Heavy metal concentration in deepwater rose shrimp species (Parapenaeus longirostris,Lucas, 1846) collected from the Marmara Sea Coast in Tekirdağ

Zn, Cd, Cr, Hg, As (total), Cu, Pb, and Ni levels of the deepwater rose shrimp (Parapenaeus longirostris, Lucas 1846), which were collected from the Tekirda? coast of the Marmara Sea, were evaluated. The Marmara Sea is the recipient of discharges from both land-based sources and the Black Sea Bosphorus stream. There are large numbers of anthropogenic activities in the coastal region of the northern Marmara Sea that include urban effluent, discharges from touristic resorts, agricultural runoff, fishing, and transportation. Heavy metal contamination of water resources may cause critical health problems for the people living around these water bodies. In deepwater rose shrimp (P. longirostris), the highest concentration level detected for Zn was 22.4?±?24.4 mg/kg in winter 2012, Cd 0.106?±?0.01 mg/kg in summer 2012, Cr 0.77?±?0.05 mg/kg in winter 2012, Hg 0.18?±?0.04 mg/kg in summer 2011, As 9.93?±?1.4 mg/kg in spring 2012, Cu 25.48?±?0.3 mg/kg in winter 2012, Pb 2.12?±?0.8 mg/kg in spring, and Ni 19.25?±?7.1 mg/kg in spring. The values of heavy metal analysis were compared to both the Turkish Food Codex (TFC) limits and international standards for human consumption. The Pb, As, and Cu levels were found to be higher than the maximum allowable limits.     

Macro- and microelement contents of some legume seeds

Macro- and microelement contents of legume seeds were determined by ICP-AES. The potassium K contents of seeds ranged between 7,426 mg/kg (Lupinus albus L.) and 16,558 mg/kg (Phaseolus vulgaris L. ssp. sphaericus Mart). In addition, while P contents of seeds changed from 2,719 mg/kg (L. albus L.) to 5,792 mg/kg (Vigna sinensis (L.) Savi), Ca contents ranged at the levels between 1,309 mg/kg (Cicer arietinum L.) and 2,781 mg/kg (L. albus L.). The microelement contents of samples were found to be different depending on several species. The iron levels of samples were determined at the levels between 90.51 mg/kg (Phaseolus mungo L.) and 152.80 mg/kg (P. vulgaris L. ssp. sphaericus Mart). In addition, Zn contents of seeds were found between 31.32 mg/kg (C. arietinum L.) and 44.75 mg/kg (V. sinensis (L.) Savi).     

Impact of transport and industrial emissions on the ambient air quality of Lahore City, Pakistan

This study was monitored to determine the changes in the micromineral and macromineral composition of common sole (Solea solea), striped red mullet (Mullus surmuletus), and whiting (Merlangius merlangus) throughout the year. Macromineral concentrations in edible parts of fish species were 444–1,559 mg/kg for Na, 1,975–5,130 mg/kg for K, 228–658 mg/kg for Mg, 187–1,105 mg/kg for Ca, and 2,341–7,341 for P, respectively. The highest mercury contents were found in the autumn months. While the highest protein and lowest fat values were found in the summer, the highest ash contents were found in the spring. Mercury content was found to be over the legislative limits in autumn samples for common sole and in summer for striped red mullet. Lead and cadmium contents of striped red mullet were found to be over the legislative limits throughout year.     

