Concentrations Of Zn In Sediments Research Articles

Assessment of heavy metal concentrations in water and sediments at Motor Park and new bridge areas, lower River Benue, Ibi, Taraba, Nigeria

Heavy metals concentration in water and sediment was investigated at the Motor Park Area and New Bridge Site of lower River Benue, Ibi, Taraba State. The heavy metals levels were examined using atomic absorption spectrophotometer (AAS) Buck Scientific model 210 VGP using spectrophotometry techniques. The highest mean concentration of Zn recorded in the sediment at the Motor Park Area was 0.55 mg/kg while the lowest value of 0.004 mg/kg was recorded for Cr at the Motor Park Area. The highest mean concentration of Mn recorded in the water was 0.375 mg/l at New Bridge Site while the lowest value of 0.00 mg/l was recorded for Cu. Values for Cu, Cd, Cr. Cu were generally low throughout the study period. There was no significant difference (p>0.005) in Zn concentrations in sediment at the sampled locations (Motor Park Area and New Bridge Site) throughout the study periods. However, Cr, Cd and Pb show variations (p<0.005) at the sampled locations. The concentration of Mn (0.375 mg/l) was not significantly different (p>0.05) from Mn (0.325 mg/l) in water between the two location, Pb value (0.343 mg/l) of water in December at the New Bridge Site exceeded the WHO recommended safe limit. However, all other metals were within the WHO and FMENV safe limit for portable drinking water. Since Pb value (0.343 mg/l) exceeded the WHO and FMENV safe limit for December. It shows that there is need for continuous monitoring of Lower River Benue waters at Ibi, Taraba State.

Potential metal phytoremediation in peri-urban wetlands using rooted macrophytes

The pollution of natural water bodies and peri-urban wetlands is frequent in the Middle Paraná River (Argentina). This work evaluates the potential use of different rooted macrophytes for metal phytoremediation in peri-urban wetlands. Macrophytes, water and sediment were collected in the study sites. Cr, Ni, Zn, Pb, total phosphorus (TP) and total Kjeldahl nitrogen (TKN) were determined in water, sediment, and different plant tissues. Industrial Park and RECU (water dump) showed the highest Cr concentrations. The highest Ni water concentration was observed in Rincón. Industrial Park showed the highest Zn water concentration. The highest Pb water concentration was observed in Industrial Park followed by Rincón. The highest Cr and Zn concentrations in sediment were registered in Industrial Park and Leyes (lake). The sites that showed the highest Ni concentrations in sediment were Industrial Park, RECU (water dump), and Leyes (lake). The high TP concentration measured in the sediment of RECU (water dump) was quite remarkable. Regarding plant tissues, the roots of Pontederia rotundifolia (Leyes, lake). showed the highest Pb concentration. Typha domingensis showed the highest concentrations of Cr, Ni and Zn, in agreement with the highest concentration in sediment. Plants presenting high biomass, such as T. domingensis, are needed to obtain an efficient metal removal from water in peri-urban wetlands. Studies focused on different rooted species will extend the knowledge about metal phytoremediation, management of peri-urban wetlands that receive pollution, and the use of treatment wetlands as nature-based solutions.

Evaluation of Nuphar lutea as bioindicator of metal pollution in freshwater ecosystems

Macrophytes have a capacity to absorb elements from the water and sediment and some species can be bioindicators of pollution. The uptake of 12 metals by Nuphar lutea from 56 water bodies was studied to evaluate its bioaccumulation potential and bioindication suitability. Study sites were grouped in three types: urban, agricultural and semi-natural (forests) according to land cover and anthropogenic activities in their surroundings. Concentrations of Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb and Zn were determined by atomic absorption spectrometry. Results highlighted higher levels of pollution (e.g. Cd, Cr, Fe, Ni and Zn concentrations in sediments) in urban and agricultural areas than in forest areas. The levels of metals in leaves were high and contents differed between sites exposed to various metal sources. The lowest concentrations of Co, Mn, Ni, Pb, Zn in plants were noted in forest areas; the highest Cd content in agricultural sites while the highest Cr, Fe, K content in urban sites. Neural networks demonstrated similarities in sediments and leaves of N. lutea in response to multi-elemental pollution. Results indicated on the possibility of using the leaves of N. lutea as an indicator of pollution in water bodies (in biomonitoring process). Eggs of Little Bitterns show high variation and their size increases with latitude.

