Canadian Environmental Quality Guidelines Research Articles

Laboratory weathering studies to evaluate the water quality impact of a lithium mining in Portugal

Lithium mining driven by the growing demand for lithium-ion batteries, has environmental consequences linked to soil and water pollution. Nevertheless, research on the environmental impacts of lithium extraction still needs to be improved, highlighting the imperative for additional research. The article addresses the potential impact of the C57 lithiniferous feldspar mine on water quality, specifically focusing on surface, groundwater and spring water samples collected at the mining site and surrounding area in Gonçalo (Guarda, Portugal). The objective is to evaluate the environmental consequences of mining activities, with particular emphasis on mineral leaching. This study aims to evaluate the water quality around the C57 mine and the potential environmental impacts of mining operations. Water samples were collected from different sources, such as surface, underground, and spring waters, and chemical analyses were carried out to determine concentrations of different parameters, which were later compared with national and international reference guidelines. In addition to analysing the water samples, weathering tests were carried out using the Soxhlet extractor method to simulate the leaching of minerals over a shorter period (about 125 days). The concentrations of the analysed elements by atomic absorption spectroscopy (Al, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb and Zn) in the weathering solutions were generally low and decreased throughout the testing period, with significant concentrations of aluminium and chromium exceed Canadian environmental quality guidelines for surface waters. The detected lithium concentrations are quite different, ranging from 8.7 to 19.8 μg/L in surface waters, from 6.9 to 74.1 μg/L in groundwater, and from 25.6 to 35.4 μg/L in spring waters, but are all below the US EPA (2021) recommendations threshold of 0.7 mg/L. Based on the findings, the article concludes that there is currently no clear evidence to indicate the environmental impact of mining activities on water quality in the analysed samples. However, weathering tests suggest potential long-term implications regarding the leaching of specific chemical elements, particularly aluminium and chromium.

A meta-analysis of the occurrence of alkylphenols and alkylphenol ethoxylates in surface waters and sediments in the United States between 2010 and 2020

Nonylphenol (NP), Octylphenol (OP), and their ethoxylates (NPEO and OPEO) have been the subject of considerable scientific and regulatory attention, primarily due to concerns about their aquatic toxicity and endocrine activity. Environmental monitoring has been conducted and reported for these substances in the United States (U.S.) for several decades. This paper develops an updated statistically based meta-analysis of the occurrence and ecological relevance of these substances in fresh and marine surface waters and sediments in the U.S. between 2010 and 2020. The overall objectives of this study were: (1) to evaluate the impact of analytical detection limits (DLs) and treatment of censored or non-detected (ND) samples on reported results, (2) to summarize and evaluate recent (2010–2020) occurrence and concentrations of these substances in surface waters and sediments, (3) to conduct an ecological screening assessment of the potential risks of these substances to aquatic organisms in surface waters and sediments for this same period, and (4) to examine temporal trends of these substances in surface waters and sediments relative to previous investigations. Given that a large proportion of all NP, NPEO, OP and OPEO samples in recent (2010–2019) U.S. monitoring studies were below their respective method Limit of Detection/Limit of Quantification (LOD/LOQ) detection frequency ranging from 0 to 24%), proxy values were imputed using robust regression of order statistics (ROS). Nationally, NP and OP concentrations in fresh surface waters and sediments have decreased from 2010 to 2019. In contrast, changes in NP and OP concentrations in marine waters and sediments were more variable with some increases noted. A screening environmental risk assessment indicated that less than 1% of all samples exceeded U.S. or Canadian environmental quality guidelines. No exceedances were noted after 2016 which indicates a low potential for risk to aquatic organisms.

Applying Grey Clustering and Shannon’s Entropy to Assess Sediment Quality from a Watershed

The evaluation of the quality of sediments is a complex issue in the Peruvian reality, mainly because there is no sampling protocol or norm for comparison, which leads to the assessment of sediments without a comprehensive analysis of their quality. In the present study, the quality of the sediments in the upper basin of the Huarmey river was evaluated in 30 monitoring points and 7 parameters, which are: arsenic, cadmium, copper, chromium, mercury, lead and zinc, which were compared according to the standards recommended by the Environmental Quality Guidelines for Sediments in freshwater bodies of Canada (Canadian Environmental Quality Guidelines - CEQG, 2002. Sediment Quality Guidelines for Protection of Aquatic Life - Fresh water according to Canadian Council of Ministers of the Environment (CCME)). The results of the evaluation, by grey clustering method and Shannon entropy, showed that 13 monitoring points resulted in good sediment quality, 1 monitoring point had moderate quality and 16 monitoring points presented poor quality; therefore, it can be concluded that the effluents and discharges of the mining activities that take place in the aforementioned location have a negative impact on environmental quality. Finally, the results obtained can be of great help for OEFA, the regional government, the municipalities and any other body that has oversight functions, since they will allow them to be more objective and precise decisions.

