Comparative Study of Mercury Accumulation in Two Fish Species, (<Emphasis Type="Italic">Cyprinus carpio</Emphasis> and <Emphasis Type="Italic">Sander lucioperca</Emphasis>) from Anzali and Gomishan Wetlands in the Southern Coast of the Caspian Sea

Anzali and Gomishan wetlands are considered as two of the most important wetlands in southern coast of Caspian Sea. To investigate mercury accumulation in these ecosystems, total mercury concentrations were measured in the muscle tissue of two fish species. Higher mercury concentrations were detected in C. carpio, an omnivorous benthic/pelagic species (Anzali wetland: 0.2 μg g⁻¹ wet weight; Gomishan wetland: 0.2 μg g⁻¹ wet weight), than in S. lucioperca, a carnivorous pelagic species (Anzali: 0.06 μg g⁻¹ wet weight; Gomishan: 0.15 μg g⁻¹ wet weight).     

Mercury and Selenium Content in <Emphasis Type="Italic">Otolithes ruber</Emphasis> and <Emphasis Type="Italic">Psettodes erumei</Emphasis> from Khuzestan Shore,Iran

In this paper the level of selenium and mercury is analyzed in edible part and liver of Psettodes erumei and Otolithes ruber two commercial fish in Persian Gulf. The average concentration of Hg and Se in edible parts of P. erumei was 0.077 ± 0.062 and 0.044 ± 0.018 (μg g⁻¹ww), and in liver was 0.127 ± 0.122 and 0.132 ± 0.610 (μg g⁻¹ww) respectively. In O. ruber, the average concentration of Hg and Se in edible parts was 0.348–0.27 and 0.06 ± 0.021 (μg g⁻¹ww) and in liver was 0.176 ± 0.174 and 0.093 ± 0.022 (μg g⁻¹ww), respectively. P. erumei has higher mean molar ratio Se/Hg (1.98) compared to O. ruber (0.88).     

Selective Bactericidal Potential of Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L. var. <Emphasis Type="Italic">japonica</Emphasis>) Hull Extract on <Emphasis Type="Italic">Microcystis</Emphasis> Strains in Comparison with Green Algae and Zooplankton

We examined the selective inhibitory potential of rice hull extract on the toxic cyanobacterium Microcystis aeruginosa, in comparison with inhibitory effects on two green algae (Ankistrodesmus convolutus and Scenedesmus quadricauda) and a zooplankton (Daphnia magna) species. The inhibitory effect of rice hull extract, measured by algal growth or zooplankton survival using four different concentrations of extract (1, 10, 100 and 1000 μg L⁻¹), was highest on Microcystis strains (average: 98%, range: 95%–99%), followed by D. magna (average: 22%, range: 10%–47%), A. convolutus (average: 20%, range: 16%–24%), and S. quadricauda (average: 8%, range: 0%–15%). Rice hull extract had only a small effect on the growth of the green algae and Daphnia, particularly in the range 1–100 μg L⁻¹, and the inhibitory effect was somewhat diminished even at the 1,000 μg L⁻¹ level, at the end of the experimental period, especially for Daphnia. Our study indicates that rice hull extract has a strong specific algicide potential when used to combat M. aeruginosa.     

Temporal Variation of Metals in Water,Sediment and Tissues of the European Chup (<Emphasis Type="Italic">Squalius cephalus</Emphasis> L.)

The aim of this study was to analyze seasonal variation of levels of Chromium (Cr), Manganese (Mn), Nickel (Ni), Copper (Cu), Zinc (Zn), Cadmium (Cd) and Lead (Pb) in water, sediment and tissues of Squalius cephalus (L., 1758) taken from five different stations chosen at Yamula Dam Lake (Kayseri, Turkey). Concentrations of metals were generally sorted as water<tissue<sediment. The highest concentration of metals in water was observed in the samples taken in the summer (Mn, 1.04 ± 0.15 mg L⁻¹; Ni, 0.42 ± 0.12 mg L⁻¹; Cu, 1.25 ± 0.88 mg L⁻¹; Zn, 3.61 ± 1.53 mg L⁻¹; Pb, 0.58 ± 0.09 mg L⁻¹). While the highest Zn (24.85 ± 21.82 μg g⁻¹) and Pb (10.89 ± 4.2 μg g⁻¹) concentrations in sediment were observed in the winter samples, the highest Mn concentration (167.2 ± 99.37 μg g⁻¹) was observed in the summer. Cd pollution was determined in sediment according to international criteria. The highest metal concentration in tissues was generally observed in the liver and the other tissues; following liver were gills and muscles. In liver tissues, while the highest accumulation of Zn (110.34 ± 13.1) and Mn (22.5 ± 14.85 μg g⁻¹), which are essential for the body, were observed in the winter, Pb (22.58 ± 7.83 μg g⁻¹) and Cd (11.77 ± 7.83 μg g⁻¹), which are toxic, were found to be higher in the summer. Also, concentrations of Mn, Cd and Pb in muscle tissues were found to be above the limits permitted.     