Impact of municipal solid waste dumpsites on trace metal contamination levels in the surrounding area: a case study in West Africa, Abidjan, Cote d’Ivoire

The impact of uncontrolled municipal dumping sites on metal contamination in the surrounding waters, sediments, and soils are of great concern in many developing countries. Total concentrations of trace metals Cd, Zn, Cu, Pb, Ni, and Co were measured in 33 sediments collected in the vicinity of the Akouedo dumpsite (Abidjan, Cote d'Ivoire) and in a baseline station. The Cu, Zn, Cd, and Pb concentrations in surface sediments around the dumpsite were at least three times higher than those at the reference station, suggesting that the Akouedo dumping site is a significant contamination source of these metals to the surrounding sediments. The extent of contamination affects sediment as deep as 100 cm. Sediment pH and total organic carbon content control the distribution of Cu, Zn, and Cd in subsurface sediments. Significant Cd, Zn, and Cu enrichments were measured at the dumpsite and its surrounding environment. Zn concentrations in the sediments might cause high ecological risks at 46% of the samples based on the sediment quality guidelines (SQGs). Single and sequential extraction results showed a low mobility rate of Cd, Cu, Pb, and Ni from sediments around the dumpsite. However, the results suggest that the high total metal concentrations in the dumpsite sediments have resulted in a significant metal load in the surrounding environment.

Metal concentrations in marine sediments of the Rio de Janeiro Coast (Brazil): A proposal to establish new acceptable levels of contamination

This work aims to propose new standards to assess the degree of sediment contamination in saline and brackish environments, since the legislation currently used in Brazil is based on Canadian/American regulations, which do not comply with the conditions in Brazil. This study is based on geochemical analyses of 340 surface sediment samples collected in the Green Coast region (Rio de Janeiro, Brazil), including Mangaratiba, Angra dos Reis and Ribeira coves and Ilha Grande and Sepetiba bays. This region is influenced by industrial, harbor, urban and tourist activities and was affected by a dam rupture episode that released contaminated material. The results show heterogeneity in the distribution and range of metal concentrations in the study area depending on the supply of metals from natural and anthropogenic sources. Environmental characteristics such as coastal and tidal currents, water temperature and salinity, local depth, sediment grain size, sedimentary dynamics and biogeochemical processes influence the dispersion or retention of metals. The pollution load index (PLI) suggests that Sepetiba Bay is the region with the most environmental degradation due to anthropogenic contamination. In this context, we propose the establishment of new levels of contamination according to the Cd, Cr, Cu, Mn, Ni, Pb, V and Zn concentrations in sediments of salt and brackish waters, considering I) background level; II) level 1 - with anthropogenic influence; and III) level 2 - contaminated. The results of this work also suggest that, except for zinc, the range of metal concentrations admitted by Brazilian legislation are quite permissive and not adequate for Brazilian coastal environments.

The impacts of waterbird-mediated elemental enrichment on chironomid assemblages from island ponds in Lake Ontario