Enrichment and distribution of metals in surface sediments of the Thanh Hoa coastal area, Viet Nam

Thirty-two surface sediment samples were collected in the Thanh Hoa coastal area, from the shore to a depth of 30 m. Grain sizes and the contents of 14 major and trace metals were measured with the goal of assessing the impact from the mainland to the coastal area of Thanh Hoa.The sand fraction ranged from 0.5 to 82.7%, and the mud fraction ranged from 17.3 to 99.5%.The contents of major and trace elements – namely, Fe, Cu, Pb, Zn, As, Cr, Co, Ni, Mn, Cd, Mo, Li, V, and Sn – in the sediments were assessed by comparison with Canadian environmental quality guidelines and indices. The concentrations of Cu, Pb, Zn, As, and Cr were higher than the interim marine sediment quality guidelines (ISQGs) benchmark but lower than the probable effect levels (PELs). The geo-accumulation (Igeo) indexes of As and Pb indicated moderate pollution; the enrichment factor (EF) indexes of Cu, Pb, Zn, Cd, As, Li, and Mn indicated minor to moderate enrichment; the contamination factor (CF) indexes of Fe, Cu, Pb, Zn, Cd, As, Co, Li, and Mn indicated moderate to considerable contamination, the CF showed considerable contamination for As and Pb in particular; the ecological risk factor (ER) indexes of Cd and As were moderate; and the degree of contamination (CD) of all 14 elements was high.On the basis of this preliminary environmental risk evaluation, the levels of some trace elements indicated potential issues for the Thanh Hoa coastal area, particularly near river mouths and the northern zone, where concentrations were higher. Thus, appropriate monitoring plans based on sound scientific knowledge are imperative for safe and sustainable development.

MERCURIO EN UN ARROYO ALTOANDINO CON ALTO IMPACTO POR MINERÍA AURÍFERA ARTESANAL (LA RINCONADA, PUNO, PERÚ)

La Rinconada, in the high Andes at southern Peru, is a town heavily engaged in artisanal gold mining, where tailings and waste are dumped into streams of river headwaters. For this reason, mercury was evaluated in surface water and sediments of the Lunar de Oro stream, in its origins at the Ananea glacier. Four points were sampled in the months of December 2014, and January and March 2015. In both segments, mercury was determined by atomic fluorescence spectrophotometry (EPA 245.2), and pH, dissolved oxygen, electrical conductivity, total dissolved solids and temperature were determined by multiparameter and in laboratory. In the four sampling points, mercury in water presented similar levels, with values between < 0.00005 and 0.00043 mg/L (n = 12), although in March, related to a lower flow, higher levels were determined (0.00034 ± 0.000032 mg/L), surpassing the Peruvian standards and the Canadian Environmental Quality Guidelines (CEQG); pH recorded an average of 3.44 ± 0.12 and oxygen 2.84 ± 0.23 mg/L, values that confirmed its low quality. Sediments showed values between 9 and 373 mg/kg, with no significant differences between zones and months, exceeding NOAA and CEQG limits for 100 % of the samples. Pollution rates confirmed that the site is extremely contaminated by mercury, corroborating its high risk for public health and the ecosystems involved.

CONCENTRACIÓN DE CADMIO EN AGUA, SEDIMENTOS, Eichhornia crassipes Y Pomacea canaliculata EN EL RÍO GUAYAS (ECUADOR) Y SUS AFLUENTES

In Ecuador there is evidence of contamination by Cd in the Gulf of Guayaquil, however, little is known about the contamination by this metal in its tributaries. Evaluating the contamination by cadmium in water, sediments, flora as Eichhornia crassipes and fauna as Pomacea canaliculata in the Guayas river and the tributaries, Daule and Babahoyo rivers was the main purpose of this research. Nine stations were sampled, five samples of water, sediment and organisms were taken on each location. Cd concentrations and bioconcentration factors (BCF) were determined. In addition, pH, temperature and salinity parameters were measured. The concentrations of Cd in water were not detectable, while in sediments eight of a total of nine stations exceeded the maximum permissible limits according to the Ecuadorian standard and the Canadian Environmental Quality Guidelines. However, the bioavailable concentrations of the metal in the sediment were lower than the probable effect level (PEL) and the Canadian reference value, minimizing possible damage to the biota. The water hyacinth accumulated higher concentrations of Cd than the gastropod and presented BCF greater than one, indicating that it is a good biomonitor of Cd, unlike the snail. Correlation was also observed between the physical and chemical parameters and the availability of the metal in the sediment and its accumulation in the organisms. It is concluded that there is contamination by Cd in the three rivers and that the E. crassipes can be used as biomonitor of bioavailability of the metal in the ecosystem.

