A 13-month survey of nematodes at three water treatment plants in southern Ontario, Canada

Nematodes were present in almost every sample of treated water from all 3 plants examined, often in high numbers (a maximum of 42.5 1⁻¹), with a considerable proportion being motile. Existing suggested standards of nematode concentrations were exceeded at each plant. Treatment processes, including coagulation, filtration and chlorination, were ineffective in immobilizing or removing most nematodes. The most significant factor in reducing nematode densities in this study was a slow-moving canal at one plant which acted as a presettling tank.High river flow, heavy rainfall and high raw water turbidity all corresponded to increases in nematode concentrations and can be used to indicate those times when extra measures to reduce numbers might be applied.Further research is recommended on the supposed pathogen carrying abilities of nematodes in drinking water.     

Small is Transient: Housebuilding Firms in Ontario,Canada 1978-98

The North American housebuilding industry has been neglected in urban and housing studies. Its firm size structure and instability have long been cause for concern, but have rarely been given more than anecdotal treatment. This paper examines the transience of housebuilders in Ontario from 1978 to 1998. Using a census of builders provided by the Ontario New Home Warranty Program, the industry's firm membership is found to be extremely transient. Most transience comes by way of new firm formation and permanent firm exits from the market, while a small cohort of builders withdraw from and re-enter the market on a regular basis. The business cycle speeds and slows these processes but flux is due primarily to the annual turnover of small builders. To reduce transience, policy makers must decide between slowing entry and perhaps raising industry concentration or allowing continued firm entry and probably transience.     

Distribution and potential significance of a gull fecal marker in urban coastal and riverine areas of southern Ontario, Canada

To better understand the distribution of gull fecal contamination in urban areas of southern Ontario, we used gull-specific PCR and qPCR assays against 1309 water samples collected from 15 urban coastal and riverine locations during 2007. Approximately, 58% of the water samples tested positive for the gull-assay. Locations observed to have higher numbers of gulls and their fecal droppings had a higher frequency of occurrence of the gull marker and a higher gull marker qPCR signal than areas observed to be less impacted by gulls. Lower gull marker occurrence and lower qPCR signals were associated with municipal wastewater (7.4%) and urban stormwater effluents (29.5%). Overall, there were no statistically significant differences in gull marker occurrence at beach sites for pore water, ankle, and chest-depth samples, although signals were generally higher in interstitial beach sand pore water and ankle-depth water than in chest-depth water samples. Overall, the results indicated that gull fecal pollution is widespread in urban coastal and riverine areas in southern Ontario and that it significantly contributes to fecal indicator bacterial loads.     

Lead contents in the surface enamel of primary and permanent teeth, whole blood, serum, and saliva of 6- to 8-year-old children

This study aimed to evaluate associations of Pb-enamel values determined in two successive enamel microbiopsies taken from a primary and a permanent tooth, and to assess how Pb-enamel correlates with Pb-blood and Pb-serum as well as whole (Pb-whole-saliva), submandibular/sublingual (Pb-sub-saliva) and parotid saliva (Pb-parotid-saliva). The study population included 444 children aged 6 to 8 years attending 4 government schools in the district of Campos Eliseos, in Ribeirao Preto, Sao Paulo State, Brazil. Whole blood, serum, parotid, submandibular/sublingual (“sub-saliva”), and whole saliva were collected in trace element-free tubes. Two successive microbiopsies were taken from the surface of a primary and a permanent tooth of each child. Lead concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS). There was a significant correlation between primary and permanent teeth in terms of Pb-enamel, for both the first and the second microbiopsies. When the median Pb-enamel values were compared between the two genders using only the highest 10th percentile Pb-enamel, there was a significant difference between girls and boys for both primary (474.2 vs 910.0 μg/g, respectively; p = 0.02) and permanent teeth (739.5 vs 1325 μg/g, respectively; p = 0.04). There were no significant correlations between Pb-enamel and Pb-blood or between Pb-enamel and lead in the 3 different salivas. However, there was a statistically significant correlation between Pb-enamel and Pb-serum when only the highest 10th percentile Pb-enamel was analyzed (r = 0.57 and p = 0.0002 for primary teeth; r = 0.56 and p < 0.0001, for permanent teeth). In conclusion, our findings have demonstrated a significant correlation between Pb-enamel found in primary and permanent teeth, as well as a significant correlation between Pb-serum and lead in primary and permanent tooth enamel. Boys presented higher Pb-enamel than girls. Our study also suggests that Pb-enamel has no correlation with Pb-blood or with lead in the 3 different salivas.     