Ring-billed gulls (Larus delawarensis) and double-crested cormorants (Phalacrocorax auritus) have nested in dense colonies across the Laurentian Great Lakes since their rapid population expansions during the early- and mid-20 th century, respectively. Dated sediment cores from ponds located near nesting sites have been used to track the history of these large colonies on islands in eastern Lake Ontario. However, less is known about avian-mediated biotransport of contaminants to these nesting sites and its effects on aquatic biota at mid-trophic levels, such as chironomids. Here, we used a paleolimnological approach to determine the extent of possible avian- mediated metal(loid) contamination of ponds in nesting sites compared to reference sites. Water from avian-im- pacted ponds had higher concentrations of Al, Cd, Cu, Fe, Pb, and Se than the reference ponds, and exceeded the Canadian Council of Ministers of the Environment (CCME) guidelines for the protection of aquatic life at some sites. Down-core geochemical analysis of elements in sediments showed that concentrations of Cd, Se, and Zn were significantly higher in impacted ponds than in reference sites and correlated significantly with stable nitrogen isotopes, a marker of avian-derived nitrogen. In sites impacted by ring-billed gulls, Cd and Zn concentrations in sediments exceeded or approached those at which frequent adverse biotic effects are expected. Metal contamination was linked to altered chironomid assemblages, with subfossil remains in the avian-impacted sites including more taxa tolerant of heavy metal contamination than reference sites. Notably, chironomids were largely absent from the sites with the highest metal concentrations. These findings have implications for understanding and managing contaminant cycling in the Great Lakes, as waterbirds that nest in dense colonies can act as biovectors that transport metals to new and unexpected locations.

Assessment of trace metals, total organic carbon and total nitrogen of a shrimp farm system in Southern Brazil

The unconsumed food in shrimp farm systems is responsible for increasing the organic compounds in sediment, and it is a potential source of trace metals. This study evaluates the total organic carbon (TOC), total nitrogen (TN), copper (Cu) and zinc (Zn) concentrations in sediments from control sites, a shrimp pond, a sedimentation basin and receiving ecosystem effluents at a semi-intensive Litopenaeus vannamei farm in southern Brazil. Copper and zinc concentrations were also analyzed in shrimp tissue. The sediment samples were taken before the effluent discharge (BD), 1 day post discharge (1PD), 10 days post discharge (10PD) and 30 days post discharge (30PD). The TOC concentrations ranged from 0.12 to 0.67%, and the TN concentrations were <0.07% in all samples. The labile Cu and Zn concentrations in sediment ranged from 0.12 to 1.27 μg g−1 and from 0.51 to 3.07 μg g−1, respectively, while the more strongly adsorbed fraction of Cu ranged from 0.3 to 2.65 μg g−1, and that of Zn ranged from 30.44 to 121.4 μg g−1. Some significant differences (p < 0.05) were observed among the sites, but they were not related to the effluent discharge. Pearson correlation analysis showed no relationship between the effluent discharge and increased TOC, TN, Cu or Zn values in the sediment, except in the 1PD sampling. The Cu and Zn concentrations in the shrimp tissues were 6.63 ± 0.2 μg g−1 and 19.76 ± 0.2 μg g−1 in pond 1 and 7.6 ± 0.51 μg g−1 and 19.13 ± 0.32 μg g−1 in pond 2. All parameters were within in accordance with the guidelines levels, and this shrimp farm did not have adverse effects on the environment when considering these parameters.

The effect of lead (Pb) and zinc (Zn) contamination on aquatic insect community composition and metamorphosis

Metal contamination of freshwater ecosystems is a great threat to aquatic insect communities. In the past, focus has been on the toxic effects on the insect larvae, despite emerging evidence showing that negative effects can occur during metamorphosis to adults. There is therefore a risk that traditional studies on insect larvae would underestimate effect from metals. In this study, we investigated the effect of lead (Pb) and zinc (Zn) on aquatic insect abundance, including metamorphosis and adult emergence at 9 lakes, near an abandoned Pb/Zn mine, with different Pb and Zn concentrations in sediment and water. Further, differences in response to metal contamination among taxa, and potential community composition changes, were also investigated. Total insect abundance was not affected by metal contamination, but Zn had a negative effect on metamorphosis and proportionally less adults emerged compared to larval abundance when the bioavailable Zn concentration in water increased. The opposite pattern was found for bioavailable Pb (negative effect on larvae but not on adult emergence). All studied insect groups had similar response to metal contamination, and no change in community structure towards dominance of more tolerant taxa was observed. Our study shows that it is important to include metamorphosis when metal toxicity is evaluated in aquatic insects, and that metals can have opposite and contradicting effects. Thus, although combined cocktail effects of metal mixtures are important to assess, effects of individual metals can be underestimated.

