Persistence behaviour of imidacloprid and its metabolites in soil under sugarcane

The persistence and metabolism of imidacloprid in soil under sugarcane were studied following application of imidacloprid at 20 and 80 g active ingredient (a.i.) ha^?1. Soil samples were collected at different time intervals (7, 15, 30, 45, 60 and 90 days after application), and the residues of imidacloprid and its metabolites (6-chloronicotinic acid, nitrosimine, imidacloprid-NTG, olefin, urea and 5-hydroxy) were quantified by high-performance liquid chromatography. In soil, the total imidacloprid residues were mainly constituted by the parent compound followed by 6-chloronicotinic acid, nitrosimine and imidacloprid-NTG metabolites. Maximum residues of imidacloprid and its metabolites were 4.29 and 7.81 mg kg^?1 in soil samples collected 7 days after the application of imidacloprid at 20 and 80 g a.i. ha^?1, respectively. At both doses, these residues declined to below the detectable limit in soil after 90 days of application. Olefin, urea and 5-hydroxy metabolites were not detected in soil. Dissipation of total imidacloprid residues did not follow the first-order kinetics with a coefficient of determination value of 0.883 and 0.838 for the recommended dose and four times the recommended dose, respectively. The half-life (T _1/2) value of total imidacloprid was observed to be 10.64 and 10.10 days for the recommended dose and four times the recommended dose, respectively.     

Dissipation and residue behavior of mepiquat on wheat and potato field application

A modified LC-MS method for the analysis of mepiquat residue in wheat, potato, and soil was developed and validated. A hydrophilic interaction liquid chromatographic column has been successfully used to retain and separate the mepiquat. Mepiquat residue dynamics and final residues in supervised field trials at Good Agricultural Practice (GAP) conditions in wheat, potato, and soil were studied. The limits of quantification for mepiquat in all samples were all 0.007 mg kg^?1, which were lower than their maximum residue limits. At fortification levels of 0.04, 0.2, and 2 mg kg^?1 in all samples, recoveries ranged from 77.5 to 116.4 % with relative standard deviations of 0.4–7.9 % (n?=?5). The dissipation half-lives (T _1/2) of mepiquat in soil (wheat), wheat plants, soil (potato), and potato plants were 4.5–6.3, 3.0–5.6, 2.2–4.6, and 2.4–3.2 days, respectively. The final residues of mepiquat were below 0.153 mg kg^?1 in soil (wheat), 0.052–1.900 mg kg^?1 in wheat, below 0.072 mg kg^?1 in soil (potato), and below 1.173 mg kg^?1 in potato at harvest time. Moreover, pesticide risk assessment for all the detected residues was conducted. A maximum 0.0012 % of acceptable daily intake (150 mg kg^?1) for national estimated daily intake indicated low dietary risk of these products.     

Persistence of chlorantraniliprole granule formulation in sugarcane field soil

Chlorantraniliprole, an anthranilic diamide insecticide with novel mode of action, is found effective against several lepidopteran as well as coleopteran, dipteran, and hemipteran pests. The present studies were carried out to study the persistence pattern of chlorantraniliprole on sugarcane field soil following application of granule formulation. The residues of chlorantraniliprole were estimated using high performance liquid chromatograph (HPLC) and confirmed by liquid chromatograph-mass spectrometry (LC-MS/MS). Following application of chlorantraniliprole (Ferterra 0.4G) at 100 and 200 g a.i. ha^?1, the average initial deposits of chlorantraniliprole were observed to be 0.88 and 1.59 mg kg^?1, respectively. These residues dissipated below the limit of quantification (LOQ) of 0.01 mg kg^?1 after 56 days of the application of insecticides at both the dosages. The half-life values (t _1/2) of chlorantraniliprole were worked out to be 8.36 and 8.25 days, at recommended and double the recommended dosages, respectively.     