Chlorinated hydrocarbon contaminants in feces of river otters from the southern Pacific coast of Canada, 1998-2004

Chlorinated hydrocarbon contaminants in coastal river otters (Lontra canadensis) were evaluated by sampling feces (scats) collected on the south coast of British Columbia, Canada. A broad survey of industrialized areas of the Strait of Georgia region was conducted in 1998, and a subsequent survey of working harbours in 2004. Samples from 1998 were analyzed for polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides, and polychlorinated dioxins (PCDDs) and furans (PCDFs), while in 2004, chemistry was confined to summation operatorPCBs and OC pesticides. Concentrations of OC pesticides were low in both years, with only dichlorodiphenyldichloroethylene (DDE; range: 0.01-2.12 mg/kg lw) and hexachlorocyclobenzene (HCB; range: 0.003-0.25 mg/kg lw) detected in all samples. In 1998, octachlorodibenzo-p-dioxin (OCDD) and other higher chlorinated PCDD/Fs were found in most samples, with OCDD ranging from 120 ng/kg lw in Clayoquot Sound to 19,100 ng/kg lw in a pooled sample from two latrines in Nanaimo. PCBs were present in all samples. In 1998 geometric mean concentrations of the sum of 59 PCB congeners ranged from 0.49 mg/kg lw in Nanaimo to 12.3 mg/kg lw in Victoria Harbour. Six years later, mean summation operatorPCBs remained elevated (geometric mean 9.5 mg/kg lw) in Victoria Harbour. Geometric mean concentrations of summation operatorPCBs from Victoria Harbour in 1998 and 2004 were >9 mg/kg lw, a published adverse effect level for reproduction. At some latrines in both Victoria and Esquimalt Harbours, concentrations of TCDD-toxic equivalents exceeded 1500 ng/kg lw, a value for health effects in otters that we derived using published information. As shown in previous studies, analysis of scats provides an efficient and non-intrusive approach to assessing contaminant threats to otter populations, and to documenting spatial trends in residues.     

Residues from past uses of organochlorine insecticides and PCB in waters draining eleven agricultural watersheds in southern Ontario, Canada, 1975–1977

Between May, 1975 and April, 1977 eleven agricultural watersheds ranging in size between 19 and 79 km² were studied for residues of persistent organochlorine insecticides and PCB. Stream water, rainwater, sediments, invertebrates and fish were analysed. The presence of DDT, its metabolites and dieldrin, insecticides that had been removed from field application between 1969 and 1972, and PCB, an industrial fire retardant that had been voluntarily restricted to ‘closed system’ use in 1971, were identified.ΣDDT was present in 93% of 949 initial stream waters and 40.6% exceeded a 3 ng/l International Joint Commission (IJC-1977) water quality objective for boundary waters of the Great Lakes. Unit area loading for ΣDDT ranged from 2.9 to 88 mg/ha/yr per watershed. Dieldrin was present in one-fifth of stream waters and 16% exceeded the 1 ng/l IJC (1977) objective. Unit area loading for dieldrin varied from zero to 28 mg/ha/yr per watershed. PCB residues were detected in 94.4% of stream waters at or above 2 ng/l and unit area loading varied from 28 to 269 mg/ha/yr per watershed.DDE and PCB were found in rainwater and this could represent a major source of contamination of PCB. The soil reservoir was the main source of DDT and dieldrin. Accumulations of all three organochlorine compounds in invertebrates and fish were between 10³ and 10⁴ times. None of the fish or invertebrates exceeded the IJC objective of 0.1 μg/g PCB.     