Occurrence of phthalic acid esters in Gomti River Sediment, India

Cadmium and lead are important environmental pollutants with high toxicity to animals and human. Soils, though have considerable metal immobilizing capability, can contaminate food chain via plants grown upon them when their built-up occurs to a large extent. Present experiment was carried out with the objective of quantifying the limits of Pb and Cd loading in soil for the purpose of preventing food chain contamination beyond background concentration levels. Two separate sets of pot experiment were carried out for these two heavy metals with graded levels of application doses of Pb at 0.4–150 mg/kg and Cd at 0.02–20 mg/kg to an acidic light textured alluvial soil. Spinach crop was grown for 50 days on these treated soils after a stabilization period of 2 months. Upper limit of background concentration levels (C _ul) of these metals were calculated through statistical approach from the heavy metals concentration values in leaves of spinach crop grown in farmers’ fields. Lead and Cd concentration limits in soil were calculated by dividing C _ul with uptake response slope obtained from the pot experiment. Cumulative loading limits (concentration limits in soil minus contents in uncontaminated soil) for the experimental soil were estimated to be 170 kg Pb/ha and 0.8 kg Cd/ha. Based on certain assumptions on application rate and computed cumulative loading limit values, maximum permissible Pb and Cd concentration values in municipal solid waste (MSW) compost were proposed as 170 mg Pb/kg and 0.8 mg Cd/kg, respectively. In view of these limiting values, about 56% and 47% of the MSW compost samples from different cities are found to contain Pb and Cd in the safe range.     

Sediment load and bioconcentration of heavy metals by shrimp (Peaneus notalis) from Epe Lagoon, Nigeria

In many developing countries, surface waters, especially rivers and lagoons, have become deposition sites for all sorts of wastes. Three sampling sites located trigonally on Epe lagoon, Lagos, Nigeria were identified, and water, sediment, and commonly farmed shrimp, Peaneus notalis, were sampled and assessed for heavy metal concentrations. Zn, Pb, Ni, Cu, Cr, Cd, and Mn were determined in the aqua regia digests of the samples by means of Perkin Elmer AAnalyst 200 atomic absorption spectrophotometer. Heavy metals occurred above detection limits at all sites. The highest load of these trace elements was found in sediment samples followed by the water samples. The levels observed in the shrimp samples, however, were much lower than WHO levels. In the distribution, zinc was the highest metal found in the samples ranging from 17.94 ± 2.60 mg/L in water to 37.85 ± 9.35 μg/g in sediments. The least was Cd 0.03 ± 0.01 mg/L in water and 0.28 ± 0.04 μg/g in sediments. Lead was the most widely varied metal in shrimp with a 84.38% coefficient of variation. Apart from Cr, the metals appeared to be fairly and evenly distributed in the sediment, with coefficient of variation ranging from 14.29% (Cd) to 24.76% (Mn) The variations were between 14.49% (Zn) and 66.67% (Cr) in the water samples. The paired t test carried out between water and sediment, water and shrimp, and shrimp and sediment was significant at p?=?0.05. Three-factor analysis of variance did not reveal any significant difference in metal burdens among the trigonally located sites under investigation. Shrimp samples showed evidence of bioaccumulation but are still below internationally established levels.     

Accumulation and health risk assessment of trace elements in <Emphasis Type="Italic">Carassius auratus gibelio</Emphasis> from subsidence pools in the Huainan coalfield in China

Microelement (As, Cd, Cr, Cu, Ni, Pb, and Zn) concentrations were determined in the muscle, skin, gill, and liver tissues of Carassius auratus gibelio collected from subsidence pools at three different coal mines in the Huainan coalfield in China. The concentrations of elements in the water were within the allowable levels for raising fish. However, the higher levels of these metals in sediment may pose potential harm on fish. It was found that the concentrations of Cr, Ni, and Zn in all fish tissues were higher, while As, Cd, and Pb levels were relatively low. Microelement accumulation appeared to be more widespread in subsidence pools than that in natural water. Elements accumulated in fish tissues differently: the highest metal concentrations were generally found in the liver tissues of the fish analyzed, whereas the lowest were recorded in the muscles. The mean element concentrations in muscle tissue from C. auratus gibelio collected from subsidence pools (As, 0.16 mg/kg; Cd, 0.06 mg/kg; Cr, 6.21 mg/kg; Cu, 1.61 mg/kg; Ni, 3.88 mg/kg; Pb, 1.76 mg/kg; and Zn, 12.80 mg/kg dry weight) were far below the allowable limit of the hygienic standard in fish proposed by the Ministry of Health in China, suggesting that the fish were safe for human consumption. A health risk assessment also suggested there was no risk from the analyzed elements for inhabitants near the Huainan coalfield that consume fish.     