Persistence and effect of processing on reduction of chlorantraniliprole residues on brinjal and okra fruits

Dissipation and decontamination of chlorantraniliprole (Coragen 18.5 SC) in brinjal and okra fruits were studied following field application at single and double doses of 30 and 60 g ai ha^?1, and the residues of the insecticide was estimated using LC-MS/MS. Initial residues of chlorantraniliprole at single and double doses on the fruits of brinjal were 0.72 and 1.48 mg kg^?1, while on okra fruits, the residues were 0.48 and 0.91 mg kg^?1, respectively. The residues reached below detectable level of 0.01 mg kg^?1 on the 10th day. Half-life of chlorantraniliprole at 30 and 60 g ai ha^?1 on brinjal was 1.58 and 1.80 days with the calculated waiting period of 0.69 and 2.38 days, whereas on okra, the values were 1.60 and 1.70 and 0 and 1.20 days, respectively. The extent of removal of chlorantraniliprole using simple decontaminating techniques at 2 h and 3 days after spraying was 40.99–91.37 % and 29.85–89.12 %, respectively, from brinjal fruits and 47.78–86.10 % and 41.77–86.48 %, respectively, from okra fruits.     

Dissipation and residues determination of propamocarb in ginseng and soil by high-performance liquid chromatography coupled with tandem mass spectrometry

Two-year field trials were performed at two experimental sites to investigate dissipation and terminal residues of propamocarb in ginseng root, stem, leaf, and soil by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Mean recoveries ranged from 80.5 to 95.6 % with relative standard deviations (RSDs) of 5.5–9.1 % at fortified levels of 0.01, 0.02, 0.05 and 0.20 mg kg^?1. The half-lives of propamocarb were 5.00–11.36 days in root, 5.07–11.46 days in stem, 6.83–11.31 days in leaf and 6.44–8.43 days in soil. The terminal residues of propamocarb were below the maximum residue limits (MRLs) of EU (0.20 mg kg^?1) and South Korea (0.50 mg kg^?1 in fresh ginseng and 1.0 mg kg^?1 in dried ginseng) over 28 days after last spraying at recommended dosage. The results provide a quantitative basis for establishing the MRL and give a suggestion of safe and reasonable use of propamocarb in ginseng.     

Persistence and dissipation of flubendiamide and its risk assessment on gherkin (Cucumis anguria L.)

A supervised open field trial was conducted to evaluate the dissipation pattern and risk assessment of flubendiamide in gherkin fruits following foliar application of Fame 480 SC at 60 and 120 g a.i.?ha^?1. Samples of gherkin fruits were drawn at different time intervals and quantified by HPLC-DAD. The maximum initial deposits of flubendiamide on gherkin were found to be 0.79 and 1.52 mg kg^?1, respectively, at recommended and double the recommended doses. The dissipation pattern of flubendiamide followed a first-order kinetics with half-lives of 1.87 to 2.16 days at 60 and 120 g a.i.?ha^?1, respectively. The limit of quantification of flubendiamide and desiodo flubendiamide was observed to be 0.01 mg kg^?1 for gherkin fruit and soil substrates. Theoretical maximum residue contribution (TMRC) for flubendiamide was calculated and found to be well below the maximum permissible intake (MPI) on gherkin fruits. Thus, the application of flubendiamide at the recommended dose on gherkin fruits presents no human health risks and safe to consumers.     

Residual behavior of quizalofop ethyl on onion (Allium cepa L.)