Arsenic,Sb and Bi contamination of soils,plants, waters and sediments in the vicinity of the Dalsung Cu-W mine in Korea

The diagnosis of lead poisoning in horses living on farmland in the vicinity of a battery recycling plant was based on clinical signs as well as on laboratory findings. Chemical analysis of six surface soils (0-15 cm) and herbage samples taken at different distances to the recycling plant showed very high total lead levels in the closest sites to the facility and a clear decrease with distance. Total lead levels in soil samples ranged from 127 to 5657 mg kg(-1), with more than 70% of lead extractable by EDTA in the most polluted soils. Lead levels in the aerial part of herbage samples were in the range of 113-4741 mg kg(-1). A water washing pre-treatment of the vegetal samples considerably diminished the concentration of lead, suggesting that airborne lead particles from the facility emissions were fixed on the shoots. The analysis of samples taken from six dead horses showed lead concentrations, expressed as mg kg(-1) (d.w.), as follows: blood: 0.20-0.89; liver: 2.5-15; kidney: 1.70-6.75. Lead intake levels, estimated according to the ingestion rate of Grammineae forage, illustrates that the apported lead through the ingestion of vegetation growing in the closest sites to the recycling plant was approximately 99.5 mg Pb/kg body weight/day surpassing the fatal dosage for horses of 2.4 mg Pb/kg body weight/day reported by Hammond and Aronson, Ann NY Acad Sci, 1964; 111: 595-611.     

Temporal and spatial trends of mercury in fish collected in the English-Wabigoon river system in Ontario, Canada

The First Nations communities of Grassy Narrows and Wabaseemong (Ontario, Canada) have been impacted by mercury pollution since the 1960s. This study was implemented with the objective of providing these communities with information on current mercury concentrations in their catch, in order to make appropriate fish consumption choices. A total of 851 fish samples, including Walleye, Northern Pike, Large-mouth Bass, and Whitefish, were collected from thirteen lakes and rivers. Total mercury was measured and the relationship between fish length, mercury concentration, and lake of origin were assessed. It was found that fish from most of the lakes exhibit a positive relationship between length and mercury accumulation. Mercury concentrations in fish collected from Clay Lake, closest to the original source of contamination, are higher than those from other lakes. Mercury concentrations have declined over the last 25 years but the gradient of contamination was still observed. Results were communicated to the communities for public health purposes.     

Effects of Housing Development on Bird Species Diversity in a Forest Fragment in Ontario, Canada

This study investigated the effects of a housing development on the number and composition of forest bird species in an adjacent remnant woodlot in Southern Ontario, Canada. The predicted effects of the development on the woodlot species were the subject of two regulatory hearings between 1979 and 1983. Theoretical evidence was presented that predicted a significant decrease in the number of interior species. The regulatory board ruled that theory was insufficient evidence upon which to predict the effects of the development, and allowed the development to proceed. To measure the effects of the development, a pre-development study undertaken by a consulting firm in 1977 was repeated in 1999, about 10 years after completion of the housing subdivision. The observed number of interior forest specialist species was found to have declined in agreement with prevailing theory, but the observed number of interior-edge and edge generalist species had unexpectedly increased. The results of this study, along with those from other recent studies, have been used to suggest mitigating measures for future developments.     

广东省茜坑铅锌多金属矿成矿地质特征与找矿前景

广东省茜坑铅锌多金属矿产于侏罗系下统金鸡组(J1j)地层中,主要受一区域控矿构造NNW向硅化角砾岩带(密集硅化构造裂隙带)的控制,矿体较连续稳定。成矿的铅锌多金属元素主要来源于岩浆的气水热液,其在围岩或母岩的裂隙带中沉淀富集,形成矿床及矿化点。沿构造走向,现已发现两个铅锌矿点,具有较大的找矿前景。     

A comparison of the isotopic composition of lead in rainwater, surface vegetation and tree bark at the long-term monitoring site, Glensaugh, Scotland, in 2007