Comparative bioaccumulation of trace metals using six filter feeder organisms in a coastal lagoon ecosystem (of the central-east Gulf of California)

The Tobari Lagoon, located in the central-east coast of the Gulf of California, receives effluents from the Yaqui Valley, one of the most extensive agricultural areas of México. The Tobari Lagoon also receives effluents from nearby shrimp farms and untreated municipal sewage. Surface sediment samples and six different species of filter feeders (Crassostrea corteziensis, Crassostrea gigas, Chione gnidia, Anadara tuberculosa, Chione fluctifraga, and Fistulobalanus dentivarians) were collected during the dry and the rainy seasons and analyzed to determine concentrations of cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), and zinc (Zn). Seasonal variations in metal concentrations in sediment were evident, especially for Cd, Cu, Hg, and Zn. The total and bioavailable concentrations of the five metals are not elevated in comparison to other areas around the world. The percentages of bioavailable respect to total concentrations of the metals varied from 0.6 % in Hg to 50.2 % for Cu. In the organisms, Hg showed the lowest concentrations (ranged from 0.22 to 0.65 μg/g) while Zn showed the highest (ranged from 36.6 to 1,702 μg/g). Linear correlations between the levels of Cu, Pb, and Zn in the soft tissues of C. fluctifraga and C. gnidia, and A. tuberculosa and C. gnidia were found. Seasonal and interspecies variations in the metal levels in filter feeders were found; F. dentivarians, C. corteziensis, and C. gigas exhibited the highest levels, could be used as biomonitors of metals contamination in this area.     

Dissipation and residue of metalaxyl and cymoxanil in pepper and soil

A simple and accurate method of determining metalaxyl and cymoxanil in pepper and soil was developed by ultra-performance liquid chromatography–photodiode array detection. The limits of detection were 0.015 mg/kg for metalaxyl and 0.003 mg/kg for cymoxanil. The limits of quantification were 0.05 mg/kg for metalaxyl in pepper and soil as well as 0.01 mg/kg for cymoxanil in pepper and soil. Recoveries of pepper and soil were investigated at three spiking levels and ranged within 77.52 to 102.05 % for metalaxyl and 87.15 to 103.21 % for cymoxanil, with relative standard deviations below 9.30 %. For field experiments, the half-lives of metalaxyl were 3.2 to 3.9 days in pepper and 4.4 to 9.5 days in soil at the three experimental locations in China. At harvest, pepper samples were found to contain metalaxyl and cymoxanil well below the maximum residue limit MRLs of the European Union (EU) following the recommended dosage and the interval of 21 days after last application.     

Biochemical properties of some Salvia L. species

Antioxidant capacity, total phenol and mineral contents of aerial parts of sage belonging to some Salvia species were established. The lowest and highest antioxidant values of Salvia dichroantha Stapf and Salvia heldreichiana Boiss. ex Benth. extracts were found as 73.855 and 80.207 mg GAE/g, respectively. While the highest total phenol was established in Salvia tomentosa Mil. (13.316 mg GAE/100 ml), the lowest level was found in Salvia halophila Hedge (6.168 mg GAE/100 ml). While K contents of plants changed between 14,518 and 24,171 mg/kg, Ca contents ranged between 12,402 and 18,553 mg/kg. P and Mg contents were found low compared with K and P values of plants. Mg content was changed between 2,118 and 2,914 mg/kg; the mean was calculated as 2,496 mg/kg. P contents of plants were determined between 1,385 to 1,910 mg/kg. As a microelement, Fe was found at the highest level. Fe contents of plants were found between 179 and 782 mg/kg.     

