Levels of organochlorine pesticide residues in marine-, surface-, ground- and drinking waters from the Eastern Cape Province of South Africa

The benefit of using in vitro bioassays to screen agricultural samples for oxidative stress: South Africa's case

Applied pesticides end up in non-target environments as complex mixtures. When bioavailable, these chemicals pose a threat to living organisms and can induce oxidative stress (OS). In this article, attention is paid to OS and the physiological role of the antioxidant defense system. South African and international literature was reviewed to provide extensive evidence of pesticide-induced OS in non-target organisms, in vivo and in vitro. Although in vitro approaches are used internationally, South African studies have only used in vivo methods. Considering ethical implications, the authors support the use of in vitro bioassays to screen environmental matrices for their OS potential. Since OS responses are initiated and measurable at lower cellular concentrations compared to other toxicity endpoints, in vitro OS bioassays could be used as an early warning sign for the presence of chemical mixtures in non-target environments. Areas of concern in the country could be identified and prioritized without using animal models. The authors conclude that it will be worthwhile for South Africa to include in vitro OS bioassays as part of a battery of tests to screen environmental matrices for biological effects. This will facilitate the development and implementation of biomonitoring programs to safeguard the South African environment.

Widespread pesticide contamination of drinking water and impact on cancer risk in Brazil

Pesticides, which are associated with endocrine dysfunction, immunological dysregulation, and cancer, are widespread sources of drinking water contamination. The state of Paraná has a population of 11 million, is the second largest grain producer in Brazil and is a leading consumer of pesticides. In this study, we analyzed the extent of drinking water contamination from 11 proven, probable, or potentially carcinogenic pesticides (alachlor, aldrin-dieldrin, atrazine, chlordane, DDT-DDD-DDE, diuron, glyphosate-AMPA, lindane-γ-HCH, mancozeb-ETU, molinate, and trifluralin) in 127 grain-producing municipalities in the state of Paraná. Extensive contamination of drinking water was found, including legacy pesticides such as aldrin-dieldrin (mean 0.047 ppb), DDT-DDD-DDE (mean: 0.07), chlordane (mean: 0.181), and lindane-HCH (mean: 2.17). Most of the municipalities were significantly above the maximum limits for each one of the currently allowed pesticides (67% for alachlor, 9.44% for atrazine, 96.85% for diuron, 100% for glyphosate-AMPA, 80.31% for mancozeb-ETU, 91.33% for molinate, and 12.6% for trifluralin). Ninety-seven percent of municipalities presented a sum of all pesticides at levels significantly above (189.84 ppb) the European Union preconized limits (<0.5 ppb). Using the mean pesticide concentration in water (ppb), the exposed population for each municipality, and the benchmark cancer risk for pesticides, we estimated the minimum number of cancer cases attributable to pesticide-contaminated drinking water during the period (total of 542 cases). More than 80% were attributed to mancozeb-ETU and diuron. Glyphosate-AMPA and diuron-attributable cases strongly correlated with the total cancer cases in the same period (R = 0.8117 and 0.8138, respectively) as well as with breast cancer cases (R = 0.7695 and 0.7551, respectively). Water contamination was significantly correlated with the sum of the estimated cancer cases for all 11 pesticides detected in each city (R = 0.58 and p < 0.0001). These findings reveal extensive contamination of drinking water in the state of Paraná and suggest that contamination may increase the risk of cancer in this region.

Pesticide residues in drinking water, their potential risk to human health and removal options

The application of pesticides in agricultural and public health sectors has resulted in substantially contaminated water resources with residues in many countries. Almost no reviews have addressed pesticide residues in drinking water globally; calculated hazard indices for adults, children, and infants; or discussed the potential health risk of pesticides to the human population. The objectives of this article were to summarize advances in research related to pesticide residues in drinking water; conduct health risk assessments by estimating the daily intake of pesticide residues consumed only from drinking water by adults, children, and infants; and summarize options for pesticide removal from water systems. Approximately 113 pesticide residues were found in drinking water samples from 31 countries worldwide. There were 61, 31, and 21 insecticide, herbicide, and fungicide residues, respectively. Four residues were in toxicity class IA, 14 residues were in toxicity class IB, 55 residues were in toxicity class II, 17 residues were in toxicity class III, and 23 residues were in toxicity class IV. The calculated hazard indices (HIs) exceeded the value of one in many cases. The lowest HI value (0.0001) for children was found in Canada, and the highest HI value (30.97) was found in Egypt, suggesting a high potential health risk to adults, children, and infants. The application of advanced oxidation processes (AOPs) showed efficient removal of many pesticide classes. The combination of adsorption followed by biodegradation was shown to be an effective and efficient purification option. In conclusion, the consumption of water contaminated with pesticide residues may pose risks to human health in exposed populations.

