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1.
Stefanie Engel 《Environmental Modeling and Assessment》2006,11(2):115-130
This paper presents a model of quality choice in the case of credence goods, i.e., when consumers cannot observe quality even after purchase. It shows that firms may voluntarily overcomply, i.e., produce high quality, even when doing so implies giving up short-run profits. This generalizes results on reputation effects derived in the IO literature for the case of experience goods. The crucial assumptions of the model are that there is a positive degree of monitoring of firms’ claims and a positive probability that the firm is of an “honest type,” i.e., always prefers to produce high quality. The result also helps explain why we see phenomena such as firms voluntarily overcomplying with environmental standards, food safety laws, etc. It is shown that overcompliance is more likely when consumers learn about all (positive and negative) monitoring results than when consumers only find out about firms that have been found cheating, as is often the case in practice. I further show that even firms that pretend to be producing high quality while really producing low quality may have an incentive to lobby for stricter monitoring. This helps explain, for example, why firms in Europe and the United States lobby for the implementation of voluntary environmental audits, third-party labeling agencies or other disclosure strategies. 相似文献
2.
3.
Negligence to consider the spatial variability of rainfall could result in serious errors in model outputs. The objective
of this study was to examine the uncertainty of both runoff and pollutant transport predictions due to the input errors of
rainfall. This study used synthetic data to represent the “true” rainfall pattern, instead of interpolated precipitation.
It was conducted on a synthetic case area having a total area of 20 km2 with ten subbasins. Each subbasin has one rainfall gauge with synthetic precipitation records. Six rainfall storms with varied
spatial distribution were generated. The average rainfall was obtained from all of the ten gauges by the arithmetic average
method. The input errors of rainfall were induced by the difference between the actual rainfall pattern and estimated average
rainfall. The results show that spatial variability of rainfall can cause uncertainty in modeling outputs of hydrologic, which
would be transport to pollutant export predictions, when uniformity of rainfall is assumed. Since rainfall is essential information
for predicting watershed responses, it is important to consider the properties of rainfall, particularly spatial rainfall
variability, in the application of hydrologic and water quality models. 相似文献
4.
Salve PR Satapathy DR Katpatal YB Wate SR 《Environmental monitoring and assessment》2007,133(1-3):87-98
Stratospheric input and photochemical ozone formation in the troposphere are the two main sources determining the ozone levels
in the surface layer of the atmosphere. Because of the importance of ozone in controlling the atmospheric chemistry and its
decisive role in the heat balance of atmosphere, leading to climate change, the examination of its formation and destruction
are of great interest. This study characterized the distribution of Ground level Ozone (GLO) in Chandrapur district is lying
between 19°25′N to 20°45′N and 78°50′E to 80°10′E. Continuous ozone analyzer was used to quantify GLO at thirteen locations
fixed by Global Positioning System (GPS) during the winter of 2005–2006. The daily GLO at all the locations ranged between
6.4 and 24.8 ppbv with an average and standard deviation of 14.9 ± 6.5 ppbv. The maximum and minimum concentration occurs
during 1300–1600 h and 0300–0500 h may be due to high solar radiation facilitating photochemical production of O3 and downward mixing from the overlying air mass and in situ destruction of ozone by deposition and/or the reaction between
O3 and NO. GIS based spatial distribution of GLO in Chandrapur district is indicates that the central core of the district and
southern sites experienced elevated levels of GLO relative to the northern and western areas. The sites near by Chandrapur
city are particularly affected by elevated GLO. The average variation of GLO with temperature shows a significant correlation
of r = 0.55 indicating a direct relationship between GLO and temperature. Similarly an attempt has been made to compare the GLO
monitored data in Chandrapur district with the reported values for other locations in Indian cities. This generated database
helps regulatory agencies to identify locations where the natural resources and human health could be at risk. 相似文献
5.
The slacks-based measure (SBM) model based on the constant returns to scale has achieved some good results in addressing the undesirable outputs, such as waste water and water gas, in measuring environmental efficiency. However, the traditional SBM model cannot deal with the scenario in which desirable outputs are constant. Based on the axiomatic theory of productivity, this paper carries out a systematic research on the SBM model considering undesirable outputs, and further expands the SBM model from the perspective of network analysis. The new model can not only perform efficiency evaluation considering undesirable outputs, but also calculate desirable and undesirable outputs separately. The latter advantage successfully solves the "dependence" problem of outputs, that is, we can not increase the desirable outputs without producing any undesirable outputs. The following illustration shows that the efficiency values obtained by two-stage approach are smaller than those obtained by the traditional SBM model. Our approach provides a more profound analysis on how to improve environmental efficiency of the decision making units. 相似文献
6.