Quizalofop ethyl, a phenoxy propionate herbicide, is used for postemergence control of annual and perennial grass weeds in broad-leaved crops in India. The experiments were designed to study the dissipation kinetics of quizalofop ethyl on onion for two seasons. A simple, rapid, and sensitive method for estimation of quizalofop ethyl residues in onion and soil was developed and validated. The recoveries of quizalofop ethyl residues from onion and soil at different spiking level range from 84.81 to 92.68 %. The limit of quantification of this method was found to be 0.01 μg g^?1. The risk assessment through consumption of the onion in comparison to its acceptable daily intake which is an important parameter for the safety of the consumer was also evaluated. Standardized methodology supported by recovery studies was adopted to estimate residues of quizalofop ethyl on onion and soil. The average initial deposits of quizalofop ethyl on onion were observed to be 0.25 and 0.33 mg kg^?1, following single application of the herbicide at 50 g active ingredient (a.i.) ha^?1 during 2009 and 2010, respectively. The half-life values (T _1/2) of quizalofop ethyl on onion crop were worked out to be 0.85 and 0.79 days, respectively, during 2009 and 2010. At harvest time, the residues of quizalofop ethyl on onion and soil were found to be below the determination limit of 0.01 mg kg^?1 following single application of the herbicide at 50 and 100 g a.i. ha^?1 for both the periods.     

Environmental fate of chlorantraniliprole residues on cauliflower using QuEChERS technique

Chlorantraniliprole, an anthranilic diamide insecticide with novel mode of action is found effective against several lepidopteran as well as coleopteran, dipteran, and hemipteran pests. The present studies were carried out to study the dissipation pattern of chlorantraniliprole on cauliflower and to suggest suitable waiting period for the safety of consumers. Quick, easy, cheap, effective, rugged, and safe method was used for the extraction and cleanup of samples and the residues of chlorantraniliprole were estimated using high-performance liquid chromatograph (HPLC) and confirmed by liquid chromatograph–mass spectrometer and high-performance thin layer chromatograph. Following three applications of chlorantraniliprole (Coragen 18.5 SC) at recommended dose (9.25 g a.i.?ha^?1) and double the recommended dose (18.50 g a.i.?ha^?1), the average initial deposits of chlorantraniliprole were observed to be 0.18 and 0.29 mg kg^?1, respectively. These deposits were found to be less than the maximum residue limit of 2.0 mg kg^?1 prescribed by the Codex Alimentarius Commission. These residues dissipated below the limit of quantification of 0.10 mg kg^?1 after 3 and 5 days at recommended and double the recommended dosages, respectively. The half-life value (T _1/2) of chlorantraniliprole was worked out to be 1.36 days following its application at recommended dosages. Hence, the use of this pesticide at recommended dosages does not seem to pose any risk, and a waiting period of 1 day is suggested for safe consumption of cauliflower curds.     

Persistence and risk assessment of spiromesifen on tomato in India: a multilocational study

Supervised field trials were conducted at four different agro-climatic locations of India to evaluate the dissipation pattern and risk assessment of spiromesifen on tomato. Spiromesifen 240 SC was sprayed on tomato at 150 and 300 g a.i.?ha^?1. Samples of tomato fruits were drawn at 0, 1, 3, 5, 7, 10 and 15 days after treatment and soil at 15 days after treatment. Quantification of residues was done on gas chromatograph–mass spectrophotometer in selective ion monitoring mode in the mass range of 271–274 (m/z). The limit of quantification of the method was found to be 0.05 mg kg^?1, while the limit of determination was 0.015 mg kg^?1. Residues were found below the LOQ of 0.05 mg kg^?1 in 10 days at both the doses of application at all the locations. Spiromesifen dissipated with a half-life of 0.93–1.38 days at the recommended rate of application and 1.04–1.34 days at the double the rate of application. Residues of spiromesifen in soil were detectable level (<0.05 mg kg^?1) after 15 days of treatment. A preharvest interval (PHI) of 1 day has been recommended on tomato on the basis of data generated under All India Network Project on Pesticide Residues. Spiromesifen 240 SC has been registered for its use on tomato by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of spiromesifen on tomato has been fixed by Food Safety Standard Authority of India, Ministry of Health and Family Welfare, Government of India as 0.3 μg/g after its risk assessment.     

