Variations In Physicochemical Parameters Research Articles

Variations in physico-chemical parameters and Chl-a concentration in Setiu Wetlands lagoon during the northeast and inter-monsoon seasons 2018

This study presents the seasonal changes of physico-chemical parameters and chlorophyll-a (Chl-a) concentration in Setiu Wetlands lagoon during the NEM (February 2018) and inter-monsoon (April 2018) seasons. The Chl-a and physico-chemical parameters of water temperature, dissolved oxygen (DO), pH and salinity were investigated for both surface and bottom waters at 3 sampling sites that are located in the upstream and downstream of the lagoon. The was a strong seasonal signal and spatial gradient in physico-chemical parameters within the Setiu lagoon. In February, when the strong northeast monsoon (NEM) prevailed, the surface and bottom waters of the lagoon were dominated by high pH and low water temperature, DO and salinity. As the weaker inter-monsoon dominated in April, the study area was characterized by low pH and high water temperature, DO and salinity. While the seasonal variation in physico-chemical properties of Setiu lagoon is well described, Chl-a concentrations varied between seasons and sampling locations. Chl-a showed an increased or only a slight change in the downstream stations but recorded a significant decreased in concentrations in the upstream station from the NEM to inter-monsoon season. Analysis of seasonal relationships clearly indicated the interchangeable negative and positive correlations of Chl, DO and salinity. These results suggest the influence of other environmental factors of the lagoon (e.g., nutrient enrichment, tidal and freshwater influx) that vary with seasons which require more detailed investigation.

Do spatial differences account for the variation in abundance of human pathogenic bacteria in waters and fishes of the monsoonal estuary?

Spatiotemporal variation of human pathogenic bacteria was observed in the surface waters of a monsoonal estuary and these bacteria were also found to be associated with the native fish of two monsoonal estuaries. The temporal variation was in accordance with any monsoonal estuary. Also, the spatial variation in physicochemical parameters and bacterial counts was very evident at any given time. For instance, one sampling location in the estuary consistently had 103 fold higher bacterial counts than the rest of the locations within the same estuary. Coliforms, Salmonella-like (SmLO) organisms, Shigella-like (SLO) organisms, Vibrio parahaemolyticus-like (VPLO) organisms and Vibrio cholerae-like (VCLO) organisms occurred at many locations, but the abundance of each group varied differently with time at different locations in the estuary. Coliforms, unlike others, showed an increase in abundance from post-monsoon to pre-monsoon season. VCLO were the most abundant amongst all. Not all the pathogenic bacteria were widespread throughout the channel indicative of dominance in spatial variation over seasonal in this estuary. Most of the fish samples showed similar trend of bacterial numbers as that in surrounding waters, except a few. Presence of sewage pollution indicator bacteria in the fish indicated that fish served as reservoirs of these bacteria. Thermal death time of randomly picked fish-associated isolates was 30 min at 80 °C and these could survive freezing temperature for 24 h and produce siderophore which can account for their pathogenic nature. The monsoonal estuaries thus render survival ground of such bacteria.

Hydrochemical characterization and evaluation of groundwater quality in Dalgan basin, SE Iran

Groundwater quality evaluation for irrigation and drinking purposes is of utmost importance in semi-arid and arid regions of the globe and is a great tool for sustainable development. This study focuses on Dalgan basin in southeast Iran with the objectives of monitoring and assessment of physicochemical parameters (pH, EC, TDS, and T), cations (K+, Na+, Ca2+, and Mg2+), major anions (Cl−, HCO3−, and SO42−), and calculation of groundwater quality indexes (WQI, and EWQI) for irrigation and drinking purposes. In this research, we also prioritize the wells based on the groundwater quality index using the analytic hierarchy process and data envelopment analysis (AHP- DEA) model. Use of multivariate statistical techniques including correlation analysis (CA) and principal component analysis (PCA) indicated that geogenic (i.e. interaction of water-rock, climatic conditions, high evaporation) and anthropogenic (i.e. agricultural fertilizer) sources are responsible for variation in physicochemical parameters in groundwater of the study area. The results of the study showed that the simultaneous use of these methods and indicators is very effective and suitable in determining groundwater quality and prioritizing wells of any region.