Identification of fungi originated from soil polluted by Dichloro Diphenyl Trichloroethane (DDT)

Since the last twenty years Merdeka Village in Merdeka Subdistrict, Tanah Karo District, Indonesia had been the centre of horticultural plant production for the North Sumatra Province. Insecticide commonly used by farmers in this area was of organochloric active ingredient, namely Dichloro Diphenyl Trichloroethane (DDT).The DDT was an insecticide that was degraded very difficultly by the soil, was toxic and persistent in the soil for decades. This insecticide caused changes in soil microbiology, including fungi. Soil sampling using a soil drill at a depth of 0-20 cm with a diagonal sampling method of 45 sample points. Subsequently the soil samples were taken to the Pesticide Laboratory at the North Sumatra Plantation Seed Germination Center for extraction using the Quechers Tube Method using three material variables, namely sodium acetate (Na-acetate), primary secondary amine (PSA) and octadecylsilane (C18) with Gas Chromatography-Mass Spectrometry (GC-MS). The results showed that DDT derivatives were found in B o’p’DDD soil at the amount of 1.6 μgKg-1, and at C o’p’DDD soil at 2.2 μgKg-1. The DDT residues in both locations B and C were classified as dangerous because they exceeded the DDT standard of 0.7 μgKg-1 dry soil which refered to the Canadian Environmental Quality Guidelines (CCME). Soil samples containing five grams of DDT residue were then isolated and fungi growing on the soil were identified. Identification of fungi showed that Mucor sp, Fusarium sp and Trichophyton sp were found.

Determination of Cr, Cu, Ni, Pb and Zn in the sediments of Mangueira Lagoon/RS/Brazil

The Mangueira Lagoon is 123 km long and 7.6 km wide at its widest point, with an average depth of 2.5 m. By the fact that this lagoon is one of the youngest geological formations on Earth (only 4.5 thousand years), little is known about the geology of its sediments. This work describes the concentration of the toxic metals Cr, Cu, Ni, Pb and Zn in surface sediments samples of Mangueira Lagoon. The sediment samples were collected and underwent pseudo-acid digestion (aqua regia / perchloric acid). The extracts obtained were analyzed by atomic absorption spectroscopy in flame. Cu and Zn were detected at all points during the test. Zn is a major element, ranging from 2.5 mg kg-1 ± 0.3% to 4.1 mg kg-1 ± 2.4%, followed by Cu with values between 2.0 mg kg-1 ± 8.5% to 2.5 mg kg-1 ± 4.2%. Considering the parameters established by the CCME (Canadian Environmental Quality Guidelines), TEL (Threshold Effect Level) and PEL (Probable Effect Level), the concentrations of toxic metals found in the surface sediment were low and showed low environmental impacts. These results constitute a contribution to a better understanding of the processes that occur in the region, serving as a basis for future work.

Assessment of Douro and Ave River (Portugal) lower basin water quality focusing on physicochemical and trace element spatiotemporal changes

ABSTRACTWater quality of Douro and Ave lower basin was evaluated regarding physicochemical parameters (pH, conductivity, dissolved oxygen and temperature), nutrient compounds (nitrates, nitrites, ammonium and orthophosphates), chlorophyll a and occurrence of trace elements (Li, Be, Al, Ti, V, Cr, Co, Ni, Cu, Zn, Se, Mo, Ag, Cd, Sb, Ba, Tl, Pb, Th and U). To study spatiotemporal variations and possible anthropogenic sources, estuarine samples were collected at nine sampling sites in Douro and five in Ave distributed along the estuaries at four sampling campaigns (spring, summer, fall and winter). According to the water quality standards for aquatic life and recreation, Douro and Ave river water quality was found out of safe limits regarding several parameters. Nitrate levels were systematically high (> 50 mg L−1 in a significant number of samples) and mean levels of trace elements were higher than the established values of Canadian Environmental Quality Guidelines for aquatic life protection for Al, Cu, Se, Ag, Cd and Pb in Douro and Ave, and also Zn in Ave. Significant spatial differences were found in Ave river estuary for trace elements with a clear trend for higher values from upstream to downstream found. Seasonal differences were also observed particularly in Douro river estuary with higher levels in spring for most elements.

