive breeding facilities were negative by PCR for Cryptosporidium spp.The captive breeding facilities obtain water for the aviaries and aquatic invertebrates to feed to the chicks from local freshwater sources. Water quality testing at the Cape Sanctuary revealed concentrations of faecal indicator bacteria in excess of safe drinking water guidelines, with peaks following heavy rainfall. CLINICAL RELEVANCE: Fluctuations in water quality associated with mammalian faecal bacteria can adversely affect bird health and impact on captive rearing of endangered wildlife.

Prevalence and characterisation of wounds in sheep attributed to attacks by kea (Nestor notabilis) on high country farms in New Zealand.

Aims: To characterise and classify wounds in sheep suspected to have been caused by attacks by kea (Nestor notabilis) (kea strike), and to report the prevalence of these wounds on five high country farms in the South Island of New Zealand.Methods: Data were collected from farms between 28 August 2012 and 20 September 2013. Sheep were examined opportunistically immediately after shearing for signs of wounds caused by kea. The age and sex of sheep were also recorded. Wounds were measured and characterised as recent, healing, or healed, and the estimated true prevalence was calculated for each farm.Results: Injuries consistent with kea strike wounds were identified in 70/13,978 (0.5%) sheep examined. The estimated true prevalence varied between farms, from 0 (95% CI = 0-0.16) to 1.25 (95% CI = 0.97-1.61)%. Of the 76 wounds identified, 61 (80%) were located in the lumbar region, and 74 (97%) consisted of full-thickness ulceration of the skin, one showed evidence of injury to muscle and one to bone. The median length of the 63 wounds measured was 6 (min 1, max 23.5) cm, and 10/63 (13%) were categorised as recently healed, 47/63 (62%) as healing, and 17/63 (22%) as recent wounds.Conclusions: The results of this study show that kea strike on sheep was occurring at a low prevalence on the high country farms surveyed. The wounds identified were survivable, but the welfare impact of kea strike on sheep should be considered in balance with the conservation status of kea. There was clear variation in the prevalence of wounds attributed to kea strike between the farms but we were not able to identify the risk factors contributing to these differences. Future studies of kea strike should examine variables such as altitude, local kea density and distribution, and differences in kea strike management and husbandry practices, and should include high country farms without a history of kea strike.

Apparent lack of efficacy of toltrazuril against Eimeria species affecting brown kiwi (Apteryx mantelli) at a captive rearing facility.

AIM: To assess the efficacy of toltrazuril against the Eimeria spp. affecting brown kiwi (Apteryx mantelli). METHODS: Droppings were collected from three brown kiwi, aged <6 months old, at a captive rearing facility in the North Island of New Zealand, between 22 February and 20 April 2017, on 14 sampling dates. Only droppings (n=30) that were excreted between 03:00 and 07:00, as determined using video surveillance, were included for analysis, reflecting the peak time for shedding of coccidial oocysts for brown kiwi. Oocysts were quantified in each sample and Eimeria species identified on the basis of oocyst morphology. All samples were collected between 2 and 10 days after the birds had been treated with 25 mg/kg toltrazuril. RESULTS: Eimeria spp. oocysts were identified in 28/30 individual samples and on 14/14 sampling dates. Oocyst counts varied from 0 to 328,080 oocysts per gram (opg), and at least one oocyst count >10,000 opg was measured on 12/14 sampling dates. Three species of Eimeria were observed, with Eimeria apteryxii and E. kiwii most commonly encountered, whereas only one sample contained E. paraurii. CONCLUSIONS AND CLINICAL RELEVANCE: In the three birds monitored at this research site, there was a high abundance of E. apteryxii and E. kiwii oocysts in droppings despite recent administration of toltrazuril. These results suggest that the populations of Eimeria spp. affecting brown kiwi at this location appear to possess an ability to survive exposure to toltrazuril. Toltrazuril is widely used at captive rearing facilities to limit the effects of coccidiosis in juvenile kiwi. If a lack of efficacy is confirmed, it will be necessary to investigate alternative treatment regimens alongside broader environmental management strategies.

The circadian variation of oocyst shedding of Eimeria spp. affecting brown kiwi (Apteryx mantelli).