Estructura de la taxocenosis de diatomeas y su relación con variables ambientales en tres cuencas de la provincia de San Luis (Argentina)

La composición y distribución de las asociaciones de algas en ecosistemas lóticos son el resultado de condiciones en el medio ambiente y en particular pueden reflejar su estructura y funcionamiento.El objetivo de este trabajo fue estudiar la relación de la riqueza, abundancia y diversidad de las especies de diatomeas con las características ambientales en tres cuencas de la provincia de San Luis. Para ello se seleccionaron 14 sitios de muestreo en tres cuencas: en la cuenca del río Conlara siete sitios, otros tres en la cuenca del río Quinto y finalmente cuatro en la cuenca del Bebedero. En cada sitio de muestreo se registraron parámetros hidráulicos y fisicoquímicos. Se colectaron muestras epilíticas que fueron obtenidas por raspado de pequeñas rocas del fondo. La estructura de la comunidad estuvo caracterizada por el predominio de las diatomeas pennales que se destacaron tanto cualitativa como cuantitativamente. Las variaciones de parámetros fisicoquímicos influyeron en la composición específica de las taxocenosis y permitieron establecer dos grupos de especies: el primero constituido por Nitzschia palea, Melosira varians, Navicula tripunctata y Halamphora veneta que se vincularon a arroyos de mayor número de orden y mayor conductividad. Mientras que Geissleria decussis, Epithemia sorex y Cymbella affinis constituyeron el segundo grupo relacionado con mayor caudal y pH, en tanto que Navicula radiosa y Rophalodia gibba estuvieron asociadas a la altitud y concentración del oxígeno disuelto, respectivamente. Una referencia florística confiable de diatomeas permite hacer diagnósticos fundamentados sobre el estado ecológico de los arroyos, así como para establecer programas de monitoreo en la provincia.

Physicochemical Foundations of Life that Direct Evolution: Chance and Natural Selection are not Evolutionary Driving Forces.

The current framework of evolutionary theory postulates that evolution relies on random mutations generating a diversity of phenotypes on which natural selection acts. This framework was established using a top-down approach as it originated from Darwinism, which is based on observations made of complex multicellular organisms and, then, modified to fit a DNA-centric view. In this article, it is argued that based on a bottom-up approach starting from the physicochemical properties of nucleic and amino acid polymers, we should reject the facts that (i) natural selection plays a dominant role in evolution and (ii) the probability of mutations is independent of the generated phenotype. It is shown that the adaptation of a phenotype to an environment does not correspond to organism fitness, but rather corresponds to maintaining the genome stability and integrity. In a stable environment, the phenotype maintains the stability of its originating genome and both (genome and phenotype) are reproduced identically. In an unstable environment (i.e., corresponding to variations in physicochemical parameters above a physiological range), the phenotype no longer maintains the stability of its originating genome, but instead influences its variations. Indeed, environment- and cellular-dependent physicochemical parameters define the probability of mutations in terms of frequency, nature, and location in a genome. Evolution is non-deterministic because it relies on probabilistic physicochemical rules, and evolution is driven by a bidirectional interplay between genome and phenotype in which the phenotype ensures the stability of its originating genome in a cellular and environmental physicochemical parameter-depending manner.