Assessment of imidacloprid degradation by soil-isolated Bacillus alkalinitrilicus

Imidacloprid is extensively used on a broad range of crops worldwide as seed dressing, soil treatment, and foliar application. Hence, the degradation potential of bacterial strains from sugarcane-growing soils was studied in liquid medium for subsequent use in bioremediation of contaminated soils. The microbe cultures degrading imidacloprid were isolated and enriched on Dorn’s broth containing imidacloprid as sole carbon source maintained at 28 °C and Bacillus alkalinitrilicus showed maximum potential to degrade imidacloprid. Clay loam soil samples were fortified with imidacloprid at 50, 100, and 150 mg kg^?1 along with 45?×?10⁷ microbe cells under two opposing sets of conditions, viz., autoclaved and unautoclaved. To study degradation and metabolism of imidacloprid under these two conditions, samples were drawn at regular intervals of 7, 14, 28, 35, 42, 49, and 56 days. Among metabolites, three metabolites were detected, viz., 6-chloronicotinic acid, nitrosimine followed by imidacloprid-NTG under both the conditions. Total imidacloprid residues were not found to follow the first-order kinetics in both types of conditions. This paper reports for the first time the potential use of pure cultures of soil-isolated native bacterium B. alkalinitrilicus and also its use along with natural soil microflora for remediation of imidacloprid-contaminated soils.     

Cadmium background concentrations to establish reference quality values for soils of São Paulo State,Brazil

Proper assessment of soil cadmium (Cd) concentrations is essential to establish legislative limits. The present study aimed to assess background Cd concentrations in soils from the state of São Paulo, Brazil, and to correlate such concentrations with several soil attributes. The topsoil samples (n?=?191) were assessed for total Cd contents and for other metals using the USEPA 3051A method. The background concentration was determined according to the third quartile (75th). Principal component analysis, Spearman correlation, and multiple regressions between Cd contents and other soil attributes (pH, cation exchange capacity (CEC), clay content, sum of bases, organic matter, and total Fe, Al, Zn, and Pb levels) were performed. The mean Cd concentration of all 191 samples was 0.4 mg kg^?1, and the background concentration was 0.5 mg kg^?1. After the samples were grouped by parent material (rock origin) and soil type, the background Cd content varied, i.e., soils from igneous, metamorphic, and sedimentary rocks harbored 1.5, 0.4, and 0.2 mg kg^?1 of Cd, respectively. The background Cd content in Oxisols (0.8 mg kg^?1) was higher than in Ultisols (0.3 mg kg^?1). Multiple regression demonstrated that Fe was primarily attributed to the natural Cd contents in the soils (R ²?=?0.79). Instead of a single Cd background concentration value representing all São Paulo soils, we propose that the concentrations should be specific for at least Oxisols and Ultisols, which are the primary soil types.     

Persistence of metaflumizone on cabbage (Brassica oleracea Linne) and soil, and its risk assessment

Metaflumizone is a novel sodium channel blocker insecticide of semicarbazone class. It provides good to excellent control of most of the economically important lepidopterous pests and certain pests in the orders Coleoptera, Hemiptera, Hymenoptera, Diptera, Isoptera, and Siphonaptera. Although metaflumizone has been marketed globally for several years and got registered in India in the year 2009, specifically for the control of DBM on cabbage, to our knowledge, no food safety aspects of metaflumizone residue on cabbage have ever been reported in the literature in India or elsewhere. The present study was undertaken to evaluate the persistence of metaflumizone on cabbage and soil, vis-a-vis its risk assessment, following two spray applications of metaflumizone 220 SC (Verismo®), each at recommended and double dose of 200 and 400 g?a.i.?ha^?1 respectively. Initial residue deposits of metaflumizone on cabbage were 0.46 and 0.51 mg?kg^?1 at recommended and 0.76 and 0.85 mg?kg^?1 at double the recommended dose following the first spray and second spray application. The residues persisted beyond 5 days from both the treatments and dissipated with the half-life ranging from 1.7–2.1 days. Initial deposits of metaflumizone on soil ranged from 0.23–0.37 mg?kg^?1 and degraded with a half life ranging from 4.0–4.8 days. No degradation product of metaflumizone was detected in cabbage and soil at any point of time. Soil samples collected from the treated field after 7 days were free from any residue of metaflumizone or its metabolites. A pre-harvest waiting period of 3 days after application was suggested based on calculation of theoretical maximum daily intake.     