A mixed-integer programming model that minimizes the social abatement cost is used to investigate whether a market equilibrium
condition could be reached in a newly proposed permit-trading market for nitrogen oxide control in Taiwan. Unlike in previous
studies, unit pollution abatement cost is determined endogenously by incorporating technology adoption as a binary decision
variable. The results show that when technologies are lumpy and irreversible, disequilibrium might occur due to firms’ inability
to manage their emission levels after installing equipment with fixed size and control capacity.
相似文献
Chao-ning LiaoEmail: |
7.
Mandal K Kumar A Tripathi N Singh RS Chaulya SK Mishra PK Bandyopadhyay LK;Council of Scientific Industrial Research 《Environmental monitoring and assessment》2012,184(6):3427-3441
Dust from haul and transport roads are the major source of air pollution in opencast coal mining areas. Dust generated during
mining operations pollutes air which causes different health problems. Various available techniques are implemented in the
field to minimize and control dust in mining areas. However, they are not very effective because dust deposited on road surfaces
are not removed by these techniques. For effective control of dust in opencast mining areas, it has to be regularly collected
from road surfaces and may be converted into solid form, and subsequently can be used as a domestic fuel considering its physicochemical
properties. The present paper describes a comparative study of qualitative and quantitative aspects of road dust samples of
four coalfields of India. The pH of the dust was found to be in the range of 5.1–7.7. Moisture, ash, volatile matter, fixed
carbon, water-holding capacity, bulk density, and specific gravity of dust samples were found to be in the range of 0.5–3.0%,
45–76%, 12.6–20.0%, 10.2–45.3%, 21.17–31.71%, 1.15–1.70, and 1.73–2.30 g cm−3, respectively. Observing the overall generation and characteristics of coal dust, it is suggested that coal dust from haul
and transport roads of mining areas can be effectively collected and used as domestic fuel. 相似文献
8.
Wigand C McKinney RA Cole ML Thursby GB Cummings J 《Environmental monitoring and assessment》2007,131(1-3):71-81
The stable nitrogen isotope ratios of some biota have been used as indicators of sources of anthropogenic nitrogen. In this
study the relationships of the stable nitrogen isotope ratios of marsh plants, Iva frutescens (L.), Phragmites australis (Cav.) Trin ex Steud, Spartina patens (Ait.) Muhl, Spartina alterniflora Loisel, Ulva lactuca (L.), and Enteromorpha intestinalis (L.) with wastewater nitrogen and land development in New England are described. Five of the six plant species (all but U. lactuca) showed significant relationships of increasing δ
15N values with increasing wastewater nitrogen. There was a significant (P < 0.0001) downward shift in the δ
15N of S. patens (6.0 ± 0.48‰) which is mycorrhizal compared with S. alterniflora (8.5 ± 0.41‰). The downward shift in δ
15N may be caused by the assimilation of fixed nitrogen in the roots of S. patens. P. australis within sites had wide ranges of δ
15N values, evidently influenced by the type of shoreline development or buffer at the upland border. In residential areas,
the presence of a vegetated buffer (n = 24 locations) significantly (P < 0.001) reduced the δ
15N (mean = 7.4 ± 0.43‰) of the P. australis compared to stands where there was no buffer (mean = 10.9 ± 1.0‰; n = 15). Among the plant species, I. frutescens located near the upland border showed the most significant (R
2 = 0.64; P = 0.006) inverse relationship with the percent agricultural land in the watershed. The δ
15N of P. australis and I. frustescens is apparently an indicator of local inputs near the upland border, while the δ
15N of Spartina relates with the integrated, watershed-sea nitrogen inputs. 相似文献
9.
