Saturday, January 31, 2015

Microplastics and the environment

We use a lot of plastic material  in our everyday life.  Once get into the environment, large pieces will turn to small plastic particles or microplastics.   Microplastics in the environment has become an important issue in aquatic environment.

What is microplastics? Microplastics is operational defined according to the size. Generally, plastic particles smaller than 5 mm are defined as microplastics.

Photo credit:

What types of microplastics are there?
(1) primary microplastics -- the plastics that are manufactured to be of a microscopic size. They are usually used in facial cleansers and cosmetics, or in the air blasting technology. In some cases, their use in medicine as vectors for drugs was reported. Microplastics ‘‘scrubbers’’, used in exfoliating hand cleansers and facial scrubs, have replaced traditionally used natural ingredients, including ground almonds, oatmeal and pumice.
(2) secondary microplastics --  from the breakdown of larger plastic debris, both at sea and on land due to physical, biological and chemical processes that reduce the structural integrity of plastic debris

What environmental problems microplastics cause?
Microplastics may pose problems in the marine environment because of the persistence of microplastics (their likely buildup in the future), and the ingestion by marine organisms. Ingestion of microplastics by species at the base of the food web causes concern as little is known about its effects. Potential effects of microplastics on marine organisms after ingestion include:

  • physical blockage or damage of digestive tract
  • leaching of plastic component chemicals into organisms
  • ingestion and accumulation of sorbed chemicals by the organism

Microplastics and POPs
persistent organic pollutants (POPs)can accumulate on microplastics, which may influence the global transport of POPs. The role of microplastics in the transfer of POPs from the environment to organisms is unknown. Because microplastics can possibly act as a carrier for POPs to enter food webs meanwhile it may lower the bioavailability of POPs to organisms in the food web.

Another concerns of microplastics and toxic chemicals is from additives such as plasticizer added to plastics during manufacture. The plasticizers, some of which have endocrine disruptive effect,  may leach out upon ingestion.

Currently, there is no study that test if microplastics can be transferred across trophic levels.

References and read more:

Friday, January 30, 2015

$$$ saving is not the most motivative way to get people to save energy

What's the best way to persuade people to save energy or choose energy saving products ?  We might think it is by calculating how much money can be saved. 

But according to a recent study on incentives and energy conservation by Asensioa and Delmas at UCLA, today's U.S. electricity prices (averaging 13 cents per kilowatt hour nationally) the amount of money consumers could save by cutting energy isn't high enough to be motivating. Reminders of the environmental health benefits of cutting electricity use are far more powerful motivation.

The study was conducted by installing smart meters and appliance-level monitoring technology in the homes of about 120 young Los Angeles couples and families in the randomized, controlled experiment. The households were sent weekly e-mails to test the power of different motivational messages.

The group that received reminders of how much money they could save by cutting back on electricity showed no net energy savings over the four-month trial. But a similar group cut energy use 8 percent after receiving e-mails about the amount of pollution they were producing, and how it has been shown to cause childhood asthma and cancer. The health message was most effective in the subset of households with children at home

The health effects of ambient air pollution from coal and natural gas-burning, the fuels that generate most of the world's electricity. Global health damage estimates already exceed $120 billion, as noted in the study.

References and more to read:

Thursday, January 29, 2015

Idling vehicle for a few minutes before driving in winter turns out to be WRONG

A driver used to park outside our office were always leaving his truck idling for quite a few minutes before he drove away. During this period, we had strong smell of gasoline in our office. Fortunately, this issue was solved by environmental safety & health so people in the office no longer suffer from toxic gas exposure.  After that, it is worthwhile for us to scrutinize the habit of leaving vehicle idle for a while before starting driving.


It is probably most people's idea that in winter, your car needs a little time to warm up before you can drive it. And that's why the driver used to park outside of my office often fire up their engines long before they start driving. With remote control, people might even start the car before leaving the office.

But this idea of idling your car during the winter turns out to be wrong! 

Before looking at why it is wrong, let's look at what is true and how people start from the truth and reach something wrong.