Mineral contents and proximate composition of Pistacia vera kernels

The mineral contents of Pistacia vera kernels were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The minimum and maximum values of K, P, Ca, Mg, and S elements ranged from 6,333 to 8,064 mg/kg, 3,630 to 5,228 mg/kg, 1,614 to 3,226 mg/kg, 1,716 to 2,402 mg/kg, and 1,417 to 1,825 mg/kg, respectively. In addition, the mean values of Fe, Zn, Cu, Mn, B, Mo, Cr and Ni elements were determined as 42.48, 20.52, 12.81, 7.48, 11.31, 0.106, 0.511 and 1.67 mg/kg, respectively. Ash levels of kernels were found between 2.28 % (Urfa) and 2.79 % (Halebi). In addition, crude oil and protein contents were determined between 48.8 % (Halebi) to 55.3 % (Siirt) and 23.33 % (Uzun) to 27.16 % (Halebi), respectively.     

Determination and study on dissipation and residue of bismerthiazol and its metabolite in Chinese cabbage and soil

A simple and accurate method for the determination of bismerthiazol and its metabolite 2-amino-5-mercapto-1,3,4-thiadiazole was developed in Chinese cabbage and soil by high-performance liquid chromatography-diode array detection in this study. The limits of detection were 0.06 mg/kg for bismerthiazol and 0.03 mg/kg for 2-amino-5-mercapto-1,3,4-thiadiazole, respectively. Recoveries of cabbage and soil were investigated at three spiking levels and were in the range of 84.0–96.0 % for bismerthiazol and 71.0–74.6 % for 2-amino-5-mercapto-1,3,4-thiadiazole, with relative standard deviations below 7.0 %. For field experiments, the half-life of bismerthiazol was 2.4–2.5 days in Chinese cabbage and 2.5–4.8 days in soil at the two experimental locations in China. Dissipation residues of 2-amino-5-mercapto-1,3,4-thiadiazole were lower than 0.72 mg/kg. Terminal residues of bismerthiazol and its metabolite were less than 3.0 and 0.3 mg/kg in Chinese cabbage, respectively. No bismerthiazol or metabolite residues were detected in soil on days 5, 7, 10, and 14 after the last spraying at the two dosage levels.     

Mercury levels in myliobatid stingrays (Batoidea) from the Gulf of California: tissue distribution and health risk assessment

With the aim of knowing Hg distribution in selected tissues of myliobatid stingrays and assessing health risk to Mexican population, Hg concentration was determined in the muscle and liver of four ray species. Total Hg levels were determined by cold vapor atomic absorption spectrophotometry. With respect to the muscle, devil rays (Mobula spp.) showed lower Hg levels (<0.22 μg g^?1) than Rhinoptera steindachneri (0.37?±?0.25 μg g^-1 wet weight). In the case of the liver, the highest Hg concentration was found in Mobula japanica (0.22?±?0.01 μg g^?1). Hg levels in the muscle and liver varied according to the species; in some case, the liver accumulated more Hg than the muscle and the opposite pattern in other cases. R. steindachneri showed a significant difference between both tissues. No significant differences of Hg levels between males and females and between juveniles and adult specimens of R. steindachneri were found. Positive correlation between Hg concentrations and disc width and total weight was not significant for R. steindachneri (Rs?<?0.36, p?>?0.05). Batoids showed Hg values below the Mexican (NOM-027-SSA1-1993) limits (1.0 μg g^?1) in fishes for human consumption. The species with the highest potential of Hg transfer to human population is R. steindachneri; however, an adult (70 kg) could consume approximately 943 g per week without representing a health risk. Nevertheless, further and continuous monitoring is needed since batoids support an important fishery in Mexican waters, being a food resource and income to coastal communities.     