Subba Rao N 《Environmental monitoring and assessment》2008,136(1-3):437-447
Trace elements are essential for human health. However, excess concentrations of these elements cause health disorders. A
study has been carried out in Visakhapatnam environs, Andhra Pradesh, India to ascertain the causes for the origin and distribution
of iron content in the groundwaters. Fifty groundwater samples are collected and analyzed for iron. The content of iron ranges
from 400 to 780 μg/l. A comparison of groundwater data with rock and soil chemistry suggests that the concentration of iron
(400–530 μg/l) in the groundwaters is derived from the rocks and soils due to geogenic processes. This concentration is taken
as a natural occurrence of iron in the groundwaters of the study area for assessing the causes for its next higher content
(>530 μg/l). Relatively higher concentration of iron (540–550 μg/l) is observed at some well waters, where the wells are located
nearby municipal wastewaters, while the very high concentration of iron (610–780 μg/l) is observed in the industrially polluted
groundwater zones, indicating the impact of anthropogenic activities on the groundwater system. These activities mask the
concentration of iron caused by geogenic origin. Hence, both the geogenic and anthropogenic activities degrade the groundwater
quality. Drinking water standards indicate that the iron content in all the groundwater samples exceeds the permissible limit
(300 μg/l) recommended for drinking purpose, causing the health disorders. Necessity of close monitoring of groundwater quality
for assessing the impact of geogenic and anthropogenic sources with reference to land use/land cover activities is emphasized
in the present study area to protect the groundwater resources from the pollution. 相似文献
10.
This paper introduces a new portable intelligent electronic nose system developed especially for measuring and analysing livestock
and poultry farm odours. It can be used in both laboratory and field. The sensor array of the proposed electronic nose consists
of 14 gas sensors, a humidity sensor, and a temperature sensor. The gas sensors were especially selected for the main compounds
from the livestock farm odours. An expert system called “Odour Expert” was developed to support researchers’ and farmers’
decision making on odour control strategies for livestock and poultry operations. “Odour Expert” utilises several advanced
artificial intelligence technologies tailored to livestock and poultry farm odours. It can provide more advanced odour analysis
than existing commercially available products. In addition, a rank of odour generation factors is provided, which refines
the focus of odour control research. Field experiments were conducted downwind from the barns on 14 livestock and poultry
farms. Experimental results show that the predicted odour strengths by the electronic nose yield higher consistency in comparison
to the perceived odour intensity by human panel. The “Odour Expert” is a useful tool for assisting farmers’ odour management
practises.
Supported by Ontario Pork, Natural Sciences and Engineering Research Council (NSERC), and Ontario Ministry of Agriculture
and Food (OMAF) of Canada. 相似文献
11.
The main objective of this research was to estimate the total mass of nitrogen discharged from various sources in Korea using
the mass balance approach. Three different nitrogen mass balances were presented: (1) agricultural activities including raising
crops and animal husbandry; (2) domestic activities, and (3) activities in forest and urban areas. These nitrogen balances
were combined to estimate riverine discharge of nitrogen to the ocean in national scale. Nitrogen inputs include atmospheric
deposition, biological nitrogen fixation, application of inorganic fertilizers/manures, animal feed/imported foodstuffs, and
meat/fish. Nitrogen outputs include ammonia volatilization, denitrification, human/animal waste generation, crop/meat production,
and riverine discharge to the ocean. The estimated total nitrogen input in Korea was 1,194.5 × 103 tons N/year. Nitrogen discharged into rivers was estimated as 408–422 × 103 tons N/year, of which 66–71% was diffuse in origin. The estimated diffuse discharges for land uses were estimated as 82 × 103 tons N/year from agricultural areas, 7 × 103 tons N/year from forestry and 75 × 103 tons N/year from urban and industrial areas. 相似文献
12.
Seventy-two squares of 100 ha were selected by stratified random sampling with probabilities proportional to size (pps) to survey landscape changes in the period 1996–2003. The area of the plots times the urbanization pressure was used as a size measure. The central question of this study is whether the sampling with probabilities proportional to size leads to gain in precision compared to equal probability sampling. On average 1.03 isolated buildings per 100 ha have been built, while 0.90 buildings per 100 ha have been removed, leading to a net change of 0.13 building per 100 ha. The area with unspoiled natural relief has been reduced by 2.3 ha per 100 ha, and the length of linear relicts by 137 m per 100 ha. On average 74 m of linear green elements have been planted per 100 ha, while 106 m have been removed, leading to a net change of −31 m per 100 ha. For the state variables ‘unspoiled natural relief', ‘ linear relicts', ‘removed linear green elements', and ‘new – removed linear green elements' there is a gain in precision due to the pps-sampling. For the remaining state variables there is no gain or even a loss of precision (`new buildings', ‘removed buildings', ‘new – removed buildings', ‘new linear green elements'). Therefore, if many state variables must be monitored or when interest is not only in the change but also in the current totals, we recommend to keep things simple, and to select plots with equal probability. 相似文献
13.