It is true that cars get worse fuel economy when it's really cold out -- they are at least 10% percent less fuel efficient and it takes longer for the engine to warm up and reach an optimal driving temperature in cold weather. Moreover, older cars that rely on carburetors as a crucial engine component  do need to warm up to work well. Without warming up, the carburetor would not necessarily be able to get the right mix of air and fuel in the engine.

During the 1980s and into the early 1990s, however, the auto industry did away with carburetors in favor of electronic fuel injection, which uses sensors to supply fuel to the engine and get the right air and fuel mix. This makes the problem of warming up the car before driving irrelevant, because the sensors monitor and adjust to temperature conditions.

Therefore, contrary to popular belief, excessive idling is not an effective way to warm up your vehicle, even in cold weather. The engine will warm up faster being driven. The best way to warm it up is to drive it. In fact, with today's computer-controlled engines, even on cold winter days, you should warm up the car no more than 30 seconds before you start driving  – but make sure that windows are free from snow and properly defrosted before driving away!  So idling does nothing for your vehicle.

But it does have several big (and avoidable) costs: 

1) Idling increases the amount of vehicle exhaust in our air. Exhaust contains many pollutants such as volatile organic compounds (VOCs), carbon monoxide (CO) and oxides of nitrogen (NOX) that contribute to air pollution and smog are linked to asthma and other lung diseases, allergies, heart disease,increased risk of infections and cancer and other health problems (that's why the environmental safety and health committee takes actions right after we report the issue).

2) An operating vehicle emits a range of gases from its tailpipe into the atmosphere, one of which is carbon dioxide CO2– the principal greenhouse gas that contributes to climate change. For every litre of gasoline used, a vehicle produces about 2.3 kilograms2 of CO2. With internal combustion engines, no technology exists for eliminating CO2 emissions, an unavoidable by-product of burning fossil fuels. One simple and effective way to reduce the production of CO2 emissions from light-duty vehicles is by choosing to eliminate unnecessary vehicle idling. This is an action that you – as a driver – can take.

3) Idling wastes fuel and money. An idling car uses between 1/5 to 7/10 of a gallon of fuel an hour. An idling diesel truck burn approximately one gallon of fuel an hour. Idling for a few minutes everyday can cost you several dollars per week – which doesn’t seem like much, but adds up in the long run

For people who are used to idle the car, welcome to use

Individual Idling Impact Calculator

and calculate the potential impact that you and your friends would have if you reduced unnecessary vehicle idling.

Some interesting fact about idling:

  • The amount of idling a driver does tends to increase with the number of people in the household. 
  • A driver living with children is more likely to idle than one without children. 
  • The frequency of idling appears to decrease as a person ages – a retiree is the least likely to idle. 
  • A person living in a rural area is more likely to idle than a driver living in an urban centre. 

References and more to read: 


Wednesday, January 28, 2015

Road salt and the environment

Before and after it snows, people often spread loads of salt all over the sidewalks and roads. I know the salt makes your winter shoes worn out more quickly. How does the salt the environment then?

Spreading Salt

Salt is applied on the roads in winter because the freezing point of salty water is lower than that of pure water. So scattering salt on ice or snow can help accelerate the melting process, opening up the roads to traffic that much sooner. It is estimated that over 50 kg of salt is used annually for every resident in the North America!

"Salt" can refer to any compound consisting of the cation from a base and the anion from an acid and which is readily dissociated in water. While sodium chloride (NaCl) is by far the most frequently used road salt in Canada, other inorganic salts used in Canada include calcium chloride (CaCl2), magnesium chloride (MgCl2) and potassium chloride (KCl). Sometimes sodium ferrocyanide (Na4Fe(CN)6·10H2O) is added as an anti-caking agent.
After it dissolves—and is split into sodium and chloride ions—it gets carried away via runoff and deposited into both surface water (streams, lakes and rivers) and the groundwater under our feet.