Environmental implications and spatial distribution of natural radionuclides and heavy metals in sediments from four harbours in the Egyptian Red Sea coast

Measurements of natural radionuclides concentrations (226Ra, 232Th and 40K) in sediments collected from sea, rivers or ocean is significant to protect the sea water ecosystem and to human health from radiation. Thirty-three sample of sediment have been collected from four ports in the Red Sea coast, Egypt for investigation by gamma-ray spectrometer using NaI(Tl) detector. The average and range activity concentrations of 226Ra, 232Th and 40K were 26(5–58), 19(4–33) and 458(16–2665)Bqkg−1 in Quseir Harbour, 30(14–53), 20(14–34) and 430(378–511)Bqkg−1 in Abu-Tartour Harbour. However, the average and range activity concentrations were 23(14–35), 21(15–32), and 602(327–821)Bqkg−1 in Touristic Harbour and 14(5–26), 13(2–23) and 489(36–950)Bqkg−1 in Hurghada harbour. These results were compared with reported ranges in the literature from other location in the world. The radiation hazard parameters; radium equivalent activity annual dose, external hazard were also calculated and compared with the recommended levels by UNSCEAR reports. Eight heavy metals (Fe, Mn, Ni, Co, Zn, Cu, Pb and Cd) have been measured and analyzed by atomic absorption spectrometer. The concentration for the investigated heavy metals overtakes the allowable limits recommended by the Canadian Environmental Quality Guidelines. Because there are no existing databases for the natural radioactivity in the sediment samples from Egyptian Red Sea ports, our results are a start to establishing a database for Red Sea harbours environment.

Performance of a hybrid pilot-scale constructed wetland system for treating oil sands process-affected water from the Athabasca oil sands

Mining leases in the Athabasca oil sands (AOS; near Ft. McMurray, Canada) produce large volumes of oil sands process-affected water (OSPW) that contain potentially problematic constituents requiring treatment prior to surface water discharge into receiving aquatic systems. The aim of this research was to identify constituents of concern (COCs) in OSPW sourced from an AOS external tailings facility and design a hybrid pilot-scale constructed wetland treatment systems (CWTS) to decrease concentrations of COCs and subsequently mitigate risks. COCs were identified based on comparisons to ambient water quality thresholds for the protection of aquatic life (i.e. Canadian Environmental Quality Guidelines [CEQGs], Alberta Environment Water Quality Guidelines [Alberta WQGs], and United States Environmental Protection Agency Water Quality Criteria [USEPA WQC]) and toxicity endpoints. Performance of the hybrid pilot-scale CWTS was evaluated by rate and extent of COC removal and change in toxicity as measured by an aquatic invertebrate Ceriodaphnia dubia. Following characterization of OSPW, specific COCs were identified as: naphthenic acids (NAs), oil and grease (O/G), metals/metalloids (Al, B, Cu, Ni, Se, and Zn), chloride, and total suspended solids (TSS). A hybrid pilot-scale CWTS was designed to promote treatment processes to alter (transfer and transform) COCs using sequential reducing and oxidizing wetland reactors and a solar photocatalytic treatment reactor using fixed film titanium dioxide (TiO2). Performance criteria were achieved as the CWTS decreased concentrations of NAs, O/G, and metals below protective thresholds and decreased toxicity to C. dubia. Results from this study provide proof-of-concept data to inform hybrid passive or semi-passive treatment approaches (i.e. constructed wetlands) that could be used to mitigate COCs contained in OSPWs.

CHARACTERISTICS OF MARINE ENVIRONMENTAL GEOCHEMISTRY FROM HA TINH TO QUANG NAM (60-100M WATER DEPTH)