Captive rearing of wild brown kiwi (Apteryx mantelli) is widely carried out to assist in the recovery of this declining species. As a consequence, high densities of immunologically naïve kiwi are commonly housed in semi-captive conditions, with the potential to result in substantial morbidity and mortality from coccidiosis caused by multiple species of Eimeria. Previous research has described circadian variation in oocyst shedding across multiple avian host species. The aim of this research was to describe any circadian variation in oocyst shedding in brown kiwi. Droppings were collected from brown kiwi (n = 4) at a single captive rearing facility using video surveillance to determine the time of excretion, and oocyst counts were undertaken. Results show that two of the Eimeria spp. affecting brown kiwi exhibit a peak in oocyst shedding between 03.00 and 07.00 with few or no oocysts shed between 08.00 and midnight. These results are not able to be explained by the current hypotheses theorising the evolutionary forces behind the development of this adaptive trait. Our findings increase the current understanding of the biology of the Eimeria spp. affecting brown kiwi and have important implications for the management of captive-reared kiwi, in particular for the accurate interpretation of faecal oocyst counts.

Dermatomycosis caused by Paranannizziopsis australasiensis in five tuatara (Sphenodon punctatus) and a coastal bearded dragon (Pogona barbata) in a zoological collection in New Zealand.

CASE HISTORY: Health monitoring of tuatara (Sphenodon punctatus) at Auckland Zoo between 2001 and 2009 showed that 58/93 tuatara had been affected by dermatitis of unknown origin. From 2011 onwards, cases of suspected fungal dermatitis underwent extensive diagnostic investigations. CLINCAL FINDINGS: Six cases of dermatomycosis were attributed to Paranannizziopsis australasiensis, five in tuatara and one in a coastal bearded dragon (Pogona barbata). Cases presented typically as raised, yellow to brown encrustations on the skin. Severe cases progressed to necrotising ulcerative dermatitis, and in the bearded dragon to fatal systemic mycosis. Following topical and systemic treatments, lesions resolved in all five tuatara. LABORATORY FINDINGS: Histopathological examination of skin biopsy samples revealed dermatitis with intralesional septate branching hyphae. Fungal culture yielded isolates morphologically resembling Chrysosporium species, and isolates were submitted for molecular confirmation and sequencing of DNA. DIAGNOSIS: All six cases were confirmed as dermatitis due to infection with P. australasiensis, on the basis of fungal culture and DNA sequencing of isolates. CLINICAL RELEVANCE: These are the first reported cases of dermatomycosis associated with P. australasiensis infection in tuatara, and the first cases in which systemic therapeutic agents have been used in the treatment of such disease. Tuatara at the Auckland Zoo are now routinely examined every 3 months and tissue samples from any lesions sent for histopathology and fungal culture. Further work to elucidate the epidemiology and significance of P. australasiensis infections in reptiles in New Zealand is important for both welfare and conservation purposes.

The impact of children's perception of an activity as play rather than not play on emotional well-being.

BACKGROUND: As an important aspect of health and development, a number of policy and practice initiatives across education, health and social care are aimed at increasing children's emotional well-being. Links have been made between young children's emotional well-being and play although empirical evidence is limited. This paper demonstrates that when children perceive an activity as play, they show more signs of emotional well-being than when they perceive the same activity as not play. METHODS: One hundred and twenty-nine children aged between 3 and 5 years participated in the study. The cues children use to differentiate play and not play were used to create an activity session that was 'like play' and an activity session that was 'not like play'. The activity itself remained constant. Children were allocated to either of the activity session types alternately and emotional well-being was measured using the Leuvens Involvement Scale. RESULTS: There was a significant difference in the level of emotional well-being displayed by children in the two activity session types. Children who undertook the 'like play' activity scored significantly higher than children who undertook the same activity but 'not like play'. Detailed observational analysis also showed increased behavioural indicators relating to emotional well-being among children participating in the 'like play' rather than 'not like play' activity session. CONCLUSION: Children demonstrate increased emotional well-being when they perceive an activity as play rather than not play. Findings support the proposition that play can be seen as an observable behaviour but also as a mental state. As well as providing important evidence as to the value of play for enhancing children's emotional well-being, findings are discussed in relation to professional practice in children's services. The paper highlights the training needs of practitioners to enable them to understand children's views about play and use this information to create playful situations which maximize the developmental potential of play.

Regulation of LKB1 expression by sex hormones in adipocytes.