The biggest concern with road salt is how it affects water quality when the snow and ice melts, the salt is washed away into lakes and streams or seeped into groundwater supplies. ~70 % of the salt applied to roads stays within the region's watershed. Once it gets there, the chemicals is difficult and expensive to remove.  The salt from the roads can cause salty groundwater. That's a health issue for people on restricted-sodium diets and a taste problem for everyone else. When salt migrates into lakes and streams, it can harm aquatic plants and animals. A heavy influx of sodium and chloride ions will disrupt the ability of freshwater organisms to regulate how fluid passes in and out of their bodies. An estimated 40 percent of the country's urban streams have chloride levels that exceed safe guidelines for aquatic life, largely because of road salt. Changes in the salinity of a pond or lake can also affect the way the water mixes as the seasons change, leading to the formation of salty pockets near the bottom and biological dead zones. Salt applied on roads can also erode the soil, and damage trees and vegetation .

With urbanization and increasing number of roads, he mounting piles of salt dumped on the road may be getting to be a bigger problem than ever. In 2004, Canada categorized road salt as a toxin and placed new guidelines on its use.

While salt can cause such problems, we still have to rely on it because it's cheap and applying it on icy road can reduce risks such as traffic accident. Although there are alternative chemicals available but the alternatives are much more expensive and the alternatives may still cause environmental problems once largely used because toxicology tells us every chemical is toxic; the dose plays a role. and they often require municipalities to invest in new spreading equipment. So far, there are no better solutions to get ice off the roads—except, perhaps, the shovel.

As we still have to rely on salt to de-ice the road, more environmental friendly way we can do include (1) cutting back salt usage by pre-wetting the salt,  which allows for more controlled application and better sticking power.  (2) Applying salt just before a storm hits, so that the snow can't adhere to the ground (this relies on accurate weather forecast!) (3) Apply salt only when the pavement temperature is below freezing but above -21 degreeC because sodium chloride doesn't work below that temperature.

References and more information, check

Monday, January 26, 2015

Delhi matches Beijing for air pollution threatening public health

Along with President Obama's state visit to India yesterday,  a number of news articles came with titles like "Obama is breathing world’s dirtiest air in New Delhi".

Such statement is presumably based on atmospheric particulate matter, which has impacts on climate and human health. Atmospheric aerosols affect the climate of the earth by changing the amount of incoming solar radiation and outgoing terrestrial long wave radiation retained in the earth's system. Particles smaller than 2.5 micrometers or PM2.5, tend to penetrate into the gas exchange regions of the lung (alveolus), and very small particles (< 100 nanometers) may pass through the lungs to affect other organs. Exposure of PM is associated with health effects such as asthma, lung cancer, cardiovascular disease, respiratory diseases, premature delivery, birth defects, and premature death.

In 2014, World Health Organization study finds Indian capital had dirtiest atmosphere of 1,600 cities around the world for PM2.5 particles. See the WHO Ambient (outdoor) air pollution database 2014 available at and embedded below

Environment is one of the focuses during Obama’s India trip . Following the agreement in November with Chinese President for both countries to limit or cut carbon emissions, Obama is expected to meet with Indian Prime Minister to discuss topics such as educe greenhouse gas emissions and boost clean energy production. Currently, India heavily relies on fossil fuels as energy source, which has transformed New Delhi into the planet’s most polluted capital and made India the third biggest national emitter of greenhouse gases.

References and more to read:

Sunday, January 25, 2015

China's new environmental law

In China, some industry polluters used to take risks and flouting environmental laws because they realize it’s cheaper to break the law than obey it. Will such situation continues?

A new Chinese environmental protection law came into effect at the beginning of this year with the aim to harmonize economic growth and environmental protection. This new environmental protection law is the most stringent law related to environmental protection in China. Environmental offenses are now facing harsher penalties.

Just two days before the new law came into effect, six polluting companies in Jiangsu were ordered by the province’s highest court to pay 160 million yuan ($26 million) for illegally dumping almost 25,000 tons of chemical waste into two rivers in 2012. Although the fines are still smaller than that in EU and US, it marked the biggest ever award in public interest environmental lawsuit in China.

Under the new law, the Ministry of Environmental Protection has gained more power. It has the right to seal premises and seize property of polluters. The new environmental law in China gives the general public more hope to combat with more serious environmental problems, yet the success of the new law still depends on how the law is enforced. In a recent Nature comment some limitations in the China's new environmental law were identified:

1) Other legislations such as agriculture, forestry, grassland and water laws can trump the environmental law and challenge its provisions.