The aim of this study is to elucidate the characteristics of marine environmental geochemistry from Ha Tinh - Quang Nam (60-100m water depth) based on analysis of geochemical parameters of seawater and surface sediments. Surface sediments that are high in absorbed capacity of toxic substances mainly accumulated in northern study area. Seawater dominantly characterized by weak alkaline-weak oxidation and contained biodegradable organic materials. Almost anion and chemical element concentrations in seawater tended to decrease with depth, with an exception for SO42-, Br-, I- concentrations that had an opposite trend, increasing with depth and B, Hg concentrations displayed a complex variation. Sedimentary environments were highly predominant by weak alkaline-strong oxidizing features and carbonate-rich materials. Concentrations of anions and chemical elements tended to be higher in central area in comparison to northern and southern regions, and positively correlated with fine sediment compositions. Organochlorine pesticides (OCPs) concentration decreased with sediment depth, whilst polychlorinated biphenyls (PCBs) concentration had no clear trend. The organic material, heavy metal, OCPs and PCBs concentrations in seawater and sediments were all lower than environmental standards. The present results have provided important baseline data for monitoring marine environment quality and protecting the marine ecosystem of Ha Tinh - Quang Nam Sea.References Addo, M.A., Okley, G.M., Affum, H.A., Acquah, S., Gbadago, J.K., 2011. Water Quality and Level of Some Heavy Metals in Water and Sediments of Kpeshie Lagoon, La-Accra, Ghana. Journal of Environment and Earth Science, 3, 487-497. Aderinola, O.J., Clarke, E.O., Olarinmoye, O.M., Kusemiju, V. and Anatekhai, M.A., 2009: Heavy metals in surface water, sediments, fish and perwinkles of Lagos Lagoon: American-Eurasian journal of agricultural &amp; environmental sciences, 5(5), 609-617. Buccolieri A., Buccolieri, G., Cardellicchio, N., Dell Atti, A., Di Leo, A., Maci, A., 2006. Heavy metals in marine sediments of Taranto Gulf (Ionian Sea, Southern Italy). Marine Chemistry 99, 227-235. Carman, C.M.I., Xiang-Dong, L., Gan, Z., Onyx, W.H.W., Yok-Sheung, L., 2007. Trace metal distribution in sediments of the Pearl River Estuary and the surrounding coastal area, South China: Environmental Pollution 147, 311-323. Esslemont G., 2000. Heavy metals in seawater, marine sediments and corals from the Townsville section, Great Barrier Reef Marine Park, Queensland. Marine Chemistry 71(3), 215-231. Glasby, G. P., Schulz, H. D., 1999. Eh, pH Diagrams for Mn, Fe, Co, Ni, Cu and As under Seawater Conditions: Application of Two New Type of Eh, pH Diagrams to the Study of Specific Problems in Marine Geochemistry. Aquatic Geochemistry 5, 227-248. Hedges, J. I., Clark, W. A., Cowie, G. L., 1988: Organic matter sources to the water column and surficial sediments of a marine bay. Limnology and Oceanography 33(5), 1116-1136. Majer A.P., Petti M.A.V., Corbisier T.N., Ribeiro A.P., Theophilo C.Y.S., de Lima Ferreira P.A. and Figueira R.C.L., 2014: Bioaccumulation of potentially toxic trace elements in benthic organisms of Admiralty Bay (King George Island, Antarctica). Marine Pollution Bulletin 79(1), 321-325. Mai Trong Nhuan, 2011: Survey on characteristics of geology, geodynamics, geological resources, geoenvironment and focasting geohazards of East Vietnam Sea from 30-100m water depth, scale 1:500.000. Achieved in Marine Natural Resources - Environment Survey Center. Naser, H.A., 2013: Assessment and management of heavy metal pollution in the marine environment of Arabian Gulf: A review. Marine Pollution Bulletin 72, 6-13. Nguyen Bieu, 1999: Survey on geology and mineral resouces in nearshore East Vietnam Sea (0-30 m water depth), scale 1:500.000. Achieved in Marine Natural Resources - Environment Survey Center. Pham Van Thanh, 2009: Report on environmental geology map of marine sediments of East Vietnam Sea (0-20 m water depth), scale 1:250.000. Project No. KC09.21/06-10. Achieved in Ministry of Science and Technology. Tran Nghi, 2004. Establishing the map of Quaternary formations of East Vietnam Sea and adjacent basin, scale 1:1.000.000. Project No. KC09-23. Achieved in Ministry of Science and Technology. Vu Truong Son, 2004. Environmental geochemistry of neashore sea from Rach Gia-Vung Tau. Doctor disertation on Geology. Achieve in VNU University of Science. Valavanidis, A., Vlachogianni, T., 2010. Metal pollution in ecosystems. Ecotoxicology studies and risk assessment in the marine environment. Sci. Adv. Environ. Toxicol. Ecot. Issues. chem-tox-ecotox. org/wp/wp-content/uploads/2010/01/02-Metals-17_01_2010. pdf [on line]. Vizzini S., Costa V., Tramati C., Gianguzza P., Mazzola A., 2013. Trophic transfer of trace elements in an isotopically constructed food chain from a semi-enclosed marine coastal area (Stagnone di Marsala, Sicily, Mediterranean). Archives of environmental contamination and toxicology 65(4), 642-653. Wang S., Jia Y., Wang S., Wang X., Wang H., Zhao Z., Liu B., 2010. Fractionation of heavy metals in shallow marine sediments from Jinzhou Bay, China. Journal of Environmental Sciences 22(1), 23-31. Canadian Council of Ministers of the Environment (CCME), 2002. Canadian sediment quality guidelines for the protection of aquatic life: Summary tables. Updated. In: Canadian Environmental Quality Guidelines, 1999: Canadian Council of Ministers of the Environment, Winnipeg. Helsinki Commission and Baltic Marine Environment Protection Commission, 2004. Heavy metal pollution to the Baltic sea in 2004. Baltic Sea Environment Proceedings, No. 108. Ministry of Natural Resources and Environment (MONRE), 2008. National technical regulation on coastal water quality - QCVN 10:2008/BTNMT. Ministry of Natural Resources and Environment (MONRE), 2011. Guideline of quantifying and regulation on analytical results of geological and mineral samples. Ministry of Natural Resources and Environment (MONRE), 2012a. National technical regulation on off-shore water quality - QCVN 44:2012/BTNMT. Ministry of Natural Resources and Environment (MONRE), 2012b. National technical regulation on sediment quality - QCVN 43 : 2012/BTNMT. CCOP:http://www.ccop.or.th/ Songthu Corporation: http://www.songthu.com.vn/