The lead concentrations and isotopic ratios (²⁰⁶Pb/²⁰⁷Pb, ²⁰⁸Pb/²⁰⁶Pb, ²⁰⁸Pb/²⁰⁷Pb) of 31 rainwater (September 2006-December 2007) and 11 surface vegetation (moss, lichen, heather) samples (October 2007) from the rural upland catchment of Glensaugh in northeast Scotland and of nine bark samples (October 2007) from trees, predominantly Scots pine, in or near Glensaugh were determined. The mean ²⁰⁶Pb/²⁰⁷Pb ratios for rainwater in 2006 and 2007 were similar to those previously determined for 2000 to 2003 at Glensaugh, yielding an average mean annual value of 1.151 ± 0.005 (± 1 SD) for the period from 2000, when an outright ban on leaded petrol came into force in the UK, to 2007. The mean ²⁰⁶Pb/²⁰⁷Pb ratio (1.146 ± 0.004; n = 7) for surface vegetation near the top (430-450 m) of the catchment was not significantly different (Student's t test) from that of rainwater (1.148 ± 0.017; n = 24) collected over the 12-month period prior to vegetation sampling, but both were significantly different, at the 0.1% (i.e. p < 0.001) and 1% (p < 0.01) level, respectively, from the corresponding mean value (1.134 ± 0.006; n = 9) for the outermost layer of tree bark. When considered in conjunction with similar direct evidence for 2002 and indirect evidence (e.g. grass, atmospheric particulates, dated peat) for recent decades in the Glensaugh area, these findings confirm that the lead isotopic composition of surface vegetation, including that of suitably located moss, reflects that of the atmosphere while that of the outermost layer of Scots pine bark is affected by non-contemporaneous lead. The nature and relative extent of the different contributory sources of lead to the current UK atmosphere in the era of unleaded petrol, however, are presently not well characterised on the basis of lead isotopic measurements.     

Modelling sediment-microbial dynamics in the South Nation River, Ontario, Canada: Towards the prediction of aquatic and human health risk

Runoff from agricultural watersheds can carry a number of agricultural pollutants and pathogens; often associated with the sediment fraction. Deposition of this sediment can impact water quality and the ecology of the river, and the re-suspension of such sediment can become sources of contamination for reaches downstream. In this paper a modelling framework to predict sediment and associated microbial erosion, transport and deposition is proposed for the South Nation River, Ontario, Canada. The modelling framework is based on empirical relationships (deposition and re-suspension fluxes), derived from laboratory experiments in a rotating circular flume using sediment collected from the river bed. The bed shear stress governing the deposition and re-suspension processes in the stream was predicted using a one dimensional mobile boundary flow model called MOBED. Counts of live bacteria associated with the suspended and bed sediments were used in conjunction with measured suspended sediment concentration at an upstream section to allow for the estimation of sediment associated microbial erosion, transport and deposition within the modelled river reach. Results suggest that the South Nation River is dominated by deposition periods with erosion only occurring at flows above approximately 250 m³ s⁻¹ (above this threshold, all sediment (suspended and eroded) with associated bacteria are transported through the modelled reach). As microbes are often associated with sediments, and can survive for extended periods of time, the river bed is shown to be a possible source of pathogenic organisms for erosion and transport downstream during large storm events. It is clear that, shear levels, bacteria concentrations and suspended sediment are interrelated requiring that these parameters be studied together in order to understand aquatic microbial dynamics. It is important that any management strategies and operational assessments for the protection of human and aquatic health incorporate the sediment compartments (suspended and bed sediment) and the energy dynamics within the system in order to better predict the concentration of indicator organism.     

Biogeochemical factors influencing net mercury methylation in contaminated freshwater sediments from the St. Lawrence River in Cornwall, Ontario, Canada