The state of persistent organic pollutants in South African estuaries: A review of environmental exposure and sources

The long-term health of many South African estuaries is impacted by pollutants entering these systems through industrial and agricultural runoff, sewage outfalls, contaminated storm water drainage, flows from informal settlements, and plastic materials in marine debris. Uncontrolled inputs combined with poor environmental management often result in elevated levels of persistent organic pollutants (POPs) in affected estuaries. Data on POPs research from 1960 to 2020 were analysed in terms of their sources, environmental investigations, and health implications. The outcome showed polychlorinated biphenyls (PCBs) and per- and poly-fluoroalkyl sulphonates (PFASs) to exceed the US EPA health advisory levels for drinking water. Concentration of organochlorine pesticides (OCPs) in water were below the WHO limits, while those in fish tissues from most estuaries were found to be below the US FDA limits. Although environmental compartments in some estuaries (e.g. Rooiels and uMngeni estuaries) seem to be less contaminated relative to other marine systems around the world, many others were polluted and critically modified (e.g. Durban Bay, Swartkops, Sundays, and Buffalo systems). Due to inconsistent monitoring methods coupled with limited data availability, temporal trends were unclear. Of the 290 estuaries in South Africa, 65 were prioritised and recommended for POPs evaluation based on their pollution sources, and a monitoring strategy was defined in terms of sampling. Government policies to curb marine pollution need to be enforced to prevent chronic contamination that leads to water quality deterioration and loss of ecosystem services.

Emerging organic contaminants in shallow groundwater underlying two contrasting peri-urban areas in Uganda

This study investigated the occurrence and seasonal variation in concentrations of emerging organic contaminants (EOCs) in shallow groundwater underlying two peri-urban areas of Bwaise (highly urbanised) and Wobulenzi (moderately urbanised) in Uganda. Twenty-six antibiotics, 20 hydrocarbons, including 16 polycyclic aromatic hydrocarbons (PAHs), and 59 pesticides were investigated. Ampicillin and benzylpenicillin were the most frequently detected antibiotics in both areas, although at low concentrations to cause direct harm to human health, but could lead to a proliferation of antibiotic resistance genes. The most frequently detected hydrocarbons in Bwaise were naphthalene and xylene while anthracene and fluoranthene were the most frequent in Wobulenzi, also at low concentrations for ecological impact at long-term exposure. Molecular diagnostic ratios indicated pyrogenic and pyrolytic sources of PAHs in both areas. Cypermethrin (for vermin control) was the most frequent pesticide in Bwaise while metalaxyl (attributed to agriculture) was the most frequent in Wobulenzi. Banned organochlorines (8) were also detected in both areas in low concentrations. The pesticide concentrations between the two areas significantly differed (Z = - 3.558; p < 0.01), attributed to contrasting land-use characteristics. In Wobulenzi (wet season), the total pesticide concentrations at all the locations exceeded the European Community parametric guideline value while 75% of the detected compounds exceeded the individual pesticide guideline value. Thus, the antibiotic and pesticide residues in shallow groundwater underlying both Bwaise and Wobulenzi pose potential adverse ecological effects at long-term exposure. Monitoring of EOCs in both highly and moderately urbanised catchments should be strengthened towards mitigating associated risks.

Natural archives of long-range transported contamination at the remote lake Letšeng-la Letsie, Maloti Mountains, Lesotho

Naturally accumulating archives, such as lake sediments and wetland peats, in remote areas may be used to identify the scale and rates of atmospherically deposited pollutant inputs to natural ecosystems. Co-located lake sediment and wetland cores were collected from Letšeng-la Letsie, a remote lake in the Maloti Mountains of southern Lesotho. The cores were radiometrically dated and analysed for a suite of contaminants including trace metals and metalloids (Hg, Pb, Cu, Ni, Zn, As), fly-ash particles, stable nitrogen isotopes, polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants such as polychlorinated biphenyls (PCBs), polybrominated flame retardants (PBDEs) and hexachlorobenzene (HCB). While most trace metals showed no recent enrichment, mercury, fly-ash particles, high molecular weight PAHs and total PCBs showed low but increasing levels of contamination since c.1970, likely the result of long-range transport from coal combustion and other industrial sources in the Highveld region of South Africa. However, back-trajectory analysis revealed that atmospheric transport from this region to southern Lesotho is infrequent and the scale of contamination is low. To our knowledge, these data represent the first palaeolimnological records and the first trace contaminant data for Lesotho, and one of the first multi-pollutant historical records for southern Africa. They therefore provide a baseline for future regional assessments in the context of continued coal combustion in South Africa through to the mid-21st century.