Mercury in Wetland Birds of Iran and Iraq: Contrasting Resident Moorhen, <Emphasis Type="Italic">Gallinula chloropus,</Emphasis> and Migratory Common Teal, <Emphasis Type="Italic">Anas crecca,</Emphasis> Life Strategies

We document mercury distribution in tissues of two waterfowls; moorhen (Gallinula chloropus; n = 6), and Common Teal (Anas crecca; n = 6) from Shadegan wetlands in Southwestern Iran. Mean value of mercury in moorhen liver was (0.36 Hg μg g⁻¹ dry weight), Common Teal had (4.34 Hg μg g⁻¹ dry weight) mercury. In all tissues, Common Teals had significantly higher mercury concentrations than moorhens (U test, p ≤ 0.05). Mercury was 12, 9, 8, and 6 times higher in liver, muscle, kidney, and feather of Common Teals. These birds have comparable diets but Common Teals are migratory and moorhens are residents of Shadegan wetlands.     

The Extent of Arsenic and of Metal Uptake by Aboveground Tissues of <Emphasis Type="Italic">Pteris vittata</Emphasis> and <Emphasis Type="Italic">Cyperus involucratus</Emphasis> Growing in Copper- and Cobalt-Rich Tailings of the Zambian Copperbelt

The extent of arsenic (As) and metal accumulation in fronds of the As hyperaccumulator Pteris vittata (Chinese brake fern) and in leaves of Cyperus involucratus, which grow on the surface of an old flotation tailings pond in the Zambian Copperbelt province, was studied. The tailings consist of two types of material with distinct chemical composition: (1) reddish-brown tailings rich in As, iron (Fe), and other metals, and (2) grey-green tailings with a lower content of As, Fe, and other metals, apart from manganese (Mn). P. vittata accumulates from 2350 to 5018 μg g⁻¹ As (total dry weight [dw]) in its fronds regardless of different total and plant-available As concentrations in both types of tailings. Concentrations of As in C. involucratus leaves are much lower (0.24–30.3 μg g⁻¹ dw). Contents of copper (Cu) and cobalt (Co) in fronds of P. vittata (151–237 and 18–38 μg g⁻¹ dw, respectively) and in leaves of C. involucratus (96–151 and 9–14 μg g⁻¹ dw, respectively) are high, whereas concentrations of other metals (Fe, Mn, and zinc [Zn]) are low and comparable with contents of the given metals in common plants. Despite great differences in metal concentrations in the two types of deposited materials, concentrations of most metals in plant tissues are very similar. This indicates an exclusion or avoidance mechanism operating when concentrations of the metals in substrate are particularly high. The results of the investigation show that Chinese brake fern is not only a hyperaccumulator of As but has adapted itself to high concentrations of Cu and Co in flotation tailings of the Zambian Copperbelt.     

Chlorpyrifos-Induced Toxicity in <Emphasis Type="Italic">Duttaphrynus melanostictus</Emphasis> (Schneider 1799) Larvae

This study investigates the effects of continuous exposure to a widely used organophosphate pesticide, chlorpyrifos, on survival, growth, development, and activity of larvae of the Asian common toad, Duttaphrynus melanostictus Schneider 1799. Larvae were continuously exposed to six different concentrations (1–1,500 μg l⁻¹) of commercial-grade chlorpyrifos for 14 days and monitored for 1 additional week. Chlorpyrifos at ≥1,000 μg l⁻¹ caused significantly high and dose-dependent mortality, and the weekly LC50_{7 day–21 day} values ranged from 3,003 to 462 μg l⁻¹. Larvae surviving exposure to ≥500 μg l⁻¹ chlorpyrifos showed significant growth impairment, delays in metamorphosis, and decreased swimming activity. Tail abnormalities were the most common morphologic deformity at concentrations of 1,000 and 1,500 μg l⁻¹ chlorpyrifos. The findings of the present study highlight the need to recognize the potential risk that agrochemicals pose to amphibians inhabiting agricultural landscapes in Sri Lanka and other Asian countries.     