DISTRIBUTION AND DIVERSITY OF FRESHWATER SNAILS OF PUBLIC HEALTH IMPORTANCE IN KUBANNI RESERVOIR AND WEIR/SEDIMENT TRAP, ZARIA, NIGERIA

Due to survival of intermediate hosts of parasites causing schistosomiasis and fascioliasis under changing environmental conditions, this research was conducted to investigate the distribution and diversity of freshwater snails between March and June, 2017. Physico-chemical parameters were analyzed according to the standard operating procedures for examination of water and wastewaters. Snails were sampled using an Ekman grab from different sites in each reservoir, counted and identified using standard identification guide. A total of 108 snails were collected and identified in Kubanni reservoir comprising Biomphalaria sp. (48.15%), Lymnaea sp. (39.81%) and Bulinus sp. (12.04%). While in Weir, 141 snails which comprised Biomphalaria sp. (53.19%), Lymnaea sp. (24.11%) and Bulinus sp. (22.70%) were collected. Shanon-Weiner diversity index for Kubanni and Weir were 0.97 and 1.02 respectively. Variation in physico-chemical parameters between the reservoirs shows no significant difference (P>0.05), except for electrical conductivity (EC; p-0.0015), total dissolved solid (TDS; p-0.0016), biochemical oxygen demand (BOD; p-0.0004) and concentration of phosphate (PO4.-0.026) The three snail species obtained were common to the two reservoirs; however species diversity is higher in Kubanni reservoir than Weir. The presence of these snails in the two reservoirs could pose a serious threat to humans coming in contact with these reservoirs, in their role as intermediate hosts of parasites that causes schistosomiasis and fascioliasis.

Seasonal and spatial variations in physico-chemical parameters of water and proximate composition of Macrobrachium macrobrachion from Ologe lagoon and Badagry creek, Lagos, Nigeria

In this study, seasonal and spatial variations in physicochemical parameters of water and proximate composition of Macrobrachium macrobrachion from Badagry Creek and Ologe Lagoon were examined. Samples of water and M. macrobrachion were collected from both stations on a monthly basis for six months. The physicochemical parameters monitored were pH, temperature, total suspended solids, total dissolved solids, total solids, total alkalinity, free carbondioxide, conductivity, salinity, dissolved oxygen, biochemical oxygen demand, ammonia and turbidity, while the proximate composition parameters were moisture content, crude protein, crude fibre, carbohydrate, crude lipids and ash. It was observed that alkalinity, salinity, dissolved oxygen, temperature and ammonia determined for both sample stations were within recommended limit of Food and Agricultural Organization, except pH for Badagry creek. There was no significant difference (p > 0.05) in seasonal variations of most physico-chemical parameters in both stations except for pH in Ologe lagoon, and electrical conductivity (EC), total dissolved solids (TDS) and total solids (TS) in both stations. Also, with the exception of EC, TDS and TS, there was no significant difference for spatial variation of physico-chemical parameters between the two stations. Moisture content, lipid and ash contents showed significant seasonal variation in Ologe lagoon, while crude protein and crude fibre recorded no significant difference. For Badagry creek, with the exception of moisture content, all other proximate composition parameters showed significant difference. However, there was no significant spatial variation in proximate composition between the prawns in Ologe lagoon and Badagry creek. There were gradual effects of season on water quality and proximate composition but these effects still support growth and survival of the prawn. However, regulatory measures should be put in place to protect these water bodies from direct/indirect human activities that can cause adverse damages.

Spatial Variability of the Physicochemical Properties of Soils from Seasonally Flooded Forest Fragments on a Tropical Plain

Flooded ecosystems are conditioned to seasonal floods that promote specific soil conditions, such as low oxygen, hydromorphism, and peculiar chemical reactions. These environments are dependent on flood pulses that determine specific ecological conditions. Ipucas are seasonally flooded discontinuous forest patches that occur exclusively in the Araguaia Plain in Central Brazil. They are located 0.40 to 1.20 m lower than the surrounding plain, which promotes an accumulation of rainwater for five to six months of the year, being entirely or partially dry during the dry season. The aim of this study was to evaluate the horizontal (centre and edge) and vertical (depths: 0–0.20 m and 0.20–0.40 m) variability of physicochemical parameters in Ipucas soils, attempting to establish the importance of flood pulses and the leaching of surrounding areas in soil formation and composition. Samples were collected during the dry season in three Ipucas of similar size and circularity using a Dutch auger. The results reveal that flood pulses promote the deposition of sediments eroded from the surrounding plain, homogenizing the characteristics of the surface soil, from the edge to the centre of the Ipucas. However, biogeochemical processes, also linked to temporary flooding, account for the differences between the surface and deeper soil horizons because anoxic conditions during flooding promote chemical reactions characteristic of anaerobic environments, modifying the pH and organic matter content, in addition to the gleying of soils subjected to flooding, which are then covered by sediments after the dry season. Finally, Ipucas soils are susceptible to anthropic changes and are dependent on seasonal flood pulses.