A critical review of different factors governing the fate of pesticides in soil under biochar application

Pesticides are extensively used in the modern agricultural system. The inefficient and extensive use of pesticides during the last 5 to 6 decades inadvertently led to serious deterioration of environmental quality with health risk to living organisms, including humans. It is important to use some environmentally-friendly and sustainable approaches to remediate, restore and maintain soil quality. Biochar has gained considerable attention globally as a promising soil amendment because it has the ability to adsorb and as such minimize the bioavailability of pesticides in soils. This review emphasizes the recent trends and implications of biochar in pesticide-contaminated soils, as well as highlights need of the pesticides use and associated environmental issues in context of the biochar application. The overarching aim of this review is to signify the role of biochar on primary processes such as effect of biochar on the persistence, mineralization, leaching and efficacy of pesticides in soil. Notably, the effects of biochar on pesticide adsorption-desorption, degradation and bioavailability under various operating/production conditions are critically discussed. This review delineates the indirect impact of biochar on pesticides persistence in soils and proposes key recommendations for future research which are essential for the remediation and restoration of pesticides-impacted soils.

Occurrence of organochlorine pesticide residues in biological and environmental matrices in Africa: A two-decade review

The widespread use of organochlorine pesticides (OCPs), essentially for the control of insects and the cultivation of food crops, has led to the pollution of ecosystems. Despite being banned several years ago in the developed world, extensive use remains ongoing on the African continent. This review summarizes the occurrence, distributions, sources, and trends of OCPs in seven environmental matrices (atmosphere, water, sediments, soils, biota, human fluids and food products) in Africa. Findings in this review revealed that α-HCH, β-HCH dichlorodiphenyltrichloroethane (DDTs), and endosulfans were the most persistent OCP residues in the African environment, particularly DDTs in breast milk samples occurring in levels above the WHO stipulated limits, thus indicating a call for concern. Also, there was paucity of data available on OCP concentrations in ambient air. Future research efforts should prioritize testing these pollutants in the atmosphere, especially in countries where they are used more frequently. While most POP analysis studies used gas chromatography coupled to electron capture detector or mass spectrometer, it is recommended that further studies should use more sensitive analytical techniques such as gas chromatography with tandem mass spectrometry (GC-MS/MS), or gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS). These instruments allow for the detection of secondary and tertiary metabolites, especially those found in water, biota and food products, which are critical vectors of OCPs to human and animal bodies. Training of farmers and other domestic users on the handling of pesticides is proposed.

Occurrence and risk evaluation of organochlorine contaminants in surface water along the course of Swartkops and Sundays River Estuaries, Eastern Cape Province, South Africa

Organochlorine contaminants were analysed in surface water from Sundays (SDE) and Swartkops Estuaries (SWE), Eastern Cape Province, which is among the largest estuaries in South Africa. The concentration of Σ₁₈OCPs ranged from 16.7 to 249.2 ng/L in autumn, 19.9-81.4 ng/L in winter, 43.6-126.8 ng/L in spring and 68.3-199.9 ng/L in summer for SDE, whereas in SWE, the values varied from 20.9 to 259.7 ng/L in autumn, 58.9-263.9 ng/L in winter, 3.2-183.6 ng/L in spring and 118.0-188.9 ng/L in summer. Among all OCPs, α-HCH, β-HCH, p,p'-DDE, p,p'-DDT, endrin, dieldrin and endrin aldehyde were predominant in surface water samples from SDE and SWE. Furthermore, the mean concentration of polychlorinated biphenyls (PCBs) ranged from 126.7 ng/L in winter to 151.0 ng/L in spring for SDE and 249.0 ng/L in spring to 727.6 ng/L in winter for SWE. Tri- and tetra-PCBs dominated the PCB homologue profile. Hierarchical cluster analysis grouped the study sites into three regions from least polluted to most polluted, indicated that SWE is more polluted compared to SDE, probably due to the influx of agricultural and industrial effluents. Carcinogenic and non-carcinogenic risk assessment revealed that the water from both estuaries is not safe for drinking, although suitable for bathing.