2) fragmented and overlapping structure of environmental governance in China make the enforcement of the environmental protection law difficult

3) No acknowledgement of citizens' basic right to live in an environment suitable for life appears in the new law. Citizens, civic groups are not allowed to bring lawsuits against the government for serious lapses in air or water quality.

4) Local government grips the environmental governance exercised by controlling the staffing and financing of local environmental protection bureaus, by which environmental governance in China is mainly exercised.

For more information, read
and watch

Saturday, January 24, 2015

Pollutants on a snowing day

(Photo taken by Xianming in a snow storm on 01/24/2015)

Snow, as rain,  is a form of precipitation in the water cycle of the earth. Different from rain, snow is a more efficient scavenger of a variety of contaminants from the atmosphere. These contaminants include salts and salt additives, heavy metals, asbestos, petroleum products such as oil and grease nutrients, bacteria, organic chemicals such as pesticides and PCBs in the air due to its high specific surface area. 

After precipitation, snow on the ground acts as a temporary storage of contaminants during sometimes month-long periods. As such, snow functions as a non-point source of pollution during snow melt. Snow melt generally occurs during a short time period, during which the concentration of contaminants in surface runoff and in receiving waters tend to increase. 
Influenced by the properties of the contaminants captured by snow, the pollutants with high water solubility are released with the initial meltwater fractions and the particulate pollutants at the end of the snowmelt. The levels of metals, suspended solids and organic contaminants may be several orders of magnitude higher than pollutant loads in rain-induced runoff. Such peak of contaminant concentrations would have a huge impact on the ecosystems. 

Therefore, disposing of snow may cause degradation to the water resources. Land disposal is generally preferred since sediments and litter can be collected, some metals can be filtered out by the underlying soils, and meltwaters can either evaporate or enter a surface water gradually thereby diluting and biodegrading the contaminants as they enter. In areas where there is significant potential for contamination of groundwater which is utilized for drinking water supply, disposal of snow into surface water bodies may be the only viable disposal alternative. However, prior to disposal, the snow should be treated for solids removal.

Snow flakes can capture chemicals that are present both in the gas phase and in the particle phase of the air

image source:

References and more information:

Friday, January 23, 2015

polystyrene containers

New York City bans polystyrene food containers

As estimated by the city’s Department of Sanitation, 28,500 tons of expanded polystyrene was discarded in 2014 and  approximately 90% of this amount consisted of single-use cups, trays, and containers.

The difficulty  to recycle economically due to heavy wax or plastic coatings, polystyrene food and beverage containers triggered their recent banning in New York City. A number of other cities, including Seattle, Portland, and San Francisco, as well as Washington, D.C. have already banned polystyrene food containers before.  Food establishments, stores, and manufacturers in New York City may not possess, sell, or offer to customers plastic foam containers and thus will be seeking alternative materials. In addition, the city will also prohibit the sale of loose-fill polystyrene—commonly called packing peanuts.

Polystyrene, is manufactured using benzene, from coal; styrene, from petroleum; and ethylene, a "blowing agent" used in the process since the crackdown on CFCs. Extracting these raw materials generates air and water pollution, and the process of whipping them together can lead to lung cancer and neurological problems in factory workers. Polystyrene is non-biodegradable and after entering the environment, it will around even after a century.
Human population using polystyrene food containers can ingest a bit of styrene with the drink and food. Researches have demonstrated that styrene has been present in our fatty tissue and breast milk for the past 30 years. 
After the banning, alternative containers will replace the foam containers.   For example, those made of recycled papers. Such alternatives may get degraded more easily than the polystyrene, however, they still cause environmental footprint. For example, from chemicals used during the manufacture stage. 
More information:

Thursday, January 22, 2015

Flame retardant-polybrominated diphenyl ethers

Polybrominated diphenyl ethers or PBDEs, are used as flame retardant in a wide array of products, including building materials, electronics, furnishings, motor vehicles, airplanes, plastics, polyurethane foams, and textiles. They are structurally akin to the PCBs and other polyhalogenated compounds, consisting of two halogenated aromatic rings.