Mercury and Selenium in a Top-Predator Fish, <Emphasis Type="Italic">Trichiurus lepturus</Emphasis> (Linnaeus, 1758), from the Tropical Brazilian Coast,Rio de Janeiro

Muscular mercury and selenium were assessed in a voracious fish from three Brazilian coastal areas with different environmental conditions. Mercury was higher in specimens from Ilha Grande Bay (0.35 ± 0.17 μg g⁻¹) than in cutlassfish from Guanabara Bay (0.30 ± 0.15 μg g⁻¹) and Buzios coast (0.13 ± 0.08 μg g⁻¹), respectively. No difference was found regarding selenium among these areas. Mercury was positively correlated with fish length and size intervals (sub-adult, small and large adult), suggesting that larger and older fish bioaccumulated more mercury. A large excess of molar selenium in relation to mercury was observed.     

Concentrations of Mercury and Other Toxic Elements in Orange Roughy, <Emphasis Type="Italic">Hoplostethus atlanticus</Emphasis>, from the Mid-Atlantic Ridge

Concentrations of the elements mercury, arsenic, cadmium and lead were measured in the muscle tissue of Orange roughy (Hoplostethus atlanticus) obtained from the Mid-Atlantic Ridge during the Mar-Eco expedition in the North Atlantic Ocean in 2004. The age of the fish varied from 1 to 139 years. To the best of our knowledge, the concentration of the heavy metals presented here is for one of the oldest fish in the literature, in addition to the fact that very little information on arsenic in Orange roughy has been previously published. The concentration of mercury in the fillet of the fish varied between 0.06 and 1.1 μg g⁻¹ w.w. Mercury was the only element that was positively correlated to the age. The concentrations of mercury were found to be below the maximum limits for Orange roughy set by EU at 1.0 μg g⁻¹ w.w, except for a 134 year fish sample with a concentration of 1.1 μg g⁻¹ w.w.     

Reproductive Consequences of Exposure to Waterborne Phytoestrogens in Male Fighting Fish <Emphasis Type="Italic">Betta splendens</Emphasis>

Phytoestrogens are plant compounds that can act as endocrine disruptors in vertebrates. Biologically active levels of phytoestrogens have been found in aquatic habitats near wood pulp and paper mills, biofuel manufacturing plants, sewage-treatment plants, and agricultural fields. Phytoestrogens are known to cause hormonal and gonadal changes in male fish, but few studies have connected these effects to outcomes relevant to reproductive success. In one experiment, we exposed sexually mature male fighting fish Betta splendens to environmentally relevant (1 μg L⁻¹) and pharmacological concentrations (1000 μg L⁻¹) of the phytoestrogen genistein as well as to a positive control of waterborne 17β-estradiol (E2; 1 μg L⁻¹), and a negative control of untreated water. In a second experiment, we exposed male B. splendens to environmentally relevant concentrations (1 μg L⁻¹) of genistein and β-sitosterol singly and in combination as well as to the positive and negative controls. All exposures were 21 days in duration. We measured sex-steroid hormone levels, gonadosomatic index (GSI), sperm concentration and motility, and fertilization success in these fish. We found that exposure to genistein did not affect circulating levels of the androgen 11-ketotestosterone or the estrogen E2 relative to negative-control fish. We also found that neither of the compounds nor their mixture affected GSI, sperm concentration or motility, or fertilization success in exposed fish relative to negative-control fish. However, fish exposed to phytoestrogens showed some evidence of fewer but more motile sperm than fish exposed to the positive control E2. We conclude that sexually mature male B. splendens are relatively immune to reproductive impairments from short-term exposure to waterborne phytoestrogens.     