Oxidative stress potential of the herbicides bifenox and metribuzin in the microalgae Chlamydomonas reinhardtii

The widespread presence of herbicides in the aquatic environment has raised awareness about the need to develop further in depth ecotoxicological risk assessments, more specifically on potential effects on photosynthetic organisms as microalgae. The majority of the information available regarding the toxicity of herbicides towards microalgae is related to traditional toxicological and regulatory-relevant endpoints such as growth inhibition, leaving a significant gap on knowledge regarding underlying interactions and damage to biological targets. In this context, this study aimed to supplement the general toxicity information of bifenox and metribuzin in the microalgae Chlamydomonas reinhardtii using a battery of selected high-throughput methods. This multiple-endpoint approach included the measurement of formation of reactive oxygen species (ROS), alterations in reduced glutathione (GSH) content, formation of lipid peroxidation (LPO), photosystem II (PSII) performance and loss of photosynthetic pigments after 24 h exposure. Results obtained showed that both herbicides caused a concentration-dependent increase in ROS formation, with bifenox showing higher but less reactive ROS. This increase in ROS production by bifenox and metribuzin was followed by alterations in the antioxidant capacity of algae, oxidative damage in the form of LPO and alterations in pigment content. Furthermore, both herbicides impacted the photosynthetic activity of algae, as seen by alterations in the maximum and effective quantum efficiency of PSII, PSII photochemistry and energy dissipation pathways, impact in the water-splitting apparatus and reduction in the electron transport rate. The inhibitory effect of metribuzin on photosynthetic processes/components was larger than that seen for bifenox. The impact of bifenox and metribuzin in the photosynthetic processes of C. reinhardtii seems to be in close association with the formation of ROS and consequent oxidative stress and damage in algal cells. Overall, this study showed that the high-throughput methods developed could successfully characterise both potential Modes of Action and adverse effects of bifenox and metribuzin in C. reinhardtii.

A review of environmental and health effects of organochlorine pesticide residues in Africa

Organochlorine pesticides (OCPs) are generally categorized as chlorinated cyclodienes, chlorodiphenylethanes, chlorinated benzenes and cyclohexanes. The presence of OCP residues in foodstuffs, water, soil, sediments, blood serum and air has generated a surge of global interest. This is due to their severe environmental and health ill-effects. OCPs are characteristically described as persistent and bio-accumulating substances prone to long-range transportation. The aim of this present study is to assess the environmental and health risks associated with OCP residues. Published works on OCPs in surface water, sediments and fish samples were reviewed. Possible non-carcinogenic (Hazard Quotient, HQ and Hazard Index, HI) and carcinogenic (Cancer Risk, CR) health effects of OCPs were assessed in fish samples. High concentrations of OCP residues were determined in environmental samples from African countries. The non-carcinogenic health assessment of OCPs in most fish samples from Nigeria revealed HI values greater than 1.0 establishing their adverse effects. The CR data of OCPs in fish samples also showed values higher than the permissible standard of 1.0 × 10^-4 indicating possible development of cancer through fish consumption.

Synergistic rhizosphere degradation of γ-hexachlorocyclohexane (lindane) through the combinatorial plant-fungal action

Fungi are usually involved in degradation/deterioration of many anthropogenic wastes due to their verse enzyme secretions and adaptive capabilities. In this study, five dominant fungal strains were isolated from an aged lindane polluted site, they were all mixed (100 mg each) together with pent mushroom compost (SMC) and applied to lindane polluted soil (5 kg) at 10, 20, 30, 40% and control 0% (soil with no treatment), these were used to grow M. maximus Jacq for 3 months. To establish lindane degradation, deductions such as Degradation rate (K1), Half-life (t1/2) and Degradation efficiency (DE) were made based on the analyzed lindane concentrations before and after the experiment. We also tested the presence and expressions of phosphoesterases (mpd and opd-A) and catechol 1,2-dioxygenases (efk2 and efk4) genes in the strains. The stains were identified as Aspergillus niger (KY693970); Talaromyces atroroseus (KY488464), Talaromyces purpurogenus (KY488468), Yarrowia lipolytica (KY488469) and Aspergillus flavus (KY693973) through morphological and molecular methods. Combined rhizospheric action of M. maximus and fungi speed up lindane degradation rate, initially detected lindane concentration of 45 mg/kg was reduced to 11.26, 9.34 and 11.23 mg/kg in 20, 30 and 40% treatments respectively making 79.76, 85.93 and 88.67% degradation efficiencies. K1 of 1.29 was recorded in control while higher K1 of 1.60, 1.96 and 2.18 /day were recorded in 20, 30 and 40% treatments respectively. The best t1/2 of 0.32 and 0.35 /day were recorded in 40 and 30% compared to control (0.54 /day). All the strains were also affirmed to possess the tested genes; opd was overexpressed in all the strains except KY693973 while mpd was overexpressed in KY693970, KY488464 but moderately expressed in KY488468, KY488469 and KY693973. However, efk genes were under-expressed in most of the strains except KY488469 and KY693973 which showed moderate expression of efk4. This work suggests that the synergistic association of the identified rhizospheric fungi and M. maximus roots could be used to remove lindane in soil at a limited time period and this combination could be used at large scale.