The influence of chemical protection on the content of heavy metals in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) growing on the soil enriched with granular sludge

The presence of heavy metals in Triticum aestivum L. growing on the soil enriched with granular sludge after chemical protection was observed. The five variants of treatments using herbicide (Chwastox Turbo 340SL) and four fungicides (Topsin M 500SC, Amistar 250SC, Artea 330EC, and Falcon 460EC) were performed. On control and experimental plots, the concentration of Ni, Pb, Cr, and Cu in wheat leaves were in the range 0.32–0.99, 0.92–1.57, 0.89–6.31, and 7.08–12.59 mg/kg and in grains 0.03 to 0.11, 0.14–0.25, 0.11–0.76, and 1.06–1.46 mg/kg, respectively. The concentration of Pb in grain protected by MCPA and 2,4-D with thiophanate-methyl and azoxystrobin was higher than the maximum levels of 0.20 mg/kg D.M. The bioconcentration factor (BCF) differed and depended on chemical protection. The highest value of BCF was achieved for Cd. The statistical analysis showed a significant correlation between concentration of metals and quality parameters of wheat. One observed significant negative correlations between Ni/Zeleny sedimentation value (r = ?0.51) and between Pb/starch content (r = ?0.57). Positive correlations were observed between Cd/yield, the number of grains/ergosterol concentration (respectively, r = 0.41, r = 0.55, r = 0.56), and Zn/thousand grain weight (r = 0.50) at a p ≤ 0.05.     

Dissipation pattern and risk quotients assessment of amisulbrom in Korean melon cultivated in plastic house conditions

Amisulbrom formulated as suspension concentrate was applied at the rate recommended for Korean melon to determine the dissipation pattern (at two different sites), the pre-harvest residue limit (PHRL), and risk assessments. Samples collected over 10 days were extracted using liquid-liquid extraction (LLE) and cleaned up with solid-phase extraction (SPE) Florisil cartridge. Residual concentrations were determined using liquid chromatography-ultraviolet detector (LC-UVD) and confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The standard showed good instrument response linearity with a correlation coefficient (R ²) = 0.9999, and the recovery ranged from 87.5 to 93.7%. The dissipation half-life calculated from two different sites were found to be 7.0 and 8.8 days for sites 1 and 2, respectively. A PHRL graph constructed from the data indicated that if the residue levels were less than 0.55–0.59 mg/kg 3 days before harvest or less than 0.61–0.74 mg/kg 7 days before harvest, then they would be lower than the maximum residue limits (MRLs) at harvest. Risk assessments showed that the risk quotient (RQ) was 4.39–3.47% at 0 day, declined to 1.53–1.63% at 10 days. Therefore, the current data indicate that the amisulbrom can be applied safely to Korean melon; hence, it is unlikely to induce adverse health effects in consumers.     

Comparative assessment of pesticide residues in grain, soil, and water from IPM and non-IPM trials of basmati rice

The integrated pest management (IPM) modules of pesticide schedule on Basmati rice were validated at field experiments conducted in Northern India for consecutive 3 years (2005–2008). The pesticide residues were found below the detectable limit (<0.01–0.001 mg/kg) in soil and irrigation water samples of Kaithal region. In Dehra Dun region of Uttrakhand, the residues of carbendazim in rice grains and soil were detected below <0.01 mg/kg level. In second year experiments (2006–2007), only four non-IPM soil samples indicated the presence of chlorpyrifos and endosulfan in the range of ND <0.001 to 0.07 mg/kg, out of 45 samples analyzed. Carbendazim applied as seed treatment at Dehradun and Kaithal field trials was found below detectable limit in both IPM and non-IPM rice grains (<0.01 mg/kg) and irrigation water (0.01 μl/ml). Chlorpyrifos was detected in five water samples from Kaithal and one from Pant Nagar in the range of 0.003–0.006 μl/L, α- and β-isomer of endosulfan in the range of 0.005–0.03, and 0.005–0.02 μl/ml, respectively, in one sample from Pant Nagar and two from Kaithal, out of a total of 22 samples. In the region of Uttrakhand and Uttar Pradesh during 2007–2008, four non-IPM samples of soil indicated trace levels of endosulfan, out of 16 samples analyzed. The residues were detected below detection limit for carbendazim (<0.01 mg/kg) in soil samples of Dehradun IPM fields and for endosulfan and carbendazim (0.001–0.01 μl/L) in water samples each from IPM and non-IPM fields of Uttar Pradesh. The results of 3-year trials of IPM module indicated basmati rice as safe and economical with pesticide residue-free rice grains.     