Liu CW Huang YK Hsueh YM Lin KH Jang CS Huang LP 《Environmental monitoring and assessment》2008,138(1-3):181-190
This study investigated total arsenic (As) and As species contents of oysters (Crassostrea gigas) in different production areas, seasons and sea locations on the southwestern coast of Taiwan. Analytical results indicate
that contents of total As, arsenite, arsenate, dimethylarsinic acid, monomethylarsonic acid and arsenobetaine in oysters are
9.90 ± 3.68, 0.091 ± 0.104, 0.033 ± 0.038, 0.529 ± 0.284, 0.037 ± 0.046 and 3.94 ± 1.33 mg/g (dry wt), respectively. A ratio
of inorganic As concentrations to total As concentrations is 1.26%. Total As contents of oysters cultured in the outer sea
are statistically significantly lower than those of oysters cultured in the inner sea. The total As contents of oysters is
the highest in Putai, where the blackfoot disease prevails. The low As contents in oysters is attributed to the low temperature
in winter, which slows the metabolism of oysters. A maximum value is 33.37 μg/g (dry) in Putai in spring, because a considerable
amount of aquacultural waste water with high As contents is discharged into adjacent drainage channels and rivers there during
that season. 相似文献
14.
The aim of this study is to determine the possibility of using Rinodina sophodes (Ach.) Massal., a crustose lichen as polycyclic aromatic hydrocarbons (PAHs) bioaccumulator for evaluation of atmospheric
pollution in tropical areas of India, where few species of lichens are able to grow. PAHs were identified, quantified and
compared to evaluate the potential utility of R. sophodes. The limit of detection for different PAHs was found to be 0.008–0.050 μg g − 1. The total PAHs in different sites were ranged between 0.189 ± 0.029 and 0.494 ± 0.105 μg g − 1. The major sources of PAHs were combustion of organic materials, traffic and vehicular exhaust (diesel and gasoline engine).
Significantly higher concentration of acenaphthylene and phenanthrene indicates road traffic as major source of PAH pollution
in the city. Two-way ANOVA also confirms that all PAHs content showed significant differences between all sampling sites (P
1%). This study establishes the utility of R. sophodes in monitoring the PAHs accumulation potentiality for development of effective tool and explores the most potential traits
resistant to the hazardous environmental conditions in the tropical regions of north India, where no such other effective
way of biomonitoring is known so far. 相似文献
15.
Hydrogeochemical characterization of contaminated groundwater in Patancheru industrial area,southern India 总被引:1,自引:0,他引:1
The groundwater is one of the most contaminated natural resources in Patancheru industrial area due to unplanned and haphazard
industrial growth and urbanization without following basic pollution control norms. The rapid industrialization initiated
in early 1970 has started showing up its after effects few years later in the form of physiochemical contamination of the
both surface and groundwater bodies of the area. It has resulted in local people being deprived of safe drinking water, plant
and aquatic life has severely affected, and situation is deteriorating over the years in the area in spite of some preventive
and remedial measures being initiated. The focus of the present study is to understand the chemical characteristics of groundwater
and geochemical processes the contaminant water is undergoing which are normally imprinted in its ionic assemblages. The water
samples collected in pre- and post-monsoon seasons from forty two groundwater and four surface water sources were analyzed
for major constituents such as Ca2+, Mg2+, Na+, K+, CO3−, HCO3−, Cl−, SO42−, NO3−, and F−, and selected samples were tested for ten important trace metals like Fe, Pb, Bi, Mn, Cr, Co, Ni, Cu, Zn, and Cd. Na+ among cations and Cl− among anions dominate the water in both the seasons where as Ca2+, HCO3−, and Cl− show significant reduction in their ionic strength in post-monsoon. The groundwater in general is of mixed type, but most
of it belong to Na+–Cl−, Na+–HCO3−, Ca2+–Mg2+–HCO3−, and Ca2+–Mg2+–Cl− facies. The Na+ and Ca2+ are in the transitional state with Na+ replacing Ca2+ and HCO3−–Cl− due to physiochemical changes in the aquifer system. The evaluation of hydrochemistry through various ionic indices, ratios,
and plots suggest that silicate–carbonate weathering, ion exchange, dissolution, and evaporation processes are responsible
for origin of the present chemical status of the groundwater which is also controlled by the contamination from extraneous
sources that could have accelerated the dissolution processes. Gibbs plots authenticate that the evolution of water chemistry
is influenced by interaction of percolating water with aquifer matrix apart from anthropogenic enrichment of elements which
get over concentrated due to evaporation. 相似文献
16.