Status of pesticides pollution in Tanzania - A review

Various studies have been conducted in Tanzania to assess the magnitude of pesticides pollution associated with pesticides application, storage, disposal as well as knowledge of farmers on pesticides handling. The studies analysed samples from different matrices covering vegetation, biota, water, sediments and soil. The objective of this review was to summarise the results of pesticides residues reported in different components of the environment to give a clear picture of pesticides pollution status in the country for law enforcement as well as for taking precaution measures. Gaps which need to be filled in order to establish a comprehensive understanding on pesticides pollution in the country have also been highlighted. Reviewed studies revealed that, most of the samples contained pesticides below permissible limits (WHO, FAO, US-EPA) except for few samples such as water from Kikavu river, Kilimanjaro region and Kilolo district, Iringa region which were detected with some Organochlorine pesticides (OCPs) above WHO permissible limits. Some soil samples from the former storage sites also contained pesticides above FAO permissible limits. Pesticides and their metabolites were also detected both in vegetation, food and biota samples. The prevalent pesticides in the reviewed studies were the organochlorines such as Dichlorodiphenyltrichloroethane (DDT), endosulfan and Hexachlorocyclohexane (HCH). Surveys to assess farmer's knowledge on pesticides handling observed poor understanding of farmers on pesticides storage, application and disposal. Decontamination of former storage areas, continuous monitoring of pesticide applications and training of farmers on proper handling of pesticides are highly recommended.

Assessment of organochlorine pesticide residues in raw food samples from open markets in two African cities

This study investigates the level of organochlorine pesticides in the raw food from open markets in Kinshasa, Democratic Republic of Congo (DRC), and Johannesburg, South Africa. It assesses the potential health risks associated with the organochlorine pesticide residues. The Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method has been developed for sample preparation. A total of 120 food samples (beans, cabbage, beef, and fish) were obtained from the open markets. The mean concentrations of organochlorine pesticides in raw foods collected from the Johannesburg market were significantly higher (p < 0.05) than those from the Kinshasa market. DDE recorded the highest mean concentration (253.58 ± 4.78 μg kg^-1) in beef from Johannesburg, and α-BHC recorded the lowest mean concentration (38.54 ± 7.46 μg kg^-1) in beans from Kinshasa. The investigation of health risk estimates revealed that the number of organochlorine pesticides exceeded the reference dose in the collected food samples.

Organochlorine Pesticide Residues in Sediments and Waters from Cocoa Producing Areas of Ondo State, Southwestern Nigeria

This study investigated levels of organochlorine pesticide (OCP) residues in water and sediment samples from eleven rivers serving as drinking water sources and receiving runoff from nearby cocoa plantations in Ondo State, Nigeria. Twenty-two composite samples of surface water and sediments (0–3 cm) were collected randomly using grab technique and replicated thrice per season. The efficiency of the two techniques [supercritical fluid extraction (SFE) and liquid/liquid extraction (LLE)] was evaluated with percentage analyte recoveries to for SFE and to 1 for LLE. Determination of OCPs by gas chromatography with electron capture detection gave higher concentrations for sediments compared to the equivalent water samples. The commonly occurring pesticide residues in the sediments were (range, μg g−1) cis-chlordane 0.03–6.99; α-endosulfan 0.03–6.99; p,p′-DDE 0.08–19.04; and dieldrin 0.01–7.62; in the sediments and dieldrin (not detected-1.51 μg L−1) in water samples, during the dry season. OCP levels were significantly higher in dry season than wet season among the rivers. The study concluded that most of the rivers in cocoa growing areas were contaminated with OCPs associated with agricultural activities.

Phytotoxicity, bioaccumulation and degradation of isoproturon in green algae

Isoproturon (IPU) is a pesticide used for protection of land crops from weed or pathogen attack. Recent survey shows that IPU has been detected as a contaminant in aquatic systems and may have negative impact on aquatic organisms. To understand the phytotoxicity and potential accumulation and degradation of IPU in algae, a comprehensive study was performed with the green alga Chlamydomonas reinhardtii. Algae exposed to 5-50 μg L(-1) IPU for 3d displayed progressive inhibition of cell growth and reduced chlorophyll fluorescence. Time-course experiments with 25 μg L(-1) IPU for 6d showed similar growth responses. The 72 h EC50 value for IPU was 43.25 μg L(-1), NOEC was 5 μg L(-1) and LOEC was 15 μg L(-1). Treatment with IPU induced oxidative stress. This was validated by a group of antioxidant enzymes, whose activities were promoted by IPU exposure. The up-regulation of several genes coding for the enzymes confirmed the observation. IPU was shown to be readily accumulated by C. reinhardtii. However, the alga showed a weak ability to degrade IPU accumulated in its cells, which was best presented at the lower concentration (5 μg L(-1)) of IPU in the medium. The imbalance of accumulation and degradation of IPU may be the cause that resulted in the detrimental growth and cellular damage.