Dissipation of S-metolachlor in plant and soil and effect on enzymatic activities

The present study aimed at evaluating the dissipation of S-metolachlor (S-MET) at three doses in maize growing on diverse physico-chemical properties of soil. The effect of herbicide on dehydrogenase (DHA) and acid phosphatase (ACP) activity was estimated. A modified QuEChERS method using LC-MS/MS has been developed. The limit of quantification (0.001 mg kg^?1) and detection (0.0005 mg kg^?1) were very low for soil and maize samples. The mean recoveries and RSDs for the six spiked levels (0.001–0.5 mg kg^?1) were 91.3 and 5.8%. The biggest differences in concentration of S-MET in maize were observed between the 28th and 63rd days. The dissipation of S-MET in the alkaline soil was the slowest between the 2nd and 7th days, and in the acidic soil between the 5th and 11th days. DT₅₀ of S-MET calculated according to the first-order kinetics model was 11.1–14.7 days (soil) and 9.6–13.9 days (maize). The enzymatic activity of soil was higher in the acidic environment. One observed the significant positive correlation of ACP with pH of soil and contents of potassium and magnesium and negative with contents of phosphorus and organic carbon. The results indicated that at harvest time, the residues of S-MET in maize were well below the safety limit for maize. The findings of this study will foster the research on main parameters influencing the dissipation in maize ecosystems.     

Dissipation kinetics and effect of different decontamination techniques on the residues of emamectin benzoate and spinosad in cowpea pods

Dissipation and decontamination of the semisynthetic macrolide emamectin benzoate and the natural insecticide spinosad on cowpea pods were studied following field application at single and double doses of 11.0 and 22 and 73 and 146 g ai ha^?1, respectively. Residues of these naturalytes were estimated using LC-MS/MS. The initial deposit of 0.073 and 0.153 mg kg^?1 of emamectin benzoate dissipated below quantitation level on the fifth and seventh day at single and double dosage, respectively. For spinosad, the initial deposits of 0.94 and 1.90 mg kg^?1 reached below quantitation level on the 7th day and 15th day at single and double dosage, respectively. The half-life of emamectin benzoate and spinosad was 1.13–1.49 and 1.05–1.39 days with the calculated safe waiting period of 2.99–6.12 and 1.09–3.25 days, respectively, for single and double dosage. Processing of the harvestable pods with different decontamination techniques resulted in 33.82 to 100 % removal 2 h after the application of emamectin benzoate and 100 % removal 3 days after spraying, while the removal was 42.05 to 87.46 % 2 h after the application of spinosad and 38.05 to 68.08 % 3 days after application.     

Cadmium accumulation characteristics of the winter farmland weeds Cardamine hirsuta Linn. and Gnaphalium affine D. Don

In a preliminary study, we found that the cadmium (Cd) concentrations in shoots of the winter farmland weeds Cardamine hirsuta Linn. and Gnaphalium affine D. Don exceeded the critical value of a Cd-hyperaccumulator (100 mg kg^?1), indicating that these two farmland weeds might be Cd-hyperaccumulators. In this study, we grew these species in soil containing various concentrations of Cd to further evaluate their Cd accumulation characteristics. The biomasses of C. hirsuta and G. affine decreased with increasing Cd concentrations in the soil, while the root/shoot ratio and the Cd concentrations in shoot tissues increased. The Cd concentrations in shoots of C. hirsuta and G. affine reached 121.96 and 143.91 mg kg^?1, respectively, at the soil Cd concentration of 50 mg kg^?1. Both of these concentrations exceeded the critical value of a Cd-hyperaccumulator (100 mg kg^?1). The shoot bioconcentration factors of C. hirsuta and G. affine were greater than 1. The translocation factor of C. hirsuta was less than 1 and that of G. affine was greater than 1. These findings indicated that C. hirsuta is a Cd-accumulator and G. affine is Cd-hyperaccumulator. Both plants are distributed widely in the field, and they could be used to remediate Cd-contaminated farmland soil in winter.     