The Status of Natural Radioactivity and Heavy Metals Pollution on Marine Sediments Red Sea Coast, At Safaga, Egypt

Natural 226Ra, 232Th and 40K radio nuclides concentration in beach Sediments along Safaga coast of Red sea, Egypt has been carried out using a NaI (Tl) gamma ray spectrometric technique. The total average concentrations of radionuclides ± uncertainty of 226Ra, 232Th and 40K were 22.2 ± 1.7, 19.2 ± 2.5, and 477.6 ± 27.6 Bqkg-1, respectively. The total average absorbed dose rate is found to be 41.4 nGyh-1, whereas the annual effective dose rate has an average value of 54 μSvy-1. The total organic matter (TOC), carbonates (CaCo3) and Heavy metals distribution have been measured at some locations, the concentration for the investigated heavy metals overtake the allowable limits recommended by the Canadian Environmental Quality Guidelines, this assigned to the ratio of metals pollution is caused by anthropogenic activities (phosphate shipment as in Abu Tartour harbor and navigation as in Touristic harbor) and or by natural impacts such in mangrove interment. Statistical analyses were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclide.

Long-term environmental impact at an abandoned gold–silver enrichment plant: A case study in Mitsero, Cyprus

The abandoned gold–silver enrichment plant of Mitsero village is located in Cyprus and is an example of the long-term environmental impact of mining activity when no rehabilitation measures are undertaken. We conducted a study at a plant that has been abandoned for 70years to investigate potential environmental contamination and, if discovered, describe the extent of the contamination. Soil and water samples were collected from five potentially-polluted zones and the results are summarized as follows: soil pH of samples collected from inside the abandoned enrichment plant was low, around 3.4 to 5.4, while samples from the tailings were extremely low, ranging between 1.9 and 2.0. The tailing samples also exhibit high leachability of metals, particularly for Cu, Fe, Zn, Cr, Pb and Mn when subjected to the SPLP. Furthermore, the samples from the tailings also contain high cyanide levels of 25.05mg/kg and 45.85mg/kg, which are well-above allowable limits of 0.9mg/kg (Canadian Environmental Quality Guidelines, 2007). It is particularly interesting that no arsenic leachability was measured for the tailings, although arsenic is present in these samples as determined by XRF analysis. Our results indicate that the low pH environment combined with high leachability of metals is reflected in the quality of water samples collected from the ephemeral stream: high levels of metals were detected in the water samples measured using ICP-OES. While the pH of the water samples was neutral (7.6), aqueous concentrations of Cu, Fe, Zn, As, Cr, Pb and Mn ranged between 173.95μg/l and 3678.8μg/l. Thus, our findings indicate that areas of the site contain significant concentrations of metals and cyanide, leading us to conclude that, in conjunction with the low soil pH in those same areas, the potential exists to form acidic runoff (regardless of the pH of the rain itself) capable of leaching metals, thus mobilizing the contaminants. That the contamination, particularly the presence of cyanide, is still found some 70years after closure makes a compelling argument for remediation of such legacy sites.