OBJECTIVE: In the adipose tissue, activation of AMP-activated protein kinase (AMPK) by phosphorylation favours local fatty acid oxidation and inhibition of lipogenesis. We have previously shown that the potent androgen dihydrotestosterone (DHT) can inhibit phosphorylation of AMPK in adipose tissue and 3T3-L1 adipocytes in a dose-dependent manner. This negative effect of DHT was reversed by oestrogen treatment. The purpose of this current study was to determine the underlying mechanisms whereby androgens and oestrogens can regulate AMPK phosphorylation in adipocytes, and whether this mechanism is receptor dependent. RESULTS: Phosphorylation of AMPK was assessed by western blot in cells treated for 24 h with testosterone or DHT (1-1000 nM). Testosterone and DHT significantly inhibited basal phosphorylation of AMPK. Addition of the androgen receptor antagonist Flutamide (1 µM) to the media reversed the negative effect of testosterone and DHT by returning AMPK phosphorylation levels to those of basal. To further dissect the mechanism underlying AMPK inhibition by testosterone or DHT, we examined the mRNA expression of the upstream activator of AMPK, namely LKB1. Testosterone and DHT treatment of murine 3T3-L1 or human SGBS adipocytes for 24 h significantly decreased the mRNA expression of LKB1. In contrast, 17ß-estradiol treatment increased LKB1 mRNA, an effect mediated by oestrogen receptor alpha. CONCLUSION: We conclude that regulation of AMPK phosphorylation by androgens and oestrogens is receptor-dependent, and demonstrate for the first time that LKB1 is regulated by sex hormones in adipocytes.

Gauging mixed climate extreme value distributions in tropical cyclone regions.

In tropical cyclone (TC) regions, tide gauge or numerical hindcast records are usually of insufficient length to have sampled sufficient cyclones to enable robust estimates of the climate of TC-induced extreme water level events. Synthetically-generated TC populations provide a means to define a broader set of plausible TC events to better define the probabilities associated with extreme water level events. The challenge is to unify the estimates of extremes from synthetically-generated TC populations with the observed records, which include mainly non-TC extremes resulting from tides and more frequently occurring atmospheric-depression weather and climate events. We find that extreme water level measurements in multiple tide gauge records in TC regions, some which span more than 100 years, exhibit a behaviour consistent with the combining of two populations, TC and non-TC. We develop an equation to model the combination of two populations of extremes in a single continuous mixed climate (MC) extreme value distribution (EVD). We then run statistical simulations to show that long term records including both historical and synthetic events can be better explained using MC than heavy-tailed generalised EVDs. This has implications for estimating extreme water levels when combining synthetic cyclone extreme sea levels with hindcast water levels to provide actionable information for coastal protection.

A High-End Estimate of Sea Level Rise for Practitioners.

Sea level rise (SLR) is a long-lasting consequence of climate change because global anthropogenic warming takes centuries to millennia to equilibrate for the deep ocean and ice sheets. SLR projections based on climate models support policy analysis, risk assessment and adaptation planning today, despite their large uncertainties. The central range of the SLR distribution is estimated by process-based models. However, risk-averse practitioners often require information about plausible future conditions that lie in the tails of the SLR distribution, which are poorly defined by existing models. Here, a community effort combining scientists and practitioners builds on a framework of discussing physical evidence to quantify high-end global SLR for practitioners. The approach is complementary to the IPCC AR6 report and provides further physically plausible high-end scenarios. High-end estimates for the different SLR components are developed for two climate scenarios at two timescales. For global warming of +2°C in 2100 (RCP2.6/SSP1-2.6) relative to pre-industrial values our high-end global SLR estimates are up to 0.9 m in 2100 and 2.5 m in 2300. Similarly, for a (RCP8.5/SSP5-8.5), we estimate up to 1.6 m in 2100 and up to 10.4 m in 2300. The large and growing differences between the scenarios beyond 2100 emphasize the long-term benefits of mitigation. However, even a modest 2°C warming may cause multi-meter SLR on centennial time scales with profound consequences for coastal areas. Earlier high-end assessments focused on instability mechanisms in Antarctica, while here we emphasize the importance of the timing of ice shelf collapse around Antarctica. This is highly uncertain due to low understanding of the driving processes. Hence both process understanding and emission scenario control high-end SLR.

Projected incremental changes to extreme wind-driven wave heights for the twenty-first century.

