Prediction of the dynamics of land use land cover using a hybrid spatiotemporal model in Iran.

Human activities are prone to be the main drivers of land use land cover (LULC) changes, which have cascading effects on the environment and ecosystem services. The main objective of this study is to assess the historical spatiotemporal distributions of LULC changes as well as estimated future scenarios for 2035 and 2045 by considering the explanatory variables of LULC changes in Zanjan province, Iran. The LULC time-series technique was applied using three Landsat images for the years 1987, 2002, and 2019. Multi-layer Perceptron Artificial Neural Network (MLP-ANN) is applied to model the relationships between LULC transitions and explanatory variables. Future land demand was calculated using a Markov chain matrix and multi-objective land optimization in a hybrid simulation model. Validation of the model's outcome was performed using the Figure of Merit index. The residential area in 1987 was 6406.02 ha which increased to 22,857.48 ha in 2019 with an average growth rate of 3.97%. Agriculture increased annually by 1.24% and expanded to 149% (890,433 ha) of the area occupied in 1987. Rangeland showed a decline concerning its area, with only about 77% (1,502,201 ha) of its area in 1987 (1,166,767 ha) remaining in 2019. Between 1987 and 2019, the significant net change was a conversion from rangeland to agricultural areas (298,511 ha). Water bodies were 8 ha in 1987, which increased to 1363 ha in 2019, with an annual growth rate of 15.9%. The projected LULC map shows the rangeland will further degrade from 52.43% in 2019 to 48.75% in 2045, while agricultural land and residential areas would be expanded to 940,754 ha and 34,727 ha in 2045 from 890,434 ha and 22,887 ha in 2019. The findings of this study provide useful information for the development of an effective plan for the study area.

Accumulation and distribution of microplastics in the sediment and coastal water samples of Chabahar Bay in the Oman Sea, Iran.

Frequency, distribution, color, and types of microplastics (<5 mm) in water and sediment of Chabahar Bay in southeastern Iran was investigated in 10 stations. Density of microplastics in water samples was between 86 and 362 particles/L (average density 218 ± 17 particle/L). In the sediment, microplastic density was between 112 and 468 particles/L (average density of 262 ± 17 particle/kg). The highest concentrations of microplastics were in stations adjacent to urban, commercial, recreational, and fishing sites. The most abundant forms in surface water and sediment were fragments (42.34%) and fibers (32.22%). Highest frequency colors were black, transparent, and white, respectively. A fourier transform infrared (FT-IR) spectrometer was used to determine micro plastic composition. Polyethylene, polyethylene terephthalate and nylon were detected. Polyethylene, a common packaging material made up 38% of the total polymers. Polyethylene terephthalate, used in clothing, liquid and food containers was found at 29% of the total microplastics.

Cd and Pb bioaccumulation in Eurasian watermilfoil (Myriophyllum spicatum) in relation to the role of metal contents in wetland sediments.

The Choghakhor Wetland in Chaharmahal and Bakhtiari Province (Iran) has a significant role in maintaining water and sediment quality, because the wetland acts as a sink for contaminants that can pollute the aquatic ecosystem and affect human health. The present study uses a simple geostatistical technique to investigate the spatial variability of Cd and Pb in the Choghakhor Wetland to link the spatial variations of sediments to heavy metal contents in Myriophyllum spicatum. It was hypothesized that the heavy metal contents in the Choghakhor Wetland sediments impacted the concentration values in macrophytes. The value of heavy metals in sediments ranges from 0.54- to 1.84-µg/g dry weight (dw) for Cd, and from 1.32- to 2.46-µg/g dw for Pb, with a mean value of 1.12- and 1.82-µg/g dw, respectively. The mean value of Cd and Pb was 1.14- and 1.67-µg/g dw, respectively, in the aquatic macrophyte Myriophyllum spicatum, with corresponding ranges of 0.9-1.83-µg/g dw and 1.33-1.95-µg/g dw. There was a spatial structure in the Cd and Pb contents in the wetland sediments, with lower contents in the northern zone despite the values quantified in the south. We observed a direct spatial relationship between the Cd content in sediments and the Cd concentration in M. spicatum, and confirmed an effect of plant uptake for Cd. However, there were no significant differences between Pb in sediments and Pb in samples of M. spicatum, which implied that other factors like discharged industrial waste could also affect the accumulation of metals in plants. It can be concluded that spatial patterns indicated differences in the territory of the sediment Cd content at the Choghakhor Wetland localization in association with sediment enrichment. However, it was surprising that Pb did not show this pattern despite anthropic pressure.

Ecological water health assessment using benthic macroinvertebrate communities (case study: the Ghezel Ozan River in Zanjan Province, Iran).