Metal release from serpentine soils in Sri Lanka

Ultramafic rocks and their related soils (i.e., serpentine soils) are non-anthropogenic sources of metal contamination. Elevated concentrations of metals released from these soils into the surrounding areas and groundwater have ecological-, agricultural-, and human health-related consequences. Here we report the geochemistry of four different serpentine soil localities in Sri Lanka by coupling interpretations garnered from physicochemical properties and chemical extractions. Both Ni and Mn demonstrate appreciable release in water from the Ussangoda soils compared to the other three localities, with Ni and Mn metal release increasing with increasing ionic strengths at all sites. Sequential extraction experiments, utilized to identify “elemental pools,” indicate that Mn is mainly associated with oxides/(oxy)hydroxides, whereas Ni and Cr are bound in silicates and spinels. Nickel was the most bioavailable metal compared to Mn and Cr in all four soils, with the highest value observed in the Ussangoda soil at 168?±?6.40 mg kg^?1 via the 0.01-M CaCl₂ extraction. Although Mn is dominantly bound in oxides/(oxy)hydroxides, Mn is widely dispersed with concentrations reaching as high as 391 mg kg^?1 (Yudhaganawa) in the organic fraction and 49 mg kg^?1 (Ussangoda) in the exchangeable fraction. Despite Cr being primarily retained in the residual fraction, the second largest pool of Cr was in the organic matter fraction (693 mg kg^?1 in the Yudhaganawa soil). Overall, our results support that serpentine soils in Sri Lanka offer a highly labile source of metals to the critical zone.     

Dissipation pattern and pre-harvest residue limit of abamectin in perilla leaves

The pre-harvest residue limit (PHRL) of abamectin (abamectin B1a and B1b) in Perilla frutescens leaves grown under greenhouse conditions were investigated using high-performance liquid chromatography with a fluorescence detector. Samples were extracted with acetonitrile. The extract was purified through a solid phase extraction procedure. Then the purified extract was derivatized with trifluoroacetic anhydride and N-methylimidazole to form a strong stable fluorescent derivative of abamectin. Finally, derivatized abamectins were conveyed to the detector via an Atlantis C₁₈ column, with water and methanol as a mobile phase. Calibration curves were linear over the calibration ranges with coefficients of determinants r ²?≥?0.999. The limits of detection and quantification were 0.0033 and 0.01 mg kg^?1 for abamectin B_1a and B_1b, respectively. Recovery was assessed in a control matrix at two different fortification concentrations, with three replicates for each concentration. Good recoveries were obtained for the target analytes and ranged from 82.11 to 93.03 %, with relative standard deviations of less than 8 %. The rate of disappearance of total abamectin on perilla leaves for recommended and double the recommended doses was described as first-order kinetics with a half-life of 0.7 days. Using the PHRL curve, we could predict the residue level of total abamectin to be 0.92 mg kg^?1 at 7 days before harvest or 0.26 mg kg^?1 at 4 days before harvest, which would be below the provisional MRL designed by the Korea Food and Drug Administration.     