ADECUABILIDAD Y COMPARACIÓN DE TÉCNICAS ESPECTROSCÓPICAS PARA EL ANÁLISIS DE MUESTRAS DE ORIGEN GEOLÓGICO

Four analytical methodologies for the determination of chemical species of environmental interest were optimized and adapted. By means of the flame atomic absorption spectroscopy technique (FAAS) it was possible to sequentially quantify Fe, Mn, Cu, Cr, Ni, Pb, and Zn concentrations in sediment, soil and rock samples. Through the formation of colorful complexes of iron species, obtained under specific and well-defined reaction conditions, and their subsequent quantification by visible spectroscopy with independent methodologies, it was possible to determine the total iron, Fe 2+ and Fe 3+ content in mine leachates. The methodologies described turned out to be precise and accurate, they are free of matrix interferences and are comparable with other validated methodologies. The linearity intervals in FAAS for the seven elements vary from 0.05 to 16 mg/L, with detection limits between 0.03 and 0.2 mg/L. With respect to the colorimetric determinations of total Fe, Fe 2+ and Fe 3+ in samples of sulfided mining leachates, linear ranges of concentration comprised between 0.05 and 17.5 mg/L were observed. The detection limits obtained were 0.05 mg/L for total Fe and Fe 2+ and 0.14 mg/L for Fe 3+ .

Trace element compartmentation in the seagrass Posidonia oceanica and biomonitoring applications

This study investigated the trace element bioaccumulation capacity of the Mediterranean seagrass Posidonia oceanica, and its suitability as a bioindicator of contamination in water and sediments. Results showed that P. oceanica leaves accumulate higher concentrations of Ni and Zn. Since P. oceanica regenerates its leaves periodically, the higher concentrations in aerial organs may suggest a “removal” strategy according to which P. oceanica accumulates greater concentrations of trace elements in its temporary organs. In turn, P. oceanica seems to adopt an exclusion strategy for toxic non-essential elements (As, Cr, Pb). Results showed also that P. oceanica organs are correlated with As, Cd, Cu, Ni, and Zn concentrations in sediments. No significant relationship was found between P. oceanica and water. This study showed that P. oceanica may adopt different tolerance strategies compared to mainland-rooted macrophytes, and its possible use as a bioindicator of trace elements in sediments should be considered.

Distribution of high Zn concentrations in unvegetated and Typha domingensis Pers. vegetated sediments

Fil: Di Luca, Gisela Alfonsina. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica. Laboratorio de Quimica Analitica; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

Effects of contaminated St. Lucie River saltwater sediments on an amphipod (Ampelisca abdita) and a hard-shell clam (Mercenaria mercenaria).

The St. Lucie estuary (SLE) ecosystem in South Florida has been shown to be contaminated with metals and pesticides. Our earlier studies also showed that aquatic organisms, especially benthic species in the SLE ecosystem, might be potentially at high risk from copper (Cu) exposure. The objectives of this study were to conduct studies with separate groups of organisms exposed to seven field-collected sediment samples from the St. Lucie River according to standard procedures to evaluate toxicity and tissue concentrations of Cu and zinc (Zn). Short term and longer term whole sediment acute toxicity studies were performed with Ampelisca abdita and Mercenaria mercenaria. Analysis of sediment chemical characteristics showed that Cu and Zn are of most concern because their concentrations in 86 % of the sediments were higher than the threshold effect concentrations for Florida sediment quality criteria and the National Oceanic and Atmospheric Administration Screening Quick Reference Tables (SQuiRTs) sediment values. There was no significant effect on survival of the tested organisms. However, increased Cu and Zn concentrations in the test organisms were found. Dry weight of the tested organisms was also inversely related to Cu and Zn concentrations in sediments and organisms. The effects on organism weight and Cu and Zn uptake raise concerns about the organism population dynamics of the ecosystem because benthic organisms are primary food sources in the SLE system and are continuously exposed to Cu- and Zn-contaminated sediments throughout their life cycle. The results of the present study also indicate that Cu and Zn exposures by way of sediment ingestion are important routes of exposure.