Spatial Variability in Physico-Chemical Parameters of Water in Lake Baringo Catchment, Kenya

Anthropogenic activities have accelerated the process of eutrophication and threatened the health of aquatic ecosystems in Lake Baringo basin. This has necessitated the analysis of its spatial variation in its physico-chemical qualities. Physicochemical parameters from 10 sampling sites distributed throughout Lake Baringo catchment. Mean values of temperature were high at the river inlets and Islands compared to the rivers. While pH and Electrical Conductivity (EC) were relatively constant across the sampling points, Total Dissolved Solids (TDS) were high at the inlets and Islands compared to the rivers, Total Nitrogen mg/ (TN), Nitrates (NO3-) Ammonia ( NH3 ), Total Phosphate (TP) Phosphate and Orthophosphate (OP) were relatively higher in the rivers compared to the inlets and Islands. Temperature ranged between (33.8oC) to (21.4 oC), pH (8.88) to (7.18), EC (543 µS/cm) to (224 µS/cm), TDS (433 mg/L) to (181mg/L), salinity (0.2ppt) to ( 0.01ppt), TN (9.98 mg/L ) to (1.32 mg/L), nitrate (5.11 mg/L) to (0.09 mg/L), NH4 (0.77 mg/L) to (0.09 mg/L), TP(2.91 mg/L) to (0.25 mg/L), OP (1.84 mg/L) to (0.09 mg/L). Nitrite values were below the detectable values <0.05. The result of the study revealed that Lake Basin is highly polluted and undergoing drastic eutrophication due to increased nutrient loading resulting in deterioration of the water quality.

Spatial and temporal variation in physico-chemical parameters at Ugbevwe Pond, Oghara, Delta State

Water quality describes the physicochemical, biological and radiological characteristics of water. A field study was conducted to determine the spatial and temporal variation in the physico-chemical, nutrients and heavy metals parameters at Ugbevwe Pond, Oghara, Delta State. Water samples were collected from three stations of which station 1 and 2 are disturb with anthropogenic activities from August, 2014 to May, 2015 covering the wet and dry seasons. A total of 34 parameters were analyzed in water using standard methods. There was no significant difference (P > 0.05) in the mean values of the physico-chemical parameters across the three stations. The test of difference in the mean values between the wet and dry season shows that twelve (12) parameters had seasonal differences (P<0.05) with electrical conductivity, salinity, total dissolved solids, sodium, ammonium-nitrogen, nitrite, iron, zinc and copper having higher values in the dry season while dissolved oxygen, phosphorus and manganese have higher values in the rainy season. The water quality index is 70.10 and is rated as Medium water quality according to the National Sanitation Foundation Water Quality Index (NSFWQI) and Waters achieving only an average rating generally have less diversity of aquatic organisms, frequently have increased algal growth and may not be suitable for recreational purposes or other purposes which involve direct contact with humans.Keywords: physicochemical parameters, pond, heavy metals, water quality index

Monitoring stream water quality of Dagwan stream, an important tributary of Dal Lake, Kashmir Himalaya