The activity of various anaerobic microbes, including sulfate reducers (SRB), iron reducers (FeRP) and methanogens (MPA) has been linked to mercury methylation in aquatic systems, although the relative importance of each microbial group in the overall process is poorly understood in natural sediments. The present study focused on the biogeochemical factors (i.e. the relative importance of various groups of anaerobic microbes (FeRP, SRB, and MPA) that affect net monomethylmercury (MMHg) formation in contaminated sediments of the St. Lawrence River (SRL) near Cornwall (Zone 1), Ontario, Canada. Methylation and demethylation potentials were measured separately by using isotope-enriched mercury species (²⁰⁰Hg²⁺ and MM¹⁹⁹Hg⁺) in sediment microcosms treated with specific microbial inhibitors. Sediments were sampled and incubated in the dark at room temperature in an anaerobic chamber for 96 h. The potential methylation rate constants (K_m) and demethylation rates (K_d) were found to differ significantly between microcosms. The MPA-inhibited microcosm had the highest potential methylation rate constant (0.016 d⁻¹), whereas the two SRB-inhibited microcosms had comparable potential methylation rate constants (0.003 d⁻¹ and 0.002 d⁻¹, respectively). The inhibition of methanogens stimulated net methylation by inhibiting demethylationand by stimulating methylation along with SRB activity. The inhibition of both methanogens and SRB was found to enhance the iron reduction rates but did not completely stop MMHg production. The strong positive correlation between K_m and Sulfate Reduction Rates (SRR) and between K_d and Methane Production Rates (MPR) supports the involvement of SRB in Hg methylation and MPA in MMHg demethylation in the sediments. In contrast, the strong negative correlation between K_d and Iron Reduction Rates (FeRR) shows that the increase in FeRR corresponds to a decrease in demethylation, indicating that iron reduction may influence net methylation in the SLR sediments by decreasing demethylation rather than favouring methylation.     

Spring-harvested game birds from the western James Bay region of northern Ontario, Canada: organochlorine concentrations in breast muscle

Although studies have assessed organochlorine concentration in breast tissue (pectoral muscle) of fall-harvested game birds in Canada, data for spring-harvested game birds are limited, especially for remote sub-arctic areas. Taking into account that most traditional Aboriginal diets include a large number of spring-harvested game birds, there is a need to assess organochlorine concentration in spring-harvested water birds with respect to suitability for human consumption. We examined organochlorine concentrations in breasts of 20 mallard ducks (Anas platyrhynchos), 20 northern pintails (A. acuta), 21 Canada geese (Branta canadensis interior), and 20 lesser snow geese (Chen caerulescens caerulescens) harvested in the spring; summer-harvested shorebirds (godwits; Limosa spp.) were also assessed as these water birds are an important part of the game bird harvest for First Nation Cree of the western James Bay region of Ontario, Canada. The most frequently detected organochlorines in striated (pectoral) muscle were SigmaPCBs (sum of 14 congeners [CBs]) and SigmaDDT (sum of DDE and DDT) followed by SigmaCHL (sum of oxy-chlordane, cis- and trans-nonachlor) and hexachlorobenzene with beta-hexachlorocyclohexane being the least frequently detected. For organochlorines that had < or =70% of the samples with detectable concentrations of an organochlorine (i.e., CBs 105, 128, 156, 170, 180, 183, cis-nonachlor, DDT, and mirex), log-linear contingency modelling revealed that the dabbling ducks had significantly more than expected detectable concentrations of most organochlorines; by contrast, geese and shorebirds had significantly less than expected detectable concentrations of most organochlorines. ANOVA for organochlorines with frequency of detection > or =70% (i.e., Aroclor 1260, SigmaPCBs, CBs 118, 138, 153, 187, DDE, hexachlorobenzene, oxy-chlordane and trans-nonachlor) revealed significant differences between bird species: Breast tissue in snow geese contained significantly less organochlorines than Canada geese (Aroclor 1260, CBs 118, 138, and 153) and godwits (Aroclor 1260, CBs 138, 153); mallards had significantly higher concentrations compared to godwits (DDE, trans-nonachlor, and SigmaCHLs), Canada geese (oxy-chlordane and SigmaCHLs), and snow geese (oxy-chlordane, trans-nonachlor, SigmaCHLs); and pintails had elevated levels compared to snow geese (CB 153, oxy-chlordane, trans-nonachlor, and SigmaCHLs) and Canada geese (oxy-chlordane). However, none of the samples analyzed in the present study exceeded the consumption guideline for organochlorines in fish or poultry with most samples being orders of magnitude less than the consumption guideline even when compared to maxima. Thus, the present spring-harvested-game bird study supports previous studies of fall-harvested game birds that contend that pectoral muscle portions are safe to eat. Nevertheless, skin and fat associated with the breast muscle may be another matter.     