Impact of dredged urban river sediment on a Saronikos Gulf dumping site (Eastern Mediterranean): sediment toxicity, contaminant levels, and biomarkers in caged mussels

Impacts of chemical contaminants associated with dumping of dredged urban river sediments at a coastal disposal area in Saronikos Gulf (Eastern Mediterranean) were investigated through a combined approach of sediment toxicity testing and active biomonitoring with caged mussels. Chemical analyses of aliphatic hydrocarbons (AHs), polycyclic aromatic hydrocarbons (PAHs), Cu, and Zn in combination with the solid phase Microtox® test were performed on sediments. Concentrations of PAHs, AHs, Cu, and Zn as well as multiple biomarkers of contaminant exposure and/or effects were measured in caged mussels. Sediments in the disposal and neighboring area showed elevated PAHs and AHs concentrations and were characterized as toxic by the solid-phase Microtox® test during and after dumping operations. Biomarker results in the caged mussels indicated sublethal effects mainly during dumping operations, concomitantly with high concentrations of PAHs and AHs in the caged mussel tissues. Cu and Zn concentrations in sediments and caged mussels were generally not elevated except for sediments at the site in the disposal area that received the major amount of dredges. High PAHs and AHs levels as well as sublethal effects in the caged mussels were not persistent after termination of operations. The combined bioassay-biomarker approach proved useful for detecting toxicological impacts of dredged river sediment disposal in sediments and the water column. Nevertheless, further research is needed to evaluate whether sediment toxicity will have long-term effects on benthic communities of the disposal area.

Heavy Metal Pollution in the Receiving Environment of the University of Dar Es Salaam Waste Stabilization Ponds

The aim of this study was to examine the availability, concentration levels and bioaccumulation of heavy metals namely; Mercury (Hg), Cadmium (Cd), Lead (Pb), Zinc (Zn) and Molybdenum (Mo) in the waste Stabilization Ponds of the University of Dar es Salaam. A total of 135 samples were analyzed, out of which 27 were samples of water, 27 of sediments and 81 samples of fish tissues. Two types of fishes were used namely; Oreochromis niloticus and Clarias gariepinus. Heavy metal concentration varied significantly between water, sediment, fish species and tissues. Hg, Cd, Zn and Mo concentrations in water and sediment were within WHO safe limits. However, Pb in water and Cd, Pb and Zn concentrations in sediments were found to be above WHO standards (p&lt;0.05). Concentration levels for Cd, Pb and Zn were above acceptable levels in Oreochromis niloticus while Hg was found to be within safe limits in both fish species (p&lt;0.05). Molybdenum was found to be below the detection limits in Oreochromis niloticus. While Cd was not detected, Pb, Zn and Mo were found highly accumulated in Clarias gariepinus (p&lt;0.05). Oreochromis niloticus accumulated metals in the increasing order from dorsal muscles &lt; gills &lt; liver while Clarias gariepinus accumulated metals in the decreasing order from dorsal muscle &lt; gills &lt; liver.Public awareness on the dangers to which fish consumers from the site are exposed is highly suggested and purposeful mitigation measures of stopping all fishing activities in these sites is needed, also animal feeding around the ponds should be forbidden.