The status of natural radioactivity and heavy metals pollution on soil at Assiut Zone in Central Upper-Egypt

Context: To examine the status of the environmental quality of the soils in Assiut zone in central Upper-Egypt, investigation was carried out to determine the concentration of natural radionuclides (radium [ 226 Ra], thorium [ 232 Th] and 40 K) and the contents of eight heavy metals (Cd, Pb, Ni, Fe, Mn, Cr, Cu, and Zn). Materials and Methods: The measurements of concentration of natural radionuclides were carried out by using the gamma spectrometry (NaI (Tl); 3× 3). Results: The results indicate that the soil samples' radioactivity concentrations of 226 Ra, 232 Th, and 40 K were ranging from 10.4 ± 0.5 to 19 ± 1 Bq/kg; 6 ± 0.3-21 ± 3 Bq/kg and 103.6 ± 5-221 ± 10 Bq/kg respectively. The typical radiation doses (D o ), the external hazard index (H ex ) and annual effective dose rate values for the corresponding samples were also estimated. The concentration of heavy metals was measured by using the atomic absorption spectrometry method. Data were analyzed by using the statistical methods. The representative H ex values for the corresponding samples were also estimated. Generally, heavy metals and major elements concentration of the sediments were found decrease in sequence of Fe > Mg > pb > Zn > Cr > Cu > Ni > Cd. In some locations, the concentration for the investigated heavy metals exceeds the permissible limits recommended by the Canadian Environmental Quality Guidelines. The highest concentration of the most heavy metals (Cd, Pb, Ni, Cr, and Zn) was found in Arab Al-Madabegh region; the sewage irrigated zone. Whereas, the lowest ones was found in the not irrigated lands, which considered as a reference point of analyses. Conclusion: The maximum admitted concentrations of toxic heavy elements in the sensitive areas revealed to be exceed from three to thirty times than the non-irrigated zone.

Polycyclic Aromatic Hydrocarbons (PAHs) in Soil and Sediment from Industrial, Residential, and Agricultural Areas in Central South Africa: An Initial Assessment

Polycyclic aromatic hydrocarbons (PAHs) are of global concern due to their ubiquitous presence, toxicity, and carcinogenicity. No data on PAHs in soils from South Africa have been published, even though it has the largest economy and industrial base in Africa. During this initial assessment, the levels of PAHs were determined in soils and sediments collected from central South Africa, specifically targeting industrial, residential, and agricultural areas. Analysis was performed by gas chromatography/mass spectrometry (GC/MS). The total concentration of PAHs (Σt-PAH) ranged between 44 and 39,000 ng/g, dw and the concentration of carcinogenic PAHs (Σc-PAH) ranged between 19 and 19,000 ng/g, dw. Pyrogenic processes were the most likely sources, with minimal petrogenic contributions. PAH levels were in the same range as levels reported from other countries, and the majority of the sites did not exceed Canadian environmental quality guidelines. Based on assumptions for dermal contact and ingestion of PAH-contaminated soil, we provisionally calculated only a small increase in cancer risk, but additional PAH inhalation could add considerably to this risk. Our data indicates a need for more analysis in industrial and residential areas, and should include air.

Use of semipermeable membrane devices to investigate the impacts of DDT (Dichlorodiphenyltrichloroethane) in the Holland Marsh environs of the Lake Simcoe watershed (Ontario, Canada)

In 2004 the Lake Simcoe Region Conservation Authority (LSRCA) initiated a sampling program to examine historic and emerging contaminants throughout the Lake Simcoe watershed. Through the sampling program it was determined that Dichlorodiphenyltrichloroethane (DDT) concentrations in sediment were exceeding the Canadian Environmental Quality Guidelines just downstream of the Holland Marsh. The objective of this study was to investigate the presence of DDT in the waters surrounding the Holland Marsh and examine if the concentrations sampled represented a potential threat to aquatic and terrestrial biota in the Holland Marsh environs. Semipermeable membrane devices were used to determine DDT concentrations at different locations within the Holland Marsh and surrounding waters for a month in 2006, 2007 and 2008. DDT concentrations were compared to fish tissue guidelines where it was found that some sections of the Marsh experience concentrations which have the potential to impact the health of biota in the immediate area. Varying weather conditions between study years revealed the importance of precipitation in transporting DDT through the marsh. Precipitation above or equaling long-term normals occurred in 2006 and 2008 which coincided with higher DDT concentrations than the significantly drier year of 2007. The information gained in this study will play a valuable role for both terrestrial and aquatic ecosystem managers in understanding how historic DDT use in the Holland Marsh may still be affecting this environment and Lake Simcoe today.