Ozone treatment and the depletion of detectable pharmaceuticals and atrazine herbicide in drinking water sourced from the upper Detroit River, Ontario, Canada

The depletion and degradation of pharmacologically active compounds (PhACs) and pesticides as a function of ozonation in drinking water treatment processes is not well studied. The A.H. Weeks drinking water treatment plant (DWTP) serves the City of Windsor, Ontario Canada, and incorporates ozone treatment into the production of drinking water. This DWTP also operates a real-time, scaled down pilot plant, which has two parallel streams, conventional and ozone plus conventional treatments. In this study water samples were collected from key points in the two streams of the pilot plant system to determine the depletion and influence of seasonal changes in water processing parameters on eighteen major PhACs (and metabolites) and seven s-triazines herbicides. However, only carbamazepine (antiepileptic), caffeine (stimulant), cotinine (metabolite of nicotine) and atrazine were consistently detectable in the raw water intake (low to sub-ng/L level). Regardless of the seasonality, the flocculation-coagulation and dual media filtration steps without ozone treatment resulted in no decrease in analyte concentrations, while decreases of 66-100% (undetectable, method detection limits 0.05-1 ng/L) of the analyte concentrations were observed when ozone treatment was part of the water processing. These findings demonstrate that ozone treatment is highly effective in depleting carbamazepine, caffeine, cotinine, and atrazine, and thus is highly influential in the fate of these compounds in drinking water treatment regardless of the seasonal time frame. Currently very few Canadian DWTPs incorporate ozonation into conventional treatment, which suggests that human exposure to these compounds via drinking water consumption may be an issue in affected communities.     

Sediment mercury dynamics and historical trends of mercury deposition in the St. Lawrence River area of concern near Cornwall, Ontario, Canada

The St. Lawrence River near Cornwall, Ontario was designated an Area of Concern by the International Joint Commission in 1985. Sediments from this area have historically been contaminated with mercury (Hg), and although concentrations have decreased since the 1970s, they still remain high. Nine sediment cores were collected from three sites within the Area of Concern in 2004/05 to determine the variability in historical profiles of Hg deposition to the river. Sediment and pore water phases were analyzed for total mercury (THg) and methyl mercury (MeHg) and cores were analyzed for ²¹⁰Pb to determine chronologies of sedimentation at these sites. Mercury diffusion rates in pore waters within the sediment column were determined to be very low (between 0 and 2.15 ng cm^− 2 year^− 1, n = 3) compared to the recent Hg sedimentation rates at these sites (183 ± 30 ng cm^− 2 year^− 1 SE, n = 9) determined by multiplying surface Hg concentrations with ²¹⁰Pb-derived sedimentation rates. These results indicate that Hg profiles in these cores accurately depict historical releases of Hg to the river bed. The influence of federal regulations in the early 1970s to restrict Hg emissions to the river was apparent in these dated sediment cores, as were the closures of several local industries in the mid 1990s. Mercury accumulation rates prior to 1970 were 60 times higher than those occurring after 1995. Methyl mercury showed surface enrichment in most of these sediment cores providing evidence that mercury methylation occurred most rapidly near the sediment surface.     

Cadmium and lead in selected tissues of two commercially important fish species from the Adriatic Sea

Baseline levels of cadmium and lead were determined in muscle tissue and liver of hake (Merluccius merluccius) and red mullet (Mullus barbatus), two commercially important fish species from the eastern Adriatic. Concentrations of trace metals in liver (Cd: 6–183 μg kg⁻¹ w. wt. ; Pb: 39–970 μg kg⁻¹ w. wt.) were within the range of recently published data for the Mediterranean. In the muscle tissue, cadmium concentrations (4.1–29 μg kg⁻¹ w. wt.) were among the lowest reported values for the Mediterranean, whereas lead levels (49–158 μg kg⁻¹ w. wt.) were within the range of values reported for various coastal areas of the Mediterranean. Presented data on cadmium and lead content in the studied fish species provide no proof of the general pollution of the Adriatic. Obtained data were tested in relation to fish length. Metal concentrations in liver decreased with the increase in fish size, whereas no significant correlation was found between trace metal levels in the muscle tissue and the length of both species. Relationships between metal concentrations and sex were also tested, but they gave no significant results. A comparison of contaminant concentrations in the edible tissue of hake and red mullet with the Croatian legislation shows that the consumption of their meat is not harmful for humans, not even for the most endangered population from the coastal region.     