Metal contents and Pb isotopes in road-side dust and sediment of Japan

In order to elucidate the sources of metals in urbanized areas, metal contents and Pb isotope ratios were determined in road-side dust and sediments samples collected from Tokyo, Osaka and Kyoto. The samples were leached using 1% HNO3 for metal concentrations and Pb isotopes analysis. Metal (Pb, Cd, Zn, As, Cr and Ni) concentrations and Pb isotopes (206Pb, 207Pb and 208Pb) in the solutions were analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The extent of anthropogenic contribution to road-side dust was assessed by comparing the metal concentration values in road-side dust of the sample sites to those of Okinawa, an unpolluted road-side dust site due to low traffic density. Considering a Pb background of 21.0ppm measured in the Okinawan road-side dust, Pb in road-side dust of Tokyo was found to be about twelve times higher which may indicate Pb pollution in the streets of Tokyo. The contaminated road-side dust can be transported into pond and river sediments during runoff and rainfall events. The concentrations of anthropogenic Pb in road-side dust and sediment were compared to those of other metals (Cd, Zn, As, Cr and Ni). There was a positive correlation found between Pb with Cd, Ni and Zn concentrations in sediment which suggests a common origin. The range of the Pb isotope ratios in road-side dust agreed well to that in the sediments (207Pb/206Pb=0.8644–0.8688 and 208Pb/206Pb=2.1044–2.170) suggesting that sediments may be contributed and transported by mean of road-side dust. Moreover, Pb isotope ratios (208Pb/206Pb and 207Pb/206Pb) confirmed that Pb pollution in the road-side dust and sediments was contributed the combination of battery and solder products.

Ecotoxicological approach for assessing the contamination of a Hawaiian coral reef ecosystem (Honolua Bay, Maui) by metals and a metalloid

The goal of this study was to assess the contamination of Honolua Bay using an ecotoxicological approach. First, the concentrations of 9 contaminants (metals and metalloid) were assessed in sediments and tropical marine organisms (alga Halimeda kanaloana, goatfish Parupeneus multifasciatus and urchin Tripneustes gratilla) sampled from Honolua and surrounding Bays. Then, the ecological parameters characterizing coral health (e.g. coral cover) were evaluated in Honolua Bay in the context of these contaminants. High concentrations of Co, Cr, Mn, Ni, and V in sediments from Honolua and Honokohau Bay were measured, but these concentrations were not mirrored in the organisms examined, except for Mn, suggesting that the metals are generally bound in chemically inert forms in these sediments. Moreover, few anthropogenic activities impact these bays and so the elevated Co, Cr, Mn, Ni and V concentrations in sediments appear to stem from their high natural background in Honolua and Honokohau watersheds. An analysis of the relationship between the ecological parameters and metal concentrations in Honolua Bay revealed a significant correlation between coral cover and Co, Cr, Mn, Ni, V, Zn concentrations in sediments, with coral cover decreasing with increasing metal concentration. Collectively, however, the data suggest that a complex mixture of land-based stressors (e.g. sediment, metals, nutrients) affect the coral health in Honolua Bay, rather than metal stress alone.

Ecological risk assessment of zinc from stormwater runoff to an aquatic ecosystem

Zinc (Zn) risks from stormwater runoff to an aquatic ecosystem were studied. Monitoring data on waterborne, porewater, and sediment Zn concentrations collected at 20 stations throughout a stormwater collection/detention facility consisting of forested wetlands, a retention pond and first order stream were used to conduct the assessment. Bioavailability in the water column was estimated using biotic ligand models for invertebrates and fish while bioavailability in the sediment was assessed using acid volatile sulfide-simultaneously extracted metal (AVS-SEM). The screening level assessment indicated no significant risks were posed to benthic organisms from Zn concentrations in sediments and pore water. As would be expected for stormwater, Zn concentrations were temporally quite variable within a storm event, varying by factors of 2 to 4. Overall, probabilistic assessment indicated low (5–10% of species affected) to negligible risks in the system, especially at the discharge to the first order stream. Moderate to high risks (10–50% of species affected) were identified at sampling locations most upgradient in the collection system. The largest uncertainty with the assessment is associated with how best to estimate chronic exposure/risks from time-varying exposure concentrations. Further research on pulse exposure metal toxicity is clearly needed to assess stormwater impacts on the environment.

