Monitoring and risk assessment of pesticides in a tropical river of an agricultural watershed in northern Thailand

The increasing application of pesticides in the uplands of northern Thailand has increased the transfer of pesticides to surface water. To assess the risk of pesticide use for stream water quality, we monitored the concentrations of seven pesticides (atrazine, dichlorvos, chlorpyrifos, dimethoate, chlorothalonil, (α-, β-) endosulfan, cypermethrin) frequently used in the Mae Sa watershed (77 km²) in water and sediment samples over a period of one and a half years (2007–2008). All investigated pesticides were recorded in the river. Chlorpyrifos was detected most often in water samples (75 % at the headwater station), while cypermethrin was most often found in riverbed (86 %) and in all suspended sediment samples. The highest concentrations of the pesticides were detected during the rainy season. About 0.002 to 4.1 % by mass of the applied pesticides was lost to surface water. The risk assessment was based on the risk characterization ratio (RCR). The RCRs of dichlorvos in water, (α-, β-) endosulfan, and cypermethrin in water and sediments were higher than unity indicating that they are likely to pose a threat to aquatic ecosystem. Finally, we discuss the role of sampling design on ecotoxicological risk assessment. Our study shows that pesticide contamination of surface waters is an environmental issue in the Mae Sa watershed and that measures need to be undertaken to reduce the loss of pesticides from soil to surface waters.     

Determination of atrazine in surface waters by combination of POCIS passive sampling and ELISA detection

Polar organic compound integrative samplers (POCIS) in combination with instrumental techniques such as LC-MS-MS were previously used to monitor environmental pollutants but the performance of alternative immunochemical methods such as ELISA (enzyme-linked immunosorbent assay) has been explored less. In the present study, POCIS technology was applied to surface water sampling in the Czech Republic, and ELISA was used as a detection technique for the herbicide atrazine. In the first study, 28 samples from streams around small municipal waste water treatment plants (WWTPs) were collected using two different devices (POCISpest and POCISpharm) over the course of 21 days. Elevated atrazine concentrations (up to 25 ng per POCIS) were found in samples down-stream of WWTPs. This observation was also confirmed in another two year study (4 sampling periods) investigating 7 river sites around a major city of Brno as well as the inlet and outlet of the city's WWTP. High atrazine levels were systematically determined at the outlet from the WWTPs (120-605 ng per POCIS). A decreasing trend in the atrazine concentrations in rivers around the city of Brno has been observed, with the highest levels observed within the first sampling period in spring 2007 (100-600 ng per POCIS, with an extreme value of 2760 ng per POCIS). Results of the atrazine ELISA were closely correlated with LC-MS/MS, which confirmed good applicability of ELISA as a cost-effective screening tool.     

The ecological condition of south Florida estuaries

An assessment of the ecological condition ofsouth Florida estuaries based on regional probabilisticmonitoring was conducted during the summer of 1995. Samples anddata were collected on water and sediment quality, benthos, andfish tissue contaminants. Elevated concentrations of metals andpesticides were measured in both sediments and fish tissue withsome exceedances of guidance values. Bottom dissolved oxygenlevels over 23–37% of the area were below state criteria. Eighty-eight percent of surface waters had greater than10% penetration of ambient light to a depth of 1.0 m. Ninepercent of the area studied in South Florida exhibited degradedbiology and impaired use based on a calculated index ofecological condition. Using the probability-based monitoringdesign, useful information of this type can be provided toresource managers regarding estuarine condition on a regional scale.     

Pesticide occurrence and aquatic benchmark exceedances in urban surface waters and sediments in three urban areas of California, USA, 2008–2011