Mineral contents of the head, caudal, central fleshy part, and spinal columns of some fishes

In the experiment, mineral contents of the head, caudal, central fleshy part, and spinal columns of fishes were determined by inductively coupled plasma atomic emission spectrometry. The Ca content of base fleshy part ranged from 1,682 to 5,505 mg/kg. The Ca contents of central fleshy part were found between 104 and 428 mg/kg. This value was found between 5,582 and 7,368 in the spinal column parts. The K content in general ranged from 2,411 (Carassius gibellio) and 4,419 mg/kg (Scomber scombrus). The highest potassium was found on the central fleshy part and ranged between 3,214 and 4,419. The P content was found mostly on the bones and it range between 28,833 and 34,726. The least phosphor amount was found on the central fleshy part. While the Cd content ranges between 0.019 ppm and 0.104 mg/kg, Cr content changed between 1.32 and 4.20 ppm.     

Histopathology alterations and lipid peroxidation as biomarkers of hydrocarbon-induced stress in earthworm, Eudrilus eugeniae

This study investigated the biomarker responses of the earthworm, Eudrilus eugeniae, exposed to sublethal concentrations of benzene, toluene and xylene (BTX) for a time span of 28 days. Lipid peroxidation (LPO) and histopathological alterations were examined. Toxicological evaluations of BTX were carried out against E. eugeniae. On the basis of the 96-h LC₅₀ value, xylene (1.212 mg/kg) was found to be the most toxic followed by toluene (1.335 mg/kg) and benzene (1.896 mg/kg) was the least toxic. The exposure of earthworms to sublethal concentrations (1/10th and 1/100th of 96 h LC₅₀) of BTX premixed with the substrate (loamy and humus soil) induced pathological changes in the clitella such as severe lesion, necrosis and dark brown pigments. The result of the lipid peroxidation assay showed a significant increase in oxidative damage with LPO values ranging from 2.58–7.8 nM/g in exposed animals when compared to 0.07 nM/g in the control group. The findings from this study suggest the use of LPO and histopathology as useful biomarkers of exposure for early detection of petroleum related stress in terrestrial ecosystems     

Ecological vulnerability: seasonal and spatial assessment of trace metals in soils and plants in the vicinity of a scrap metal recycling factory in Southwestern Nigeria

The concentrations of selected heavy metals in the soil and vegetation in the immediate vicinity of a metal scrap recycling factory were determined in the dry and wet seasons using the Atomic Absorption Spectrophotometer. The results showed that the soil pH in all the sites indicated slight acidity (from 5.07 to 6.13), high soil organic matter content (from 2.08 to 5.60 %), and a well-drained soil of sandy loam textural composition. Soil heavy metal content in the dry season were 0.84–3.12 mg/kg for Pb, 0.26–0.46 mg/kg for Cd, 9.19–24.70 mg/kg for Zn, and 1.46–1.97 mg/kg for Cu. These values were higher than those in the wet season which ranged from 0.62–0.69 mg/kg for Pb, 0.67–0.78 mg/kg for Cd, 0.84–1.00 mg/kg for Zn, and 1.26–1.45 mg/kg for Cu. Except for cadmium in the dry season, the highest concentrations occurred in the northern side of the factory for all the elements in both seasons. An increase in the concentrations of the elements up to 350 m in most directions was also observed. There was no specific pattern in the level of the metals in the leaves of the plant used for the study. However, slightly elevated values were observed in the wet season (Pb 0.53 mg/kg, Cd 0.59 mg/kg, Cu 0.88 mg/kg) compared with the dry season values (Pb 0.50 mg/kg, Cd 0.57 mg/kg, Cu 0.83 mg/kg). This study showed that the elevated concentrations of these metals might be associated with the activities from the recycling plant, providing the basis for heavy metal pollution monitoring and control of this locality that is primarily used for agricultural purposes.     