Factorial Kriging Analysis As a Tool for Explaining the Complex Spatial Distribution of Metals in Sediments

Rivers flowing through urbanized and industrial areas are usually greatly damaged by anthropogenic activities discharging contaminants. Characterizing the spatial distribution of pollutants in sediments is of high importance for selecting a suitable remediation operation, but is a complex task because this spatial variability is the result of various physical and chemical mechanisms occurring at different scales. Factorial Kriging Analysis (FKA) was applied on data collected in a canalized river (Scarpe, France) for that purpose, because this geostatistical technique allows to decompose a given variable into components of different spatial correlations and map them separately. This decomposition is meaningful provided that it can be related to physical phenomena occurring at the identified spatial scales. FKA applied to Cd and Zn concentrations in sediments of the Scarpe river proved to be effective, allowing their mapping to be decomposed in a first map related to a short-range spatial correlation corresponding to hot spots interpreted as the impact of industrial and urban inputs located along the canal, and a second map related to a long-range spatial variability associated with long pollutant plumes interpreted as the effect of one major upstream pollutant input.

Cd AND Zn ACCUMULATION IN PLANTS FROM THE PADAENG ZINC MINE AREA

Significant cadmium (Cd) contamination In soil and rice has been discovered in Mae Sot, Tak province, Thailand where the rice-based agricultural systems are established in the vicinity of a zinc mine. The prolonged consumption of Cd contaminated rice has potential risks to public health and health impacts of Cd exposed populations in Mae Sot have been demonstrated. The Thai government has prohibited rice cultivation in the area as an effort to prevent further exposure. Phytoextraction, the use of plants to remove contaminants from soil, is a potential option to manage Cd–contaminated areas. However, successful phytoextraction depends on first identifying effective hyperaccumulator plants appropriate for local climatic conditions. Five sampling sites at Padaeng Zinc mine, Tak province were selected to collect plant and soil samples. Total Cd and Zn concentrations in sediments or soils were approximately 596 and 20,673 mg kg−1 in tailing pond area, 543 and 20,272 mg kg−1 in open pit area, 894 and 31,319 mg kg−1 in stockpile area, 1,458 and 57,012 mg kg−1 in forest area and 64 and 2,733 mg kg−1 in Cd contaminated rice field. Among a total of 36 plant species from 16 families, four species (Chromolaena odoratum, Gynura pseudochina, Impatiens violaeflora and Justicia procumbens) could be considered as Cd hyperaccumulators since their shoot Cd concentrations exceeded 100 mg Cd kg−1 dry mass and they showed a translocation factor > 1. Only Justicia procumbens could be considered as a Zn hyperaccumulator (Zn concentration in its shoot more than 10,000 mg Zn kg−1 dry mass with the translocation factor > 1).

Pollutants in drainage channels following long‐term application of Mancozeb to banana plantations in southeastern Mexico

AbstractThe aim of this study was to investigate how long‐term Mancozeb application to banana plantations affects the occurrence of pollutants in drainage‐channel sediment and water under tropical conditions. We estimated the possible accumulation of Mancozeb's principal metabolite ethylenethiourea (ETU), as well as manganese (Mn) and zinc (Zn) as components in channel sediment and water. We took samples during the tropical‐rainfall season and the low‐rainfall season. For sediment samples, we determined the contents of ETU, Mn, and Zn. For water samples, we determined the concentration of ETU. Additionally, we took water samples from a runnel that is the receiving body of hydraulic flow from the system. In both seasons, ETU in the sediment was near the detection limit (0.01 mg kg–1) and did not show any accumulation. However, Mn in sediment at all sampling sites exceeded the threshold values for aquatic life of 630 mg kg–1 with values between 635 and 7256 mg kg–1. The Zn concentrations in sediment varied from 87 to 190 mg kg–1 and exceeded the threshold values for aquatic life of 98 mg kg–1 at several sites. Furthermore, we determined an accumulation of these heavy metals in the sediments of the banana‐planted zone in comparison with sediments in pasture reference sites. In contrast to the low concentration of ETU in sediment, its concentration in drainage and runnel water (5.9–13.8 μg L–1) exceeded the EU threshold value for drinking water (0.1 μg L–1) by up to nearly 140 times. However, the threshold value for aquatic life was not exceeded. We conclude that long‐term Mancozeb application does lead to a severe accumulation of Mn in sediments and of ETU in surface water. New strategies should be used to control black Sigatoka, including integrated methods of pest control so that long‐term negative effects on the environment can be avoided.