The ecological complexity of the Thai-Laos Mekong River: I. Geology, seasonal variation and human impact assessment on river quality

The objective of this study is to assess the variation of pollution in the Thai–Laos Mekong associated with seasonal dynamics concomitant with the natural geological features and human activities that impact on the adverse quality of the river. The complex ecology of the 1500 km stretch of the Thai-Laos Mekong River has been studied in this paper to understand the relationship with the geomorphology, with the sub-tropical monsoonal climate and the impact of human activity. Sub-surface geology controls the nature and extent of the drainage basin and of the river channel. The volume flow of the river varies naturally and dynamically in phase with the rainfall; traditional models based on steady state hydraulics are inappropriate. Continuous erosion of the river banks and bed generates a sediment load of impure silt, mica, quartz and clay minerals that inhibits light penetration and limits the primary productivity of the river. The river separates two countries at different stages of development; it flows through or close to eight non-industrial conurbations (Populations 350,000–2,000,000) but is otherwise sparsely populated. The river is used for subsistence agriculture, village transport, fishing including aquaculture and as a source of domestic water. Hydroelectricity is generated from the Laos tributaries. The river is a depository for partially treated urban waste and untreated village waste, hence populations of E.coli bacteria sometimes render the water unsuitable for drinking unless treated with the highest value of 240/100ml found at station 7 during the summer season of 2003. Furthermore the river is polluted by trace metals, notably cadmium and mercury, and by Polycyclic Aromatic Hydrocarbons (PAHs), which are particularly concentrated in the sediments. Previous work has shown that cadmium and mercury exceed the Probable Effect Level (PEL) values of Canadian Environmental Quality Guidelines and that the PAH concentrations were also greater than the Interim Sediment Quality Guidelines (ISQG). Consequently the fish stock, a vital source of protein for the local human population maybe seriously affected. As conflict between the demands of human activities will be exacerbated by the continuing development of the basin; monitoring must be continued and a better model of the river's ecology is needed to predict the impact of development.

DNA damage in earthworms (Eisenia spp.) as an indicator of environmental stress in the industrial zone of Coatzacoalcos, Veracruz, Mexico

Coatzacoalcos, Veracruz is one of the major industrial areas of Mexico. Presently, the Coatzacoalcos River and the areas surrounding the industrial complex are considered by various authors to be some of most polluted sites in Mexico. The objective of this study was to determine if earthworms could be used as indicators of environmental stress in the Coatzacoalcos industrial zone. Often, detritivores and decomposers such as earthworms are the first to be affected when the soil is contaminated. We collected soil samples to be used for persistent organic pollutants (POPs) quantification by gas chromatography. Concentrations of hexachlorobenzene, lindane and total polychlorinated biphenyls (PCBs) in the soil were above the maximum permissible limits of the Canadian Environmental Quality Guidelines (CEQG). Comet assay was conducted in coelomocytes of wild earthworms collected in Coatzacoalcos and compared with the control earthworms. We found DNA damage in earthworms from Coatzacoalcos that was significantly higher (P < 0.05) in comparison to laboratory earthworms. Earthworms are an appropriate organism to use as an indicator of environmental impact in contaminated sites. DNA damage recorded in the earthworms provides clear evidence of environmental impacts by the chemical industry on the wildlife of this region.

Metal concentrations in water, sediment, and fish from sewage-fed aquaculture ponds of Kolkata, India

The concentrations of lead, cadmium, chromium, copper, and zinc were investigated in the sewage-fed pond water, sediment, and the various organs of Labeo rohita, Catla catla, Cirrhinus mrigala, Oreochromis mossambicus, and Cyprinus carpio cultured in sewage-fed ponds, Kolkata, India. Among the metals, cadmium, lead, and zinc were detected in water and, except lead, were below the water quality guideline levels for the protection of freshwater aquatic life proposed by CEQG (Canadian Environmental Quality Guidelines) and AENV (Alberta Environment). Therefore, lead could pose danger to aquatic organisms. All the five metals were detected in the sediment and, except cadmium and lead, were below the sediment quality guideline levels for aquatic life proposed by EPA (Environmental Protection Agency). Therefore, these two metals could be toxic to aquatic organisms. Significant (P > 0.05) differences were observed among the five fish species for all these metals accumulation. Also, significant (P > 0.05) differences were noticed among these metals accumulation in fish organs. Cadmium showed the least bioaccumulation, while zinc showed the highest bioaccumulation in all the fish species. Though the metal concentration in the different fish tissues was variable, the highest concentration was found in kidney and the lowest in the muscle. Concentrations of these metals in the muscle tissue of all the fish species were well below the consumption safety tolerance in fish set by WHO/FAO, and thus, so far as these metals are concerned, these sewage-fed cultured fishes are safe and suitable for human consumption.