Changes in water level,land use,and hydrological budget in a semi-permanent playa lake,Southwest Spain 总被引:1,自引:0,他引:1
Rodríguez-Rodríguez M Green AJ López R Martos-Rosillo S 《Environmental monitoring and assessment》2012,184(2):797-810
Medina playa lake, a Ramsar site in western Andalusia, is a brackish lowland lake of 120 ha with an average depth of 1 m.
Water flows into Medina from its 1,748-ha watershed, but the hydrology of the lake has not previously been studied. This paper
describes the application of a water budget model on a monthly scale over a 6-year period, based on a conceptual hydrological
model, and considers different future scenarios after calibration to improve the understanding of the lake’s hydrological
functioning. Climatic variables from a nearby weather station and observational data (water-level evolution) were used to
develop the model. Comparison of measured and predicted values demonstrated that each model component provided a reasonable
output with a realistic interaction among the components. The model was then used to explore the potential consequences of
land-use changes. Irrigation of olive groves would significantly reduce both the hydroperiod (becoming dry 15% of the time)
and the average depth of the lake (water level <0.5 m 40% of the time). On the other hand, removal of an artificial overflow
would double the average flooded surface area during high-water periods. The simulated water balance demonstrates that the
catchment outputs are dominated by lake evaporation and surface outflow from the lake system to a creek. Discrepancies between
predicted and observed water levels identify key areas of uncertainty for future empirical research. The study provides an
improved basis for future hydrological management of the catchment and demonstrates the wider utility of this methodology
in simulating this kind of system. This methodology provides a realistic appraisal of potential land-use management practices
on a catchment-wide scale and allows predictions of the consequences of climate change. 相似文献
17.
The analysis of data of the ground-level ozone concentration and accumulated ozone exposure over a threshold of 40 ppb (AOT40)
in the rural areas of Lithuania is presented. Trends in the annual ozone mean, 95{th} and 25{th} percentiles were determined
as statistically not significant at Preila and Rugsteliskes sites during the 1994hbox{–}2004 period. Trends in the ozone concentration
and its percentiles in the air masses arriving to Preila station in “polluted” and “unpolluted” sectors have been examined.
Statistically significant changes in the ozone annual mean and 25th percentile were found in air masses in both “polluted”
and “unpolluted” sectors in the 1988hbox{–}2002 period. The trend analysis in the ozone monthly mean and percentiles for each
month of the year revealed the main changes in the ozone level in both sectors during January-May. Insignificant downward
trends in monthly 95th percentile in “unpolluted” sector and upward trends in “polluted” sector were found during summer months.
Values of AOT40 for the protection of forests as well as crops and semi-natural vegetation were determined during the 1994–2004
period. The estimated AOT40 values for the protection of forests were lower than the critical level at Lithuanian rural sites
but AOT40 values for the protection of crops and semi-natural vegetation were found to be higher than the critical level at
both sites. 相似文献
18.
Dedecker AP Goethals PL D'heygere T Gevrey M Lek S De Pauw N 《Environmental monitoring and assessment》2005,111(1-3):223-241
This study aimed at analysing the relationship between river characteristics and abundance of Gammarus pulex. To this end, four methods which can identify the relative contribution and/or the contribution profile of the input variables
in neural networks describing the habitat preferences of this species were compared: (i) the ‘PaD‘ (‘Partial Derivatives‘)
method consists of a calculation of the partial derivatives of the output in relation to the input variables; (ii) the ‘Weights‘method
is a computation using the connection weights of the backpropagation Artificial Neural Networks; (iii) the ‘Perturb‘method
analyses the effect of a perturbation of the input variables on the output variable; (iv) the ‘Profile‘ method is a successive
variation of one input variable while the others are kept constant at a fixed set of values. The dataset consisted of 179
samples, collected over a three-year period in the Zwalm river basin in Flanders, Belgium. Twenty-four environmental variables
as well as the log-transformed abundance of Gammarus pulex were used in this study. The different contribution methods gave similar results concerning the order of importance of the
input variables. Moreover, the stability of the methods was confirmed by gradually removing variables. Only in a limited number
of cases a shift in the relative importance of the remaining input variables could be observed. Nevertheless, differences
in sensitivity and stability of the methods were detected, probably as a result of the different calculation procedures. In
this respect, the ‘PaD‘method made a more severe discrimination between minor and major contributing environmental variables
in comparison to the ‘Weights‘, ‘Profile‘ and ‘Perturb‘ methods. From an ecological point of view, the input variables ‘Ammonium‘
and to a smaller extent ‘COD‘, were selected by these methods as dominant river characteristics for the prediction of the
abundance of Gammarus pulex in this study area. 相似文献
19.