Physicochemical properties and mineral contents of seven different date fruit (Phoenix dactylifera L.) varieties growing from Saudi Arabia

The date (Phoenix dactylifera L.) fruits (Soukari, Soulag, Barhi, Khulas, Rozaiz, Soughi and Monaif) were evaluated with respect to some physical and chemical properties. While crude protein contents of fruits change between 1.51 % (Soulag) to 2.41 % (Soughi), crude fibre contents ranged between 1.91 % (Soukari) to 3.90 % (Barhi). Vitamin C contents of date samples changed between 971.82 mg/kg (Soughi) to 1,453.15 mg/kg (Barhi). Antioxidant activity of date fruits ranged from 80.07 IC₅₀ (Soukari) to 81.21 IC₅₀ (Soulag). The highest phenolic content was found in Khulas with a mean value of 198 mg GAE/100 g. Energy values of date fruits ranged from 3,725 kcal/kg (Soulag) to 3,870 kcal/kg (Soukari). Sucrose contents of date fruits changed between 1.02 % (Soulag) to 55.71 % (Soukari). Mineral contents of several date fruits were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Date samples contain potassium at a range between 7,468 mg/kg (Khulas) to 9,619 mg/kg (Soulag). Phosphorus contents of fruits were found between 1,848 mg/kg (Soulag) to 3,066 mg/kg (Rozaiz) and followed by magnesium and calcium. The highest Zn (9.33 mg/kg), Cu (4.27 mg/kg) and Mn (3.26 mg/kg) were found in Rozaiz, Soukari and Barhi samples, respectively.     

Trace element concentration and speciation in selected urban soils in New York City

A long history of urbanization and industrialization has affected trace elements in New York City (NYC) soils. Selected NYC pedons were analyzed by aqua regia microwave digestion and sequential chemical extraction as follows: water soluble (WS); exchangeable (EX); specifically sorbed/carbonate bound (SS/CAR); oxide-bound (OX); organic/sulfide bound (OM/S). Soils showed a range in properties (e.g., pH 3.9 to 7.4). Sum of total extractable (SUM_TE) trace elements was higher in NYC parks compared to Bronx River watershed sites. NYC surface horizons showed higher total extractable (TE) levels compared to US non-anthropogenic soils. TE levels increased over 10 year in some of the relatively undisturbed and mostly wooded park sites. Surface horizons of park sites with long-term anthropogenic inputs showed elevated TE levels vs. subsurface horizons. Conversely, some Bronx River watershed soils showed increased concentrations with depth, reflective of their formation in a thick mantle of construction debris increasing with depth and intermingled with anthrotransported soil materials. Short-range variability was evident in primary pedons and satellite samples (e.g., Pb 253?±?143 mg/kg). Long-range variability was indicated by Pb_TE (348 versus 156 mg/kg) and Hg_TE (1 versus 0.3 mg/kg) concentrations varying several-fold in the same soil but in different geographic locations. Relative predominance of fractions: RES (37 %)?>?SS/CAR (22 %)?>?OX (20 %)?>?OM/S (10 %)?>?EX (7 %)?>?WS (4 %). WS and EX fractions were greatest for Hg (7 %) and Cd (14 %), respectively. RES was predominant fraction for Co, Cr, Ni, and Zn (41 to 51 %); SS/CAR for Cd and Pb (40 and 63 %); OM/S for Cu and Hg (36 and 37 %); and OX for As (59 %).