Molecular dissection of atrazine-responsive transcriptome and gene networks in rice by high-throughput sequencing

The residue of atrazine (a herbicide) has become hazards in environments due to its intensive use. However, its molecular toxicity to on plants and human beings is not fully understood. In this study, we performed high-throughput sequencing of atrazine-exposed rice (Oryza sativa) to analyze global expression and complexity of genes in the crop. Four libraries were constructed from shoots and roots with or without atrazine exposure. We sequenced 5,751,861, 5,790,013, 5,375,999 and 6,039,618 clean tags that corresponded to 220,806, 111,301, 248,802 and 114,338 distinct tags for Root-Atr (root control, atrazine-free), Shoot-Atr (shoot control, atrazine-free), Root+Atr (root treated with atrazine) and Shoot+Atr (shoot treated with atrazine) libraries, respectively. Mapping the clean tags to gene databases generated 18,833-21,007 annotated genes for each library. Most of annotated genes were differentially expressed among the libraries. The most 40 differentially expressed genes were associated with resistance to environmental stress, degradation of xenobiotics and molecular metabolism. Validation of gene expression by quantitative RT-PCR confirmed the deep-sequencing results. The transcriptome sequences were further subjected to Gene Orthology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and showed modified biological functions and metabolic pathways. Our results not only highlight the transcriptional complexity in rice with atrazine but also represent a major improvement for analyzing transcriptional changes on a large scale in xenobiotics-responsive toxicology.

Bioaccumulation and catabolism of prometryne in green algae

Investigation on organic xenobiotics bioaccumulation/biodegradation in green algae is of great importance from environmental point of view because widespread distribution of these compounds in agricultural areas has become one of the major problems in aquatic ecosystem. Also, new technology needs to be developed for environmental detection and re-usage of the compounds as bioresources. Prometryne as a herbicide is widely used for killing annual grasses in China and other developing countries. However, overuse of the pesticide results in high risks to contamination to aquatic environments. In this study, we focused on analysis of bioaccumulation and degradation of prometryne in Chlamydomonas reinhardtii, a green alga, along with its adaptive response to prometryne toxicity. C. reinhardtii treated with prometryne at 2.5-12.5 μg L(-1) for 4 d or 7.5 μg L(-1) for 1-6 d accumulated a large quantity of prometryne, with more than 2 mg kg(-1) fresh weight in cells exposed to 10 μg L(-1) prometryne. Moreover, it showed a great ability to degrade simultaneously the cell-accumulated prometryne. Such uptake and catabolism of prometryne led to the rapid removal of prometryne from media. Physiological and molecular analysis revealed that toxicology was associated with accumulation of prometryne in the cells. The biological processes of degradation can be interpreted as an internal tolerance mechanism. These results suggest that the green alga is useful in bioremediation of prometryne-contaminated aquatic ecosystems.

Endocrine disrupting chemicals in New Orleans surface waters and Mississippi Sound sediments

Endocrine disrupting compounds (EDCs), represented by steroid hormones, organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and bisphenol A have been determined in four sediment cores from the Gulf of Mexico, from New Orleans surface water (Lake Pontchartrain and Mississippi River), and from the influent and effluent of a New Orleans municipal sewage treatment plant. During the five-month monitoring of selected EDCs in the Mississippi River (MR) and Lake Pontchartrain (LP) in 2008, 21 of 29 OCPs in MR and 17 of 29 OCPs in LP were detected; bisphenol A was detected in all of the samples. Steroid hormones (estrone, 17β-estradiol and 17α-ethinylestradiol) were detected occasionally. Total EDC (OCPs + PCBs + steroid hormones + bisphenol A) concentrations in the two surface water samples were found to vary from 148 to 1112 ng L(-1). Strong correlation of the distribution of total OCPs, total PCBs and total EDCs between solid and water phases was found in LP, while moderate or no correlation existed in MR. OCPs, PCBs, steroid hormones, and bisphenol A were all detected in the ocean sediments, and total EDCs were measured in the range of 77 to 1796 ng g(-1) dry sediment weight. The EDCs were also found in untreated and treated municipal sewage samples with a removal efficiency of 83% for OCPs but no removal efficiency for 17α-ethinylestradiol.