Urban pesticide use has a direct impact on surface water quality. To determine the extent of pesticide contamination, the California Department of Pesticide Regulation initiated a multi-area urban monitoring program in 2008. Water and sediment samples were collected at sites unaffected by agricultural inputs in three areas: Sacramento (SAC), San Francisco Bay (SFB), and Orange County (OC). Samples were analyzed for up to 64 pesticides or degradates. Multiple detections were common; 50 % of the water samples contained five or more pesticides. Statewide, the most frequently detected insecticides in water were bifenthrin, imidacloprid, fipronil, fipronil sulfone, fipronil desulfinyl, carbaryl, and malathion. Bifenthrin was the most common contaminant in sediment samples. Key differences by area: OC had more pesticides detected than SAC or SFB with higher concentrations of fipronil, whereas SAC had higher concentrations of bifenthrin. The most frequently detected herbicides were 2,4-D, triclopyr, dicamba, diuron, and pendimethalin. Key differences by area: OC and SFB had higher concentrations of triclopyr, whereas SAC had higher concentrations of 2,4-D and dicamba. Detection frequency, number of pesticides per sample, and pesticide concentration increased during rainstorm events. In water samples, all of the bifenthrin, malathion, fipronil, permethrin, and λ-cyhalothrin detections, and most of the fipronil sulfone and cyfluthrin detections were above their lowest US EPA aquatic benchmark. Diuron was the only herbicide that was detected above its lowest benchmark. Based on the number of pesticides and exceedances of aquatic benchmarks or the high number of sediment toxicity units, pesticides are abundant in California surface waters.     

Trends in background levels of persistent organic pollutants at Kosetice observatory, Czech Republic.2) Part II. Aquatic and terrestrial environments 1996-2005

A multimedia sampling of ambient air, wet deposition, surface water, sediment, soil and biota has been performed at Kosetice background observatory in the southern Czech Republic since 1988. An integrated monitoring approach was applied to assess the current state, anthropogenic impacts, and possible future changes of terrestrial and freshwater environments. Average PCB concentrations in the individual matrices calculated from ten years of sampling on multiple sites varied between 2 ng g(-1) in sediment and 7 ng g(-1) in soil or moss. DDT concentrations were lower in moss and needles (2 ng g(-1) and 4 ng g(-1), respectively) than in sediment (11 ng g(-1)) and soil (20 ng g(-1)), while the HCH level was higher in moss and needles (5 ng g(-1) and 6 ng g(-1), respectively) than in soil or sediment (1 ng g(-1) and 2 ng g(-1), respectively). The highest average level of PAHs was found in soil (600 ng g(-1)), while it was lower in needles (230 ng g(-1)), moss (210 ng g(-1)) or sediment (210 ng g(-1)). Time related trends of concentration levels of persistent organic pollutants in all matrices were investigated. Moss and needle trend patterns resembled those of the ambient air, showing a slight concentration decrease of all compounds, except for hexachlorobenzene. The soil, water and sediment concentrations showed a similar decrease of PAHs, PCBs, and HCHs, but there was no clear trend for DDTs and HCB.     

Trace elements in the livers of cod (Gadus morhua L.) from the Baltic Sea: levels and temporal trends

This paper presents and discusses the levels and temporal trends of concentrations of Cd, Pb, Hg, Cu, Zn, and As in livers and Hg in the muscle tissues of cod (Gadus morhua L) from the Baltic Sea during the period 1994–2010. Concentrations of Pb, Hg, and Cd exhibited significant downward trends. Cu and Zn concentrations exhibited upward trends in the period 1994 to 2010. No trends were detected for concentrations of As. The temporal trends identified in heavy metal concentrations in cod livers corresponded to the directions of changes in concentrations of these elements introduced into the Baltic Sea via river runoff and atmospheric emission, and those in surface and deep waters of the Baltic. Downward trends in the concentrations of toxic metals in cod livers suggest that advantageous changes are occurring in concentrations of heavy metals in the environment of the southern Baltic Sea.     

Occurrence and distribution of benzothiazole in the Schwarzbach watershed (Germany)

This study quantifies the regional distribution of the micropollutant benzothiazole (BT) in river water by sampling 15 river sites in the Schwarzbach watershed (about 400 km(2)) from November 2008 to February 2010. Additionally, wastewater samples from three municipal wastewater treatment plants (WWTPs) in Germany were analyzed. BT was detected in all wastewater influent and effluent samples as well as in all river water samples collected downstream of wastewater discharge. This corroborates the ubiquitous occurrence of BT in the aqueous environment. Concentrations were between 58 and 856 ng L(-1) in the river water. The observed mean concentration at the outlet of the investigated catchment was 109 ng L(-1). With only a few exceptions, temporal and spatial variations of BT concentrations in river water were low. Rather similar BT concentrations over a wide range of river discharge indicate that dilution along the mainstream is negligible and, thus, supports the hypothesis that paved surface runoff during rain events is an important BT source not only for wastewater influent but also for river water. This was supported by detecting the highest BT concentrations at sampling locations close to the dense highway network around the city of Frankfurt. Since BT was also detected in river water collected from locations that were clearly unaffected by wastewater effluent discharge, surface runoff must be considered as a diffuse source of BT in river water.     