Macroinvertebrates are without spinal cord living organisms that spend their main phases of metamorphosis in water; so, changing the ecological structure of their communities represents environmental health condition. The main purpose of this study was to identify the macroinvertebrate families as a biological indicator and, consequently, determining the water ecological quality in the Ghezel Ozan River, NW Iran. The sampling was conducted at 18 stations in autumn 2017. At the same time, dissolved oxygen, temperature, turbidity, electrical conductivity, fecal and total coliform, BOD5, COD, phosphate, nitrate, nitrite, ammonia, chloride, and sulfate were measured based on APHA in each station. Then, based on the collected data, the NSFWQI, IRWQIsc, EQR, and BMWP/ASPT indices were calculated. In total, 1778 individual belong to 12 orders and 22 families were identified, which the most abundant order was Ephemeroptera by 47.8%. Except for the pH, COD, DO, and nitrogen compounds, other studied parameters were exceeded from their acceptable level. It seems that the geological characteristics are very effective in changing the parameters especially salinity. The best water quality was at Kharmaneh-Sar station (7), which runs from the protected area at high altitudes without human pressure. Also, the trend of water quality decreases from the upstream to downstream, which is completely in line with human activities. Therefore, the results of this study can well illustrate the role of land use and geology changes on the macroinvertebrate communities, which can be used to evaluate the ecological integrity of the river. Regular monitoring of river water quality and controlling and managing the quantity and quality of fish farms along the river can help in the ecological health of the river.

Survey of heavy metals in internal tissues of Great cormorant collected from southern wetlands of Caspian Sea, Iran.

The level of mercury, iron, copper, and zinc was measured in 18 Great cormorants (Phalacrocorax carbo) collected from Anzali and Gomishan wetlands in the south of the Caspian Sea. The mean level of metals in dried tissues of the muscle, liver, and kidney was 2.26, 5.71, 3.79-Hg; 943.54, 379.97, 348.05-Fe; 42.64, 14.78, 60.79-Cu, and 71.97, 134.63, 77.82-Zn, respectively (mg/kg). There was no significant different between genders in terms of accumulation of metals, except for copper in the kidney. The results of Pearson correlation showed a positive and strong relationship between the fat in the liver and mercury (r = 0.95, R2 = 0.90). Also, there was a significant difference between the values of all metals with the allowable limits presented in EPA, WHO, and CCME, where all of values were above standard levels. Thus, as the muscles of the bird are sometimes eaten by humans, this result is a serious warning. Nevertheless, the relatively high levels of heavy metals accumulated in different tissues of Great cormorant at that time are a result of their high weight and nourishment they have at the terminal days of their migration due to lack of natural physical activity. Regarding to the importance of heavy metals in birds, we suggest the same study to be conducted on the species in other seasons and wetlands.

Monitoring and assessment of water health quality in the Tajan River, Iran using physicochemical, fish and macroinvertebrates indices.

BACKGROUND: Nowadays, aquatic organisms are used as bio-indicators to assess ecological water quality in western regions, but have hardly been used in an Iranian context. We, therefore, evaluated the suitability of several indices to assess the water quality for an Iranian case study. METHODS: Measured data on biotic (fish and macroinvertebrates) and abiotic elements (28 physicochemical and habitat parameters), were used to calculate six indices for assessment of water quality and the impact of human activities in the Tajan river, Iran. GIS, uni- and multivariate statistics were used to assess the correlations between biological and environmental endpoints. RESULTS: The results showed that ecological condition and water quality were reduced from up- to downstream. The reduced water quality was revealed by the biotic indices better than the abiotic ones which were linked to a variety of ecological water quality scales. CONCLUSION: The fish index showed a strong relationship with long-term database of physicochemical parameters (12 years (94%)), whereas macroinvertebrates index is more correlated with short-term data (76%). Meanwhile, the biotic and abiotic elements in this study were also classified well by PCA. Pulp and wood plants and sand mining are indicated to have the most negative effects on the river ecosystem.

Assessment of ecological quality of the Tajan River in Iran using a multimetric macroinvertebrate index and species traits.

The objectives of this study were to assess the biological water of the Iranian Tajan River using different metrics, i.e., a Multimetric Macroinvertebrate Index (MMI) and a traits-based method. Twenty-eight physico-chemical parameters, 10 habitat factors, and abundance of macroinvertebrates were obtained for 17 sites. The Shahid-Rajaie dam divides the Tajan River into an up- and downstream part, with different land uses. Eighteen metrics were used to represent four components of ecosystem quality, including tolerance (Hilsenhoff, SIGNAL), diversity (Margalef, Shannon-Wiener, Simpson, and Evenness), abundance (total number of taxa, individuals, Ephemeroptera, Plecoptera, Trichoptera, EPT, and Insects), and composition of assemblages (% Ephemeroptera, % Plecoptera, % Trichoptera, and % EPT Taxa). The integrated MMI was calculated by averaging the obtained scores of all indices. In the next step, we gathered information on 22 biological traits of macroinvertebrates to evaluate whether (group of) traits could be identified that are indicative for specific or general stress. Result showed a decrease in MMI from upstream (very good water quality) to downstream (bad) due to human activities. Industrial activities like pulping and papermaking operations or sand mining in the downstream part had more effects than agriculture and fish ponds in the upstream part. A redundancy analysis biplot showed the variation between the modalities of trait of macroinvertebrates and their correlation with physico-chemical parameters in Tajan River. The findings show that traits can be indicative for different kind of stress but that more effort has to be put in gathering data sets to disentangle the effect of habitat quality, pollution, and the physico-chemical properties of high- versus lowland rivers.