The assessment of water quality of the Dagwan stream encompassing spatiotemporal variations in physicochemical parameters and all important and relevant hydrological attributes was carried out at five different sites for a period of 1 year (June 2014–May 2015). Statistical techniques like analysis of variance (ANOVA), cluster analysis, and regression analysis applied to datasets revealed spatiotemporal variations. ANOVA and Tukey’s box plot was applied and resulting F values showed the significance of observed variation of each parameter at 5% level of significance in which some parameters do not change significantly. The higher positive and negative relationship among various analyzed water quality parameters were described by general linear regression model (P < 0.0001). The study of physicochemical parameters signify that the quality of its water substantially declines while moving downstream. The water quality sites were classified into significant clusters (clusters I and II) by cluster analysis. Cluster I (sites I and II) is illustrated by similar and better water quality whereas cluster II (sites II, IV, and V) is considered to be of moderately reduced water quality, thereby reflecting the different physicochemical characteristics and quality class. The results from water quality index (WQI) validate that water of the Dagwan stream falls within the excellent to very good category of water quality class. While comparing the results with WHO standards, the water quality was in permissible limits. The escalating level of pollution from upstream to downstream sites indicated slight anthropogenic stress in the downstream areas of the Dagwan stream.

Sources evaluation and ecological risk assessment of heavy metals accumulated within a natural stream of Durgapur industrial zone, India, by using multivariate analysis and pollution indices

In this study, variations in physicochemical parameters and heavy metal contamination in water–sediments of a natural stream in the Durgapur industrial zone have been investigated. pH, COD, Cl−, CN− and heavy metals, viz. Pb, Hg and Fe concentrations in channel water, are higher than Indian standards. Metal concentrations in sediments are many folds higher than background value, where Pb, Cd, Hg and Cr contents exceed the sediment quality guidelines. Contamination factor (Cf) value of channel water follows the order of Hg > Pb > Fe > Cr > Cd > Cu > Ni, whereas enrichment factor and geo-accumulation index (Igeo) values in channel sediments are in the order of Hg > Cr > Ni > Pb > Cd > Fe > Cu. The assessment of contamination index (Cd), modified contamination index (mCd) and pollution load index indicates that channel water and sediment samples in the study area are strongly contaminated by heavy metals. Sediment samples based on PELQ and ERMQ are highly toxic, with high degree of potential ecological risk at all the monitored stations. Multivariate analysis infers that heavy metals in channel water and sediments are majorly sourced from industrial discharge.

How methane yield, crucial parameters and microbial communities respond to the stimulating effect of antibiotics during high solid anaerobic digestion

To comprehensively understand how antibiotics affect anaerobic digestion, their stimulating effects on methane production cannot be ignored; however, few studies have evaluated these effects. This study investigated the stimulating effects of three typical antibiotics (oxytetracycline, sulfadimethoxine, and norfloxacin) on high solid anaerobic digestion. The results showed that 100 mg/L antibiotics exhibited a strong stimulating effect on CH4 yield; while other external carbon sources had no obvious effects. The stimulating effect was more obvious under low inoculation ratios, which could improve the system processing capacity of feed sludge. Lower lag phases were given by the modified Gompertz model when stimulating effects occurred. The variations of physicochemical parameters and microbial Venn maps both showed that day 5 was a critical point for digestion time. The relative abundance of Methanosarcina was enhanced when the stimulating effect occurred, whereas Methanoculleus decreased. Different microbial characteristics were obtained for different samples from the heat maps.

Deterioration in the water quality of an urbanised estuary with recommendations for improvement