Distribution and temporal variation of trace metal enrichment in surface sediments of San Jorge Bay, Chile

Cu, Pb, and Hg concentrations were determined in surface sediment samples collected at three sites in San Jorge Bay, northern Chile. This study aims to evaluate differences in their spatial distribution and temporal variability. The highest metal concentrations were found at the site “Puerto”, where minerals (Cu and Pb) have been loaded for more than 60 years. On the other hand, Hg does not pose a contamination problem in this bay. Cu and Pb concentrations showed significant variations from 1 year to another. These variations seem to be a consequence of the combination of several factors, including changes in the loading and/or storage of minerals in San Jorge Bay, the dredging of bottom sediments (especially at Puerto), and seasonal changes in physical–chemical properties of the water column that modify the exchange of metals at the sediment–water interface. Differences in the contamination factor and geoaccumulation index suggest that pre-industrial concentrations measured in marine sediments of this geographical zone, were better than geological values (average shale, continental crust average) for evaluating the degree of contamination in this coastal system. Based on these last two indexes, San Jorge Bay has a serious problem of Cu and Pb pollution at the three sampling locations. However, only Cu exceeds the national maximum values used to evaluate ecological risk and the health of marine environments. It is suggested that Chilean environmental legislation for marine sediment quality—presently under technical discussion—is not an efficient tool for protecting the marine ecosystem.     

Determination of fecal contamination indicator sterols in an Australian water supply system

This paper reports a reconnaissance survey of the concentrations of sterol compounds (as indicators of fecal contamination) in a large water supply system in southeast Australia comprising a network of rivers, channels, and drains. Levels of coprostanol and cholestanol were determined in surface water and bottom sediment using gas chromatography–mass spectrometry analysis across 17 strategic sampling sites and over 12 months. Clear differences in the levels of fecal contamination were observed among sites. Four sites routinely contained high levels of the fecal indicator sterols indicated from surface water and sediment sample analysis. Coprostanol concentrations at each location varied from 0 ng/L at the reference site to 11,327 ng/L in a surface water sample of a drain directly downstream of a knackery. The majority of the sites contained coprostanol in the range of 500 to 800 ng/L. Since no fecal-associated sterol compounds were detected at the external reference sites, these were assumed to be free from fecal contamination. Sewage water discharge and/or substantial water runoff maybe the principal factors contributing to fecal contamination of the supply drains and channels.     

Historical data review and source analysis of PCBs/Arochlors in the Lower Leon Creek Watershed

PCBs have been banned since the late 1970s, but concentrations still exist in sediments and riverine fish and continue to exceed regulatory limits which can result in negative health effects. This study looks at historical records of PCB and Arochlor concentrations in surface water, sediments, and fish tissue for the Lower Leon Creek, Bexar County in Texas. Temporal analysis on the concentrations of PCBs and Arochlors was conducted for detection and exceedance of selected screening criteria. In addition, the half-lives of select PCB congeners were calculated for 2007–2012 data to ascertain differences in PCB concentrations with their hydrophobicity. Source analysis was conducted to determine the potential contributing sources of PCB contamination using source data (landfills, outfalls, etc.) and the PCB exceedance data. For sediment and fish tissue sampling results, historic data shows high concentrations of PCB/Arochlors over the course of several decades. The historical data is characterized as being widely variable for detections in Arochlors and concentrations between years, with a dramatic drop in concentrations detected starting in 2009. Overall, the sampling locations adjacent to and downstream from the former Kelly Air Force Base have the highest concentrations of PCB/Arochlors over the longest period of time. The results of this work will aid regulatory agencies in addressing impairment.     