Bioaccumulation and degradation of pesticide fluroxypyr are associated with toxic tolerance in green alga Chlamydomonas reinhardtii

The herbicide fluroxypyr is widely used for controlling weeds and insects but intensive use of fluroxypyr has resulted in its widespread contamination in soils and aquatic ecosystems. To evaluate the eco-toxicity of fluroxypyr to green algae, bioaccumulation and degradation of fluroxypyr in Chlamydomonas reinhardtii, a model unicellular alga, along with its biological adaptation to fluroxypyr toxicity were investigated. The microalgae were treated with fluroxypyr at 0.05-1.00 mg l(-1) for 2 days or 0.50 mg l(-1) for 1-5 days. The growth of C. reinhardtii was stimulated at low levels of fluroxypyr (0.05-0.5 mg l(-1)) but inhibited at high concentrations (0.75-1.00 mg l(-1)). Fluroxypyr was significantly accumulated by C. reinhardtii. Interestingly, the accumulated fluroxypyr could be rapidly degraded in the cells. On day 5 more than 57% of cellular fluroxypyr was degraded. Our results indicated that accumulation and degradation of fluroxypyr occurred simultaneously. Treatment with 0.05-1.00 mg l(-1) fluroxypyr for 30 min induced significant production of reactive oxygen species and as a consequence resulted in accumulation of peroxides and DNA degradation. Additionally, activities of several major antioxidant enzymes were activated in C. reinhardtii exposed to high levels of fluroxypyr. Overall, the present studies represent the initial comprehensive analyses of the green alga C. reinhardtii in adaptation to the fluroxypyr-contaminated aquatic ecosystems.

Reproductive toxicity in male mice caused by organic extracts in tap water from the Jialing River in Chongqing, China

BACKGROUND

Recently, male reproductive disturbances caused by organic pollutants have aroused particular public concern about the safety of drinking water. The aim of this study was to investigate the toxicity of organic extracts (OE) in tap water from the source of the Jialing River in China on the reproductive system of male mice.

METHODS

Kunming male mice were randomly divided into four groups, which included a solvent control (dimethylsulfoxide), a low-, mid-, and high-dose of OE (12.5, 25, and 50 l/kg bw/day, respectively) treated groups. Mice were administered intraperitoneal injections of OE at different doses for five consecutive days. On the 15th day, after treatments, the mice were sacrificed.

RESULTS

The results showed that the number of epididymal sperm in the high OE group was decreased significantly (p<0.05); however, the frequency of sperm abnormalities in all treated groups were increased significantly (p<0.05). In addition, serum testosterone and follicle-stimulating hormone levels in the treated groups were also decreased significantly (p<0.05), and mid- and high-doses of OE resulted in a significant decrease in the activity of acid phosphatase and increased activity of γ-glutamyl transpeptidase (p<0.05). Histological changes were observed in the mid- and high-dose OE-treated groups.

CONCLUSIONS

The findings of this study suggest that mid and high doses of OE could disturb the male reproductive system in mice. The potential adverse effects of these compounds on the male reproductive system are worthy of further study.

Evaluation of ovotoxicity in female mice caused by organic extracts in tap water from Jialing River in Chongqing, China

BACKGROUND

Recently, toxic effects of widespread organic pollutants have received much attention due to the hazards they pose to female reproductive health. The aim of the present study was to determine the female reproductive toxicity of organic extracts (OE) in tap water from the Jialing River in Chongqing, China.

METHODS

In our experiment, Kunming female mice that exhibited normal estrous cycles were randomly divided into 4 groups, which included a control group (OE 0 L/kg bw) as well as low- (OE 12.5 L/kg bw/day), mid- (OE 25 L/kg bw/day), and high-dose (OE 50 L/kg bw/day) groups. Mice were continually administered intraperitoneal injections of OE at different doses for 5 consecutive days. On the 15th and 30th day after treatments, half of the mice were sacrificed separately.

RESULTS

The results showed that OE decreased relative ovary weights and prolonged the duration of estrous cycle with concomitant increase in estrous phase. There was a significant decrease in the number of corpora lutea of OE-treated mice, but no significant differences were found in healthy and atretic follicle populations compared to control. Ultrastructure observation regarding granulosa cells of the ovary revealed that OE treatment caused mitochondrial swelling together with endoplasmic reticulum expansion.

CONCLUSIONS

All these data indicate that OE could exert adverse effects on the development of ovary and also a slight suppressive effect on reproductive functions.