Water quality characteristics of the heavily urbanised and industrialised Swartkops River and Estuary in the Eastern Cape have been the focus of several studies since the 1970s. Overloaded and poorly maintained wastewater treatment works (WWTWs), polluted stormwater runoff and solid waste have all contributed to the deterioration in the water quality of the river and estuary. The objective of this study was to determine the current water quality status of the Swartkops Estuary, by investigating spatial and temporal variability in physico-chemical parameters and phytoplankton biomass and where possiblerelate this to historical water quality data. The present study found evidence suggesting that water is not flushed as efficiently from the upper reaches of the estuary as was previously recorded. Reduced vertical mixing results in strong stratification and persistent eutrophic conditions with phytoplankton blooms (&gt; 20 μg chl a·L−1), extending from the middle reaches to the tidal head of the estuary. The Motherwell Canal was and still is a major source of nitrogen (particularly ammonium) to the estuary, but the Swartkops River is the primary source of phosphorus with excessive inputs from the cumulative effectof three WWTWs upstream. An analysis of historical water quality data in the Swartkops Estuary (1995 to 2013) shows that all recorded dissolved inorganic phosphorus measurements were classified as hypertrophic (&gt; 0.1 mg P·L−1), whereas 41% of dissolved inorganic nitrogen measurements were either mesotrophic or eutrophic. If nutrient removal methods at the three WWTWs were improved and urban runoff into the Motherwell Canal better managed, it is likely that persistent phytoplankton blooms and health risks associated with eutrophication could be reduced.

Occurrence and diversity of microalgae in phytoplankton collected from freshwater community ponds of Hooghly District, West Bengal, India

A study on diversity, seasonal occurrence, distribution percentage of microalgal taxa and physico-chemical parameters of five community ponds, located in Chinsurah town, Hooghly district of West Bengal, has been carried out. Correlation between occurrence of microalgal genera and some parameters of environment, physico-chemical nature of natural water bodies were explored by Canonical Correspondence Analysis (CCA). Diversity indices have been calculated using PAST software program. A total of 23 microalgal taxa belonging to four algal classes were recorded and the study indicated that the microalgal diversity vary with variation in physico-chemical parameters of water and light intensity. Out of these genera, occurrence of Chodatella sp. in late summer and Tetrallantos sp. and Synechocystis sp. in winter season were specific. In CCA, multiple variables (dissolved oxygen, water temperature, electrical conductivity, pH, light intensity and inorganic phosphorous) played a significant role in occurrence of microalgal taxa. Observation concluded that the Chlorophycean members were dominant throughout the study period and the Shannon–Wiener diversity index was highest for a site with large number of Chlorophycean member. This study will help in future to assess water quality.

Investigation of microbial communities in the field-scale co-composting of sewage sludge and organic municipal solid wastes

The alternative methods should be used to treat sewage sludge and municipal solid wastes which are mostly landfilled in Turkey. Therefore co-composting of these waste streams is a suitable disposal method yielding a useful product. The aim of this study was to investigate the microbial community during the field scale co-composting of sewage sludge and organic municipal solid wastes with addition of bulking agents. Aerated static pile of approximately 26 m3 was used for composting process during 56 days. Investigations of diversity dynamics depending on the temperature were determined by denaturing gradient gel electrophoresis and sequencing of bacterial 16SrDNA-PCR products. The variations of physicochemical parameters and biodegradability during the process were also monitored. The results showed that most of microbial group's role in composting process was temperature dependent and composting was designated by its characteristic thermal profile.

Investigation of microbial communities in the field-scale co-composting of sewage sludge and organic municipal solid wastes

The alternative methods should be used to treat sewage sludge and municipal solid wastes which are mostly landfilled in Turkey. Therefore co-composting of these waste streams is a suitable disposal method yielding a useful product. The aim of this study was to investigate the microbial community during the field scale co-composting of sewage sludge and organic municipal solid wastes with addition of bulking agents. Aerated static pile of approximately 26 m3 was used for composting process during 56 days. Investigations of diversity dynamics depending on the temperature were determined by denaturing gradient gel electrophoresis and sequencing of bacterial 16SrDNA-PCR products. The variations of physicochemical parameters and biodegradability during the process were also monitored. The results showed that most of microbial group's role in composting process was temperature dependent and composting was designated by its characteristic thermal profile.