Mixture Toxicity Assessment of Nickel and Chlorpyrifos in the Sea Bass <Emphasis Type="Italic">Dicentrarchus labrax</Emphasis>

The present research work was designed to study Dicentrarchus labrax biotransformation and detoxification responses to acute exposure to nickel (Ni) and chlorpyrifos (CHP). Sexually immature sea bass were treated by intraperitoneal injection of nickel chloride (500 μg kg⁻¹), chlorpyrifos (10 mg kg⁻¹), and their binary mixture for 1, 3, and 7 days. Ni and CHP accumulation was quantified in liver after the exposure periods. The following biological responses were measured: (1) NADPH cytochrome P450 reductase (NCR) activity, as phase I biotransformation parameter; (2) gluthathione S-transferase (GST) activity as a phase II conjugation enzyme, acetylcholinesterase activity, and metallothionein (MT) content. Ni bioaccumulation in the liver resulted in an increasing uptake up to 15.48 μg g⁻¹ wet weight (Ni-treated animals) and 16.73 μg g⁻¹ wet weight (mixture-treated animals) after 7 days of exposure. CHP accumulation showed a distinct pattern in animals exposed to the mixture of chemicals in comparison with CHP-treated animals. NCR activity exhibited a marked activation in CHP and mixture-treated animals. GST activity was significantly increased starting from 1 day exposure in CHP-treated animals and after 3 days in Ni-treated animals. MT accumulation increased in all conditions, with a marked synergetic effect after 7 days of exposure. These data should be carefully considered in view of the biological effects of mixture pollutants, particularly in fish farming conditions.     

Effect of Copper on Growth and Enzyme Activities of Marine Diatom, <Emphasis Type="Italic">Odontella mobiliensis</Emphasis>

The 72-h IC₅₀, 7-d no observable effect concentration (NOEC), low observable effect concentration (LOEC), Chronic values were derived for copper on the growth of marine diatom, Odontella mobiliensis. The effect of copper was also studied on cell morphology, size, nitrate reductase and antioxidant enzymes (Catalase, Superoxide dismutase and peroxidase). The 72-h IC₅₀ of 298.4 ± 28.3, NOEC of 15.6, LOEC of 29.6 and chronic value of 21.5 μg Cu L⁻¹ were found in the present study. The chlorophyll a was significantly decreased with increasing concentrations of copper. The length of the cell (apical axis) was extended from 30.14 ± 5.98 μm at control to 71.4 ± 6.29 μm at 574 μg Cu L⁻¹, the spines were absent at 574 μg L⁻¹ and the cell structure was entirely damaged at 926 μg Cu L⁻¹. The antioxidant enzymes viz. Catalase, Peroxidase activities and Melondialdehyde were increased whereas the Nitrate reductase and activity was reduced at 21.5 μg Cu L⁻¹ during 7 days exposure.     

Impact of Elevated CO<Subscript>2</Subscript> and O<Subscript>3</Subscript> Concentrations on Biogenic Volatile Organic Compounds Emissions from <Emphasis Type="Italic">Ginkgo biloba</Emphasis>

In natural environment with ambient air, ginkgo trees emitted volatile organic compounds 0.18 μg g⁻¹ h⁻¹ in July, and 0.92 μg g⁻¹ h⁻¹ in September. Isoprene and limonene were the most abundant detected compounds. In September, α-pinene accounted for 22.5% of the total. Elevated CO₂ concentration in OTCs increased isoprene emission significantly in July (p < 0.05) and September (p < 0.05), while the total monoterpenes emission was enhanced in July and decreased in September by elevated CO₂. Exposed to elevated O₃ increased the isoprene and monoterpenes emissions in July and September, and the total volatile organic compounds emission rates were 0.48 μg g⁻¹ h⁻¹ (in July) and 2.24 μg g⁻¹ h⁻¹ (in September), respectively. The combination of elevated CO₂ and O₃ did not have any effect on biogenic volatile organic compounds emissions, except increases of isoprene and Δ3-carene in September. Foundation item: The National Natural Science Foundation of China (No. 90411019).     