Integration of multi-disciplinary geospatial data for delineating agroecosystem uniform management zones

The aim of this study was the development of analytical methods for the simultaneous determination of 25 selected pharmaceuticals, metabolites, and pesticides, belonging to the various chemical classes, in river sediments and their corresponding surface and ground water with the purpose of monitoring the contamination levels. The methods were based on the solid-phase extraction as the sample preparation method for water samples, and the ultrasonic solvent extraction for the sediment samples, followed by the liquid chromatography–tandem mass spectrometry. High recoveries were achieved for extraction from both water and sediment samples for the majority of analytes. Low limits of detection were achieved for all investigated compounds in the water sample (1–5 ng L^?1) as well as in the sediment (1–3 ng g^?1). Applicability of the developed methods was demonstrated by determination of pharmaceutical and pesticide residues in 30 surface water, 44 groundwater, and 5 sediment samples from the Danube River Basin in Serbia. Sixty percent of target compounds were detected in environmental samples. The most frequently detected analytes in river sediments were the pesticides dimethoate and atrazine, while carbamazepine and metamizole metabolites 4-AAA and 4-FAA were the most frequently found in water samples.     

Concentrations of DDTs and dieldrin in Long Island Sound sediment

The concentrations of three frequently detected organochlorine pesticides (OCPs) and one degradation product, p,p'-DDT, p,p'-DDD, dieldrin, and p,p'-DDE were determined in recently collected (2005-2006) and archived (1986-1989) surficial sediments and sediment cores from Long Island Sound (LIS). The concentration of dieldrin ranged from 0.05 to 5.27 ng g(-1) dry weight in the surficial sediments, and from 0.05 to 11.7 ng g(-1) dry weight in the sediment cores. Total DDXs (the sum of p,p'-DDE, p,p'-DDD and p,p'-DDT) concentrations ranged from 1.31 to 33.2 ng g(-1) in surficial sediments and 1.11 to 66.4 ng g(-1) in sediment cores. The results indicate that the three OCPs and DDE were still widely present in LIS surficial sediments two decades after the use of these pesticides in the United States was banned. In addition, the surficial concentrations did not decrease significantly when compared to the concentrations in archived samples collected two decades ago. Sediments in the western part of LIS were more contaminated (with concentrations in some western sites being still above probable effect levels) than those in the eastern part, probably as a result of the net westward sediment transport in LIS. The three OCPs and DDE were detected at all depths (down to ~50 cm) in the sediment cores, and concentration profiles indicated a depositional sedimentary environment with significant sediment mixing. Such mixing may redistribute OCPs deposited earlier (deeper in sediment bed) to the sediment surface and lead to enhanced persistence of OCP concentrations in surficial sediments.     

Seasonal distribution, source investigation and vertical profile of phenolic endocrine disrupting compounds in Dianchi Lake, China

Phenolic endocrine disrupting compounds, including nonylphenol-di-ethoxylate (NP2EO), nonylphenol-mono-ethoxylate (NP1EO), 4-nonylphenol (4-NP), bisphenol A (BPA), 4-cumylphenol (4-CP) and 4-tert-octylphenol (4-t-OP), were investigated in water, surface sediment and sediment cores in Dianchi Lake to track their seasonal distributions, pollution sources and historical trends. The concentrations of NP2EO, NP1EO, 4-NP, BPA, 4-CP and 4-t-OP were up to 295.14, 448.48, 45.28, 530.33, 8.96 and 21.37 ng L(-1) in water, and up to 297.11, 809.63, 4.58, 166.87, 3.62 and 40.69 ng g(-1) dry weight in surface sediment, respectively. Except BPA in water, concentrations of all the other phenolic compounds in both of the matrices were higher in January than in July, 2011. The concentrations decreased significantly with an increase in distance from the sampling locations which were adjacent to the urban areas (Kunming City, Chenggong City and Jinning City). The pollution of phenolic EDCs came mainly from industry, agriculture and daily life. The relationships between the concentrations of target compounds and the six water quality parameters were evaluated. There were significant positive correlations between concentrations of phenolic compounds in water and in surface sediment. For sediment cores, three clearly separated maxima occurred in segments 0-5 cm (the late 2000s), 5-10 cm (the early and mid of 2000s) and 20-25 cm (the mid of 1980s), respectively. NP2EO, NP1EO and BPA were the three dominant compounds in the lake.     