PBDEs bioaccumulate in blood, breast milk, and fat tissues. Bioaccumulation is of particular concern in such instances, especially for personnel in recycling and repair plants of PBDE-containing products.
photo source:

People are also exposed to these chemicals in their domestic environment because of their prevalence in common household items.  PBDEs have been found in common foods such as salmon, ground beef, butter, and cheese and also in indoor dust, sewage sludge, and effluents from wastewater treatment plants.

There is also growing concern that PBDEs share the environmental long life and bioaccumulation properties of polychlorinated dibenzodioxins. With levels found in households, PBDEs could reduce fertility in humans. Because of their toxicity and persistence, the industrial production of some PBDEs is restricted under the Stockholm Convention, a treaty to control and phase out major persistent organic pollutants (POPs).

Despite of the regulations,  there is still huge amount of PBDEs in products in use.
A recent study has estimated 60% of the stock of PBDEs (most Deca-Mixture) in 2014 will remain in the use phase in 2020. Such estimation considers only the first use (no reuse and/or storage) of PBDE-containing products. Additional PBDEs will be in the use phase in the future via reuse of PBDE containing material.

For more information in PBDE stock and emissions, read this article recently published in Environmental Science & Technology

Wednesday, January 21, 2015

Inert Ingredients of Pesticides

Besides active ingredients that kill insects, rodents, or weeds, chemicals in pesticide also include the so-called inert ingredients—chemicals in pesticides that perform functions other than controlling pests.

Examples of inert ingredients are emulsifiers, solvents, aerosols, fragrances and dyes. Many pesticides companies treat information on inert ingredients of their products as proprietary and are not willing to disclose such ingredients. Therefore, no health and safety information about the inert ingredients that are already on the market.

However, pesticide manufacturers and the Environmental Protection Agency are in the pressure from consumers and environmental advocacy groups to reveal all of the chemicals in pesticide formulations, including the inert ingredients. Let's see what actions will be taken by pesticide manufacturers and the Environmental Protection Agency under such pressure.

More info:

Tuesday, January 20, 2015

Indoor PCBs can be problematic!

This paper (Inhalation and Dietary Exposure to PCBs in Urban and Rural Cohorts via Congener-Specific Measurements) published by Ampleman et al. in the latest issue of Environmental Science & Technology did a very comprehensive study on indoor PCB levels and once again highlighted the important contribution of polychlorinated biphenyls (PCBs) from indoor sources to human exposure.

PCBs are persistent organic chemicals that were used in construction materials and electrical products produced before 1979. PCBs have been demonstrated to cause cancer, as well as a variety of other adverse health effects on the immune system, reproductive system, nervous system, and endocrine system. See the USEPA website for more information.

With regulations, PCB levels in the general environment have decreased substantially. However, in buildings built between 1950 and 1979, indoor concentrations of PCBs may still be  at high levels. Based on my previous studies, PCB concentrations measured in the air of contaminated buildings in Toronto Canada can be over 100 ng/m3 (,   Human with an inhalation rate of 18m3/d would inhale ~1600 ng/d assuming 90% of time spent in the indoor environment. For people with body weight of 70 kg, body weight normalized exposure just from inhalation would be over 20 ng/kg bw /d

The U.S. EPA has calculated prudent public health levels that maintain PCB exposures below the "reference dose" - the amount of PCB exposure that EPA does not believe will cause harm. EPA's reference dose (RfD) is 20 ng PCB/kg body weight per day.

Based on the information provided by the USEPA, "the largest source of PCB exposure for most individuals in uncontaminated buildings is diet, which contributes roughly 50-60% to total PCB exposure.Typical indoor and outdoor air contains a small amount of PCBs, and inhalation exposure accounts for another 25 to 35% of total exposure. Together, these non-school sources of PCBs generally result in exposures that are significantly below the reference dose. "

However, for PCB contaminated indoor environment, indoor exposure pathway could be even higher than dietary exposure and pose health risk to inhabitants. While environmental regulations require PCB contaminated soil and sediment to be remediated, how about PCB contaminated indoor environment then?