Effects of Nitrite and Toxic <Emphasis Type="Italic">Microcystis Aeruginosa</Emphasis> PCC7806 on the Growth of Freshwater Rotifer <Emphasis Type="Italic">Brachionus Calyciflorus</Emphasis>

Over the last two centuries, anthropogenic activities have increased the nitrogen amount in aquatic ecosystems, which has resulted in increased occurrences of blooms of cyanobacteria. This study investigated the effects of nitrite and the cyanobacterium Microcystis aeruginosa on population growth in the rotifer Brachionus calyciflorus. The rotifer was treated for 12 days with nitrite alone (medium containing 0, 3, 6, 10 mg NO₂ ⁻ –N L⁻¹), M. aeruginosa alone (medium containing 0 mg NO₂ ⁻–N L⁻¹ + 5.0 × 10⁵ cell ml⁻¹ M. aeruginosa precultured at 0, 3, 6, 10 mg NO₂ ⁻–N L⁻¹), and nitrite in combination with M. aeruginosa (medium containing 3, 10 mg NO₂ ⁻–N L⁻¹ + 5.0 × 10⁵ cell ml⁻¹ M. aeruginosa precultured at corresponding nitrite concentrations). We observed that a nitrite concentration of 10 mg NO₂ ⁻–N L⁻¹ markedly inhibited the growth of B. calyciflorus; however, rotifer growth declined slightly in the presence of M. aeruginosa precultured at 6 mg NO₂ ⁻–N L⁻¹. Furthermore, reduced population growth of B. calyciflorus was observed when it was treated with both nitrite and M. aeruginosa compared to nitrite alone or M. aeruginosa alone. These results suggested that a high tolerance of B. calyciflorus to nitrite levels may be attributed to the absence of specific respiratory structures and pigments; and that the increased toxicity of nitrite in combination with M. aeruginosa may have been due to increased production of microcystin. It is also possible that nitrite and microcystin could act in a synergistic way in causing toxicity.     

Dissipation of Pendimethalin in Soil and Its Residues in Chickpea (<Emphasis Type="Italic">Cicer arietinum</Emphasis> L.) Under Field Conditions

Disappearance of pendimethalin in the soil of chickpea (Cicer arietinum L.) at 0–110 days, and terminal residues in plant samples have been studied under field conditions. Pendimethalin was applied as pre-emergence herbicide at 750, 350 and 180 g a.i. ha⁻¹ in winter, in chickpea crop. The dissipation of pendimethalin in the chickpea field soil conditions followed first order kinetics showing a half-life of 11.23 days averaged over all doses. Low pendimethalin residues were found in plant samples. 0.025, 0.015, <0.001 μg g⁻¹ residues of pendimethalin were found in grains at 750, 350 and 185 g a.i. ha⁻¹ treatments, respectively. Much lower pendimethalin residues were found in straw viz. 0.015 to <0.001 μg g⁻¹ at 750, 350 and 185 g a.i. ha⁻¹ treatments, respectively.     

Removal of Methyl Parathion in Water,by <Emphasis Type="Italic">Dugesia dorotocephala</Emphasis>

The aim of this study was to determine the efficiency of Dugesia dorotocephala on Methyl parathion removal. An initial concentration of 1.25 μg mL⁻¹ of MeP was used to evaluate the removal capacity of planarian. A first-order removal kinetics was obtained with a disappearance rate constant (k _r) of 0.49 days⁻¹ and 69% efficiency on contaminant removal. This is significantly different (p < 0.5) from the degradation occurring in control systems, leading us to conclude that D. dorotocephala effectively removes MeP from contaminated water.     

Toxicokinetics of Waterborne Trivalent Arsenic in the Freshwater Bivalve <Emphasis Type="Italic">Corbicula fluminea</Emphasis>

Arsenite (As^III) uptake and elimination kinetics were studied in a freshwater bivalve, Corbicula fluminea, exposed to several nominal concentrations of As^III (0, 100, 300, 500, and 1000 μg L⁻¹) in a static 28-day assay, followed by a depuration stage of 14 days. At the end of each sampling time (days 0, 7, 28, and 42) whole-body portions were surveyed for total As concentrations and, complimentarily, surveyed for whole-body metallothionein (MT) induction to assess its role as a defense mechanism against exposure to As^III. Histochemical evaluation of the digestive gland was performed to verify As deposition and elimination in the tissue. Results show a significant increase in whole-body total As after 28 days of exposure for all treatments, followed by a decrease at the end of the depuration phase. Biodynamic kinetic models for As uptake and elimination were obtained from bioaccumulation data during the exposure phase, for all As treatments, by estimating uptake and elimination rate constants. Bioconcentration factors (BCFs) were estimated by the ratio of these constants. Results revealed that exposure to higher concentrations of As^III causes a decrease in BCFs, suggesting that C. fluminea triggers effective regulatory mechanisms when exposed to higher concentrations of the metalloid. Significant induction of MT was detected during the exposure phase, followed by a decrease in MT concentration to control levels after depuration for all treatments. No significant differences in MT concentrations were observed between treatments. This finding may confirm the role of MT as part of the As regulation process, but its independence relative to concentrations of As^III in water suggests that MT induction is not dose dependent. The histochemical evaluation provided clear evidence that As was effectively accumulated in the digestive gland during exposure and eliminated during depuration. The present work demonstrated that C. fluminea is capable of regulating As, even at exposures as high as 1000 μg L⁻¹ of waterborne As^III. Pedro M. Costa, Hugo M. Santos and Mário S. Diniz contributed equally to this work.     