Occurrence of selected antibiotics in Jiulongjiang River in various seasons, South China

The concentrations of six sulfonamides (SAs) and three tetracyclines (TCs) were investigated in Jiulongjiang River during the low water season and the high water season. They were monitored in both surface water and sediment. Total concentrations of all these antibiotics varied from 31 to 25,771 ng g(-1) in sediment samples. In water they ranged from 60 to 2607 ng L(-1) during the low water season and from ND (not detected) to 134 ng L(-1) during the high water season. At the sites nearby breeding farms, chlorotetracycline was found to have the highest concentration of 1036 ng L(-1) in water and 14,666 ng g(-1) in sediments. According to the published data, the concentrations of sulfamethazine, sulfameter and TCs at these sites were higher than that in most rivers. The concentrations during the low water season were tens to hundreds of times higher than that in the high water season. The lower concentrations of TCs in the high water season might result from both dilution and photo-degradation, while dilution and bio-degradation might lead to the lower concentrations of SAs. However, further study is needed to clarify the specific reasons. Concerning the relationship between sediment and water samples, the pseudo-partitioning values of TCs were much higher than SAs. It indicates that the TCs are prone to accumulate in the sediment.     

The history of hexachlorobenzene accumulation in Svalbard fjords

In the present study, we investigated the spatial and historical trends of hexachlorobenzene (HCB) contamination in dated sediments of three Svalbard fjords (Kongsfjorden, Hornsund, Adventfjorden) differing in environmental conditions and human impact. HCB concentrations ranging from below limit of quantification (6.86 pg/g d.w.) to 143.99 pg/g d.w. were measured. The highest concentrations were measured in two surface sediment layers of the core collected in Hornsund near the melting glacier. The lowest concentrations of HCB were measured in Adventfjorden, suggesting that local source of HCB is not significant and global transport processes are the major transport pathways. The history of HCB deposition did not fully reflect the history of HCB emission (largest in 1950s and 1960s). In case of several sediment cores, the HCB enrichment in surface (recent) sediments was noticed. This can indicate importance of secondary sources of HCB, e.g., the influx of HCB accumulated over decades on the surface of glaciers. Detected levels of HCB were generally low and did not exceed background concentration levels; thus, a negative effect on benthic organisms is not expected.     

Statistical analysis of PM10 concentrations at different locations in Malaysia

Malaysia has experienced several haze events since the 1980s as a consequence of the transboundary movement of air pollutants emitted from forest fires and open burning activities. Hazy episodes can result from local activities and be categorized as "localized haze". General probability distributions (i.e., gamma and log-normal) were chosen to analyze the PM(10) concentrations data at two different types of locations in Malaysia: industrial (Johor Bahru and Nilai) and residential (Kota Kinabalu and Kuantan). These areas were chosen based on their frequently high PM(10) concentration readings. The best models representing the areas were chosen based on their performance indicator values. The best distributions provided the probability of exceedances and the return period between the actual and predicted concentrations based on the threshold limit given by the Malaysian Ambient Air Quality Guidelines (24-h average of 150 μg/m(3)) for PM(10) concentrations. The short-term prediction for PM(10) exceedances in 14 days was obtained using the autoregressive model.     

The changes in different ozone metrics and their implications following precursor reductions over northern Taiwan from 1994 to 2007

The changes of different O₃ metrics such as O_{3_avg} (daily mean), O_X (NO₂ + O₃), O_{3_8h} (daily maximum 8-h moving average), O_{3_max} (daily maximum 1-h average), and exceedances of O_{3_8h} and O_{3_max} at 16 air quality monitoring stations over northern Taiwan from 1994 to 2007 are evaluated. The O_{3_avg} at the background site displays an increasing trend at 0.54 ±0.21 ppb (1.28 ±0.49%) per year. The O_X at urban sites shows a significant increase, indicating that even with the effect of reduced NO titration increasing photochemical production is evident. The exceedances of O_{3_8h} (>80 ppb) are about 14.9% higher than O_{3_max} (>120 ppb) with more exceedances at coastal or background sites, where the anthropogenic O₃ precursor emissions are lower. In addition to increasing background O₃ and reductions in NO titration, increasing O₃ production efficiency also plays a key role in the increase of moderate to high O₃ concentrations. The findings help explain the different trends in exceedances and levels of O_{3_8h} and O_{3_max} and are likewise important in the formation of O₃ control strategies.     