Monday, January 19, 2015

From sample to data within 5 min-On Mercury!

Recently I learnt how to analyze total mercury in environmental samples using the Direct Mercury Analyzer. As my research primarily focuses on environmental organic chemistry, I was amazed how quickly the concentration data can be retrieved starting from the fresh samples: 1min sample weighing time + ~5 min instrument time. As many as 100 samples and QCs can be analyzed in a batch

As a comparison, PCB analysis from air samples (hundreds of have I analyzed!) : Soxhlet extraction (18 h) or ASE (40 min) + rotoevaporation (30 min) + Column (2h) + nitrogen evaporation (~6-8h) + instrument time (~60 min) + chromatogram processing time (need to double check auto integration of the peaks in the chromatogram 10 min)

So how does this amazing DMA work?

Direct mercury analysis incorporates thermal decomposition, catalytic conversion, amalgamation, and atomic absorption spectrophotometry.

Controlled heating stages  first dry and then thermally decompose a sample introduced into a
quartz boat. A continuous flow of oxygen carries the decomposition products through a hot catalyst bed where halogens, nitrogen, and sulfur oxides are trapped. All mercury species are reduced to Hg(0) and are then carried along with reaction gases to a gold amalgamator where the mercury is selectively trapped. All non-mercury vapors and decomposition products are flushed from the system
by the continuous flow of gas. The amalgamator is subsequently heated and releases all trapped mercury to the single-beam, fixed-wavelength atomic absorption spectrophotometer. Absorbance
is measured at 253.7 nm as a function of mercury content.

Image source:

Sunday, January 18, 2015

Analyzing trend of time series data from environmental monitoring

Had a chat with a colleague on analyzing trend of time series data from environmental monitoring.

Often,  the Mann-Kendall (MK) test (Mann 1945, Kendall 1975) is used to test if the variable consistently increases (decreases) through time, but the trend may or may not be linear.

Why not using linear regression instead? 
Regression analysis requires that the residuals from the fitted regression line be normally distributed. But the MK test is a non-parametric (distribution-free) test, which is based on the rank of the data. The measurements do not have to be normally distributed or that the trend, if present, is linear.

The MK test can be computed if there are missing values and values below the one or more limits of detection (LD), but the performance of the test will be affected. The time between samples should be sufficiently large so that there is no correlation between measurements collected at different times.

H0: No monotonic trend
A positive (negative) value of MK statistics indicates that the data tend to increase (decrease) with time.

MK test can be performed with R Package ‘Kendall’ and function MannKendall(x)
where x a vector of data, often a time series
For autocorrelated time series, the block bootstrap may be used to obtain an improved significance test.

Value of MannKendall(x)
A list with class Kendall.
tau:Kendall’s tau statistic
sl: two-sided p-value
S: Kendall Score
D: denominator, tau=S/D
varS: variance of S
Generic function print.Kendall and summary.Kendall are provided to print the output.

Good resources with more information on this:

Friday, January 16, 2015

2014 as the hottest year! (globally)

According to information released by NASA and NOAA today, 2014 was the hottest year ever on record for the globe as a whole and the 38th consecutive year of above-average temperatures.

Also in 2014, the midwest US and Canada experienced a winter colder than average and the western US hit a record-high temperature.

Thursday, January 15, 2015

How the seawater at different depth of the ocean is sampled?

Ocean is the reservoir for many contaminants.  To analyze these contaminants and assess their ecological risk, the first step is to sample collection. What device is used to sample seawater of different depth ? 

Photo (taken by Xianming Zhang): seawater sampling using a CTD device on the Endeavor Research Cruise.

CTD (conductivity, temperature, and depth) is a package of electronic instruments that measure these properties. The CTD is lowered into the water to measure the salinity, temperature, depth and take samples through the water column. The CTD is attached to a metal frame, which holds water-sampling bottles to collect water at different depths. The sample bottles can be closed with computer control when the CTD is at a give depth. 
Along with seawater, gorgeous scenery is also sampled:  

(Photo of sunset from the research cruise close to the coast of New Jersey)