Bioaccumulation of Aluminum by <Emphasis Type="Italic">Lemna gibba</Emphasis> L. from Secondary Treated Municipal Wastewater Effluents

In this study, Lemna gibba as a sample aquatic plant was used to remove Al from a municipal secondary waste water effluence. Lemna gibba was acclimatized to the effluent in situ. The concentration of Al in the plant samples was examined for 7 days. Lemna gibba accumulated 500 μg Al g⁻¹ on the first day and reached saturation level with an increase of 100 μg g⁻¹ on the second day. The results indicated that Lemna gibba can be used as an effective aquatic plant at low costs for the treatment of municipal secondary waste water effluent. It was also noted that the plant should be harvested every 2 days for obtaining maximum efficiency.     

Accumulation of Microcystins in Nile Tilapia, <Emphasis Type="Italic">Oreochromis niloticus</Emphasis> L., and Effects of a Complex Cyanobacterial Bloom on the Dietetic Quality of Muscles

The aim of this study was to investigate the kinetics of accumulation and elimination of microcystins in the tissues of Nile tilapia (Oreochromis niloticus) and to evaluate the effect of cyanobacterial exposure on fish muscle quality (levels of total fat and ash, protein, dry matter and the composition of saturated, monounsaturated and polyunsaturated fatty acids). Fish were exposed for 28 days to a natural cyanobacterial bloom with total microcystin concentration around 1,200 μg g⁻¹ biomass dry weight. The hepatopancreas accumulated microcystins up to 350 ng g⁻¹ fresh weight, but concentrations in muscle were generally below the detection limit (2 ng g⁻¹ fresh weight). Following the exposure, fish were moved to the clean water, but only minor microcystin removal from the hepatopancreas was observed during a 4 week depuration period. Exposures of tilapia to the complex cyanobacterial bloom had only minor and temporary impacts on the investigated parameters of dietetic quality.     

Water-Quality Parameters and Total Aerobic Bacterial and <Emphasis Type="Italic">Vibrionaceae</Emphasis> Loads in Eastern Oysters (<Emphasis Type="Italic">Crassostrea virginica</Emphasis>) From Oyster-Gardening Sites

Oyster gardening is a practice designed to restore habitat for marine life and to improve water quality. This study determined physical and chemical water-quality parameters at two oyster gardening sites in the Delaware Inland Bays and compared them with total aerobic bacteria and Vibrionaceae concentrations in Eastern oysters (Crassostrea virginica). One site was located at the end of a man-made canal, whereas the other was located in an open bay. Measured water parameters included temperature, dissolved oxygen (DO), salinity, pH, total nitrogen, nitrate, nitrite, total phosphorus, and total suspended solids. The highest Vibrionaceae levels, as determined by the colony overlay procedure for peptidases, were at the canal site in September (3.5 × 10⁵ g⁻¹) and at the bay site in August (1.9 × 10⁵ g⁻¹). Vibrionaceae levels were significantly greater during the duration of the study at the canal site (P = 0.01). This study provides the first baseline levels for total Vibrionaceae in the Delaware Inland Bays. Minimum DO readings at the bay and canal sites were 3.0 and 2.3 mg l⁻¹, respectively, far less than the state-targeted minimum threshold of 5.0 mg l⁻¹. Total phosphorus levels exceeded recommendations of ≤0.1 mg l⁻¹ at the bay and canal sites for all monthly samplings, with mean monthly highs at both sites ≥0.68 mg l⁻¹ in August. Nitrogen occasionally exceeded the recommended level of 1.0 mg l⁻¹ at both sites. Overall, waters were highly degraded from high phosphates, nitrogen, and total suspended solids as well as low DO.