Global climate change will alter wind sea and swell waves, modifying the severity, frequency and impact of episodic coastal flooding and morphological change. Global-scale estimates of increases to coastal impacts have been typically attributed to sea level rise and not specifically to changes to waves on their own. This study provides a reduced complexity method for applying projected extreme wave changes to local scale impact studies. We use non-stationary extreme value analysis to distil an incremental change signal in extreme wave heights and associate this with a change in the frequency of events globally. Extreme wave heights are not projected to increase everywhere. We find that the largest increases will typically be experienced at higher latitudes, and that there is high ensemble model agreement on an increase (doubling of events) for the waters south of Australia, the Arabian Sea and the Gulf of Guinea by the end of the twenty-first century.

Cosmos 954: search for airborne radioactivity on lichens in the crash area, northwest territories, Canada.

The fission product radioactivity detected on lichens in the vicinity of the impact area of the Soviet satellite Cosmos 954 does not exceed the background levels found in the general area as a result of past nuclear explosions.

Technique and preliminary findings for in vivo quantification of brain motion during injurious head impacts.

Computational models of the human brain are widely used in the evaluation and development of helmets and other protective equipment. These models are often attempted to be validated using cadaver tissue displacements despite studies showing neural tissue degrades quickly after death. Addressing this limitation, this study aimed to develop a technique for quantifying living brain motion in vivo using a closed head impact animal model of traumatic brain injury (TBI) called CHIMERA. We implanted radiopaque markers within the brain of three adult ferrets and resealed the skull while the animals were anesthetized. We affixed additional markers to the skull to track skull kinematics. The CHIMERA device delivered controlled, repeatable head impacts to the head of the animals while the impacts were fluoroscopically stereo-visualized. We observed that 1.5 mm stainless steel fiducials (∼8 times the density of the brain) migrated from their implanted positions while neutral density targets remained in their implanted position post-impact. Brain motion relative to the skull was quantified in neutral density target tests and showed increasing relative motion at higher head impact severities. We observed the motion of the brain lagged behind that of the skull, similar to previous studies. This technique can be used to obtain a comprehensive dataset of in vivo brain motion to validate computational models reflecting the mechanical properties of the living brain. The technique would also allow the mechanical response of in vivo brain tissue to be compared to cadaveric preparations for investigating the fidelity of current human computational brain models.

Estrogen and adiposity--utilizing models of aromatase deficiency to explore the relationship.

Estrogen has an important role to play in energy homeostasis in both men and mice. Lack of estrogen results in the development of a metabolic syndrome in humans and rodents, including excess adiposity, hepatic steatosis (in male but not female aromatase knockout (ArKO) mice) and insulin resistance. Estrogen replacement results in a prompt reversal of the energy imbalance symptoms associated with estrogen deficiency. A corollary to the perturbed energy balance observed in the ArKO mouse is the death by apoptosis of dopaminergic neurons in the hypothalamic arcuate nucleus of male ArKO mice, an area of the brain pivotal to the regulation of energy uptake, storage, and mobilisation. An extension of our work exploring the relationship between estrogen and adiposity has been to examine the role played by androgens in energy balance. We have demonstrated that an increased androgen to estrogen ratio can promote visceral fat accumulation in the rodent by inhibiting AMPK activation and stimulating lipogenesis. Therefore, understanding the regulation of energy homeostasis is becoming an increasingly fascinating challenge, as the number of contributors, their communications, and the complexity of their interactions, involved in the preservation of this equilibrium continues to increase. Models of aromatase deficiency, both naturally occurring and engineered, will continue to provide valuable insights into energy homeostasis.

Network analysis of wildlife translocations in New Zealand.

AIMS: To identify network measures with relevance to disease spread in a network of movements derived from the Department of Conservation (DOC) translocation records from 1970 to mid-2014, and to identify conservation sites that should be prioritised for surveillance activities and improvements to data collection to make the best use of network analysis techniques in the future. METHODS: Data included the source and destination of translocated specimens, the species and the dates the translocations were expected to occur. The data were used to construct a directed, non-weighted network in which a translocation event represented a tie in the network. Network density, in-degree (movements entering a node of interest) and out-degree (movements leaving a node of interest) and reciprocity were calculated. RESULTS: The data analysed consisted of 692 unique translocations between 307 sites, with the majority (518; 73%) being for birds. The constructed network for bird, reptile and frog translocations comprised 260 nodes, with 34/260 (13%) having two-way movements and 47/260 (18%) non-reciprocal movements. The median degree score (sum of in- and out-degree) was two (min 0, max 36) with a mean of 3.5 in a right skewed distribution. Most sites acted as receivers or senders of consignments with only a few having both high in- and high out-degree, and thus had characteristics that made them sites of interest for surveillance activities. These included the National Wildlife Centre at Mount Bruce, Tiritiri Matangi Island and Te Kakahu (Chalky Island). CONCLUSIONS: The presence of linking sites that join larger clusters within the network creates the potential for rapid disease spread if a pathogen were to be introduced. The important sites that supply or receive specimens for translocations are already well recognised by those performing translocations in New Zealand, and this paper provides further information by quantifying their role within the network.

