This study evaluates the physico-chemical parameters and heavy metals in water, sediments and Tympanotonus fuscatus obtained from three sample sites along Iko River in Eastern Obolo LGA, AkwaIbom State. The heavy metal analysis results on Pb, Cd and Ni in sediments and Tympanotonus fuscatus were used to estimate the human health and ecological risk assessment of the study area. The human health risk assessment tools utilized in this study were estimated dietary intake (EDI), total hazard quotient (THQ) and hazard index (HI) while sediment pollution parameters evaluated were contamination factor (CF), contamination degree (CD), pollution load index (PLI) and geoaccumulation index (Igeo). Results obtained showed that EDI of Cd in periwinkle in the study sites ranged from 0.2 – 6.4 µg/kg-bw/day and exceeded the provisional tolerable dietary intake (PTDI), while EDI for Pb (0.0004 – 2.6 µg/kg-bw/day) and Ni (0.32 – 2 µg/kg-bw/day) was within the limit for all sites, except Ni in site II (34 µg/kg-bw/day) which was higher than the PTDI of 5 µg/kg-bw/day. The THQ of Cd in all sites was greater than 1, while Pb and Ni generally recorded THQ < 1. The hazard index (HI) was as follows: site I (2.36), sites II (24.44) and site III (6.5), highlighting a potential hazardous effect to humans as a result of the consumption of Tympanotonus fuscatus obtained from site II and III. The sediment pollution assessment revealed that the contamination factor (CF) and geoaccumulation index, Igeo of Cd were far above the permissible limits while Pb and Ni were mostly within limits. The estimated contamination degree (CD) and pollution load index (PLI) showed a high degree of pollution, which can be mainly attributed to the high degree of Cd contamination in the sediment. Therefore, the area under investigation is highly polluted and the periwinkle obtained from Iko river in the study area is unfit for human consumption.

The concentrations of Particulate Matter (PM) were determined in tropical wetlands air basin of Cawthorne Channel, Awoba and Krakrama. The sampling was performed with well calibrated equipment (A MultiRAE PLUS (PGM -50), a programmable Multi Gas monitor with an electrochemical sensor). Parameters measured were particulate matter with 1 µm, 2.5 µm (PM 2.5 ), 7 µm (PM 7 ) , 10 µm (PM 10 ) and Total suspended particulate (TSP). Seasonal variations were displayed by all fractions of particulate matter. TSP at Cawthorne Channels was observed, with very high concentration in January (346.1 µg/m 3 ) at the upwind and (401.7 µg/m 3 ) downwind in dry season. This was followed by wet season measurement. The PM 10 results at Cawthorne Channels also showed strong seasonal variations with very high concentration in January (313.6 µg/m 3 ) at the upwind and (367.5µg/m 3 ) downwind. Of all the respirable particulate size fractions studied, allowable International Standard according to USEPA (1990), was exceeded in PM 10 and PM 7 . PM 2.5 had values that were generally below 60.0 µg/m 3 while PM 1 had values below 10.0 µg/m 3 . The TSP levels exceeded 250.0 ug/m 3 , being Nigerian National allowable limit. The respirable particulate matter had no statistical difference between the upwind and downwind directions (p< 1) 0.05 .

This study investigates the accumulation of heavy metals in the tissues of Callinectes sapidus (blue crab) in the study area and evaluating the human health risk of their consumption. The tissues of concern were the gills, muscles and hepatopancreas in the male and female crab species, while the heavy metals assessed were Cd, Ni and Pb. Heavy metals levels in the tissues of Callinectes sapidus ranged as follow: Ni: hepatopancreas (182.97–313.53 mg/kg), gills (129.93–192.14mg/kg), muscles (93.09–165.84 mg/kg); Pb: hepatopancreas (22.86–39.65 mg/kg), gills (13.46–21.35 mg/kg), muscles (2.73 – 6.32 mg/kg); Cd: hepatopancreas (2.04 –9.03 mg/kg), gills (0.12–4.995 mg/kg), muscles (0.105–2.835 mg/kg), respectively. The highest metal concentrations were observed in the hepatopancreas tissue and in the female of the crab species. Furthermore, the metals’ levels were generally higher than the permissible level by FAO/WHO in seafood. To assess the heavy metals health risk to the inhabitants of the study area, the daily intake of metal (DIM) and total hazard Quotient (THQ) were estimated and were found to exceed the recommended values. The results reflect the risk of exposure for the period of life expectancy considered, and revealed that the inhabitants of the study area are highly exposed to the health risks associated with             these metals.

This study ascertains the amount of heavy metal and hydrocarbon content in an area exposed to crude oil exploration and exploitation activities. The study area is the Qua Iboe River in the Niger Delta region of Nigeria and the study samples were Nypa palm (Nypa fruticans) leaves obtained along the shores of the river. The concentration of Pb, Cd, Cu and Ni in the leaves were determined using the Atomic Absorption Spectrophotometer while Total Hydrocarbon Content was determined using Gas Chromatography, coupled with the flame ionization detector (GC-FID). Results obtained showed that in site I, Pb mean concentration was 1.068±0.014 mg/kg, Cd (0.017±0.003 mg/kg), Cu (2.390±0.204 mg/kg), Ni (0.012±0.001 mg/kg) and THC (124.361.7± 1120.502 mg/kg) while for site II: Pb (1.076±0.025 mg/kg), Cd (0.028±0.003 mg/kg) Cu (0.037±0.007 mg/kg) Ni (2.049±0.024 mg/kg) and THC (311,813.4± 2950.291 mg/kg). Heavy metal concentration in the study sites were largely within the WHO permissible limits with the exception of Cd in site II. Generally, the amount of heavy metals and THC were higher in the study sites than in the control site, which was an area with negligent oil exploitation and industrial activities. Therefore, the elevated concentration of heavy metals and THC in the study sites may be attributed to the various industrial activities sited in the area.

This study investigates the concentrations of total petroleum hydrocarbon (TPH) and total hydrocarbon content (THC) in soil samples from auto-mobile mechanic workshop in Ikot Akpaden, Mkpat Enin. Soil samples were collected in triplicate at different points within the vicinity of auto-mobile mechanic workshop at Ikot Akpaden represented as site A and control samples were obtained within the frontage of Chemistry Department, AKSU represented as site C. Soxhlet extraction and shaking methods were used  for the extraction of the total petroleum hydrocarbons and total hydrocarbon content respectively. Each of the sample extracts were purified using column chromatography to remove moisture, polar hydrocarbons, colour interferences and any impurities before GC analysis. Total petroleum hydrocarbons and THC were analyzed using Gas Chromatography (GC-FID) and UV-VISIBLE spectrophotometer respectively. The results obtained from TPH analysis indicates that; 15,223.4 mg/kg was recorded from the auto-mobile mechanic workshop and 808.507 mg/kg was recorded from the control samples. The results from the two stations were higher than the department of petroleum resources (DPR) permissible limit of 50 mg/Kg for soils. There was significant difference in the concentration of total hydrocarbon content, the result obtained showed that, the three sampling point at the mechanic workshop has THC level in the order; A1>A3>A2. The concentration of THC obtained in the three points were greater than the 0.6 mg/Kg limit of total hydrocarbons content allowed by the DPR. The study revealed that the soils were polluted as a result of indiscriminate disposal of waste petroleum products (used engine oil, petrol, diesel and other lubricants) directly on the soil, as well as dumping and burning of waste at the auto-mobile mechanic workshops. Hence, there is need for a holistic and sustainable monitoring and remediation of the environment for a cleaner and healthier environment.