Simulating the impact of forest management scenarios in an agricultural landscape of southern Quebec, Canada, using a geographic cellular automata

Forest remnants are vital for the overall heterogeneity and health of rural landscapes. However, deforestation is a significant process afflicting large numbers of agroforested regions of the world. The Maskoutains regional county municipality (RCM) in southern Quebec, Canada, experiences intense deforestation that has reached critical levels. The goal of this study is to develop a geographic cellular automata (GCA) to model land-use change in this region and test the influence of different management scenarios on the fate of the forested remnants. The GCA was built using a 100 m cell size, a Moore neighborhood configuration, a 3 years time step resolution and probabilistic transition rules derived from the comparison of two land-use maps for the years 1999 and 2002. Four groups of management scenarios were tested: (1) status quo (SQ), (2) reduced deforestation (RD), (3) promotion of ligniculture (L), and (4) protection of forest connectivity (CONN). Results indicate that none of the scenarios succeed in maintaining the actual levels of forest area. However, certain scenarios (amongst the RD and CONN), significantly alter the loss of forest areas in the short to mid-term and delay the fragmentation, reduction, and isolation of forest patches.     

How knowledge and political ideology affects rental housing policy in Ontario,Canada: application of a knowledge paradigms framework of policy change

A case study of the Tenant Protection Act in Ontario, Canada is presented. A Conservative government elected in 1995 introduced an Act to deregulate rents and amend the Ontario Human Rights Code to allow use of income criteria to screen potential tenants. Document review and in‐depth interviews with tenant advocates were applied to understand how tenant advocates in Toronto used knowledge and other strategies to influence the legislation in the context of a new framework of policy change. The findings revealed that while different forms of knowledge, scientific, anecdotal and critical, had some influence on the process, the political ideology of the government played a significant role in determining the influence of opponents to legislation. The research concludes that while the neo‐liberal political ideology of the government did not consistently influence policy making in all areas, housing policy was particularly sensitive to political ideology. While the views of tenants did not influence the Conservative government, they did influence the policies of the Opposition parties that called for the restoration of social housing and rent control. On 2 October 2003, an Opposition party supporting these positions was elected in the Ontario general election.     

The transformation of the agroforestry landscape in the nineteenth century: a case study in southern Quebec (Canada)

Although recent landscape changes have been extensively studied, we possess very little information about the nature and extent of changes before aerial photographs were available. To contribute to this knowledge, we propose to explore the information within the Canadian censuses of the nineteenth century, documentary sources still very underused in landscape dynamics studies. The importance of these data lies in the fact that information is provided at the scale of each lot between 1842 and 1871, and at the township scale for subsequent years (1881–1951). In this study, nominative data provided for a rural township (139 km²) located in southern Quebec were coupled with detailed information about geomorphologic features using GIS.The analyses indicated two main phenomena. First, characterization of global landscape dynamics revealed the extent and rapidity of change. The evolution of land-use shows an increase of about 40% in improved areas between 1842 and 1871. while cumulative data show improved areas occupying nearly 83% of the total areas in 1891. These results contrast with recent landscape dynamics (1958–1993) which display relatively minor changes. Second, at the landscape type scale as well as at the surface deposit scale, analysis of nominative data failed to show any clear relationship between landscape dynamics and the spatial entities considered, whereas recent land-use patterns are closely linked to surface deposits. Thus, constant fluctuation in the agroforestry landscape and the lack of influence of abiotic characteristics on land-use dynamics represent two specific characteristics of this nineteenth century landscape.