Investigation of mortalities associated with Salmonella spp. infection in wildlife on Tiritiri Matangi Island in the Hauraki Gulf of New Zealand.

CASE HISTORY: Salmonellosis was suspected as the cause of death in eight wild animals on Tiritiri Matangi Island, in the Hauraki Gulf of New Zealand, between November and September 2011, including three hihi (Notiomystis cincta), a tuatara (Sphenodon punctatus), a masked lapwing (Vanellus miles novaehollandiae), and a saddleback (Philesturnus carunculatus). An outbreak investigation to identify the source and distribution of infection was undertaken over the summer of 2011-2012. CLINICAL AND LABORATORY FINDINGS: Surveillance of five species of forest bird (n=165) in December 2011 returned a single positive result for Salmonella spp. Environmental sampling of 35 key water sources and hihi supplementary feeding stations conducted in December 2011 and March 2012 returned isolates of S. enterica subspecies houtenae and S. enterica serovar Saintpaul from a stream, a dam and a supplementary feeding station. The same serotypes were identified in tissue samples collected from post mortem specimens of the affected birds, and their similarity was confirmed by pulsed-field gel electrophoresis. DIAGNOSIS: Mortality in wildlife associated with infection with S. enterica subspecies houtenae and S. enterica serovar Saintpaul. CLINICAL RELEVANCE: This is the first detection of these Salmonella spp. from wild birds in New Zealand. Our study highlights how active surveillance in response to observed disease emergence (here mortalities) can provide important insight for risk assessment and management within populations of endangered species and inform risk assessment in translocation planning.

Ventral dermatitis in rowi (Apteryx rowi) due to cutaneous larval migrans.

The rowi is a critically endangered species of kiwi. Young birds on a crèche island showed loss of feathers from the ventral abdomen and a scurfy dermatitis of the abdominal skin and vent margin. Histology of skin biopsies identified cutaneous larval migrans, which was shown by molecular sequencing to be possibly from a species of Trichostrongylus as a cause of ventral dermatitis and occasional ulcerative vent dermatitis. The predisposing factors that led to this disease are suspected to be the novel exposure of the rowi to parasites from seabirds or marine mammals due to the island crèche and the limited management of roost boxes. This is the first instance of cutaneous larval migrans to be recorded in birds. Severe and fatal complications of the investigation resulted in the death of eight birds of aspergillosis and pulmonary complications associated with the use of bark as a substrate in hospital. Another bird died of renal failure during the period of hospitalisation despite oral and intravenous fluid therapy. The initiating cause of the renal failure was not determined. These complications have the potential to undermine the working relationship between wildlife veterinarians and conservation managers. This case highlights that intensive conservation management can result in increased opportunities for novel routes of cross-species pathogen transmission.

Quality collaboratives: lessons from research.

Quality improvement collaboratives are increasingly being used in many countries to achieve rapid improvements in health care. However, there is little independent evidence that they are more cost effective than other methods, and little knowledge about how they could be made more effective. A number of systematic evaluations are being performed by researchers in North America, the UK, and Sweden. This paper presents the shared ideas from two meetings of these researchers. The evidence to date is that some collaboratives have stimulated improvements in patient care and organisational performance, but there are significant differences between collaboratives and teams. The researchers agreed on the possible reasons why some were less successful than others, and identified 10 challenges which organisers and teams need to address to achieve improvement. In the absence of more conclusive evidence, these guidelines are likely to be useful for collaborative organisers, teams and their managers and may also contribute to further research into collaboratives and the spread of innovations in health care.

Influence of salinity on bioremediation of oil in soil.