Distribution and sources of polycyclic aromatic hydrocarbons in Wuhan section of the Yangtze River, China 总被引:9,自引:0,他引:9
Polycyclic aromatic hydrocarbons (PAHs) are important organic contaminants with great significance for China, where coal burning
is the main source of energy. In this study, concentrations, distribution between different phases, possible sources and eco-toxicological
effect of PAHs of the Yangtze River were assessed. PAHs in water, suspended particulate matters (SPM) and sediment samples
at seven main river sites, 23 tributary and lake sites of the Yangtze River at the Wuhan section were analyzed. The total
concentrations of PAHs in the studied area ranged from 0.242 to 6.235 μg/l in waters and from 31 to 4,812 μg/kg in sediment.
The average concentration of PAHs in SPM was 4,677 μg/kg, higher than that in sediment. Benzo(a)pyrene was detected only at
two stations, but the concentrations were above drinking water standard. The PAHs level of the Yangtze River was similar to
that of some other rivers in China but higher than some rivers in foreign countries. There existed a positive relationship
between PAHs concentrations and the TOC contents in sediment. The ratio of specific PAHs indicated that PAHs mainly came from
combustion process, such as coal and wood burning. PAHs may cause potential toxic effect but will not cause acute biological
effects in sedimentary environment of the Wuhan section of the Yangtze River. 相似文献
20.
Basmadjian E Perkins EM Phillips CR Heilprin DJ Watts SD Diener DR Myers MS Koerner KA Mengel MJ Robertson G Armstrong JL Lissner AL Frank VL 《Environmental monitoring and assessment》2008,138(1-3):239-253
The prevalence of toxicopathic liver lesions in demersal fish on the San Pedro Shelf, California was determined for a 15-year
period (1988–2003). Fish livers were sampled at fixed locations as part of the Orange County Sanitation Districts (OCSD) ocean
monitoring program. Histopathological examination of selected fish liver tissues was studied to determine whether the wastewater
discharge had affected fish health. The prevalence of toxicopathic lesion classes neoplasms (NEO), preneoplastic foci of cellular
alteration (FCA), and hydropic vacuolation (HYDVAC) varied among species and locations. For all species sampled, severe lesions
occurred in 6.2% of the fish examined (n = 7,694). HYDVAC (4.1%) was the most common toxicopathic lesion type followed by FCA (1.4%) and NEO (0.7%). HYDVAC occurred
only in white croaker (Genyonemus lineatus), accounting for 84.8% of the toxicopathic lesions for this species. Prevalence of HYDVAC, NEO, and FCA in white croaker
was 15.2, 2.0, and 0.7%, respectively. The prevalence of HYDVAC and NEO in white croaker increased with age and size but there
was no sexual difference. A linear regression model was used for hypothesis testing to account for significant differences
in fish size (and age for croakers) at the different sampling locations. This analysis showed that for HYDVAC there was no
spatial or location effect for lesion rate or size/age of onset. For NEO, the model predicted that white croaker near the
wastewater outfall may acquire these lesions at a smaller size/younger age, and at a higher rate, than at other sites. However,
this result may be biased due to the unequal size frequency distributions and the low prevalence of NEO in white croaker at
the different sampling sites. Bigmouth sole (Hippoglossina stomata) had a prevalence of FCA and NEO of 1.3 and 0.35%, respectively, but the prevalence and distribution of lesions was too few
for statistical testing. There was no sexual difference for lesion prevalence in hornyhead turbot (Pleuronichthys verticalis) and the prevalence of FCA and NEO was 3.4 and 0.37%, respectively. FCA prevalence increased with size in hornyhead turbot
and there were no significant spatial differences for lesion rates and fish size at lesion onset. Overall, consistent spatial
differences for lesion prevalence were not demonstrated and highlight the analytical difficulties of detecting a possible
point source impact when the effect is rare, correlated with the size/age structure of the population, and may be caused by
exposure to unknown multiple sources. Thus, the usefulness of liver histopathology as a point-source monitoring tool is best
applied to where the spatial scale of impact generally exceeds the home range of the target species. 相似文献