Physicochemical parameters and phytoplankton as indicators of the aquatic environment in karstic springs of South China

As the concentrated discharge outlet of an aquifer or groundwater system, a karst spring is partly independent from the aquifer, due to its formation of a pool or lake after outcropping onto the surface. Understanding how to evaluate the unique and sensitive environment of the karst spring is essential for water resource protection. Five karst springs in South China were investigated by analyzing their hydrodynamic conditions, variations in physicochemical parameters, and phytoplankton community structures. Dominated by regional or local groundwater flow, these springs had different catchment area characteristics and hydrogeological conditions. The results showed that, although they had similar water quality, their physicochemical parameters needed to be distinguished and evaluated in different ways in order to determine the cause of the observed degradation in spring water quality. Ca2+, HCO3−, and specific electrical conductivity were the major parameters reflecting the impact of regional flow from the aquifer; pH, dissolved oxygen, and water temperature indicated the local environment in and around the springs; while nitrogen and CODMn both related to the aquifer and local environment, depending on seasonal variation and human activities. The comparison of long-term nitrate data revealed that environmental pressure has increased over time. Water deterioration of Lingshui Spring was attributed to the strong interaction of surface water and groundwater. High nutrient concentrations did not correspond with the highest phytoplankton abundance or the most species. The phytoplankton community structures in the karst springs varied from place to place, depending on the hydrogeological conditions and the surrounding environment. The water environment status, as reflected by the combination of water quality indices and biological indicators, could more comprehensively represent overall water health.

Physico-chemical parameters of Itahari sub-metropolitan fish pond, Nepal

Itahari Sub-metropolitan pond is located in the centre of the city. Influence of variations in physico-chemical parameters on aquatic flora and fauna especially in fishes brought strong stress on fishes and increases the incidence of diseases leading to high mortality. Due to lack of adequate knowledge about it, productivity of ponds is very low. In the present study, maximum and minimum variations and correlation between different physico-chemical parameters - air temperature, water temperature, pH, turbidity, total dissolved solids, dissolved carbon dioxide, ammonia, dissolved oxygen, biological oxygen demand, chloride, total alkalinity, total hardness and phosphate were taken into consideration. The water quality of fish ponds were normal except high fluctuation of chloride 4.0 - 44.87mg/l and ammonia 0.48-13.6 mg/l during manuaring period and casual addition of wastes like toilet cleaners, caustic potash etc.. Due to sudden fall in DO less than 4 mg/l during April and May, 2014 and increment of ammonia after addition of toilet wastes in Sept.19, 2015 ; mass mortality of fishes Labeo rohita, Cirrhina mrigala, Hypothalamichthys molitrix, Aristichthysnobilis occurred in the study site.

From environmental data acquisition to assessment of gardeners' exposure: feedback in an urban context highly contaminated with metals.

Although growing vegetables in urban gardens has several benefits, some questions in relation with the safety of foods remain when the self-production is carried out on highly contaminated garden soils. To better assess the local population's exposure to Cd and Pb induced by the past activities of a lead smelter, a participatory program was initiated in 115 private kitchen gardens located in northern France to assist gardeners in understanding their soil environment. The challenge included contributing to the database of urban garden soils with the collection of a large number of samples: 1525 crops grouped into 12 types (leaf, fruiting, root, stem and bulbous vegetables, tubers, cabbages, leguminous plants, celeriac, fresh herbs, fruits, and berries), 708 topsoils, and 52 samples of self-produced compost. The main results were as follows: (i) topsoils were strongly contaminated by Cd and Pb compared to regional reference values; (ii) great variability in physicochemical parameters and metal concentrations in topsoils; (iii) the highest concentrations of Cd and Pb for celeriac and fresh herbs and the lowest for fruits and fruiting vegetables; (iv) a high percentage of vegetables that did not comply with the European foodstuff legislation; and (v) most self-produced compost samples were strongly contaminated. This study aimed to raise awareness and generate functional recommendations to reduce human exposure and to provide useful data that could be considered in other environmental contexts.