Distribution of microbiological indicators of fecal pollution in the riverine substrates

Distribution of fecal microorganisms in water, periphyton, and sediment was studied along the ?rnovnica river (Croatia) over a 1.5-year period. It was found that periphyton was inhabited by the highest number of investigated bacteria, while lower numbers of them were found in sediment and the lowest in surface water of the river. The concentrations of fecal microorganisms in periphyton and partly in sediment were found to be significantly higher in the middle of the river course, near the town of ?rnovnica, while according to the analysis of surface water the highest degree of pollution was reached on its estuary. The results were explained with respect to bacterial?Calgal associations. Considering the fact that most of the river microorganisms are associated with periphyton and sediment particles and only a small number of them is in the free-living form, microbiological analysis of both periphyton and sediment together with water samples has been suggested when fecal pollution of a river is concerned.     

Water quality status and trends in agriculture-dominated headwaters; a national monitoring network for assessing the effectiveness of national and European manure legislation in The Netherlands

Large nutrient losses to groundwater and surface waters are a major drawback of the highly productive agricultural sector in The Netherlands. The resulting high nutrient concentrations in water resources threaten their ecological, industrial, and recreational functions. To mitigate eutrophication problems, legislation on nutrient application in agriculture was enforced in 1986 in The Netherlands. The objective of this study was to evaluate this manure policy by assessing the water quality status and trends in agriculture-dominated headwaters. We used datasets from 5 agricultural test catchments and from 167 existing monitoring locations in agricultural headwaters. Trend analysis for these locations showed a fast reduction of nutrient concentrations after the enforcement of the manure legislation (median slopes of ?0.55 mg/l per decade for total nitrogen (N-tot) and ?0.020 mg/l per decade for total phosphorus (P-tot)). Still, up to 76 % of the selected locations currently do not comply with either the environmental quality standards (EQSs) for nitrogen (N-tot) or phosphorus (P-tot). This indicates that further improvement of agricultural water quality is needed. We observed that weather-related variations in nutrient concentrations strongly influence the compliance testing results, both for individual locations and for the aggregated results at the national scale. Another important finding is that testing compliance for nutrients based on summer average concentrations may underestimate the agricultural impact on ecosystem health. The focus on summer concentrations does not account for the environmental impact of high winter loads from agricultural headwaters towards downstream water bodies.     

The Status of Pesticide Residues in the Drinking Water Sources in Meiliangwan Bay, Taihu Lake of China

The study was carried out to assess the levels of pesticide residues in the water of Meiliangwan Bay, Taihu Lake of China. The most commonly employed organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs) and herbicide atrazine were analyzed. The water samples were collected seasonally from Meiliangwan Bay within a period of one year. The pesticides were analyzed by gas chromatography (GC) with μECD or NPD after solid-phase extraction (SPE), which was confirmed by GC with an ion trap mass spectrometry (MS). The mean concentrations were 1.98 ng/l for lindane, 0.378 ng/l for heptachlor epoxide, 0.367 ng/l for p,p′-DDE, 0.496 ng/l for p,p′-DDD, 1.06 ng/l for p,p′-DDT and 51.6 ng/l for dichlorvos, 39.0 ng/l for demeton, 346 ng/l for dimethoate, 4.12 ng/l for methyl parathion, 11.6 ng/l for malathion, 2.17 ng/l for parathion and 217 ng/l for atrazine. Generally, low concentrations of OCP were found, whereas the concentrations of the OPPs and atrazine in the water of Taihu Lake were relatively high. Heptachlor epoxide and lindane were the two most commonly encountered OCPs while dichlorvos, demeton and dimethoate were found to have much higher concentrations and occurrences than other OPPs.