Spills from oil production and processing result in soils being contaminated with oil and salt. The effect of NaCl on degradation of oil in a sandy-clay loam and a clay loam soil was determined. Soils were treated with 50 g kg(-1) non-detergent motor oil (30 SAE). Salt treatments included NaCl amendments to adjust the soil solution electrical conductivities to 40, 120, and 200 dS m(-1). Soils were amended with nutrients and incubated at 25 degrees C. Oil degradation was estimated from the quantities of CO(2) evolved and from gravimetric determinations of remaining oil. Salt concentrations of 200 dS m(-1) in oil amended soils resulted in a decrease in oil mineralized by 44% for a clay loam and 20% for a sandy-clay loam soil. A salt concentration of 40 dS m(-1) reduced oil mineralization by about 10% in both soils. Oil mineralized in the oil amended clay-loam soil was 2-3 times greater than for comparable treatments of the sandy-clay loam soil. Amending the sandy-clay loam soil with 5% by weight of the clay-loam soil enhanced oil mineralization by 40%. Removal of salts from oil and salt contaminated soils before undertaking bioremediation may reduce the time required for bioremediation.

Adsorption and desorption of metolachlor and metolachlor metabolites in vegetated filter strip and cultivated soil.

Previous studies have indicated that dissolved-phase metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(methoxy-1-methylethyl) acetamide] transported in surface runoff is retained by vegetative filter strips to a greater degree than either metolachlor oxanilic acid 12-[(2-ethyl-6-methylphenyl) (2-methoxy-1-methylethyl)amino]-2-oxo-acetic acid] (OA) or metolachlor ethanesulfonic acid [2-[(2-ethyl-6-methylphenyl) (2-methoxy-1-methylethyl-1)amino]-2-oxoethanesul-fonic acid] (ESA), two primary metabolites of metolachlor. Adsorption-desorption of ESA and OA in vegetated filter strip soil (VFSS) has not been evaluated, yet these data are required to assess the mobility of these compounds in VFSS. The objective of this experiment was to compare metolachlor, ESA, and OA adsorption and desorption parameters between VFSS and cultivated soil (CS). Adsorption and desorption isotherms were determined using the batch equilibrium procedure. With the exception of a 1.7-fold increase in organic carbon content in the VFSS, the evaluated chemical and physical properties of the soils were similar. Sorption coefficients for metolachlor were 88% higher in VFSS than in CS. In contrast, sorption coefficients for ESA and OA were not different between soils. Relative to metolachlor, sorption coefficients for ESA and OA were at least 79% lower in both soils. Metolachlor desorption coefficients were 59% higher in the VFSS than in the CS. Desorption coefficients for ESA and OA were not different between soils. Relative to metolachlor, desorption coefficients for ESA and OA were at least 66% lower in both soils. These data indicate that the mobility of ESA and OA will be greater than metolachlor in both soils. However, higher organic carbon content in VFSS relative to CS may limit the subsequent transport of metolachlor from the vegetated filter strip.

Water flow patterns in subsurface flow constructed wetlands designed for on-site domestic wastewater treatment.

Bypass flow in subsurface flow constructed wetlands, which may be related to several wetland characteristics, reduces detention time and may result in inadequately treated wastewater. Subsurface flow constructed wetlands, 2.3 m wide by 4.8 m long and containing a gravel matrix, were used to investigate the impact of wetland depth, inlet pipe location, loading volume, and plants on water flow. Flow patterns were determined using blue dye or bromide as tracers. The blue dye adsorbed to the gravel and was not an effective tracer for following water movement. Water dispersed as it flowed through the wetland, and approximately two pore volumes of added water were required to displace approximately 99% of the bromide tracer added as a pulse. In 17 and 25 cm deep wetlands, water flow was uniform with depth, and inlet depth had little influence on water flow patterns. Water flow in a 40 cm deep wetland was not uniform with depth for either inlet pipe placement. The presence of plants caused preferential water flow around root masses, thereby, limiting their potential to interface with wastewater. Water mixing by dispersion from the surface to deeper depths may enhance aeration. Bromide was first detected in effluent after only 0.5 pore volumes of tap water had been added. This indicates that detention time for some wastewater would be less than expected, since plug flow is usually assumed in subsurface flow constructed wetlands. This occurrence should be considered for time-dependent treatments, such as fecal coliform and biological oxygen demand reduction.