Growth-inhibition patterns and transfer-factor profiles in arsenic-stressed rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Arsenic (As) accumulation in rice owing to uptake from the soil is a critical human health issue. Here, we studied the chemical properties of As-treated soils, growth inhibition patterns of As-stressed rice plants, changes in the As content of soil and soil solutions, and the relationship between As accumulation and As transfer factor from the soil to the rice organs. Rice plants were cultivated in a greenhouse under four concentrations of As: 0 (control), 25, 50, and 75 mg kg^?1. A significant positive correlation was found between available P₂O₅ and exchangeable K and between As concentration and available P₂O₅ or exchangeable K. The As concentration for 50% shoot growth inhibition was 50 mg kg^?1. As levels in roots and shoots were positively correlated with the growth stages of rice. The transfer factor (TF)_root/soil increased with As concentration at the tillering stage but decreased at the heading stage. TF_root/soil and TF_shoot/soil were higher at the heading stage than at the tillering stage. As accumulation in the 25 mg kg^?1 treatment was higher during the heading stage, whereas no difference was found at the tillering stage. As accumulation was related to plant biomass and soil As concentration. We found that As accumulation was greater at As concentrations that allowed for plant growth and development. Thus, species-specific threshold concentrations must be determined based on As phytotoxicity for the phytoremediation of As-contaminated soils. Hence, developing practical approaches for managing safe crop production in farmlands with an As contamination of 25 mg kg^?1 or less is necessary.     

Multivariate analysis of potentially toxic metals in sediments of a tropical coastal lagoon

Surface sediments collected from the Lagos Lagoon, Nigeria, and three adjoining rivers were analysed for their physicochemical properties and pseudo-total concentration of the potentially toxic metals (PTM) Cd, Cr, Cu, Pb and Zn. The concentration of the PTM varied seasonally and spatially. Odo-Iyaalaro was observed to be the most polluted river, with highest concentrations of 42.1 mg kg^?1, 102 mg kg^?1, 185 mg kg^?1, 154 mg kg^?1 and 1040 mg kg^?1 of Cd, Cr, Cu, Pb and Zn, respectively, while Ibeshe River was the least contaminated, apart from a site affected by Cu from the textile industry. Some of the sediments were found to be above the consensus-based probable effect concentrations and Dutch sediment guideline for metals. Overall metal concentrations were similar to those reported for other tropical lagoon and estuarine systems affected by anthropogenic inputs as a result of rapid urbanisation. Due to the large number of samples, principal component analysis was used to examine relationships within the data set. Generally, sediments collected during the dry season were observed to have higher concentration of PTM than those collected during the rainy season. This means that PTM could accumulate over a prolonged period and then be released relatively rapidly, on an annual basis, into tropical lagoon systems.     

An assessment of contamination of the Fusaro Lagoon (Campania Province,southern Italy) by trace metals

The Fusaro Lagoon is a shallow lagoon, located in SW Italy, largely influenced in the last decades by several anthropic impacts. The study examined the pollution status of the lagoon, during year 2011–2012 at nine sampling stations with the aim to find out proper measurements of water lagoon restoration. Concentrations of heavy metals (HMs) (aluminium [Al], barium [Ba], cadmium [Cd], copper [Cu], iron [Fe], manganese [Mn], vanadium [V] and zinc [Zn]) were examined in water, sediments and specimens of the ascidian Ciona intestinalis sp. A. Low levels of dissolved oxygen concentration were detected at many stations, with mean values of 5.2–6.4 mg L^?1. The redox potential of surface waters was also low, ?2.7 to 50.7 mV. Sediments possessed high organic matter content, 17.7–29.4 %. In sediments, the mean Zn level, 251.4 mg kg^?1, was about sixfold higher than that recorded in year 2000 (38.5 mg kg^?1) and considerably higher than that recorded in 2007 (191 mg kg^?1). The mean levels of Cd were outstandingly high, with a mean value of 70.5 mg kg^?1, about 30- and 50-fold higher than those determined in 2000 and 2007, respectively. Cadmium (Cd), Cu and nickel (Ni) appeared in excess with respect to most current guidelines, reaching significant pollution levels. C. intestinalis sp. A was detected only at few stations, with metals accumulated preferentially in the body in respect to the tunic, from 1.2 times for Zn (178 mg kg^?1) to 4.0 times for V (304 mg kg^?1). Data suggests the necessity of an immediate action of eco-compatible interventions for environmental restoration.