Comparison of the sensitivity of different toxicity test endpoints in a microalga exposed to the herbicide paraquat

The use of herbicides constitutes the principal method of weed control but the introduction of these compounds into the aquatic environment can provoke severe consequences for non-target organisms such as microalgae. Toxic effects of these pollutants on microalgae are generally evaluated using phytotoxicity tests based on growth inhibition, a population-based parameter. However, physiological cellular endpoints could allow early detection of cell stress and elucidate underlying toxicity mechanisms. Effects of the herbicide paraquat on the freshwater microalga Chlamydomonas moewusii were studied to evaluate growth rate and cellular parameters such as cellular viability and metabolic activity assayed by flow cytometry and DNA damage assayed by the comet assay. Sensitivity of growth and parameters assayed by flow cytometry were similar, showing a significant effect in cultures exposed to a paraquat concentration of 0.1 microM or higher, although in cultures exposed during 48 h to 0.05 microM, a significant stimulation of cellular fluorescein fluorescence was observed, related to cellular metabolic activity. After only 24 h of herbicide exposure significant DNA damage was observed in microalgal cells exposed to all paraquat concentrations assayed, with a 23.67% of comets in cultures exposed to 0.05 microM, revealing the genotoxicity of this herbicide. Taking into account the results obtained, comet assay provides a sensitive and rapid system for measuring primary DNA damage in Chlamydomonas moewusii, which could be an important aspect of environmental genotoxicity monitoring in surface waters.

Assessment of organochlorine pesticide pollution in Upper Awash Ethiopian state farm soils using selective pressurised liquid extraction

Upper Awash Agro Industry Enterprises (UAAIE) is one of the major state farms in Ethiopia with known large-scale pesticide use. Although organochlorine pesticides (OCPs) have been applied for about three decades, no studies have been carried out on levels of residue in the region. In this work a fast selective pressurised liquid extraction (SPLE) methodology has successfully been applied for screening of 13 OCPs in 12 soil samples from different fields in UAAIE, which further strengthen this methodology. Quantitative and qualitative analyses were done using a dual column gas chromatography-electron capture detection system (GC-ECD) and a GC equipped with a mass spectrometer (MS), respectively. The main contaminants identified comprised of previously used persistent organic pollutants (POPs) and currently used insecticides. Low concentrations or non-detectable levels of certain OCPs (aldrin, dieldrin, endrin, and heptachlor) indicate a positive phasing out of these persistent organic pollutants (POPs). Similarly HCHs were found in few soils and at low concentrations. Endosulfans and DDTs were detected in substantial amounts in the soils with Sigmaendosulfans up to 56000 and SigmaDDTs up to 230 ng g(-1) dry weight, which is a threat to the surrounding and downstream ecosystems, especially considering that the investigated OCPs constituted 29000 l of the 63000 l of pesticide applied annually on the fields. Additional concerns must be raised concerning synergistic effects of all pesticides added.

Pesticide residues in rain water from Hisar, India

Presence of pesticide residues was studied in rain water during 2002 employing multi residue analysis method by gas liquid chromatography equipped with ECD and NPD detectors and capillary columns. The presence of pesticide residues in surface aquatic system triggered the investigation of the presence of pesticides in rain water. A total of 13 pesticides were detected in rain water samples. Among the different groups of pesticides, organochlorines were present in the range of 0.041-7.060 ppb with maximum concentration of p,p'-DDT up to 7.060 microg l(-1). Synthetic pyrethroids were present ranging from 0.100 to 1.000 microg l(-1) and organophosphates in the range of 0.050-4.000 microg l(-1) showing maximum contamination with cypermethrin (1.000 microg l(-1)) and monocrotophos (4.000 microg l(-1)) of the respective groups. Almost 80% samples showed the residues above MRL of 0.5 ppb fixed for multi residues and on the basis of single pesticide, 16-50% samples contained residues above the MRL value of 0.1 ppb.

Sample preparation for chromatography: An African perspective

Africa as a continent has its unique challenges for analytical chemists in sample preparation for chromatographic analyses. The areas of agriculture, environment, food and health provide formidable challenges when it comes to method development, for example, drought can result in inadequate supplies of good quality water. The testing of water quality necessitates the development of assay methods that can be employed to not only determine the quantities of pesticides associated with malaria and tsetse fly eradication programmes, but also to monitor mycotoxins or neurotoxins. Urbanisation has also meant that endocrine disruptors such as phthalate esters need to be monitored. This review will profile some of the activities by analytical chemists practising in the African continent, who seek to address some of the challenges in sample preparation for chromatographic analyses.